DE202022100954U1 - Flow cell with improved structure - Google Patents

Abstract

Flow cell (10) through which fluid can flow, having at least two base plates (12, 14), between which at least one flow element (16) with at least one fluid guide (18) for guiding a fluid flow (20) is arranged, the flow element (16) at least in part is made of a sealing material and is in sealing contact with the base plates (12, 14) or a protective layer present on the base plates (12, 14), in that the base plates (12, 14) can be fixed to one another by pressing the flow-through element (16) between them, wherein at least one base plate (12, 14) has at least one fluid connection (28) fluidically connected to the fluid guide (18) and optionally at least one further functional connection, and in particular wherein the base plates (12, 14) have connecting means (34) for mechanically connecting two flow cells ( 10) have.

Description

The present invention relates to a flow cell of improved construction. The present invention relates in particular to a flow cell with which a very wide range of applications is possible in a simple manner.

Flow cells are known for a variety of applications. Due to the different areas of application, the flow cells are usually specifically designed in order to be able to enable the desired properties. Thus, known flow cells are usually only suitable for specific detailed solutions.

EP 1 502 313 B1 relates to membrane-based electrochemical cells, particularly proton exchange membrane (PEM) fuel cell stacks. In one embodiment, a membrane electrode assembly is inserted between two connection plates. In another embodiment, the assembly includes, in the following order, a terminal plate, a membrane electrode assembly, a bipolar plate, a second membrane electrode assembly, and a second terminal plate. The connecting plates have fluid guides.

WO 2018/044236 A1 describes a flow frame for an electrochemical cell, comprising: a frame body comprising a plurality of elongate members arranged to define a boundary of the flow frame and allow an electrolyte solution to flow within the boundary of the flow frame; and one or more support beams disposed within the frame body and connected to at least two of the plurality of elongate members.

However, the solutions known from the prior art can still have potential for improvement, in particular with regard to their structure.

It is therefore the object of the present invention to provide a measure by which at least one disadvantage of the prior art is at least partially overcome. It is in particular an object of the present invention to provide a solution by means of which the construction and/or the applicability of flow cells can be improved.

The object is achieved according to the invention by a flow cell with the features of claim 1. Preferred embodiments of the invention are disclosed in the subclaims, in the description and in the figures, with further features described or shown in the subclaims or in the description or the figures individually or in any combination, unless the context clearly indicates the contrary.

The present invention relates to a flow cell through which fluid can flow, having at least two base plates, between which at least one flow element with at least one fluid guide for guiding a fluid flow is arranged, the flow element being formed at least in part from a sealing material and sealingly on the base plates or one on the base plates present single-layer or multi-layer protective layer, in that the base plates can be fixed to one another by pressing the flow-through element between them, wherein at least one base plate has at least one fluid connection fluidically connected to the fluid guide and optionally at least one further functional connection, and wherein the base plates have connection means for mechanically connecting two flow cells .

A flow cell of this type can allow significant advantages over the solutions from the prior art.

A flow cell through which fluid can flow is described. The term “through which fluid can flow” should be understood to mean that the flow cell has at least one inlet and at least one outlet through which a fluid, such as a gas or a liquid, can flow. Furthermore, the flow cell can in principle be suitable for a wide variety of applications, such as an electrochemical flow cell, an analytical flow cell, a reaction cell, etc., without being limited to the aforementioned properties.

The flow cell comprises two base plates, between which at least one flow element with at least one fluid guide for guiding a fluid flow is arranged. The two base plates are thus arranged opposite one another with regard to the flow element and can serve to ensure the mechanical stability of the flow cell. Furthermore, the base plates, like the flow-through element, can be used to connect corresponding functionalities, as will be described in more detail below.

The at least one flow element is arranged between the base plates and is in particular fixed by the base plates, it serves to guide the fluid and accordingly has at least one fluid guide. The fluid flowing through or through the flow cell Flowing fluids thus flow through the fluid guide.

The flow-through element is at least partially made of a sealing material and is in sealing contact with the base plates or a protective layer provided on the base plate. Correspondingly, preferably at least the areas of the flow element that come into contact with the base plates or with the protective layer should be made of a sealing material.

A sealing material is to be understood in particular as a material which is suitable for preventing a fluid from escaping between the components to be sealed. Accordingly, it can be advantageous if the sealing material is an elastic material which can cling to the contact component when pressure is exerted, in order to bring about a sealing effect in this way. This allows an extremely robust seal to be made possible. For example, the sealing material can include an elastic plastic such as a thermoplastic elastomer (TPE), a polyurethane resin or also EPDM (ethylene propylene diene rubber). An example includes the product sold under the name Santoprene, which comprises ethylene propylene diene rubber particles (EPDM) in a polypropylene (PP) matrix. Other examples include sealing materials made from hard plastics, such as polyethylene foam or expanded polytetrafluoroethylene (ePTFE), or flat gasket materials, such as graphite. In principle, the selection of the sealing material should be adapted to the fluid to be used in order to prevent the sealing material from being negatively influenced by the fluid or components present in the fluid.

The sealing material can also bring about a sealing effect in that the base plates can be fixed to one another by pressing the flow-through element between them. The base plates can thus be mechanically connected to one another and the flow-through element pressed between them, which in turn presses the sealing material against the base plates. This can be realized, for example, by using screws and nuts or threads to move the base plates towards one another and thus to press the flow-through element between them. The base plates thus also serve to exert surface pressure on the flow element, which can also be referred to as a flow frame module, and thus enable sealing. As a result, the seal is particularly tight and leaks can be significantly reduced or even completely prevented, which can also further reduce the susceptibility to errors.

A suitable and in particular predefined surface pressure can be advantageous in order to protect the materials on the one hand and to achieve a defined sealing effect on the other. A defined surface pressure can be set, for example, by using a torque wrench to tighten corresponding screws that connect the base plates to a specific torque.

Alternatively, one or more spacers, such as washers or shims, can be arranged between the base plates and connecting screws, for example, in order to set a defined distance between the base plates. In other words, it can be advantageous for at least one non-compressible spacer to set a defined distance between the base plates to be arranged between the base plates. The compression of the sealing layers can thus be adjusted more precisely via the distance between the base plates. This can be used to advantage if the base plates are connected by screws and the screws can be removed from the side so that the spacers can remain on the screw. Additional tools, such as a torque wrench, are no longer necessary and there is no susceptibility to errors, since the screws cannot be tightened further than the shims allow.

In principle, an advantageous sealing effect can be made possible by a high and adjustable surface pressure if at least one layer functioning as a sealing layer forms a sealing bead.

Furthermore, the tightness can also be particularly advantageous if membranes or sensors are integrated, since the sealing layers that form a flow-through element consist largely or entirely of an elastic material. The membranes or sensors used can therefore be largely or completely surrounded by sealing material and can therefore be installed tightly. For example, round holes can be created in the flow element or the sealing materials, for example by locally melting the thermoplastic elastomer, through which sensors can be introduced. The electrical contacts can also be integrated into the flow element. In this case, connections can be present on the base plates and then lead an electrical line into the flow-through element, or the electrical contacts can run directly into the flow-through element. The same may apply to sensors or other functionalities.

A symmetrical distribution of the sealing surface can ensure an even surface pressure. In addition, internal support structures can specifically support the gasket layers at the sealing edges. Several gasket layers can form a composite component after they have been connected, for example by pressing, gluing or welding.

With regard to the connection of functionalities to the base plates or to at least one base plate, it is provided that at least one base plate has at least one fluid connection, such as a hose connection, which is fluidically connected to the fluid guide, and optionally at least one further function connection. With regard to the positioning of the fluid connections, it can be advantageous for them to lie asymmetrically on the baseplate or have an asymmetrical distance from the central axis in a direction perpendicular to the flow direction, in particular in the plane of the baseplates. In this way, the fluid connections can be placed closer to one another, while the flow channels from the two base plates can flow past one another. This can be particularly advantageous for stacks of multiple layers or cells.

Thus, a feed line for the fluid that is to flow through the flow cell and a discharge line for the fluid that has flowed through the flow cell can be provided on at least one base plate or on both base plates. The fluid connections can be screwed into the base plate, for example. It is preferred if the fluid connections are inserted, such as screwing, into the base plate in such a way that the inner end of the fluid connection, such as a hose connector thread, is flush with the base plates. This enables subsequent sealing layers to lie directly on the hose connector and, thanks to the very good sealing effect that is made possible in this way, the fluid flowing through never has contact with the base plates. With regard to chemical resistance, fluid connections made of plastic can be advantageous.

The fluid connections or the supply line and the discharge line are then expediently connected to the fluid guide. However, it is possible for the base plates to be designed in the same way and thus for the basic connection option for functionalities to be provided on both base plates, whether they are used or not.

It goes without saying that, depending on the application, more than two fluid connections can also be provided and thus more than one supply line and more than one discharge line can be provided in order to use a plurality of fluid flows.

In principle, it can be advantageous if the base plates have a plurality of through holes or functional bores, which can be used to introduce functional connections or also to connect base plates to one another, for example by means of screws. For this purpose, it can be advantageous if the inner walls of the holes are equipped with an internal thread.

To connect two base plates of a flow cell, it can also be advantageous if the base plates have U-shaped material recesses on the sides. As a result, for example, screws or a screw-nut arrangement can be inserted from the side and the base plates can be screwed on in such a way that the flow-through element can be pressed in between the base plates. Correspondingly, it can be particularly preferred that two base plates arranged opposite one another with regard to the flow-through element have U-shaped recesses open at the side for receiving fastening screws for fastening the base plates to one another.

For example, the base plates can be made of stainless steel. In addition, it can be advantageous for particularly good adaptability if the base plates are shaped identically.

The flow cell described thus has a modular structure which, with a reduced number of components, enables a particularly high degree of adaptability to the desired application. Depending on the application, one or more flow-through elements can be arranged and fixed between the two base plates, which are tailor-made for the desired application. Expensive modifications to the entire flow cell are therefore not necessary. The modular structure of the cell allows it to be used for various applications, such as in electrochemistry, as a heat exchanger or in membrane processes, or their combination in one cell, such as a temperature-controlled electrochemical cell. Examples of corresponding applications are therefore in particular those that require a planar flow.

In research and development, for example, flexible and reliable cells are required for electrochemical processes and other applications. The modular cell according to the invention offers a flexible platform on the various applications can be implemented.

In addition, the size of the flow cell can also be tailored by fixing several base plates to one another and using a corresponding fluidic connection. In other words, the base plates of the cell are scalable, for example two base plates of the same width can be combined into one base plate for a larger cell. This can be advantageous, for example, since different cell sizes are usually required for the development of electrochemical processes, smaller cells for initial experiments, then larger cells for scale-up. So far, various cells have been used that differ significantly in their geometry and flow control. Measurements are therefore not directly comparable with one another. In addition, previous cells from the prior art are often only tailored for a specific cell architecture and are therefore only suitable for a single application. With different cell sizes, the cell design changes. In the case of a scale-up, it is therefore not possible to clearly distinguish which effects are due to the larger electrode area and which are due to the changed design. In contrast, the cell geometry according to the invention remains largely identical even when scaling with several base plates.

The problems described above can thus be overcome according to the invention, with a high level of reliability of the functionality being possible due to a low susceptibility to errors due to simple adaptability and a small number of components.

The components of the flow cell, such as the flow element, combine several functions for which a number of components were required in the prior art, such as the seal on both sides, electrical contacts, flow distributors, connection options for sensors, etc. This shows that the structure of the flow cell is significantly simplified compared to the solutions from the prior art, which can reduce costs and simplify maintenance. In addition, assembly can be simplified and accelerated, for example by the end user.

Fewer components and, for example, screws that can be removed from the side enable quick assembly. Indentations on the edges of the flow-through units are preferably used as a marker for the internal flow guidance, so that it is possible to check from the outside whether the cell has been assembled correctly. This simplifies assembly even further. To this end, it can be particularly advantageous for the flow-through element to have functional information on an outer surface for displaying at least one of the type of a function and a functional position.

At least one base plate can preferably have a viewing window, which provides a view into a fluid guide. In this configuration, for example, a reaction or, in principle, the functioning of the flow cell can be checked, which can improve an application. In addition, optical analysis can be used, for example, which is directed through the viewing window into the fluid guide. With regard to the chemical resistance, it can also be advantageous that the viewing window is provided with a protective layer on a side facing the flow-through element.

It can also be preferred that at least one flow structure is provided in at least one fluid guide or that the fluid guide forms a flow structure. A flow structure is basically any structure that influences the flow of the fluid, for example by introducing turbulence, or which can divide a fluid flow or allow it to deviate from a straight flow. In this configuration, the applicability can be improved even further, since the flow behavior can be adapted in a targeted manner and, moreover, the fluid flow can be divided and/or directed in a targeted manner. As a result, the fluid flow can be treated and guided in the desired manner.

With regard to the flow structure, it can be preferred that this is selected from a flow distributor, a flow field and a turbulence-generating structure. This makes it possible to guide the fluid flows and thus the substance flows in the flow cell in a suitable manner. Uniform flow profiles are thus easily possible.

The flow dividers may include, for example, a fluid impervious partition. In principle, a membrane or an electrode is also possible as a flow distributor, which can be advantageous in particular for electrochemical applications.
In the context of the present invention, “flow distributor” means in particular structures in the inlet and outlet of the cell. The flow distributors have two functions in particular. First, they lead to a uniform flow along the cell and thus, for example, along an active electrode surface, which can be accompanied by a homogeneous velocity distribution. Furthermore, as is also possible for other flow structures, the force of the surface pressure of the overlying layers can be absorbed, such as one Electrode and an electrode frame, which can allow advantageous sealing.

For example, flow fields can increase the residence time of the fluid stream in the cell. Non-limiting examples include, for example, meander structures or spiral structures.

Structures that generate turbulence can also be advantageous depending on the application. Examples include woven fabrics, scrims, or basically 3D structures.

The flow structure can preferably have punctiform contact points for contacting an adjacent layer, such as an electrode or a membrane. In this configuration, effective functionality can continue to be provided by the only small coverage of the adjacent layers with the flow structure, without this being reduced by the flow structure covering a large area of the adjacent layer.

Correspondingly, it becomes clear that at least one fluid guide, in which the flow structure can be present, can be delimited by a membrane or an electrode.

Furthermore, it can be preferred that the flow structure is compressible along the thickness of the flow-through element. This configuration allows a particularly good absorption of force by the flow structure and can also make it possible for a defined flow behavior to be possible due to a defined arrangement of the flow structure.

It can also be preferred that the functional connection is selected from an electrical connection and a sensor connection.

Sensors can be of great importance as they can be used to monitor reactions or other functions in the flow cell, which can be of great benefit to the application.

Electrical connections are advantageous for electrochemical applications, for example. Special electrical contacts can be used for electrochemical cells, which are positioned directly on the base plates and, if necessary, integrated into the flow unit. The contacts are preferably compatible with all common electrode types and can allow two separate lines for current flow and potential measurement. It is possible to prevent the electrode contact from having too high a resistance and leading to voltage losses, as is the case in some prior-art laboratory cells.

Electrical contacts are implemented, for example, through the sealing area, such as through sealing layers, of the flow-through element via self-adhesive metal strips, such as copper strips, for example, the adhesive layer of which is itself also conductive. The metal strips can, but do not have to, be self-adhesive. A connection to the sealing material can be glued, welded or plugged in, for example. Coated metal strips are advantageous for chemical resistance.

The preferably thin metal strips can contact different types of electrodes gently and with low resistance. For surface contacting of the electrodes, porous metal structures, for example metal grids or metal foams, are melted or inserted into the flow element, for example into the sealing layers made of thermoplastic elastomer, so that the metal structure and seal are in one plane, but the metal structure is on at least one side, preferably on the back , remains contactable.

As already indicated above, the base plates can be made at least partially, for example completely, from metal, preferably stainless steel. This allows the baseplates to be sufficiently rigid and stable so that it does not bend or break too much under the forces required. Corresponding connections can be provided in plastic sleeves, for example.

It can be preferred that the flow cell has more than two base plates. It can be preferred that the flow cell has the same number of base plates on both sides with regard to the flow element. In this configuration, comparatively large flow cells can also be produced in a simple manner by connecting two or more base plates to one another on each side and by adapting the flow element accordingly. To connect the base plates, bores or holes located in the base plates can be used, for example, to which the base plates are screwed. The flow element can then be easily adjusted.

This configuration offers the advantage of a comparatively large active surface, for example an electrode surface, without having to use different base plates in each case. A particularly wide range of applications can thus be made possible using fewer components. Furthermore, with a large base area that can be produced in this way, the inner structure can remain the same compared to small structures and can only be expanded in length.

The fluid connections of both base plates can then be used accordingly in order to conduct a fluid through a common fluid guide.

It may further be preferred that a plurality of flow elements are provided in a stacked arrangement. In this configuration, in particular, flow elements can be used for different material flows, such as for gas flows and liquid flows. As a result, for example, different electrochemical cells or half-cells can be arranged on a comparatively small base area, which can enable a particularly advantageous range of applications.

It is further preferred that at least one flow-through element is constructed at least partially in a multi-layer structure along its thickness, with the plurality of layers being connected to one another and thus forming a single component. The layers can be inextricably connected to each other, or detachably. This configuration enables a particularly wide range of adaptability and thus a very wide field of application of the flow cell. For example, a flow-through element can consist largely or also exclusively of elastic material. Several layers of the flow-through element can then be connected, for example, by pressing and/or gluing and/or welding. As described above, turbulence-generating structures or other flow structures or also electrical contacts can be embedded in the multi-layer structure.

Accordingly, it can be advantageous for the flow-through element to have electrical contacts for making electrical contact with an electrode arranged in the flow-through element or adjacent to the flow-through element, with the electrical contact being at least partially embedded in a plastic layer. Particularly preferably, the flow-through element can have electrical contacts for making electrical contact with an electrode arranged in the flow-through element or adjacent to the flow-through element, with the electrical contact being at least partially embedded in a plastic layer

The multi-layer structure is preferably designed in such a way that flow-through elements do not or only weakly adhere to one another or to adjacent layers, such as electrodes or membranes.

The invention is explained below by way of example with reference to the attached drawings, whereby the features presented below can represent an aspect of the invention both individually and in combination, and the invention is not limited to the following drawing, the following description and the following exemplary embodiment is.

• 1 eine Ansicht einer fluiddurchströmbaren Flusszelle gemäß einer Ausgestaltung der vorliegenden Erfindung;
• 2 eine Ansicht einer fluiddurchströmbaren Flusszelle gemäß einer weiteren Ausgestaltung der vorliegenden Erfindung;
• 3 eine Explosionsansicht eines Teils einer Flusszelle gemäß einer Ausgestaltung der Erfindung;
• 4 eine Ausgestaltung eines Durchflusselements für eine Flusszelle nach 3;
• 5 weitere Ausgestaltungen eines Durchflusselements für eine Flusszelle nach 1;
• 6 eine weitere Ausgestaltung einer erfindungsgemäßen Flusszelle;
• 7 eine schematische Schnittansicht durch das System aus 6;
• 8 eine schematische Ansicht eines Durchflusselements;
• 9 eine weitere Ausgestaltung eines Durchflusselements für eine Flusszelle nach 1;
• 10 die Ausgestaltung aus 9 in einer Explosionsdarstellung;
• 11 eine Detailansicht einer Membran der Ausgestaltung aus 9;
• 12 eine Detailansicht des Durchflusselements aus 9;
• 13 eine Ausgestaltung einer Strömungsstruktur für eine Fluidführung;
• 14 eine weitere Ausgestaltung einer Strömungsstruktur für eine Fluidführung;
• 15 eine weitere Ausgestaltung einer Strömungsstruktur für eine Fluidführung;
• 16 eine weitere Ausgestaltung einer Strömungsstruktur für eine Fluidführung;
• 17 eine weitere Ausgestaltung einer Strömungsstruktur für eine Fluidführung; und
• 18 eine weitere Ausgestaltung einer Strömungsstruktur für eine Fluidführung.

Show it:

• 1 a view of a flow cell through which fluid can flow according to an embodiment of the present invention;
• 2 a view of a flow cell through which fluid can flow according to a further embodiment of the present invention;
• 3 Figure 12 shows an exploded view of a portion of a flow cell according to an embodiment of the invention;
• 4 an embodiment of a flow element for a flow cell 3 ;
• 5 further configurations of a flow element for a flow cell 1 ;
• 6 a further embodiment of a flow cell according to the invention;
• 7 a schematic sectional view through the system 6 ;
• 8th a schematic view of a flow element;
• 9 a further embodiment of a flow element for a flow cell 1 ;
• 10 the design 9 in an exploded view;
• 11 a detail view of a membrane of the embodiment 9 ;
• 12 a detailed view of the flow element 9 ;
• 13 an embodiment of a flow structure for a fluid guide;
• 14 a further configuration of a flow structure for a fluid guide;
• 15 a further configuration of a flow structure for a fluid guide;
• 16 a further configuration of a flow structure for a fluid guide;
• 17 a further configuration of a flow structure for a fluid guide; and
• 18 a further configuration of a flow structure for a fluid guide.

In the 1 a flow cell 10 through which fluid can flow is shown, which is designed according to an exemplary embodiment of the present invention. The flow cell 10 comprises two base plates 12, 14, between which a flow element 16 with a fluid guide 18 for Füh ren of a fluid flow 20 is arranged. It can be seen that the base plates 12 , 14 each have a viewing window 22 which allows a view into the fluid guide 18 .

The base plates 12, 14 are in particular made of stainless steel and have a large number of holes 24 or openings or also material recesses 26, which are suitable and used for introducing functionalities.

For this purpose, the holes 24 can have an inner wall with a thread, for example, or a screw-nut arrangement 27 can be introduced into a hole 24 or a material recess 26 . So is in the 1 shown that holes 24 can be used to provide appropriate connections or to bring the connections into the holes 24. More precisely shows 1 that a base plate 12 fluidly connected to the fluid guide 18 fluid connections 28 has. Of these, two fluid connections 28 fluid inlets can be used as fluid inlets and two fluid connections 28 can be used as fluid outlets, which can guide corresponding fluid flows into respective fluid guides 18 . In this way, different fluid flows or material flows can be conducted through the flow cell 10 . In addition, power connections or electrical connections 30 are shown as further functional connections. Electrodes 40, for example within flow-through element 16, can be actuated or set to a corresponding potential by means of these.

The openings 24 also make it possible, for example, to attach attachment means 32 for attaching the flow cell 10 to a substrate. The fastening means 32 can be screwed to the substrate, such as a suitable support or surface, or simply serve as a base. Furthermore, the openings 24 can serve as connecting means 34 for mechanically connecting two base plates 12 .

In the 2 1 shows that a flow cell 10 can have a plurality of base plates 12, 14. The base plates 12, 14 on one side are connected to one another using connecting plates 38, which can be screwed into the holes 24 on both sides. A comparatively large structure of a flow element 16 or also a plurality of small structures of the flow elements 16 can then be provided within the flow cell 10, as these are described below.

The other figures show different examples of the use of the flow cells 10, in which case the flow elements 16 in particular can be changed.

In the 3 1, an exploded view of an electrochemical half-cell that can be formed in a flow cell 10 is shown. According to 3 First, a base plate 12 is shown, which has corresponding fluid connections 28 serving as inlets and outlets for different substance streams or fluid streams 20 . A viewing window 22 is also shown, which is preferably provided with a chemically resistant protective layer. Adjacent to the base plate 12, a first flow element 16 is provided, which is designed, for example, for a gas flow as a material flow and can be used. A further flow-through element can be provided as a catholyte structure and can, for example, conduct a liquid material flow. An electrode 40 is shown in a corresponding electrode frame 41 between the flow-through elements 16 . Such an arrangement can form an electrochemical half-cell. A membrane 42 , which is present in a membrane frame 43 , can now be provided on the side of the second flow-through element 16 opposite the base plate 12 . Another half-cell can now be connected in reverse order, in order to form an electrochemical cell.

Such an electrochemical cell is also in the 3 shown. According to 3 the two liquid streams F ₁ and F ₂ and the two gas streams G ₁ and G ₂ are shown as fluid streams 20. The liquid streams are respectively separated from the gas streams by electrode 40 and the gas streams flowing outside of the liquid streams are separated by electrodes 40 and base plates 12, 14, not shown. However, it should be pointed out that the fluid flows or the material flows preferably have no contact with the base plates 12, 14. For example, a chemically resistant sealing layer lies on the base plates 12, 14, for example if a viewing window 22 can be omitted, or a chemically resistant transparent film 22 can be provided, which can be made of, for example, perfluoroethylene propylene (FEP), perfluoroalkoxy polymers (PFA), polypropylene (PP), polyvinyl chloride (PVC), or other materials may be designed to protect about a viewing window 22.

Furthermore, the liquid flows are separated from one another by the membrane 42 . Basically, there are several possibilities for constructing the membrane 42 . For example, ion exchange membranes that are permeable to ions, possible or porous non-conductive membranes that are out designed as a diaphragm that is permeable to liquids. Exemplary materials from which the membranes may be constructed include the product sold under the Nafion name.

the 5 FIG. 1 shows further configurations of the functionality of a flow cell 10 with a plurality of flow elements. In principle, it should be mentioned that each flow element 16 can carry a material flow, ie a specific liquid flow or a specific gas flow.

In the 5a) two examples are shown, which are designed with plate electrodes 46 as electrodes 40 . In the embodiment on the left, two plate electrodes 46 are used as electrodes 40, which delimit two liquid flows F1, F2, which in turn are separated from one another by a membrane 42. 5a) shows a further embodiment on the right, in which a liquid flow F ₁ is delimited by two plate electrodes 46 as electrodes 40 .

In the 5b) an example is shown, which differs from the example of 5a) differs in that a plate electrode 46 is replaced by a gas diffusion electrode 48 as the electrode 40 which has a liquid flow F2 from one to 1 added gas stream G1 separates. Furthermore, as in 4a) a first liquid flow F1 is shown, which is separated from the second liquid flow F2 by a membrane 42 and is also delimited by a further electrode 40 designed as a plate electrode 46.

In the 5c ) two further configurations are shown which have a membrane-electrode assembly (MEA) 44 . In the embodiment on the left, a liquid flow F1 and a gas flow G1 are shown. The liquid flow F1 is arranged between the membrane 42 of the MEA 44 and a plate electrode 46 as the electrode 40 . The gas flow is located adjacent to the gas diffusion electrode 48 of the MEA 44 . 5c ) shows a further configuration on the right, in which two gas streams G1, G2 are separated from one another by a membrane-electrode unit 44. The membrane electrode assembly 44 includes two gas diffusion electrodes 48 between which a membrane 42 is arranged.

the 5 The example on the right shows a cell stack, all cell architectures on the left (a,b,c) can also be integrated as a stack (several cells stacked on top of each other).

the 7 shows a flow cell 10 with two base plates 12, 14 and a flow element 16, the example in the 7 is shown. In particular, the flow elements 16 are functionally connected to one another in such a way that electrical half-cells are formed. Thus, different flow elements 16 each carry a fluid stream 20, namely an anode gas stream A ₁ and an anolyte stream A ₂ , separated by an anode 50, and also a cathode gas stream K ₁ and a catholyte stream K ₂ , which are separated from one another by a cathode 52.

Purely by way of example and only by way of explanation, the material flows can be designed as follows. A1 and K1 can be gases and A2 and K2 can be liquids. As concrete examples, A1 may be oxygen produced, A2 may be acidic electrolyte such as sulfuric acid solution, K1 may be carbon dioxide, and K2 may be slightly alkaline electrolyte such as potassium hydrogen carbonate solution.

7 shows this arrangement in a schematic sectional view, sealing elements 54 also being shown, which seal a gap or a contact 56 between two elements of the base plates 12, 14. Flow structures 66 are also shown, which can be, for example, rubber layers in various designs, with the flow structures 66 also being able to be shown basically as force absorbing elements through which a flow can flow.

This is in the 8th an embodiment of a flow element 16 is shown. According to 8th a basic structure 17 is shown, which can have a multi-layer construction of firmly joined layers. Furthermore, flow structures 66 are shown, which can be embodied as flow distributors 74 or as turbulence-generating structures 72 and serve as force absorbing structures and can thus absorb the force when individual layers are joined together.

In 8th It is further indicated that the flow element 16 has functional indicia 84 on an outer surface for indicating at least one of the type of a function and a functional position. The functional information 84 can thus be used to identify from the outside where there are fluid inlets, fluid outlets or flow structures 66, but without being limited to this.

the 9 and 10 show another structure of a half cell as part of a flow cell 10, which together with another, corresponding half cell part of a flow cell 10, in particular between two base plates 12, 14 can be arranged, wherein 10 an exploded view of 9 indicates. The fluid streams 20 run into the image plane or out of the image plane.

In detail is in the 9 and 10 the outer contacting 58 of an electrode 40 is shown, which is present adjacent to a chemically resistant layer or protective layer 23, which is present at a viewing window, not shown, of the base plate 12. The contacting 58 is arranged on a rubber element 60 which in turn is arranged adjacent to a fluid guide 18 . A via 62 is provided in the rubber element 60 and provides an electrical contact from the contact 58 to a gas diffusion electrode 48 . The rubber element 60 or the flow-through element 16 is thus formed from a sealing material and rests on the busbars or contacts 58 and a transparent, chemically resistant film between the contacts 58 .

A metal mesh 64 can optionally be provided between the rubber element 60 and the gas diffusion electrode 48, which can improve the contact. It is also shown that a flow element 66 , here more precisely a mixer geometry 68 , is arranged in the fluid guide 18 . On the opposite side of the gas diffusion electrode 48 there is in turn a rubber element 60 or a flow element 16 which has a further fluid guide 18 which in turn is provided with a mixer geometry 68 as a flow element 66 . This arrangement is completed by a membrane 42, which is made of Nafion, for example.

The membrane 42 is enclosed in a frame 76 designed as an envelope and made of a sealing material (eg ePTFE or Santoprene), as shown in FIG 11 is shown. For this purpose, two thin layers of sealing material are placed one on top of the other and connected in such a way, for example welded or glued, that a pocket remains free between the layers, into which a membrane 42 can be inserted. For this purpose, the upper sealing layer has two incisions through which a membrane 42 can be inserted. The lower sealing layer has the same geometry, without the two cuts in the corners. This has the advantage of allowing the membrane 42 to be inserted flat and tight without the membrane curling or puckering.

The half-cell described can in turn be arranged in a mirrored form on the membrane 42, lying against the membrane 42 and starting with the flow-through element 16, for example in a flow cell 10 between the base plates 12, 14, so that the base plates 12, 14 on the contacts 58 or the viewing windows 22 abut in such a way that there is still a sealing layer between the contacts 58 and the base plates 12,14. The base plates 12, 14 should be electrically isolated from the electrical contacts, otherwise a short circuit can occur via the screws which connect both plates.

The rubber elements 60 of the flow-through elements 16 can be covered with a non-stick layer such as ePTFE or PP so that adhesion can be prevented.

A flow element or a rubber element 60 forming the basic structure 17 usually consists of several layers which are held together by the natural adhesion of the rubber or alternatively are connected to one another by gluing or welding or hot pressing. The resulting stack of several rubber elements, electrodes and membrane can be easily detached from one another again if the outer surfaces of the rubber elements do not stick or have no or only weak adhesion. This is possible, for example, with an applied non-stick layer made of ePTFE or PP. This can be advantageous, since under certain circumstances strongly adhering rubber elements 60 can destroy sensitive electrodes and membranes during dismantling if a flow-through element 16 is to be detached from the membrane 42 or the electrode 40 . Catalyst particles adhering to the electrode 40 as a result could then falsify subsequent tests.

Various configurations of the basic structures 17 of flow elements 16 are in FIG 12 shown. The lower area is intended to show that the flow element 16 or in particular its basic structure 17, i.e. the area surrounding the fluid duct, is of multi-layer design, with the multiple layers or layers 76 forming a coherent unit and being connected to one another, for example by gluing or welding or presses. Up in the 12 are examples of different layer sequences.

A) shows a single-layer structure, for example made of rubber, b) shows a two-layer structure with a lower layer 78b made of rubber and an upper layer 78a made of a harder plastic, which can prevent adhesion, c) shows a two-layer structure with a lower layer 78b made of a comparatively harder plastic and an upper layer 78a made of rubber, with only the upper layer 78a having a sealing bead 80 and shows d) the structure corresponding to c) with the difference that the lower layer 78b also has a supporting bead 82 positioned corresponding to the sealing bead . In principle, the rubber layers can enable very good sealing, which can be improved by the sealing bead 80 . The support bead 82 in the lower layer 78b of the embodiment according to d) can reinforce the formation of the sealing bead 80, which can further improve the sealing effect through locally increased surface pressure.

Basically, a compressible or elastomeric layer adjacent to that of the flow element 16 can be opaque, such as Santoprene, covering only the edges of a viewing window. The layer can then lie between the viewing window and a stainless steel sheet of the base plate. The compressible layer can also be transparent, such as using PDMS, covering the entire viewing window. The layer then lies between the viewing window and the durable film.

It is advantageous that the external contacting 58 or the busbars and the chemically resistant, transparent film lie on one level and form a planar contact surface for the flow-through elements 16 lying thereon, which improves the tightness. It is advantageous if materials with the same thickness are compressible or incompressible along the viewing window 22 and along the base plate 12, 14, so that a flat contact surface is maintained in the pressed state.

Examples of flow structures 66, which may be present in fluid guides 18, are in FIG 13 until 18 shown.

The 13 the configuration of a mixer geometry 68 through which a fluid can flow, with adjacent flow distributors. In the 13 shown mixer geometry is also in the 14 and 15 shown where 14 shows a detailed view.

the 15 shows a further detailed side view of a flow element 66, it being intended to indicate that the flow element 66 is, in particular, elastically deformable.

the 16 shows a simple lattice structure, which can serve as a flow element 66 or as a mixer geometry 68 or as a turbulence-generating structure 72.

17 shows a punctiform structure, which can be present as a contact surface to adjacent layers, such as an electrode 40 or a membrane 42.

18 FIG. 12 shows a flow field 70 that lengthens the fluid flow in the flow cell 10 and thus increases the residence time of the fluid in the flow cell 10. FIG.

The figures shown thus illustrate the range of application of the flow cells 10, which is only possible by adapting the flow element 16, which is arranged between the base plates 12, 14. In other words, a modular system of different flow frames or flow elements 16 allows different cell architectures within the same basic structure. As indicated, the base plates 12 , 14 provide connection options for electrical power and a plurality of separate material flows which run into the flow-through element 16 . The base plates 12, 14 of the flow cells 10 can be connected to one another for scale-up, in particular screwed together, so that they form a longer combined cell. Geometry and flow control remain identical.

The invention on which this utility model application is based came about in a project funded by the BMBF under grant number 03SF0589.

Reference List

10

flow cell

12

base plate

14

base plate

16

flow element

17

basic structure

18

fluid guidance

20

fluid flow

22

viewing window

23

protective layer

24

through hole

26

material recess

27

screw and nut arrangement

28

fluid connection

30

electrical connection

32

fasteners

34

lanyard

38

connection plate

40

electrode

41

electrode frame

42

membrane

43

membrane frame

44

membrane electrode assembly

46

plate electrode

48

gas diffusion electrode

50

anode

52

cathode

54

sealing element

56

investment

58

contacting

60

rubber element

62

via

64

metal mesh

66

flow structure

68

mixer geometry

70

flow field

72

turbulence generating structure

74

flow distributor

76

frame

78

layer

80

sealing bead

82

support bead

84

Feature Note

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

• EP 1502313 B1 [0003]
• WO 2018/044236 A1 [0004]

Claims (18)

Flow cell (10) through which fluid can flow, having at least two base plates (12, 14), between which at least one flow element (16) with at least one fluid guide (18) for guiding a fluid flow (20) is arranged, the flow element (16) at least in part is made of a sealing material and is in sealing contact with the base plates (12, 14) or a protective layer present on the base plates (12, 14), in that the base plates (12, 14) can be fixed to one another by pressing the flow-through element (16) between them, wherein at least one base plate (12, 14) has at least one fluid connection (28) fluidically connected to the fluid guide (18) and optionally at least one further functional connection, and in particular wherein the base plates (12, 14) have connecting means (34) for mechanically connecting two flow cells ( 10) have. Flow cell (10) through which fluid can flow claim 1 , characterized in that at least one flow element (16) is constructed at least in part along its thickness in a multi-layer construction, the plurality of layers (78) being connected to one another. Flow cell (10) through which fluid can flow claim 1 or 2 , characterized in that the flow-through element (16) has electrical contacts for making electrical contact with an electrode (40) arranged in the flow-through element (16) or adjacent to the flow-through element (16), the electrical contacting being at least partially embedded in a plastic layer. Flow cell (10) through which fluid can flow according to one of Claims 1 until 3 , characterized in that at least two external contacts are provided for contacting an electrode (40) arranged in the flow-through element (16) or adjacent to the flow-through element (16). Flow cell (10) through which fluid can flow according to one of Claims 1 until 4 , characterized in that at least one flow structure (66) is provided in at least one fluid guide (18) or at least one fluid guide (18) forms a flow structure (66). Flow cell (10) through which fluid can flow claim 5 , characterized in that the flow structure (66) is selected from a flow distributor (74), a flow field (70) and a turbulence inducing structure (72). Flow cell (10) through which fluid can flow claim 5 or 6 , characterized in that the flow structure (66) has punctiform contact points for contacting an adjacent layer. Flow cell (10) through which fluid can flow claim 5 until 7 , characterized in that the flow structure (66) is compressible along the thickness of the flow element (16). Flow cell (10) through which fluid can flow according to one of Claims 1 until 8th , characterized in that the flow cell (10) has more than two base plates (12, 14). Flow cell (10) through which fluid can flow according to one of Claims 1 until 9 , characterized in that a plurality of flow elements (16) are in a stacked arrangement. Flow cell (10) through which fluid can flow according to one of Claims 1 until 10 , characterized in that two base plates (12, 14) arranged opposite one another with regard to the flow element (16) have U-shaped material recesses (26) open at the side for receiving fastening screws for fastening the base plates (12, 14) to one another. Flow cell (10) through which fluid can flow according to one of Claims 1 until 11 , characterized in that between the base plates (12, 14) at least one non-compressible spacer for setting a defined distance between the base plates (12, 14) is arranged. Flow cell (10) through which fluid can flow according to one of Claims 1 until 12 , characterized in that the flow element (16) has function indicia (84) on an outer surface for indicating at least one of a function type and a function position. Flow cell (10) through which fluid can flow according to one of Claims 1 until 13 , characterized in that at least one base plate (12, 14) has a viewing window (22) which provides a view into a fluid guide (18), the viewing window (22) preferably having a protective layer on a side facing the flow element (16). is provided. Flow cell (10) through which fluid can flow according to one of Claims 1 until 14 , characterized in that the functional connection is selected from an electrical connection (30) and a sensor connection. Flow cell (10) through which fluid can flow according to one of Claims 1 until 15 , characterized in that the base plates (12, 14) have a plurality of through holes (24). Flow cell (10) through which fluid can flow according to one of Claims 1 until 16 , characterized in that at least one fluid guide (18) is delimited by a membrane (42) or an electrode (40). Flow cell (10) through which fluid can flow according to one of Claims 1 until 17 , characterized in that at least one layer functioning as a sealing layer forms a sealing bead (80).

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