Fuel cell device and method for producing a fuel cell device

Abstract

The invention relates to a fuel cell device (10) and to a method for producing such a fuel cell device (10), comprising at least one component (14, 18, 36, 39), in particular a processor unit (14), preferably a heat exchanger (18, 36, 39), which is at least partly made of steel. The steel of the at least one component (14, 18, 36, 39) is intended to be at least partly covered, preferably coated, with a metal material (56) and / or a ceramic material (58).

Description

[0001] Description

[0002] Title of a

[0003] The present invention relates to a fuel cell device and to a method for producing a fuel cell device, wherein at least one component, in particular a processor unit, preferably a heat exchanger, of the fuel cell device is at least partially made of steel.

[0004] State of the art

[0005] Fuel cell devices are known from the prior art which comprise at least one processor unit, such as a heat exchanger, wherein the processor units are made of steel.

[0006] Disclosure of the invention

[0007] The present fuel cell device with the features of the main claim has the advantage that the steel of the at least one component is at least partially covered, preferably coated, with a metallic material and / or a ceramic material.

[0008] In the context of this invention, a “component” is to be understood as meaning in particular a unit and / or a component of the fuel cell device.

[0009] For the purposes of this invention, a "unit" is understood to mean, in particular, a processor unit and / or a fuel cell unit. In particular, a fuel cell unit is a fuel cell stack and / or a fuel cell.

[0010] Preferably, a fuel cell stack comprises a plurality of fuel cells.

[0011] In the context of this invention, a "processor unit" is to be understood in particular as a unit or component of the fuel cell device that is not a fuel cell unit, or a fuel cell and / or a fuel cell stack. In particular, the processor unit is one for the, preferably 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, such as a fuel gas, air, and / or an exhaust gas. The processor unit is preferably a reformer, an afterburner, and / or a heat exchanger.

[0012] In the context of the invention, a “component” is to be understood in particular as a prefabricated and / or prefabricated section for the construction of the fuel cell device. Such a section can be comprised by a unit of the fuel cell device and / or correspondingly be a section of a unit. For example, it can be a section of a fuel cell unit, such as a (support) plate of a fuel cell stack. However, such a section can also not be comprised by a unit and / or, for example, be a section of the fuel cell device outside of a unit. For example, it can be a section that connects different units, such as a pipe for media routing.

[0013] The features listed in the subclaims enable advantageous developments of the invention according to the main claim.

[0014] It is advantageous if the metallic material comprises aluminium (Al), nickel (Ni), titanium (Ti), cobalt (Co), silicon (Si), copper (Cu) and / or manganese (Mn) and / or the ceramic material comprises an oxide, a nitride and / or a carbide, in particular of the metallic material, preferably aluminium oxide (Al2O3), silicon nitride (SisNzi) and / or titanium carbide (TiC).

[0015] In an advantageous embodiment, the at least one component, in particular the processor unit, preferably comprises the heat exchanger, between which heat transfer is provided, wherein at least one of the at least two media guide spaces is covered, preferably coated, with the metallic material and / or the ceramic material. It is advantageous if the at least one media guide space covered, preferably coated, with the metallic material and / or the ceramic material is provided to guide a medium, in particular air, to be supplied to a fuel cell unit.

[0016] It is also advantageous if the at least one media guide space covered, preferably coated, with the metallic material and / or the ceramic material is provided to guide a medium, in particular exhaust gas, to be discharged from a fuel cell unit.

[0017] It is also advantageous if both of the at least two media guide spaces are covered, preferably coated, with the metallic material and / or the ceramic material.

[0018] The present method for producing a fuel cell device, in particular a fuel cell device according to the preceding description, has the advantage over the prior art that the steel of the at least one processor unit is at least partially covered, preferably coated, with a metallic material and / or a ceramic material.

[0019] In an advantageous embodiment, the metallic material is at least partially oxidized, nitrided and / or carbidized before the assembly of the at least one processor unit, in particular to the ceramic material.

[0020] Preferably, the metallic material is at least partially oxidized, nitrided and / or carbidized by a thermal treatment, preferably in a furnace.

[0021] In a further advantageous embodiment, the metallic material is at least partially oxidized, nitrided and / or carbidized after the assembly of the at least one processor unit, in particular to the ceramic material.

[0022] Preferably, the metallic material is at least partially oxidized, nitrided, and / or carbidized during operation, particularly during initial operation, of the fuel cell device. The present invention makes it possible to simplify the manufacture of a fuel cell device and improve the operating characteristics of a fuel cell device. In particular, a simpler and more cost-effective fuel cell device can be provided in which power loss over the service life of the fuel cell device is reduced, while simultaneously increasing operational reliability and protecting the environment.

[0023] Drawings

[0024] An embodiment of the invention is shown schematically in the drawings and explained in more detail in the following description.

[0025] Fig. 1 is a schematic circuit diagram of an embodiment of a fuel cell device,

[0026] Fig. 2 is a schematic representation of a cross section of a heat exchanger of the embodiment of the fuel cell device from Fig. 1.

[0027] Description of the embodiments

[0028] Fig. 1 shows a schematic circuit diagram of an exemplary embodiment of a fuel cell device 10. The fuel cell device 10 comprises two fuel cell units 12. In the exemplary embodiment shown, the fuel cell units 12 are designed as fuel cell stacks comprising a plurality of fuel cells, in this case solid oxide fuel cells (SOFCs). Furthermore, the fuel cell device 10 comprises a plurality of processor units 14.

[0029] In the context of this invention, a "processor unit" is understood to mean, in particular, a unit or component of the fuel cell device 10 that is not a fuel cell unit 12, or a fuel cell stack and / or a fuel cell. In particular, the processor unit 14 is a unit for the, preferably 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, such as, for example, a fuel B, RB, air L, and / or an exhaust gas A, KA, AA. The processor unit 14 is preferably a reformer 26, an afterburner 28, and / or a heat exchanger 18, 36, 39.

[0030] One of the processor units 14 is a heat exchanger 18 arranged in an air supply 16 for heating oxygen-containing air L supplied to the fuel cell units 12. In the present case, the air L is supplied, for example, during normal operation, to a cathode chamber 20 of the fuel cell units 12, while reformed fuel RB, in this case hydrogen, is supplied to an anode chamber 22. In the fuel cell units 12, the reformed fuel RB is electrochemically converted with the aid of oxygen from the air L, generating electricity and heat.

[0031] The reformed fuel RB is produced by supplying fuel B, in this case natural gas, to the fuel cell device 10 via a fuel supply 24, which fuel B is reformed in a further processor unit 14, in this case a reformer 26.

[0032] Furthermore, the fuel cell units 12 are connected on the exhaust side to another processor unit 14, in this case to an afterburner 28. Exhaust gas from the fuel cell units 12 is supplied to the afterburner 28, in this 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 cathode exhaust gas KA contains unused air L or unused oxygen, while the anode exhaust gas AA contains any unreacted, reformed fuel RB and / or any unreformed fuel B. By means of the afterburner 28, the anode exhaust gas AA, or the unreacted, reformed fuel RB possibly contained therein and / or the non-reformed fuel B possibly contained therein, is combusted with the admixture of the cathode exhaust gas KA, or the oxygen of the air L contained therein, whereby additional heat can be generated.

[0033] The hot exhaust gas A produced during combustion in the afterburner 28 is discharged from the afterburner 28 via an exhaust gas duct 34 via a further processor unit 14, in this case via a heat exchanger 36. The heat exchanger 36 is in turn fluidly connected to the reformer 26, so that heat is transferred from the hot exhaust gas A to the fuel B fed to the reformer 26. Accordingly, the heat of the hot exhaust gas A can be used to reform the supplied fuel B in the reformer 26. Downstream of the heat exchanger 36 there is a further processor unit 14, in this case the heat exchanger 18, 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 supply 16. Accordingly, the remaining heat of the hot exhaust gas can be used to preheat the supplied air L in the air supply 16.

[0034] Furthermore, the fuel cell device 10 has a return line 38, by means of which a portion of the anode exhaust gas AA can be diverted from the anode exhaust gas line 32 and fed to an anode recirculation circuit 40. The diverted anode exhaust gas AA passes through a further processor unit 14, in this case a further heat exchanger 39.

[0035] By means of the anode recirculation circuit 40, the branched portion of the anode exhaust gas AA can be returned or recirculated to the respective anode chamber 22 of the fuel cell units 12 and / or to the reformer 26, so that any unreacted, reformed fuel RB contained in the branched anode exhaust gas AA can subsequently be converted in the fuel cell unit 12 and / or any unreformed fuel B contained in the branched anode exhaust gas AA can subsequently be reformed in the reformer 26. This can further increase the efficiency of the fuel cell device 10. Furthermore, fresh fuel B can be admixed to the branched anode exhaust gas AA recirculated in the anode recirculation circuit 40 via the fuel supply line 24.By means of the further heat exchanger 39, heat can then be transferred from the branched anode exhaust gas AA from the return line 38 to the fuel mixture in the anode recirculation circuit 40 resulting from the addition of the fresh fuel B for thermal processing.

[0036] Via compressors 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 coordinated with one another.

[0037] To ensure a stable design of the components of the fuel cell device 10, in the exemplary embodiment shown in particular the processor units 14, such as the heat exchangers 18, 36 and / or 39, these are at least partially made of steel, in the present case completely in a first step. In the exemplary embodiment shown, the steel is, in particular, temperature-resistant, stainless steel. The present fuel cell device 10 is characterized in that the steel of at least one component of the fuel cell device, in the exemplary embodiment shown the steel of at least one of the processor units 14, is at least partially covered, in the case shown coated, with a metallic material 56 and / or a ceramic material 58.

[0038] In the illustrated embodiment, the metallic material 56 can also be understood as a metallic layer 56. In the illustrated embodiment, the ceramic material 58 can also be understood as a ceramic layer 58.

[0039] The metallic material may comprise aluminum (Al), nickel (Ni), titanium (Ti), cobalt (Co), silicon (Si), copper (Cu), and / or manganese (Mn). In the case shown, the metallic material comprises aluminum (Al).

[0040] The ceramic material may comprise an oxide, a nitride, and / or a carbide, in this case the metallic material, for example, aluminum oxide (Al2O3), silicon nitride (SiNzi), and / or titanium carbide (TiC). In the case shown, the ceramic material comprises aluminum oxide (Al2O3).

[0041] The metallic material 56 and / or the ceramic material 58, in this case aluminum (Al) and aluminum oxide (Al2O3), can significantly reduce the release of chromium from the steel of at least one of the components of the fuel cell device 10 (so-called chromium evaporation) during operation of the fuel cell device 10. This, in turn, makes it possible to reduce power losses over the service life of the fuel cell device 10 and simultaneously increase the operational reliability of the fuel cell device 10.

[0042] In the embodiment shown, the processor units 14, in the present case the heat exchangers 18 and 36, comprise at least two media guide spaces 50, between which heat transfer is provided.

[0043] Accordingly, Fig. 2 shows a schematic representation of a cross section of a heat exchanger 18 of the exemplary embodiment of the fuel cell device 10 from Fig. 1. In the exemplary embodiment shown, the heat exchanger 18 comprises two media guide spaces 50, specifically a first media guide space 52 and a second media guide space 54.

[0044] At least one of the at least two media guide spaces 50, in the case shown the first media guide space 52, is covered, preferably coated, with the metallic material 56 and / or the ceramic material 58, in the case shown with aluminum (Al) and / or aluminum oxide (Al2O3). Within the scope of the invention, this can also be understood in particular to mean that a wall 60 of the media guide space 50, preferably on the inside with respect to a media guide, is covered, preferably coated, with the metallic material 56 and / or the ceramic material 58, in the case shown with aluminum (Al) and / or aluminum oxide (Al2O3). This makes it possible to specifically reduce chromium evaporation in a media guide space 50. Thus, a chromium content in a corresponding media flow of the fuel cell device 10 can be specifically reduced.

[0045] In the case shown, one of the at least two media guide spaces 50, in this case the first media guide space 52, is at least substantially completely covered or coated with the metallic material 56 and / or the ceramic material 58, or with the aluminum (Al) and / or the aluminum oxide (Al2O3).

[0046] In the exemplary embodiment shown, the at least one media guide chamber 50 covered, preferably coated, with the metallic material 56 and / or the ceramic material 58, in the case shown the first media guide chamber 52, is intended to guide a medium B, RB, L, in this case air L, to be supplied to a fuel cell unit 12. In this way, it is possible to specifically prevent chromium evaporation from taking place in the first media guide chamber 52 of the heat exchanger 18 during operation of the fuel cell device 10 and the chromium released thereby from entering the fuel cell unit 12 via the media flow to be supplied to the fuel cell unit 12, in this case the air flow. Accordingly, chromium enrichment in the fuel cell unit 12 can be at least substantially prevented, which in turn reduces power losses in the fuel cell unit 12 caused by chromium enrichment.

[0047] In an alternative exemplary embodiment, which is not illustrated, it would also be possible for the at least one media guide chamber 50 covered, preferably coated, with the metallic material 56 and / or the ceramic material 58, in particular with aluminum (Al) and / or aluminum oxide (Al2O3), to be provided to guide a medium A, AA, KA, in particular exhaust gas A, to be discharged from the fuel cell unit 12. Within this framework, it would be possible for the second media guide chamber 54 of the heat exchanger 18 to be covered, preferably coated, with the metallic material 56 and / or the ceramic material 58, in particular with aluminum (Al) and / or aluminum oxide (Al2O3).Within this framework, however, it would also be possible for the media guide chamber of the heat exchanger 36, which carries the exhaust gas A, to be covered, preferably coated, with the metallic material 56 and / or the ceramic material 58, in particular with aluminum (Al) and / or aluminum oxide (Al2O3). In both cases, it is possible to specifically prevent chromium evaporation from taking place in the corresponding media guide chamber of the heat exchanger 18 or 36 during operation of the fuel cell device 10, and for any chromium released thereby to escape from the fuel cell device 10, in particular into the atmosphere, via the media flow to be discharged from the fuel cell unit 12, in this case the exhaust gas flow. Accordingly, the risk of chromium accumulation in the atmosphere can be reduced, which in turn increases safety and also protects the environment.

[0048] In a further alternative embodiment, which is not illustrated, it would also be possible for both of the at least two media guide spaces 50 of the heat exchanger 18 to be covered, preferably coated, with the metallic material 56 and / or the ceramic material 58, in particular with aluminum (Al) and / or aluminum oxide (Al2O3). This can reduce both power losses in the fuel cell unit 12 caused by chromium enrichment and the risk of chromium accumulation in the atmosphere, increasing safety and protecting the environment.

[0049] For the exemplary embodiment shown, at least one of the components of the fuel cell device, in the case shown at least one of the processor units 14, in this case the heat exchanger 18, specifically the first media guide space 52, is coated with the metallic material 56, for the exemplary embodiment shown with aluminum (Al), before assembly of or into the fuel cell device 10.

[0050] Within the scope of the invention, it is now possible for the metallic material 56 to be at least partially oxidized, nitrided, and / or carbidized prior to assembly of the at least one component, in the case shown, the at least one processor unit 14, presently the heat exchanger 18. Specifically, in the case shown, the aluminum (Al) would be oxidized to aluminum oxide (Al2O3). This would enable a cost-effective method for forming a ceramic material 58 on the steel of a processor unit 14.

[0051] It is conceivable that the metallic material 56 is at least partially oxidized, nitrided, and / or carbidized by a thermal treatment, for example, in a furnace. This would enable a particularly cost-effective method for forming a ceramic material 58 on the steel of a processor unit 14 in the case shown.

[0052] For the exemplary embodiment shown, however, the metallic material 56, or the aluminum (Al), is alternatively oxidized, nitrided, and / or carbidized, at least partially after assembly of the at least one component, or processor unit 14, in the present case of the heat exchanger 18. This makes it possible to eliminate the step of oxidizing, nitriding, and / or carbidizing, for example, in a furnace, which in turn simplifies the manufacture of the fuel cell device 10.

[0053] For the exemplary embodiment shown, the metallic material 56 is at least partially, in the present case substantially, oxidized, nitrided, and / or carbidized during operation, or initial operation, of the fuel cell device 10. Specifically, in the present case, the aluminum (Al) is oxidized to aluminum oxide (Al2O3) during operation, or initial operation, of the fuel cell device 10. This also involves a thermal treatment, and it occurs during operation, or initial operation, of the fuel cell device 10. This can particularly simplify the manufacture of the fuel cell device 10.

[0054] Accordingly, the fuel cell device 10 of the illustrated embodiment comprises a component, in the illustrated case a processor unit 14, specifically a heat exchanger 18, which is at least partially covered or coated with both the metallic material 56, or aluminum (Al), and the ceramic material 58, or aluminum oxide (Al2O3), but at different times. Thus, in the illustrated embodiment, the component or processor unit 14, in this case the heat exchanger 18, is coated only with the metallic material 56, or aluminum (Al), before and during assembly of or into the fuel cell device 10. After operation, or initial operation, of the fuel cell device 10, or after oxidation, nitriding, and / or carbidization of the metallic material 56, the component or processor unit 14 isThe processor unit 14, in this case the heat exchanger 18, is coated only with the ceramic material 58, or aluminum oxide (Al2O3), in the illustrated embodiment. Accordingly, the operation, or rather the initial operation, of the fuel cell device 10 can still be understood as part of the method for manufacturing the fuel cell device 10.

[0055] In both cases of thermal treatment, before assembly, e.g. in a furnace, or during operation of the fuel cell device 10, this is advantageously carried out in a temperature range between 350 °C and 1100 °C, in particular between 500 °C and 950 °C, preferably at a temperature of 850 °C.

[0056] During a thermal treatment in a temperature range between 500 °C and 950 °C, an advantageous oxidation, nitriding and / or carbidization, in the present case of at least 70%, of the metallic material 56 to the ceramic material 58, in particular the oxidation of the aluminum (Al) to the aluminum oxide (Al2O3), is achieved.

[0057] During a thermal treatment at a temperature of 850 °C, a particularly advantageous oxidation, nitriding and / or carbidization of almost the entire metallic material 56, in this case at least 90% of the metallic material 56, to the ceramic material 58, in particular the oxidation of the aluminium (Al) to the aluminium oxide (Al2O3), is achieved.

[0058] In the illustrated embodiment, the steel covered or coated by the metallic material 56 or metallic layer 56 has a thickness of 100 μm, while the metallic material 56 or metallic layer 56 has a thickness of 1-2 μm. During oxidation, nitriding, and / or carbidization of the metallic material 56 or metallic layer 56, its thickness is reduced, so that the resulting ceramic material 58 or ceramic layer 58 has a thickness of 0.5-2 μm. This forms a sufficiently thick ceramic layer 58, which particularly advantageously avoids the previously explained chromium evaporation.

Claims

Claims 1. Fuel cell device (10), comprising at least one component (14, 18, 36, 39), in particular a processor unit (14), preferably a heat exchanger (18, 36, 39), which is at least partially made of steel, characterized in that the steel of the at least one component (14, 18, 36, 39) is at least partially covered, preferably coated, with a metallic material (56) and / or a ceramic material (58).

2. Fuel cell device (10) according to claim 1, characterized in that the metallic material (56) comprises aluminum (Al), nickel (Ni), titanium (Ti), cobalt (Co), silicon (Si), copper (Cu) and / or manganese (Mn) and / or the ceramic material (58) comprises an oxide, a nitride and / or a carbide, in particular of the metallic material (56), preferably aluminum oxide (Al2O3), silicon nitride (Si5Nzi) and / or titanium carbide (TiC).

3. Fuel cell device (10) according to one of claims 1 or 2, characterized in that the at least one component (14, 18, 36, 39), in particular the processor unit (14), preferably the heat exchanger (18, 36, 39), comprises at least two media guide spaces (50, 52, 54) between which heat transfer is provided, wherein at least one of the at least two media guide spaces (50, 52, 54) is covered, preferably coated, with the metallic material (56) and / or the ceramic material (58).

4. Fuel cell device (10) according to claim 3, characterized in that the at least one media guide space (52) covered, preferably coated, with the metallic material (56) and / or the ceramic material (58) is provided to guide a medium (B, RB, L), in particular air (L), to be supplied to a fuel cell unit (12). Fuel cell device (10) according to claim 3 or 4, characterized in that the at least one media guide chamber covered, preferably coated, with the metallic material (56) and / or the ceramic material (58) is provided for guiding a medium (A, AA, KA), in particular exhaust gas (A), to be discharged from a fuel cell unit. Fuel cell device (10) according to claim 3, characterized in that both of the at least two media guide chambers (50, 52, 54) are covered, preferably coated, with the metallic material (56) and / or the ceramic material (58).Method for producing a fuel cell device (10), in particular a fuel cell device (10) according to one of the preceding claims, wherein at least one component (14, 18, 36, 39), in particular a processor unit (14), preferably a heat exchanger (18, 36, 39), of the fuel cell device (10) is at least partially formed from steel, characterized in that the steel of the at least one component (14, 18, 36, 39) is at least partially covered, preferably coated, with a metallic material (56) and / or a ceramic material (58). Method according to claim 7, characterized in that the metallic material (56) is at least partially oxidized, nitrided, and / or carbidized before assembly of the at least one component (14, 18, 36, 39), in particular to form the ceramic material (58).Method according to claim 8, characterized in that the metallic material (56) is at least partially oxidized, nitrided, and / or carbidized by a thermal treatment, preferably in a furnace. Method according to claim 7, characterized in that the metallic material (56) is at least partially oxidized, nitrided, and / or carbidized after assembly of the at least one component (14, 18, 36, 39), in particular to the ceramic material (58). Method according to claim 10, characterized in that the metallic material (56) is at least partially oxidized, nitrided and / or carbidized during operation, in particular initial operation, of the fuel cell device (10).

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