Method for manufacturing a fuel cell stack, as well as fuel cell stack

Abstract

Method for manufacturing a fuel cell stack (10), in particular for a prototype of a fuel cell stack (10), which comprises at least one metallic solid component (1) formed from a support component (2) and furthermore an at least partial coating for the support component (2), wherein the solid component (1) is arranged to come into direct contact, at least in the area of ​​the coating, with at least one of the media which are supplied to and / or discharged from the fuel cell stack (10), comprising the following steps: a) Manufacturing the respective support component (2) using an additive manufacturing process; and b) Applying the coating to the respective substrate (2) by means of a physical and / or chemical vapor deposition process, wherein the coating is formed as an at least two-layer system (3), wherein the system (3) comprises at least one substrate layer (4a, 4b) comprising at least one chemical element from the group consisting of titanium, niobium, hafnium, zirconium, tantalum, and a top layer (3a) facing away from the substrate (2), and wherein the system (3) comprises at least one first substrate layer (4a) facing the substrate (2) in the form of a metallic alloy layer comprising the chemical elements titanium and niobium, and further comprises at least one second substrate layer (4b) facing away from the substrate (2) comprising at least one chemical element from the group consisting of titanium, niobium, hafnium, zirconium,Tantalum and furthermore comprising at least one non-metallic element from the group nitrogen, carbon, boron, fluorine.

Description

[0001] The invention relates to a method for manufacturing a fuel cell stack, in particular for a prototype of a fuel cell stack, which comprises at least one solid metallic component, each consisting of a support component and at least a partial coating for the support component. The invention further relates to a fuel cell stack manufactured according to the method.

[0002] It has become clear that implementing fuel cell systems in small series or in a prototype or pilot phase using industrially established processes such as deep drawing or injection molding does not allow for economical production. The small quantities required for this application make the manufacturing costs unattractive, and the possibilities for rapid design changes are limited.

[0003] The production of metallic bipolar plates using 3D printing and their subsequent coating is already known from US 2016 093 898 A1, where a coating made of gold, nitride materials or TiO2 / gold is disclosed.

[0004] DE 10 2009 010 279 A1 describes the production of a bipolar fuel cell plate by depositing a conductive layer onto a metal plate using an atomic layer deposition (ALD) process.

[0005] DE 10 2013 108 413 A1 describes a method for manufacturing a fuel cell stack, in which components with gas channel structures are formed using additive manufacturing processes.

[0006] German patent application DE 10 2015 222 972 A1 discloses a catalyst and a process for its production. The catalyst and a support material are welded together, the support material being built up layer by layer by 3D printing. The catalyst is used in a reformer for producing hydrogen-containing fuel gas, which is intended for use in a fuel cell. The reformer with catalyst processes a hydrocarbon-containing fuel gas, which is then supplied to the fuel cell.

[0007] DE 100 17 200 A1 describes a metal bipolar plate for use in a PEM fuel cell with a corrosion-resistant, electrically conductive multilayer system. A first layer, applied to a substrate, is a metallic layer composed of metals or alloys or intermetallic compounds of titanium, zirconium, tantalum, niobium, chromium, aluminum, molybdenum, and / or tungsten. Two metallic substrate layers may be provided. Furthermore, a second outer metal-metalloid layer is provided, consisting of the metals titanium, zirconium, tantalum, niobium, chromium, aluminum, molybdenum, and / or tungsten bonded to nitrogen, oxygen, or carbon.

[0008] DE 10 2006 029 473 A1 discloses a fuel cell contact element with a TiO2 layer and a conductive layer.

[0009] However, the construction of a fuel cell stack requires not only bipolar plates, but also a large number of different solid components, the individual production of which is time-consuming and expensive.

[0010] The object of the invention is therefore to provide an efficient method for the production of functional fuel cell stacks in a small series or in a prototype or pilot phase, the functionality of which can be ensured.

[0011] The following requirements must be met by the solid components used in fuel cell stacks: - High corrosion resistance to a surrounding medium, and / or - high resistance to anodic or cathodically polarizing loads, - low surface resistance of a surface of the substrate or its coating facing an electrolyte, and - low production costs.

[0012] The problem is solved for the process for manufacturing a fuel cell stack, in particular for a prototype of a fuel cell stack, which comprises at least one metallic solid component, each consisting of a support component and at least a partial coating for the support component, wherein the solid component is arranged to come into direct contact, at least in the area of ​​the coating, with at least one of the media which are supplied to and / or discharged from the fuel cell stack, by the following steps: a) Manufacturing the respective support component using an additive manufacturing process; and b) Application of the coating to the respective substrate by means of a physical and / or chemical vapor deposition process, wherein the coating is formed as a layer system of at least two layers, wherein the layer system comprises at least one base layer comprising at least one chemical element from the group titanium, niobium, hafnium, zirconium, tantalum and a top layer facing away from the substrate, and wherein the layer system comprises at least one first base layer facing the substrate in the form of a metallic alloy layer comprising the chemical elements titanium and niobium and further comprises at least one second base layer facing away from the substrate comprising at least one chemical element from the group titanium, niobium, hafnium, zirconium, tantalum and further comprises at least one non-metallic element from the group nitrogen, carbon, boron,Fluorine is formed.

[0013] The following substances are understood here to be media that are supplied to and / or removed from the fuel cell stack: - Gases, such as oxygen or air and / or a fuel gas, especially hydrogen or methane; - Vapors, especially water vapor, and - Liquids, especially water.

[0014] The method according to the invention enables the rapid and efficient provision of a prototype of a fuel cell stack at low manufacturing costs and with excellent functionality.

[0015] The additive manufacturing process is in particular a 3D printing process, especially selective laser melting (SML), electron beam melting (EBM) or selective laser sintering.

[0016] In a further, particularly preferred embodiment of the method, the additive manufacturing process is implemented using a 3D screen printing process. Like the 3D printing processes mentioned above, 3D screen printing involves the layer-by-layer production of components. However, unlike the so-called 3D printing processes, a highly productive printing process is used in which a powder-based suspension is transferred to a substrate through a rigid printing mask (screen) using a squeegee and then dried. This printing process is repeated until the desired component height is reached. In a final sintering step, the formed component is solidified.

[0017] Underoxidation, i.e., oxidation of the surface of a substrate with a coating applied to that surface, typically leads to the delamination of overlying precious metal layers. Corrosion protection on metallic substrates, such as those made of steel, especially stainless steel, or titanium, is optimized by applying a coating system with at least two layers. This is particularly advantageous on the surfaces of metallic substrate components formed by 3D printing, which therefore have a rougher surface than metal components formed by conventional methods such as continuous casting, ingot casting, or sintering. The multi-layered coating ensures improved protection of the 3D-printed component's surface compared to a single-layer application, as any minor defects that may occur are eliminated by the subsequent layer.

[0018] According to the invention, the layer system is formed comprising at least one substrate layer which comprises at least one chemical element from the group consisting of titanium, niobium, hafnium, zirconium, and tantalum.

[0019] The layer system comprises, in particular, a first substrate layer facing the support component in the form of a metallic alloy layer comprising the chemical elements titanium and niobium, in particular 20-50 wt.% niobium and the remainder titanium, and furthermore at least a second substrate layer facing away from the support component comprising at least one chemical element from the group titanium, niobium, zirconium, hafnium, tantalum and furthermore at least one non-metallic element from the group nitrogen, carbon, boron, fluorine.

[0020] In particular, a two-layer system has proven effective, with a first underlay layer made of TiNb and a second underlay layer made of TiC.

[0021] According to the invention, at least one substrate layer and a cover layer facing away from the support component are formed, wherein a substrate layer system comprising at least a first substrate layer and at least a second substrate layer, as well as a cover layer facing away from the support component, is formed on the substrate layer system. This is particularly advantageous when corrosive environmental media are present, especially when the corrosive media contain chlorides.

[0022] The coating thus consists of a layered system comprising a top layer facing away from the substrate and a base layer system arranged between the substrate and the top layer. This ensures the required corrosion resistance and the required low surface resistance of the solid metallic component.

[0023] In a particularly preferred embodiment, the underlay system is provided with a second underlay layer comprising the chemical elements a) Titanium, niobium and further carbon and fluorine, or b) Titanium, niobium and nitrogen, is especially made of (Ti 0,67 Note 0,33 ) 1-x N x formed with x= 0.40 - 0.55.

[0024] The material is referred to as (Ti 0,67 Note 0,33 ) 1-x N x with x= 0.40 - 0.55 such that the second substrate layer is formed by atomizing a target made of Ti0, 67 Note 0,33 is produced by incorporating nitrogen from the gas phase into the second substrate layer at a concentration of 40 to 55 at%.

[0025] The second underlay layer is preferably arranged between the first underlay layer and the top layer.

[0026] The second layer of substrate can still contain up to 5 at% oxygen.

[0027] The top layer is preferably formed from a homogeneous or heterogeneous solid metallic solution containing either a first chemical element from the group of noble metals in the form of iridium in a concentration of at least 99 at% or a first chemical element from the group of noble metals in the form of iridium and a second chemical element from the group of noble metals in the form of ruthenium, wherein the first chemical element and the second chemical element together are present in a concentration of at least 99 at%. and contains at least one other non-metallic chemical element from the group comprising nitrogen, carbon, and fluorine, with oxygen and / or hydrogen optionally present only in trace amounts. This coating is electrically conductive, electrocatalytically active, and corrosion-resistant.

[0028] A homogeneous metallic solution (Type 1) is understood to mean that the aforementioned non-metallic chemical elements are dissolved in the metal lattice in such a way that the lattice type of the host metal or host metal alloy does not change substantially.

[0029] A heterogeneous metallic solution is defined as one in which, in addition to the metal-containing phase, one of the non-metallic chemical elements is also present in its elemental form within a mixed phase. For example, depending on the specific phase diagram, elemental carbon may be present alongside the alpha phase (Type 1).

[0030] Depending on the deposition conditions, the top layer can be metastable or stable in a thermodynamic sense.

[0031] It has been shown that with a carbon-containing coating layer, thus through the use of the metalloid or non-metallic chemical element carbon, the conductivity of the coating layer is higher than that of gold, and that at the same time its oxidation stability in an acidic solution is significantly higher than the voltage of 2000 mV of a standard hydrogen electrode. Depending on the specific embodiment, measured specific electrical resistances are comparable to those of gold (under standardized conditions, i.e., at a contact force of 140 N / cm²). 2 The specific electrical resistance of gold is approximately 10 mΩ cm. -2 at room temperature (T = 20°C).

[0032] Another important advantage is that the iridium does not degrade at voltages above the value E = 2.04 - 0.059 Ig pH- -0.0295 Ig (IrO4) 2-oxidized and dissolves. In the solid solution, the lower-valent iridium is stabilized to such an extent that the otherwise typical oxidation at approximately 1800 mV in 1 mol / L (1N concentrated) sulfuric acid (H₂SO₄) no longer occurs. The stabilization is determined by the gain in free partial mixing energy ΔG. Misch the solid solutions or compounds.

[0033] The top layer is preferably formed with a layer thickness of at least 1 nm to a maximum of 10 nm.

[0034] For example, with a layer thickness of approximately 10 nm, when using Ir x -C 1-x only 4 µg iridium per cm 2 of the top layer. For a 10 nm thick gold layer, more than 20 µg of gold per cm² are required. 2can be used. The advantage of the top layer compared to a gold layer is its high oxidation stability up to voltages well above 2000 mV compared to a standard hydrogen electrode in 1 N concentrated sulfuric acid.

[0035] The coating significantly increases the stability of, for example, iridium-containing dimensionally stable anode electrodes.

[0036] The at least one non-metallic chemical element, namely carbon and / or nitrogen and / or fluorine, is preferably present in the coating layer at a concentration in the range of 0.1 at.% to 1 at.%. In particular, the non-metallic chemical element carbon is present in the coating layer at a concentration in the range of 0.10 to 1 at.%. In particular, the non-metallic chemical element nitrogen is present in the coating layer at a concentration in the range of 0.10 to 1 at.%. In particular, the non-metallic chemical element fluorine is present in the coating layer at a concentration of up to a maximum of 0.5 at.%.

[0037] In particular, a top layer has proven effective which a) comprising at least 99 atm% iridium and further comprising carbon; or b) comprises at least 99 atm% iridium and furthermore carbon and trace amounts of oxygen and / or hydrogen; or c) comprising at least 99 at% iridium and further carbon and fluorine, optionally also trace oxygen and / or hydrogen; or d) comprising in total at least 15 to 98.9 atm% iridium and 0.1 to 84 atm% ruthenium and furthermore carbon; or e) comprising in total at least 15 to 98.9 atm% iridium and 0.1 to 84 atm% ruthenium, and furthermore carbon and traces of oxygen and / or hydrogen; or f) comprising in total at least 15 to 98.9 at% iridium and 0.1 to 84 at% ruthenium and furthermore carbon and fluorine, optionally further comprising traces of oxygen and / or hydrogen.

[0038] Furthermore, the top layer can contain at least one chemical element from the group of base metals. This at least one chemical element from the group of base metals is preferably formed by aluminum, iron, nickel, cobalt, zinc, cerium, or tin and / or is present in the coating in a concentration range of 0.005 to 0.01 at%.

[0039] In a further advantageous embodiment of the coating layer, it comprises at least one chemical element from the group of refractory metals, in particular titanium and / or zirconium and / or hafnium and / or niobium and / or tantalum. It has been shown that the addition of these refractory metals also partially controls the amount of H₂O₂ and ozone produced during electrolysis.

[0040] Another advantage of using these metals - either in their elemental form or in the form of compounds - is that they form self-protecting, stable and conductive oxides under corrosion conditions.

[0041] The coating, comprising at least one refractory metal, exhibits high conductivity and high corrosion resistance, particularly in a temperature range of 0 to approximately 200 °C. This results in outstanding properties for continuous use in applications such as fuel cells.

[0042] The at least one chemical element from the group of refractory metals is preferably contained in the top layer in the concentration range of 0.005 to 0.01 at%.

[0043] If at least one chemical element from the group of base metals is present in the form of tin, then this element and at least one chemical element from the group of refractory metals are together contained in the top layer in a concentration range of 0.01 to 0.2 at%.

[0044] It has proven beneficial if the top layer also contains at least one additional chemical element from the group of precious metals in a concentration range of 0.005 to 0.9 atm%. The chemical element from the group of precious metals is, in particular, platinum, gold, silver, rhodium, and palladium.

[0045] It has proven effective if all chemical elements from the group of precious metals, i.e. together with iridium and ruthenium, are contained in the top layer in a concentration range of greater than 99 at%.

[0046] The problem is solved for a fuel cell stack comprising at least two fuel cells, in particular polymer electrolyte fuel cells, by manufacturing the fuel cell stack according to the inventive method. This results in functional stacks that can be manufactured particularly quickly and can therefore also serve as prototypes. A fuel cell stack according to the invention, especially with polymer electrolyte fuel cells, has proven to be particularly advantageous with regard to its electrical properties and corrosion resistance.

[0047] The at least one solid metallic component is preferably designed as a component of the type of a bipolar plate and / or an electrode and / or a current transmission device and / or a gas guidance device and / or a coolant guidance device and / or an end plate.

[0048] In particular, a fuel cell stack contains at least two solid metallic components of different types. Specifically, 3D-printed, coated end plates, used to clamp the cells of a stack, are used in combination with 3D-printed, coated current-carrying devices. Furthermore, 3D-printed, coated end plates may be used in combination with 3D-printed, coated bipolar plates.

[0049] A fuel cell stack comprising several bipolar plates with a coating including a base layer system and a top layer has proven effective.

[0050] The fuel cell stack can include, in particular, low-temperature polymer electrolyte fuel cells or high-temperature polymer electrolyte fuel cells.

[0051] A solid metallic component comprises a metallic support component and a layer system applied to at least some areas of the support component's surface. In particular, the layer system is applied across the entire surface of one or both sides of a plate-shaped support component.

[0052] The metallic support component is made in particular of steel or titanium, preferably of stainless steel.

[0053] The thickness of a support component, for example for a bipolar plate, is preferably less than 1 mm and is in particular less than or equal to 0.5 mm.

[0054] Advantageously, a thickness of less than 10 nm for the topcoat is sufficient to protect against resistance-increasing oxidation of the second undercoat layer. To ensure reliable corrosion protection, sublayers of the undercoat system are formed from at least one refractory metal, applied in at least two layers to the steel, particularly stainless steel: first as a metal or alloy layer (first undercoat layer) and then as a metalloid layer (second undercoat layer). This double layer beneath the topcoat ensures, on the one hand, electrochemical adaptation to the substrate material, i.e., the material from which the substrate is formed, and on the other hand, prevents pore formation due to oxidation and hydrolysis processes.

[0055] Electrochemical adaptation to the substrate material is necessary because both the metalloid layer (second substrate layer) and the top layer are very noble metals. If pores were to form, high local cell potentials would build up, resulting in unacceptable corrosion currents. The metallic first substrate layer is preferably made of titanium, niobium, zirconium, tantalum, or hafnium, or alloys of these metals, which are less noble than the substrate material, particularly steel, and initially react during corrosion processes to form insoluble oxides or voluminous, sometimes gel-like, hydroxo compounds of these refractory metals. This process closes the pores and protects the base material from corrosion. The process represents a self-healing mechanism of the coating system.

[0056] In particular, a second substrate layer in the form of a nitride layer serves as a hydrogen barrier and thus protects the substrate, especially made of stainless steel, the bipolar plate as well as the metallic first substrate layer from hydrogen embrittlement.

[0057] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and the Fig. 1 and Fig. 2. This shows Fig. 1 a solid component and Fig. 2 schematically a fuel cell stack.

[0058] Fig.Figure 1 shows a solid component 1 comprising a metallic support component 2 formed by an additive manufacturing process, here made of stainless steel, and a layer system 3 applied over the entire surface of one side of the support component 2. The layer system 2 comprises a top layer 3a and a base layer system 4 comprising a first base layer 4a and a second base layer 4b.

[0059] In a first embodiment, the metallic support component 2 in the form of a conductor, here for a bipolar plate of a polymer electrolyte fuel cell for the conversion of (reformed) hydrogen, is made of a stainless steel, in particular of a so-called authentic steel with very high known requirements regarding corrosion resistance, e.g. with the DIN ISO material number 1.4404.

[0060] Using a coating process, for example a vacuum-based deposition process (PVD), the layer system 3 is formed on the 3D-printed substrate 2. In a single process step, the substrate 2 is first coated with a 0.5 µm thick titanium layer, then with a 1 µm thick titanium nitride layer, and finally with a 10 nm thick iridium-carbon layer (top layer 3a). The top layer 3a is open on one side, as only one surface of the top layer is in contact with the second substrate layer 4b.

[0061] In a second embodiment, the 3D-printed metallic support component 2 is first coated with a first substrate layer 4a in the form of a metallic alloy layer with a thickness of 100 nm, wherein the metallic alloy layer has the composition Ti 0,67 Note 0,33 exhibits. Subsequently, a second substrate layer 4b with a thickness of 400 nm of the composition (Ti) is applied. 0,67 Note 0,33 ) 1-x N x with x=0.40 - 0.55. A top layer 3a with a thickness of 10 nm and a composition of iridium-carbon is applied to this.

[0062] The advantage lies in the exceptionally high resistance to oxidation of the solid component 1. Even when used as a bipolar plate with a continuous load of +3000 mV compared to a standard hydrogen electrode, no increase in resistance is observed in a sulfuric acid solution with a pH of 3. Externally, the free surface of the cover layer 3a, i.e., the area of ​​the cover layer 3a facing away from the support component 2, remains silvery-white even after 50 hours of continuous load at +2000 mV compared to a standard hydrogen electrode. Even under a scanning electron microscope, no corrosion traces extending through the thickness of the cover layer 3a towards or reaching the support component 2 are visible.

[0063] The top layer 3a of the second embodiment can be applied using both vacuum-based PVD sputtering technology and a cathodic arc coating process, also known as vacuum arc evaporation. Despite a higher number of droplets, in other words, an increased number of metal droplets compared to sputtering technology, the top layer 3a produced using the cathodic arc coating process also exhibits the advantageous properties of high corrosion resistance and stable surface conductivity compared to the top layer 3a produced using sputtering technology.

[0064] In a third embodiment not according to the invention, the layer system 3 is formed on a 3D-printed support component 2 in the form of a structured stainless steel perforated sheet. The support component 2 is electrolytically polished in an H2SO4 / H3PO4 bath prior to the application of the layer system 3. After the application of a single base layer in the form of a tantalum carbide layer several thousand nm thick, a top layer 3a in the form of an iridium-carbon layer several hundred nm thick is applied.

[0065] The advantage of the tantalum carbide substrate layer lies not only in its exceptional corrosion resistance but also in the fact that it does not absorb hydrogen and thus serves as a hydrogen barrier for the support component 2. This is particularly advantageous if titanium is used as the material for the support component.

[0066] The advantage of the metalloid layer interposed and / or closed on both sides in the layer system, or of the second substrate layer, which in the simplest case is formed, for example, from titanium nitride, is its low electrical resistance of 10-12 mΩ cm. -2 . Likewise, the top layer can also be formed without a second underlayer or metalloid layer, potentially increasing resistance.

[0067] For gas or coolant guidance systems, such as those formed with a 3D-printed stainless steel support component 2, a coating in the form of a simple two-layer system has proven effective. This system consists of a first base layer of titanium and a second base layer of TiC applied to the support component. A further top layer is not required.

[0068] Fig.Figure 2 schematically shows a fuel cell stack 10 comprising a plurality of fuel cells 20 electrically connected in series. The fuel cells 20 are clamped together via end plates 30, 31. Fuel gas 50, for example in the form of hydrogen, and air 60 as an oxygen carrier are supplied in the area of ​​the end plates 30, 31, and exhaust gas 70 and water 80 are discharged. The current generated in the fuel cell stack 10 is conducted away via current feedthroughs 40, 41. At least two bipolar plates are typically provided per fuel cell 20. The at least one solid metallic component 1 (compare Figure 2) Fig.1) can be designed as a component of the type of a bipolar plate of the fuel cells 20 and / or an electrode and / or a current-carrying device 40, 41 and / or a media guide device for media, here in the form of fuel gas 50, air 60, exhaust gas 70, water 80 or coolant 90, and / or an end plate 40, 41. At least one solid metallic component can also be used in a humidifier unit (not shown here) that is connected to a fuel cell stack.

[0069] Table 1 shows some example layer systems with their characteristic values. Table 1: Layers and selected characteristic values Layer system / layer thickness Specific surface resistance in mΩ / cm -2 at T = 20°C Corrosion current at V standard hydrogen column in µA cm -2 aqueous sulfuric acid solution (pH=3) at T=80°C Oxidation stability at 2000 mV measured as change in surface resistance in mΩ cm -2 Target value: < 20 mΩ cm -2 1 Gold / 3 µm (as reference) 9 > 100 Pittingstrom 9 -10 2 Ti / 0.5 µmTiN / 1 µmIr 0.99 - C 0,01 / 10nm 8 0,001 12 3 You 0.67 Nb 0.33 / 0.1 μm(Ti 0,67 Nb 0,33 ) 1-x N x mitx = 0.40 − 0.55 / 0.4 μmIr 0,99 - C 0,01 / 10 nm 7-8 0,01 1-2 4 Zr / 0,5 µmZrN / 1 µmIr 0,99 - C 0,01 / 10 nm 11 0,001 11-12 5 Ta / 0.05 µmTaC / 0.5 µmIr 0,991- C 0,009 / 5 nm 10 0,001 17-18 3 ZrB2 / 0,3 µmIr 0,7 - B 0,3 / 5 nm 7 Pitting reaction after 4h stress

[0070] Table 1 shows only a few exemplary coating systems. Advantageously, the coating systems according to the invention show no increase in resistance under anodic loading of +2000 mV relative to a normal hydrogen column in sulfuric acid solution at a temperature of 80 °C for several weeks. The coating systems applied in high vacuum using a sputtering or ARC process, or in a fine vacuum using a PECVD process (plasma-enhanced chemical vapor deposition) or an ALD process (atomic layer deposition), were partially discolored after this loading period. However, no visible signs of corrosion or significant changes in surface resistance occurred. Reference symbol list 1 solid component 2 Support component 3-layer system 3a Top layer 4-layer system 4a first layer of documents 4b second layer of documents 10 fuel cell stack 20 fuel cells 30, 31 End plate 40, 41 Current feedthrough arrangement 50 Fuel gas 60 air 70 exhaust gas 80 water 90 Coolant

Claims

[1] Method for manufacturing a fuel cell stack (10), in particular for a prototype of a fuel cell stack (10), which comprises at least one metallic solid component (1) formed from a support component (2) and furthermore an at least partial coating for the support component (2), wherein the solid component (1) is arranged to come into direct contact, at least in the area of ​​the coating, with at least one of the media which are supplied to and / or discharged from the fuel cell stack (10), comprising the following steps: a) Manufacturing the respective support component (2) using an additive manufacturing process; and b) Applying the coating to the respective substrate (2) by means of a physical and / or chemical vapor deposition process, wherein the coating is formed as an at least two-layer system (3), wherein the system (3) comprises at least one substrate layer (4a, 4b) comprising at least one chemical element from the group consisting of titanium, niobium, hafnium, zirconium, tantalum, and a top layer (3a) facing away from the substrate (2), and wherein the system (3) comprises at least one first substrate layer (4a) facing the substrate (2) in the form of a metallic alloy layer comprising the chemical elements titanium and niobium, and further comprises at least one second substrate layer (4b) facing away from the substrate (2) comprising at least one chemical element from the group consisting of titanium, niobium, hafnium, zirconium,Tantalum and furthermore comprising at least one non-metallic element from the group nitrogen, carbon, boron, fluorine. [2] Method according to claim 1, wherein the top layer (3a) is formed from a homogeneous or heterogeneous solid metallic solution which either contains a first chemical element from the group of noble metals in the form of iridium in a concentration of at least 99 at% or contains a first chemical element from the group of noble metals in the form of iridium and a second chemical element from the group of noble metals in the form of ruthenium, wherein the first chemical element and the second chemical element are together present in a concentration of at least 99 at%, and furthermore contains at least one non-metallic chemical element from the group comprising nitrogen, carbon, fluorine, furthermore optionally oxygen and / or hydrogen are present only in trace amounts. [3] Method according to claim 2, wherein the at least one non-metallic chemical element of the cover layer (3a) is provided in a concentration in the range of 0.1 to 1 at% in the cover layer (3a). [4] Method according to any one of claims 1 to 3, wherein fluorine is contained as a non-metallic chemical element in the concentration range up to a maximum of 0.5 at% in the cover layer (3a). [5] Method according to any one of claims 1 to 4, wherein the additive manufacturing process is carried out by means of a 3D printing process, in particular by selective laser melting (SML), electron beam melting (EBM) or selective laser sintering. [6] Method according to any one of claims 1 to 4, wherein the additive manufacturing process is carried out using a 3D screen printing process. [7] Fuel cell stack (10) comprising at least two fuel cells (20), in particular polymer electrolyte fuel cells, wherein the fuel cell stack (10) is manufactured according to a method according to any one of claims 1 to 6. [8] Fuel cell stack (10) according to claim 7, wherein the at least one metallic solid component (1) is designed as a component of the type of a bipolar plate and / or an electrode and / or a current transmission device and / or a media conduction device and / or an end plate. [9] Fuel cell stack (10) according to claim 8, wherein at least two metallic solid components (1) of different types are present. [10] Fuel cell stack (10) according to one of claims 7 to 9, wherein it comprises several solid components (1) of the bipolar plate type with a coating according to claim 1.

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