Method for manufacturing an assembly for an electrochemical cell device

Abstract

The invention relates to a method (52) for manufacturing an assembly (50) for an electrochemical cell device (10), in particular a fuel cell device (10), wherein the assembly (50) comprises at least one sheet (54), preferably made of steel, wherein the sheet (54) is first mounted (S1) in a carrier (56), wherein the carrier (56) covers a first free area (62a) of the sheet (54), followed by coating (S2) the sheet (54) mounted in the carrier (56) with a first layer (70a), preferably with a protective layer (72).

Description

The invention relates to a method for producing an assembly for an electrochemical device according to the preamble of the independent claim. The invention further relates to an assembly produced by such a method and to an electrochemical device comprising such an assembly.Prior ArtElectrochemical cell devices such as fuel cell systems or electrolysis systems typically have heat exchangers for heat recovery. In this way, the overall efficiencies can be advantageously increased, in particular in high-temperature systems, such as SOFC or SOEC systems. Such heat exchangers usually comprise steel with a high chromium content (above 10 percent by weight). At temperatures of more than 500° C. in combination with high atmospheric humidity or humidity of the medium, chromium evaporation can occur, as a result of which critical amounts of chromium can be released. Chromium VI can damage the electrochemical cell of the system, for example, so-called chromium poisoning of the SOFC cathode can occur, which leads to a significant power loss of the cell.Therefore, it is necessary to lower the chromium emissions of the heat exchanger, one method is to prevent chromium evaporation by suitably coating the respective steel surfaces, typically using metallic or ceramic coatings. Such coated steel sheets, however, have the disadvantage that they interfere with the further processing for the production of the heat exchangers, for example during welding.Disclosure of the InventionAdvantagesThe present invention describes a method of manufacturing an assembly for an electrochemical cell device. The electrochemical cell device may be a fuel cell device, particularly a high temperature fuel cell device such as a solid oxide fuel cell (SOFC). The assembly has at least one sheet metal, preferably made of steel or stainless steel. First, the sheet is mounted in a carrier, wherein the carrier covers a free area of the sheet. The sheet mounted in the support is then coated with a protective layer. Because the carrier covers the clearance area, the clearance area is not coated with the protective layer. In other words, the free region is free of the protective layer. During coating, a free region of the sheet which is not covered by the carrier is coated with the protective layer.This has the advantage that the sheet is coated with the protective layer only in the desired regions and the free region is free from the beginning of the protective layer and is directly ready for welds. In particular, it is not necessary to locally remove the protective layer before welding. This enables a fast, efficient and cost-effective manufacturing process of the assembly. It is also possible in this way in a simple and efficient manner to provide regions on the sheet metal which, for functional reasons, have to be free of the protective layer.An electrochemical cell device or cell device for short is to be understood in particular as a device which is provided for the electrochemical conversion of at least two fluids. The electrochemical cell device has an electrochemical cell unit which electrochemically converts the two fluids, and components which electrically supply the electrochemical cell unit, i.e. emit and / or supply electrical energy, and components which supply the electrochemical cell unit with the at least two fluids. The supplies can be made actively-for example by supply lines, pumps, fluid reservoirs, etc.-or passively-for example with ambient air as fluid-without active transport. Advantageously, the electrochemical cell device also has components for transporting away and / or recycling the reacted fluids. The electrochemical cell device advantageously also has components for the heat transport, in particular for the temperature control of the electrochemical cell unit, for example for the use of waste heat. Examples of cell devices are fuel cell devices or electrolysis devices.An electrochemical cell unit or cell unit for short is to be understood in this context as meaning, in particular, a unit having a plurality of electrochemical cells. Typically, the electrochemical cells are arranged stacked on top of one another in a unit of cells. Examples of electrochemical cell units are fuel cell units or electrolysis cell units. Electrochemical cell units are often also referred to as stacks of electrochemical cells; in particular, the terms fuel cell stacks or electrolysis cell stacks are known.An electrochemical cell is to be understood here in particular as an arrangement which provides usable electrical energy by chemical reactions or is provided for chemically obtaining or converting substances by applying a voltage. An electrochemical cell has at least two or more functional layers. The functional layers comprise at least two electrode layers and a separating layer or electrolyte layer. The electrode layers each have the function of an electron conductor and are conductively connected to the separating layer or electrolyte layer. Also important for the electrode layers is ion transport and a catalytic activity or oxygen exchange capacity between electrode layer and gas phase. The separating layer or electrolyte layer has in particular the function of an ion conductor. Furthermore, the separating layer or electrolyte layer is provided for separating the two gas spaces, for example the separation between air and fuel gas in a fuel cell. During operation, at least two fluids are typically actively or passively supplied to an electrochemical cell, which fluids are electrochemically reacted. A fluid may be liquid and / or gaseous.In particular, an electrochemical cell is to be understood as meaning a fuel cell or an electrolysis cell. For example, the electrochemical cell is provided to convert a fuel to generate electrical energy by supplying an oxidant in an electrochemical combustion process. Alternatively or additionally, the electrochemical cell can be provided to divide a fluid into at least two components in a separation process with the supply of electrical energy. Examples of electrochemical cells are electrolysis cells or fuel cells.A fuel cell device is to be understood in particular as a device which forms in particular an, in particular functional, component, in particular a structural and / or functional component, of a fuel cell system or the entire fuel cell system. In this context, a fuel cell system is to be understood to mean, in particular, a system for stationary and / or mobile recovery, in particular electrical and / or thermal energy, using at least one fuel cell unit.A fuel cell system includes one or a plurality of fuel cell units. Typically, a fuel cell system includes components and conduits that are provided to supply fuel and air to the fuel cell unit. Furthermore, a fuel cell system has components and lines in order to discharge exhaust gases from the fuel cell unit. Fuel cell systems advantageously have a recirculation circuit, having components and lines, which is provided for the purpose of returning unconverted fuel and / or unconverted air into the fuel cell unit. Overall, a fuel cell unit has at least one or a plurality of fans which are provided for conveying a fluid, in particular a gaseous fluid. The fluid can be, in particular, a fuel, an air, an exhaust gas or a combination of the aforementioned. The fans can be, in particular, fans of an air supply, fans of a fuel supply, a fan of an exhaust gas discharge and / or a fan of a recirculation circuit. The fuel cell system advantageously has one or more heat exchangers, in particular in order to resupply heat of the exhaust gas or in particular of the anode exhaust gas and cathode exhaust gas to the fuel cell unit, in particular to supply the fluids supplied to the fuel cell unit, in particular air, fuel and / or recirculate. In the present case, the terms heat exchanger and heat exchanger are used interchangeably.In this context, a fuel cell unit is to be understood to mean, in particular, a unit having a plurality of fuel cells. Typically, the fuel cells are arranged stacked on top of one another in a fuel cell unit; such a fuel cell unit is also referred to as a fuel cell stack. A fuel cell is provided in particular for converting at least one chemical reaction energy of at least one, in particular continuously supplied, combustion gas, in particular hydrogen, and of at least one oxidizing agent, in particular oxygen, in particular into electrical energy. The fuel cell can be designed in particular as a solid oxide fuel cell (SOFC). It is also conceivable for the fuel cell to be designed in the manner of a proton conductor or proton-conducting oxide or a proton-conducting oxide (PCO). Such fuel cells are also referred to as protonic ceramic fuel cell (PCFC). However, the present invention is independent of the type of fuel cells, so the electrolysis device also functions for other types of fuel cells. Typically, in a fuel cell unit, a plurality of fuel cells are electrically connected in series with each other.A fuel supply is to be understood as a source for a fuel which is supplied to the fuel cell device. For example, the fuel feed can be a connection for an external fuel feed, for example from a natural gas grid or from a hydrogen cylinder. A fuel can be, for example, natural gas, hydrogen or a mixture of natural gas and hydrogen. In variants, other fuels and mixtures of fuels are also conceivable, for example the fuel B can comprise natural gas, hydrogen, methane, ammonia and / or coal gas or synthesis gas. The fuel cell device can advantageously also have two or more fuel feeds, so that operation with different fuels is possible, in particular for example a fuel feed for natural gas and a fuel feed for hydrogen.In this context, a recirculation circuit or an anode recirculation circuit is to be understood as meaning, in particular, a fluid connection or a fluid path which is provided for supplying a fuel-containing or hydrogen- and water-containing anode off-gas from at least one fuel cell unit to a mixing point or to a mixing section at which the anode off-gas is mixed with the at least substantially pure fuel or hydrogen. In particular, the recirculation circuit is provided for the purpose of feeding unconverted fuel or hydrogen to the fuel cell unit again on the anode side. In particular, the mixture of the anode off-gas and the fuel or hydrogen is provided for being supplied to the fuel cell unit on the anode side. Typically, a recirculation circuit comprises a recirculation blower which is provided for moving a recirculate. The recirculation circuit can in particular have a fuel feed line and / or a recirculation line or anode exhaust gas line.A flow direction of the recirculate is also to be understood in particular as a flow direction of a recirculate fuel mixture.A recirculate is to be understood in particular as meaning a fuel-containing or hydrogen-containing and water-containing anode off-gas of at least one fuel cell unit. A recirculate fuel mixture is to be understood in the context of this invention as meaning a gas mixture of a fuel-containing or hydrogen- and water-containing anode off-gas from at least one fuel cell unit with fresh fuel.Within the scope of the present invention, lines are to be understood as meaning lines which are provided for carrying a fluid. A fluid can be in particular liquid or gaseous. A fluid is to be understood as meaning, in particular, air, fuel, recirculate, exhaust gases-in particular anode exhaust gas and cathode exhaust gas. For example, an air supply line is provided for the purpose of conducting air. A conduit typically fluidly connects two components of the fuel cell device. It is also conceivable for a line to connect a plurality of components of the fuel cell device fluidically in series to one another. For example, the air supply line can connect an air source to an air blower and the air blower to the fuel cell unit. It is conceivable that a line is provided for different fluids depending on the operating state and / or depending on the line section. For example, it is conceivable that the recirculate is injected in a feed line for the fuel at an mixing section, so that a mixture of the fuel and the recirculate flows downstream of the mixing section. For example, a conduit may comprise one tube or a plurality of tubes. In particular, a line can have a plurality of line sections which, for example, connect different components to one another in terms of flow.An electrolysis device is to be understood in particular as a device which is provided for recovering fuel from at least one base material and electrical current-in particular hydrogen from electrical current and water-by electrolysis. For this purpose, the electrolysis device has an electrolysis unit which is supplied with a medium as base material-for example water-and advantageously with the auxiliary medium. The medium is reduced in the electrolysis unit with the supply of electrical energy in a redox reaction, oxygen also being formed. In particular, the electrolysis unit generates a product gas which has the reduced medium and an exhaust gas which has the oxygen. The reduced medium is discharged from the electrolysis unit and represents the fuel, for example hydrogen. Accordingly, the electrolysis device has components and lines for supplying the medium and the fuel to the electrolysis unit, for providing electrical energy, and for discharging the reduced medium and the exhaust gas from the electrolysis unit and optionally storing them. Furthermore, the electrolysis device has components and lines in order to bring the respective fluids to the temperatures necessary for the electrolysis or in order to process the waste heat produced in the electrolysis unit. An auxiliary medium is to be understood in particular as a sufficiently inert gas which is provided for expelling the oxygen from the electrolysis unit. The auxiliary medium is advantageously also provided for heating up or cooling down the electrolysis unit. Possible auxiliary media are, for example, air, CO 2 or N 2, air is typically used.An electrolysis unit is to be understood in particular as a component which has at least one electrolysis cell. Typically, an electrolysis unit has a plurality of electrolysis cells which are electrically connected to one another in series, wherein the electrolysis cells are advantageously stacked. A stack of electrolysis cells is also referred to as an electrolysis stack. The electrolysis unit can also be designed as a stack module. A stack module is to be understood as a plurality of electrolysis stacks which can be electrically connected individually, in parallel with one another or in series with one another and are arranged, for example, on a common chassis or a common carrier or in a common housing.The electrolysis cell is an electrochemical cell which is provided by chemical reactions for the chemical recovery or conversion of substances by application of an electrical voltage. The electrolysis cell has at least two electrode layers and a separating layer or electrolyte layer, which in particular has the function of an ion conductor. The electrolysis cell preferably has an electrode layer which is designed as an oxidation electrode or air electrode and is designed in particular for contact with the oxidant and / or a cleavage product. Preferably, at least one electrode layer is formed as a fuel electrode, in particular for contact with the fuel and / or a further cleavage product. The air electrode defines an anode side of the electrolysis cell, the fuel electrode defines the cathode side of the electrolysis cell.The electrolysis cell is preferably a solid oxide electrolysis cell (SOEC), in particular a high temperature SOEC. Alternatively, the electrolysis cell can also be designed as a protonic ceramic electrolysis cell (PCEC) based on a proton-conducting oxide (PCO). However, the present invention is independent of the type of electrolysis cells, so the electrolysis device also functions for other types of electrolysis cells; for example, an electrolysis unit based on proton-permeable polymer membranes or proton exchange membrane or polymer electrolyte membrane (PEM) is also conceivable.A fluid supplied to the cell unit is therefore to be understood in particular as a fuel, air, oxygen, medium, auxiliary medium and / or recirculate.A feed line is to be understood in particular as a line which is provided for a fluid supplied to the cell unit, in particular a feed line for fuel, air, medium or auxiliary medium.In this context, a module is to be understood as a unit and / or a component of the electrochemical cell device.A unit is to be understood within the scope of this invention to mean, in particular, a processor unit and / or an electrochemical cell unit.Within the scope of this invention, a processor unit is to be understood as meaning in particular a component of the electrochemical cell device which is not an electrochemical cell unit and / or an electrochemical cell. In particular, the processor unit is a medium, such as a combustion gas, an air and / or an exhaust gas, for example, for pre- and / or post-processing, preferably chemical and / or thermal, at least one medium to be converted and / or converted in an electrochemical cell unit. The processor unit is preferably a reformer, an afterburner and / or a heat exchanger.Within the scope of the invention, a component is to be understood as meaning, in particular, a prefabricated and / or prefabricated part for the construction of the electrochemical cell device. Such a portion may be comprised by a unit of the electrochemical cell device and / or may correspondingly be a portion of a unit. Thus, this can be in particular a part of an electrochemical cell unit, such as a (carrier) plate of a stack of electrochemical cells, in particular a (carrier) plate of a fuel cell stack or of an electrolysis stack. However, such a section may also not be comprised by a unit and / or, for example, be a section of the electrochemical cell device outside a unit. Thus, this can be in particular a part which connects various units, such as a tube for carrying media.The assembly is preferably a heat exchanger or heat exchanger and the sheet or coated sheet is provided as a heat exchanger plate or a part of a heat exchanger plate.It is also conceivable that the assembly is the electrochemical cell unit and the sheet or coated sheet is provided as part of a housing of the electrical cell unit.A heat exchanger or heat exchanger is to be understood in particular as a component which is provided for transferring the waste heat from a product fluid or exhaust gas converted by the electrochemical cell unit to at least one fluid supplied to the electrochemical cell unit. Such a heat exchanger is also referred to as a recuperation heat exchanger. In the present case, the terms heat exchanger and heat exchanger are used interchangeably. For example, in the context of a fuel cell system, it is advantageous if the assembly is the heat exchanger, which transfers the heat of the exhaust gas to the air supplied to the fuel cell unit. It is also conceivable in the context of a fuel cell system that the assembly is the heat exchangers which transfer the waste heat of the exhaust gas to a fuel and / or recirculate supplied to the fuel cell unit.The sheet metal is preferably made of a steel, particularly preferably of a stainless steel. It is conceivable that in the step of coating one or both sides of the sheet are coated. It is in particular conceivable for a first side of the sheet metal to be coated first and for a second side of the sheet metal to be coated in a further process step.Coating is to be understood in particular as a production step in which a firmly adhering layer-in particular first layer or second layer-is applied to the at least one sheet metal. This can be a chemical, mechanical, thermal and / or thermomechanical coating process. In particular, the coating can be carried out using vacuum coating techniques, such as, for example, chemical vapor deposition (CVD), physical vapor deposition (PVD), in particular sputtering or cathode sputtering, and by spray coating, nozzle coating and / or printing, in particular inkjet printing. However, the present invention is generally not dependent on the choice of the coating method and other types of coating are also conceivable.A carrier is to be understood in particular as a mechanical device which is provided for mechanically fixing or retaining at least the process step of coating the production method of the assembly. After the completion of the coating and optionally further process steps which require such a fixing, the at least one sheet is detached from the carrier and, for example, further processed. In particular, the carrier is not part of the assemblies or of the electrochemical cell device.A first free region is to be understood as a region of the metal sheet which is not coated in the method during the at least one process step of the coating, in particular is not coated with a first layer.In particular, the first free region is free of a first layer after carrying out the method according to the invention.A second free region is to be understood as a region of the metal sheet which is not coated in the method during the at least one process step of the coating, in particular is not coated with a second layer. In particular, the free region after carrying out the method according to the invention is free of a second layer. Accordingly, an nth clearance region is to be understood in particular as a region of the metal sheet which is not coated in the method during the at least one process step of the coating, in particular is not coated with an nth layer, wherein n is a natural number. In particular, after carrying out the method according to the invention, the nth clearance region is free of an nth layer.A main region is to be understood as a region of the metal sheet which is coated during the at least one process step of the coating in the method, in particular is not coated with the first layer. It is conceivable that the main region is also coated with a second layer and, if appropriate, with further, n-th layers.Advantageously, the first layer is a protective layer. A protective layer is to be understood in particular as a view which is designed to protect the sheet metal from external influences, in particular in such a way that the effect of such influences on the sheet metal is reduced or reduced. Thermal and / or chemical effects are in particular conceivable. A protective layer is also to be understood advantageously in particular as a layer which prevents or at least reduces the deposition of material from the sheet metal. In this way, a protective layer can prevent chromium, in particular chromium VI, from emerging from the metal sheet. In this way, the protective layer can protect in particular the electrochemical cell or the electrochemical cell unit. In particular in the case of an SOFC stack, chromium VI can damage the SOFC cathode by chromium; this so-called chromium poisoning can lead to a significant loss of power of the stack.The features listed in the dependent claims allow advantageous refinements of the method.The method is further improved if the carrier has a first element, onto which the sheet metal is first arranged and the sheet metal is subsequently pressed against the first element by a second element of the carrier. In particular, the first element of the carrier and the second element of the carrier cooperate to mechanically fix or retain the sheet metal for coating. This enables a particularly simple and reliable holding of the sheet metal. It is possible in particular for the first element and the second element to fix the metal sheet in a form-fit connection and / or a force-fit or friction-fit connection. It is also conceivable that the carrier or the first element and the second element are designed to fix a plurality of metal sheets. It is furthermore conceivable that the first element and / or the second element are each arranged on one side of the sheet metal when the sheet metal is mounted in the carrier. Preferably, the first sheet is arranged on a first side of the sheet and the second sheet is also arranged on a second side of the sheet arranged opposite the first side when the sheet is mounted in the carrier. In other words, the sheet is preferably arranged between the first sheet and the second sheet when the sheet is mounted in the carrier.The method can be improved even further if a second free region of the sheet is covered and the sheet is subsequently coated with a second layer. In this way, the sheet can be coated in a simple and efficient manner with two types of layers, which are optionally arranged on different sections of the sheet. It is conceivable here for the second free region to have an overlap region with the first free region. It is also conceivable that the method provides n clearance areas, wherein n is a natural number greater than 1, and n layers are provided, wherein the nth clearance area is free of the nth layer after the coating of the metal sheet with the nth layer.It is conceivable, for example, for the carrier to have at least one cover element, which the sheet metal is used to cover the second free region during the coating with the second layer. When coating with the first layer, the at least one cover element is in a neutral position, which enables coating of the first free region with the first layer, as long as the first free region is not arranged there, which is then covered with another cover element, for example the first element and / or second element of the carrier. For example, the cover element can have a flap or be formed with a movable coupling element, for example with a hinge, so that it can be arranged selectively in a covering state and a non-covering state. In general, it is conceivable for the carrier to have n cover elements each, which are provided for covering the nth clearance region, wherein at least one of the n cover elements is formed at least partially, for example, by the first element and / or by the second element.In advantageous embodiments of the method, the first free region is arranged at least in sections along the edge of the sheet metal. This has the advantage that the carrier or a first element and / or second element of the carrier can not only cover the sheet metal at the free region opposite the first layer, but can also fix or retain the sheet metal particularly well.The fact that a region is arranged along the edge of the sheet metal is to be understood in this context in particular as meaning that the region extends along the edge of the sheet metal at least over a length of at least 50%, preferably at least 70%, particularly preferably at least 90%, of a total length of the edge of the sheet metal. Advantageously, the region is arranged within a surface section which extends from the edge with a length into the inner region of the metal sheet, wherein the length is at most 20% of an average longitudinal extension of the metal sheet, preferably at most 15%, particularly preferably at most 10%.A particular embodiment is present if the carrier has a cover element which is provided for covering the first free region and / or second free region, wherein the cover element is largely formed as a grid, wherein the grid line sections are formed to cover at least the respective first free region and / or second free region of the metal sheet. This enables a particularly efficient reception of in particular a plurality of metal sheets, in particular if the first clearance region and / or the second clearance region are each arranged along the edge of the respective metal sheet. Advantageously, the cells of the grid spanned by the grid line sections correspond to a size of metal sheets which are to be processed in the method. In advantageous variants, the grid is a rectangular grid and enables efficient processing of rectangular or largely rectangular metal sheets. Depending on the geometry of the metal sheets, other grid geometries are also conceivable, for example triangular or hexagonal grids. Irregular grids or grids with respectively different grid cell geometries are also conceivable, for example with round or circular cells for accommodating circular metal sheets.The method is particularly advantageous if the first layer comprises a metallic material, preferably aluminum (Al) and / or a ceramic material. In this way, a particularly reliable and effective protective layer can be realized. Conceivable further metals or semimetals are nickel (Ni), titanium (Ti), cobalt (Co), silicon (Si), copper (Cu), manganese (Mn), gold (Au), tungsten (W) or tungsten carbide (WC), molybdenum (Mo) or molybdenum nitride (MoN, Mo 2 N) and / or rhenium (Re). Refractory metals are also conceivable in particular as metals. Aluminum compounds and / or aluminum alloys are also conceivable. Advantageous ceramic materials are, in particular, Al 2 O 3, ternary aluminum compounds such as Ti 2 AlN, Al-O-N, AlCrN, Si x N y, mixed oxides having a spinel structure, for example (Mn,Co) 3 O 4, ( Fe,Co,Ni,Mn,Cu) 3 O 4, ( Cu,Mn) 3 O4, (Mn,Cr) 3 O 4 and / or mixed oxides having a perovskite structure, for example (La,Sr,Ca)CrO 3, LaCrO 3.The method is further improved if the first layer and / or the second layer is applied to the sheet metal by physical vapor deposition (PVD). This enables a particularly uniform and smooth coating. PVD can be realized, for example, by evaporation methods or by sputtering. For example, the sheet metal can be coated by means of at least one cathode. It is particularly advantageous if the PVD is carried out with a rotating cathode. In this way, the uniformity of the coating can be further increased.Advantageously, the first layer and / or the second layer can also be produced by chemical vapor deposition (CVD), in particular plasma-enhanced chemical vapor deposition (PACVD). In principle, the method according to the invention is not dependent on the coating method, plasma coating, spraying, printing, spraying, electroplating and so forth are also conceivable. For the preferred coating with Al or aluminum compounds or aluminum alloys, in particular, alloying is also conceivable. For the coating with Al 2 O 3 PVD or PECVD are advantageous; for the coating with Si x N y PECVD is suitable.It is further advantageous if the second layer is formed as a functional layer, in particular with a chromium getter substance. The chromium getter substance, in particular in combination with a protective layer, offers a particularly good protective effect against chromium poisoning of the electrochemical cell.A functional layer is to be understood in particular as a layer which functions during the conversion of a medium or fluid of the electrochemical cell device. In particular, the functional layer can be provided for a post-treatment of exhaust gases or for the pre-treatment or cleaning of media or fluids supplied by the electrochemical cell.A chromium getter substance is to be understood in particular as a substance which chemically and / or mechanically binds chromium, in particular chromium VI, or so that the bound chromium either remains bound in the functional layer or is more easily removable from the respective fluid stream in the bound form, for example because the chromium is bound in particles which can be filtered out easily. Examples of chromium getter substances typically comprise alkaline earth metals, in particular strontium (Sr), and / or oxides of transition metal oxides (TMO).Furthermore, an assembly produced by a method according to the present invention, in particular a heat exchanger, for an electrochemical device is advantageous. The assembly has at least one sheet metal, wherein the sheet metal has at least one first free region and has a main region which is coated at least with the first layer. Such an assembly has a particularly high durability and reliability. The first free region advantageously has a weld seam which is particularly robust.The assembly advantageously has a medium guidance chamber, wherein the main region is arranged in the medium guidance chamber and the medium guidance chamber is provided to guide a medium to be supplied to an electrochemical cell unit-in particular fuel cell unit-and / or a medium to be discharged to an electrochemical cell unit-in particular fuel cell unit. During operation, the main region is exposed to the medium to be supplied and / or medium to be discharged or in contact therewith. Because the main region which is coated with the at least first layer, the medium is protected from deposits. If the main region has a functional layer, the medium can be implemented by means of the functional layer.An electrochemical device, in particular a fuel cell device, having at least one assembly according to the present invention, in particular a heat exchanger, is also advantageous. The electrochemical device may also advantageously be an electrolytic cell device. Such an electrochemical device can be operated particularly safely and reliably on account of the advantages of the assembly.DRAWINGSExemplary embodiments of the method, the assembly and the electrochemical cell device according to the present invention are illustrated in the drawings and are explained in more detail in the following description. They show FIG. 1 shows a schematic illustration of the fluidic interconnection of a fuel cell device with a module, FIG. 2 shows a schematic illustration of the method for producing the assembly, FIG. 3 is a sectional view of metal sheets mounted on a carrier during the production of the assembly, and FIGS. 4 and 5 show two variants of the support with assembled sheets in a plan view.DESCRIPTION OF THE INVENTIONIn the various embodiments, like parts are given the same reference numerals.FIG. 1 shows a schematic circuit diagram of an exemplary embodiment of an electrochemical cell device 10, which is designed as a fuel cell device 10 by way of example. The fuel cell device 10 includes, for example, two fuel cell units 12, a first fuel cell unit 12 aand a second fuel cell unit 12 b. In the exemplary embodiment shown, the fuel cell units 12 are designed as fuel cell stacks which have a multiplicity of fuel cells, in the present case solid oxide fuel cells (SOFC). In the exemplary embodiment shown in FIG. 1, the first fuel cell unit 12 ais a first fuel cell stack. In the exemplary embodiment shown in FIG. 1, the second fuel cell unit 12 bis a second fuel cell stack.Furthermore, the fuel cell device 10 comprises a plurality of processor units 14. a processor unit 14 is to be understood within the scope of this invention to mean in particular a unit or component of the fuel cell device 10, which is not a fuel cell unit 12. In the present case, the processor units 14 are units for the chemical and / or thermal pre- and / or post-processing of at least one medium to be converted and / or converted in a fuel cell unit 12, such as a fuel gas, an air and / or an exhaust gas.One of the processor units 14 is a heat exchanger 18 arranged in an air feed 16 for heating an oxygen-containing air L fed to the fuel cell units 12. In the fuel cell units 12, the reformed fuel RB is electrochemically reacted by cooperation of oxygen from the air L to generate current and heat.The reformed fuel RB is generated by supplying fuel B, in the present case natural gas, for example, to the fuel cell device 10 via a fuel supply 24, which fuel B is reformed in a further processor unit 14, in the present case a reformer 26.Furthermore, the fuel cell units 12 are connected on the exhaust gas side to a further processor unit 14, in the present case to an afterburner 28. The afterburner 28 is supplied with exhaust gas from the fuel cell units 12, in the present case cathode exhaust gas KA via a cathode exhaust gas duct 30 and a portion of the anode exhaust gas AA via an anode exhaust gas duct 32. The anode off-gas AA, or the unconverted reformed fuel RB optionally contained therein and / or the unconverted fuel B optionally contained therein, is burned by means of the afterburner 28, with admixture of the cathode off-gas KA or of the oxygen contained therein of the air L, as a result of which additional heat can be generated.The hot exhaust gas A formed during the combustion in the afterburner 28 is discharged from the afterburner 28 via an exhaust gas duct 34 via a further processor unit 14, in the present case via a heat exchanger 36. The heat exchanger 36 is in turn connected to the reformer 26 in terms of flow, so that heat is transferred from the hot exhaust gas A to the fuel B supplied to the reformer 26. Accordingly, the heat of the hot exhaust gas A can be used for reforming the supplied fuel B in the reformer 26. In the exemplary embodiment, the heat exchanger 36 is, for example, of the same type as the heat exchanger 18 and thus also an assembly 50.Downstream of the heat exchanger 36, a further processor unit 14, in the present case the heat exchanger 18, is located in the exhaust gas duct 34, so that the remaining heat of the hot exhaust gas A can be transferred to the supplied air L in the air feed 16. Accordingly, the remaining heat of the hot exhaust gas can be used for preheating the supplied air L in the air duct 16.In addition, the fuel cell device 10 has a recirculation line 38 by means of which a part of the anode off-gas AA can be branched off from the anode off-gas line 32 and fed to an anode recirculation circuit 40. In this case, the branched-off anode exhaust gas AA passes through a further processor unit 14, in the present case a further heat exchanger 39.By means of the anode recirculation circuit 40, the branched-off part of the anode off-gas AA can be recirculated or fed back to the respective anode space 22 of the fuel cell units 12 and / or the reformer 26, with the result that the unconverted reformed fuel RB optionally contained in the branched-off anode off-gas AA can be converted in the downstream in the fuel cell unit 12 and / or the unconverted fuel B optionally contained in the branched-off anode off-gas AA can be reformed in the downstream in the reformer 26. Thereby, the efficiency of the fuel cell device 10 can be further increased. In addition, fresh fuel B can be mixed via the fuel feed line 24 with the branched anode exhaust gas AA recirculated in the anode recirculation circuit 40. By means of the further heat exchanger 39, heat can then be transferred for thermal processing from the branched-off anode exhaust gas AA from the return line 38 to the fuel mixture formed by the admixture of the fresh fuel B in the anode recirculation circuit 40.By means of fans 42 in the respective lines, the supply of air L in the air supply 16, the supply of fuel B in the fuel supply 24 and the recirculation rate of the anode exhaust gas AA in the anode recirculation circuit 40 can be regulated and / or matched to one another. The anode recirculation circuit 40 includes a recirculation blower 48. The recirculation blower 48 is a blower 42.Furthermore, the fuel cell device 10 has a heating element 44, in the present case additionally, for heating the air L supplied to the fuel cell units 12 in a bypass line 46, whereby the operating efficiency of the fuel cell device 10 is increased.As can be clearly seen, in the exemplary embodiment, both fuel cell units 12 are supplied with air L via the air feed 16 and an air blower 58. The two fuel cell units 12 are fluidically connected in parallel via the air feed 16. The two fuel cell units 12 thus have a common air supply 16, 42. The two fuel cell units 12 thus have a common air supply, wherein an air L conveyed by the air blower 58 is guided to the respective fuel cell unit 12 via two air supplies 16 connected fluidically in parallel to one another. The air blower 58 is a blower 42. The same air flow L is largely supplied to both fuel cell units 12 by the common air supply 16.In the exemplary embodiment shown in FIG. 1, both fuel cell units 12 are supplied with fuel B or reformed fuel RB via the fuel feed and, for example, a reformer 26. The fuel B or the reformed fuel RB are transported in each case by a blower 42 at the fuel feed 24 and by a blower 42 in the anode recirculation circuit 40, the recirculation blower 48. In this case, in the exemplary embodiment, the fuel cell units 12 are fluidically connected in parallel to the reformer 26. The two fuel cell units 12 thus have a common fuel supply 24, 26, 42. In the exemplary embodiment shown, this common fuel supply 24, 26, 42 provides the two fuel cell units 12 with a substantially identical basic quantity of fuel.In other words, the two fuel cell units 12 have a common fuel supply, wherein fuel B or reformed fuel RB conveyed by fans 42 is guided to the respective fuel cell unit 12 via two fuel feeds 24 connected fluidically in parallel to one another. The common fuel feed 24 supplies, in particular, largely the same fuel stream B or stream of reformed fuel RB to both fuel cell units 12.FIG. 2 schematically shows a method 52 for producing the assembly 50. In a second step S 2 of the S 2 coating, sheet 54 mounted in carrier 56 is coated with a first layer 58 a, which is, for example, a protective layer 60 made of aluminum.FIG. 3 schematically illustrates the arrangement of the metal sheet 54 on the carrier 56 during the coating S 2. By way of example, a variant is depicted in which the carrier 56 is designed to support a plurality of metal sheets 54. FIG. 3 shows a sectional view from the side through the carrier 56 and the metal sheets 54. three metal sheets 54 a, 54 b, 54 care visible by way of example in the sectional view. Each of the sheets 54 has, by way of example, a first side 58 aand a second side 58 b. By way of example, the first side 58 ais oriented upward with respect to a direction of gravity. The second side 58 bis correspondingly oriented downward with respect to the direction of gravity. The carrier 56 includes a first member 60 aand a second member 60 b. The sheets 54 are clamped between the first member 60 aand the second member 60 bfor coating S 2, respectively. By way of example, the first element 60 ais arranged here in each case on the first side 58 aof the metal sheets 54. By way of example, the second element 60 bis arranged here in each case on the second side 58 bof the metal sheets 54.The metal sheets 54 each have a first free region 62 a. The first free region 62 ais, for example, arranged in each case on the edge 64 of the metal sheets 54. By way of example, the first free region 62 ais arranged in each case on the first side 58 aand the second side 58 bof the metal sheets 54. As can be clearly seen, in the state in which it is mounted on the carrier 56, the first free region 62 ais covered by the carrier 56. By way of example, the first element 60 acovers the first clearance region 62 aon the first side 58 a. By way of example, the second element 60 bcovers the first clearance region 62 aon the second side 58 b. A main region 66, which is arranged in each case on the first side 58 aand second side 58 bof the metal sheets 54, is not covered by the carrier 56.In the method 52, a first layer 70 ais applied to the main region 66 during the coating S 2. The first layer 70 ais applied by way of example by a first cathode 68 aand a second cathode 68 b. Both cathodes 68 are each designed as rotating cathodes 68. By way of example, the first cathode 68 ais arranged above the second sheet metal 54 bor on its first side 58 a. By way of example, the second cathode 68 bis arranged below the third sheet 54 cor on its second side 58 b.In the state of the process step of the coating S 2 that has not yet been completed, as depicted in FIG. 3, the first metal sheet 54 ais still uncoated. The second sheet 54 bis coated by the first cathode 68 aon the first side 58 aand already has a first layer 70 aon the first side 58 a. The third sheet 54 cis already coated by the first cathode 68 aon the first side 58 aand has the first layer 70 aon the first side 58 a. Furthermore, the third sheet 54 cis coated by the second cathode 68 bon the second side 58 band already has a first layer 70 aon the second side 58 b. As can be clearly seen, on the third sheet 54 c, the first layer 70 ais arranged on the main region 66 in each case on the first side 58 aand second side 58 b. As can also be clearly seen, on the third sheet 54 c, the first clearance region 62 ais uncoated on the first side 58 aand on the second side 58 band is free of the first layer 70 a, respectively.In the exemplary embodiment shown in FIG. 3, the cathodes 68 are arranged in a fixed position in a production line, not shown in detail, the carrier 56 with the metal sheets 54 is guided horizontally past the cathodes 68, in the illustration from left to right, so that the metal sheets are in each case coated one after the other firstly on the first side 58 aand then on the second side 58 b.FIG. 4 shows a plan view of the carrier 56 from FIG. 3 with a plurality of assembled metal sheets 54. In the plan view, the first element 60 aof the carrier 56 can be seen. At the top right in FIG. 4, one of the metal sheets 54 after the coating (S 2) is depicted in an enlarged manner by way of example. As can clearly be seen, the metal sheets 54 are all of the same type and each of rectangular design. The first clearance portion 62 ais disposed at the edge 64 of the panel 54 and has the shape of a rectangular frame. The main region 66 is surrounded by the first free region 62 a, is rectangular and is coated with the first layer 70 a, which is formed, for example, as a protective layer 72 made of aluminum. The sheet 54 is formed, for example, from a stainless steel. The protective layer 72 reduces the emissions of chromium VI from the main region 66 at high temperatures. It is advantageously provided that in a later production step, the sheet metal is welded into the assembly 50 along the edge 64 at the first free region 62 a.As can also be clearly seen, the carrier 56 is largely designed as a grid 74. By way of example, the first element 60 aof the carrier 56 is formed as a cover element 75 which is formed to cover the first free region 62 a. In particular, the first element 60 aand the cover element 75 are largely designed as a grid 74. The second element 60 bof the carrier 56 is designed to be complementary to the first element 60 ain FIG. 4 and is provided as a cover element 75 for covering the first free region 62 aon the second side 58 bof the metal sheets 54 facing away from the observer. Accordingly, the second element 60 bis also largely designed as a grid 74. The grid 74 is formed by a plurality of grid line portions 76. There are a first group of grid line portions 76a and a second grid line portions 76b. The first grid line sections 76 aare each arranged substantially parallel to one another. The second grid line sections 76 bare each arranged largely parallel to one another. The first grid line sections 76 are each arranged substantially perpendicularly to the second grid line sections 76 b. In this manner, the grid line portions 76 span a rectangular grid 74 having rectangular grid cells. Each of the metal sheets 54 is arranged, for example, between adjacent grid line sections 76, more precisely in each case between two adjacent first grid line sections 76 aand between two adjacent second grid line sections 76 b, which together cover the first free region 62 aat the edge 64. In other words, the sheets 54 are each arranged in the grid cells of the grid 74.FIG. 5 shows a variation of the carrier 56. the illustration corresponds to the illustration in FIG. 4, a plan view of the variant of the carrier 56 with a plurality of mounted metal sheets 54 being depicted. The carrier 56 of the variant shown in FIG. 5 has all the features of the variant shown in FIG. 4, and the carrier 56 in FIG. 5 additionally has a second cover element 78. The second cover element 78 is exemplarily strip-shaped, the strips of the second cover element 78 extend exemplarily parallel to the first grid line portions 76 aand are respectively arranged between two adjacent first grid line portions 76 a. By way of example, the strips of the second cover element 78 are each arranged at a distance of one quarter of the distance from two adjacent first grid line sections 76 ato the respective next first grid line section 76 a.The second cover element 78 is provided, for example, for covering a second free region 62 bon each of the metal sheets 54. By way of example, the second free region 62 bdividates the main region 66 on each side 58 a, 58 bof each sheet 54 into in each case two subareas. The second cover element 78 is designed such that it can be connected to the second element 60 aand first cover element 75, respectively, and can be repeatedly released and connected. It is contemplated that the sheets 54 will first be mounted into the carrier 56 without the second cover member 78 and the main portion 66 will be coated with the first layer 70a. The first free region 62 ais covered by the carrier 56 or the first cover element 75 and remains free of the first layer 70 a. The second strip-shaped free region 62 bis not covered and is coated with the first layer 70 a. Thereafter, the second cover member 78 is mounted on the carrier 56 so as to cover the second clearance portion 62 b. The metal sheet 54 is then coated with a second layer 70 b, which is formed, for example, as a functional layer 80. The main region 66 is coated with the second layer 70 b, while the second free region 62 bremain free of the second layer 70 b.After the coating S 2, a sheet 54 is present, for example, which has a main region 66, for example having two partial regions, which is coated with the first layer 70 aand the second layer 70 b, a first free region 62 awhich is free from the first layer 70 aand from the second layer 70 b, and a second free region 62 bwhich is coated only with the first layer 70 a.

Claims

Method (52) for producing an assembly (50) for an electrochemical cell device (10), in particular a fuel cell device (10), wherein the assembly (50) has at least one sheet (54), preferably made of steel, wherein firstly the sheet (54) is mounted (S1) in a carrier (56), wherein the carrier (56) covers a first free region (62a) of the sheet (54), subsequent coating (S2) of the sheet (54) mounted in the carrier (56) with a first layer (70a), preferably with a protective layer (72).Method (52) according to Claim 1, wherein the carrier (56) has a first element (60a), on which the sheet (54) is initially arranged and the sheet (54) is subsequently pressed against the first element (60a) by a second element (60b) of the carrier (56).Method (52) according to one of the preceding claims, characterized in that a second free region (62b) of the sheet (54) is covered and the sheet (54) is subsequently coated (S2) with a second layer (70b).Method (52) according to one of the preceding claims, characterized in that the first free region (62a) is arranged at least in sections along the edge (64) of the sheet (54).Method (52) according to one of the preceding claims, characterized in that the carrier (56) has at least one cover element (75, 78), which is provided for covering the first free region (62a) and / or second free region (62b), wherein the at least one cover element (75, 78) is largely designed as a grid (74), wherein the grid line sections (76) are designed to cover at least the respective first free region (62a) and / or second free region (62b) of the metal sheet (54).Method (52) according to one of the preceding claims, characterized in that the first layer (70a) comprises a metallic material, preferably aluminium (Al) and / or a ceramic material.Method (52) according to one of the preceding claims, characterized in that the first layer (70a) and / or the second layer (70b) is applied to the sheet (54) by physical vapor deposition (PVD).Method (52) according to one of the preceding claims, characterized in that the second layer (70b) is formed as a functional layer (80), in particular with a chromium getter substance.Assembly (50), in particular heat exchanger (18, 36, 39) for an electrochemical cell device (10), comprising at least one sheet (54), wherein the sheet (54) comprises at least one first clearance region (62a) and a main region (66) which is coated at least with the first layer (70a), produced by a method (52) according to the preceding claims.Assembly (50) according to Claim 9, having a medium guidance space, wherein the main region (66) is arranged in the medium guidance space and the medium guidance space is provided for guiding a medium (B, RB, L) to be supplied to an electrochemical cell unit (12), in particular fuel cell unit (12), and / or a medium (A, AA, KA) to be discharged to an electrochemical cell unit (12), in particular fuel cell unit (12).Electrochemical cell device (10), in particular fuel cell device (10), having at least one assembly (50) according to Claim 9 or 10, in particular a heat exchanger (18, 36, 39).

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