EP3596769A1

EP3596769A1 - Functionalized, porous gas guiding part for an electro-chemical module

Info

Publication number: EP3596769A1
Application number: EP18716884.4A
Authority: EP
Inventors: Christian BIENERT; Wolfgang SCHAFBAUER; Matthias Rüttinger
Original assignee: Plansee SE
Current assignee: Plansee SE
Priority date: 2017-03-16
Filing date: 2018-02-22
Publication date: 2020-01-22
Also published as: TW201836207A; CA3055590A1; US20200020957A1; AT15927U1; KR20190128188A; JP2020511754A; WO2018165683A1; CN110603677A

Abstract

The invention relates to a gas-guiding part (10, 10'), which is porous or at least porous in some sections, for an electro-chemical module (20). The electro-chemical module (20) has at least one electro-chemical cell unit (21) which has a layer structure (23) with at least one electro-chemically active layer, and a metallic, gas-tight housing (24; 25), which forms a gas-tight process gas chamber (26) with the electro-chemical cell unit (21). The housing (24; 25) extends on at least one side beyond the region of the electro-chemical cell unit (21), thereby forming a process gas-guiding chamber (27; 27'), which is open to the electro-chemical cell unit and has at least one gas passage opening (28; 28') for feeding and/or discharging the process gas in the region of the process gas guiding chamber (27; 27'). Thereby, the gas guiding part (10, 10) is adapted for arrangement inside the process gas-guiding chamber (27; 27) and the surface of said gas guiding part is functionalized for interaction with the process gas.

Description

FUNCTIONALIZED, POROUS GAS GUIDING PART FOR

ELECTROCHEMICAL MODULE

The present invention relates to a functionalized porous gas guide member for placement in an electrochemical module according to claim 1 and claim 4 and an electrochemical module according to claim 18.

The porous gas guide part according to the invention is in a

electrochemical module used, inter alia, as

High-oxide solid oxide fuel cell (SOFC), solid oxide electrolyzer cell (SOEC) and reversible solid oxide fuel cell (R-SOFC). In the basic configuration, an electrochemically active cell of the

electrochemical module, a gas-tight solid electrolyte, which is arranged between a gas-permeable anode and gas-permeable cathode. The electrochemically active components such as anode, electrolyte and cathode are often formed as comparatively thin layers. A thereby necessary mechanical support function can by one of

electrochemically active layers, e.g. through the electrolyte, the anode or the cathode, which are then each made correspondingly thick (in these cases we speak of an electrolyte, anode or cathode-supported cell), or by an electrolyte these functional layers separately formed component, such as a ceramic or metallic carrier substrate. In the latter concept with a separately formed, metallic

Carrier substrate is referred to as a metal supported cell (MSC). In an MSC, since the electrolyte whose electrical resistance decreases with decreasing thickness and with increasing temperature can be made comparatively thin (for example, with a thickness in the range of 2 to 10 μm), MSCs can be made comparatively low

Operating temperatures of about 600 ° C to 800 ° C (while, for example, electrolyte-supported cells are operated in part at operating temperatures of up to 1000 ° C). Because of their specific advantages, MSCs are

especially for mobile applications, such as for electrical Supply of passenger cars or commercial vehicles (APU - auxiliary power unit) suitable.

Usually, the electrochemically active cells are as flat

Individual elements formed, which in conjunction with appropriate

(Metallic) housing parts (such., Interconnector, frame plate, gas lines, etc.) are stacked on a stack and electrically contacted in series. Corresponding housing parts accomplish in the individual cells of the stack each separate supply of process gases, which in the case of a fuel cell, the supply of the fuel (for example, hydrogen or hydrocarbon-containing fuels such as natural gas or biogas) to the anode and the oxidant (oxygen, air) Means cathode, as well as the anode-side and cathode-side derivative of the gases produced during the electrochemical reaction. Relative to a single electrochemical cell, a process gas space is formed in each case within a stack on both sides of the electrolyte, it being of essential importance for the functioning of the stack that they are reliably separated from one another in a gas-tight manner. The stack can be in

closed construction, or, as exemplified in EP 1 278 259 B1

be described in open design, in which only one

Process gas space, in the case of a fuel cell, for example, the anode-side process gas space in which the fuel is supplied or the reaction product is discharged, is sealed gas-tight, while, for example, the

Oxidant flows through the stack freely.

In particular, in the operation of the electrochemical module as a fuel cell with hydrocarbonaceous fuels such as natural gas in the application of various challenges: The fuel cell is very sensitive to contamination of the fuel with, for example, sulfur or chlorine, which significantly affect the efficiency and lifetime and for what appropriate precautions must be taken , Of

Further, for the electrochemical reaction from the

hydrocarbon-containing fuel hydrogen gas can be generated. A industrially established process for this purpose is the steam reforming, in which in one Endothermic reaction of hydrogen is released and usually takes place in a stack upstream of the spatially separated apparatus. In addition to this external reforming a so-called internal reforming is known in which the hydrogen production and the electrochemical reaction take place together at the anode and to the reforming catalyst directly at the anode or at an MSC directly on the electrochemically active metallic carrier substrate, where the electrochemical reaction of Fuel cell takes place, is arranged. An example of this is given in US 2012/0121999 A1, in which the electrochemically active region of the carrier substrate is functionalized with a reforming catalyst. An advantage of

Linkage of these two reactions is due to direct heat transfer, since the electrochemical reaction is exothermic and the reforming is endothermic. However, disadvantages are possible

Carbon deposits or coking in the active region of the cell, in particular at the anode, which may affect the electrochemical functioning of the cell.

For high efficiency of the electrochemical module, it is important to uniformly supply the electrochemically active layers by the process gases, i. on the one hand a uniform supply of the educt gases or a uniform discharge of the resulting reaction gases. It should only occur the lowest possible pressure drop. The supply takes place within an electrochemical module in the horizontal direction by means of distribution structures, which are usually integrated in the interconnector.

Interconnectors, which also effect the electrical contacting of adjacent electrochemical cells, have for this purpose on both sides gas guiding structures, which may, for example, be knobbed or wavy. For many applications, the interconnector is formed by a correspondingly shaped, metallic sheet-metal part, which is designed to be as thin as possible, as far as possible, in the same way as other components in the stack for weight optimization. This can be mechanical

Stresses, such as occur during production or in the operation of the stack, especially at the edge easily to deformation or Cracks in welds lead, whereby the required gas tightness is at risk.

A uniform supply of hydrogen is particularly challenging in internal reforming, for example, as in US 2012/0121999 A1, since the formation of hydrogen depends on the flow of fuel gas and is also closely linked to the temperature distribution of the fuel cell.

The object of the present invention consists in the further development of an electrochemical module and in the provision of a gas guide part with which the performance of the electrochemical module or its

Lifetime is positively influenced.

This object is achieved by the gas guide part according to claim 1 and

Claim 4 and an electrochemical module according to claim 18 solved. Advantageous developments are specified in the dependent claims.

The gas guide part according to the invention is used for an electrochemical module, which is used as a high-temperature fuel cell or

Solid oxide fuel cell (SOFC), solid oxide electrolyzer cell (SOEC) and reversible

Solid oxide fuel cell (R-SOFC) can be used. The basic structure of such an electrochemical module has an electrochemical cell unit, which has a layer structure with at least one electrochemically active layer and can also include a carrier substrate. When

Electrochemically active layers are understood inter alia to be an anode, electrolyte or cathode layer, if appropriate the layer structure can also have further layers (made of, for example, cerium-gadolinium oxide between the electrolyte and the cathode). Not all of the electrochemically active layers must be present, but rather only one electrochemically active layer (for example the anode), preferably two

electrochemically active layers (eg anode and electrolyte), and the further layers, in particular those for completing an electrochemical cell unit, can only be applied later. The electrochemical cell unit can be used as electrolyte supported cell (electrolyte supported cell), anode supported cell (anode supported cell) or as Formed cathode-supported cell (the eponymous layer is made thicker and performs a mechanical supporting function). In a metal substrate-supported cell (MSC), a preferred embodiment of the invention, the layer stack is on a porous, plate-shaped, metallic support substrate having a preferred thickness, typically in the range of 170 μm to 1.5 mm, in particular in the range of 250 μm 800 pm, arranged in a gas-permeable, central region. The carrier substrate forms part of the electrochemical cell unit. The application of the layers of the layer stack is carried out in a known manner, preferably by means of PVD (PVD: Physical

Vapor phase deposition) such as e.g. by sputtering, and / or thermal coating method such as e.g. Flame spraying or plasma spraying and / or by wet chemical methods such. Screen printing, wet powder coating, etc., wherein for the realization of the entire layer structure of a

electrochemical cell unit also several of these methods can be combined. The anode is usually the electrochemically active layer following the carrier substrate, while the cathode is formed on the side of the electrolyte remote from the carrier substrate.

Alternatively, however, a reverse arrangement of the two electrodes is possible.

Both the anode (in an MSC, for example, formed from a composite consisting of nickel and yttria fully stabilized zirconia) and the cathode (in an MSC, for example formed from mixed conducting perovskites such as (La, Sr) (Co, Fe) 03) are gas permeable , Between the anode and the cathode, a gas-tight solid electrolyte made of a solid ceramic material of metal oxide (e.g., yttria) is fully stabilized

Zirconia) which is conductive to oxygen ions but not to electrons. Alternatively, the solid electrolyte may also be conductive to protons, which relates to a younger generation of SOFCs (e.g.

Solid electrolyte of metal oxide, in particular of barium-zirconium oxide, barium-cerium oxide, lanthanum-tungsten oxide or lanthanum-niobium oxide).

The electrochemical module further comprises at least one metallic gas-tight housing, which with the electrochemical cell unit a forms gas-tight process gas space. The process gas space is limited in the area of the electrochemical cell unit by the gas-tight electrolyte. On the opposite side of the process gas space is usually limited by the interconnector, which is considered in the context of the present invention as part of the housing. The interconnector is gas-tightly connected to the gas-tight element of the electrochemical cell unit, optionally in combination with additional housing parts, in particular circumferential frame plates or the like, which form the remaining delimitation of the process gas space. In MSCs, the gas-tight connection of the interconnector preferably takes place by means of soldering and / or soldering

Welded connections via additional housing parts, for example. Circumferential frame plates, which in turn are gas-tightly connected to the carrier substrate and so together with the gas-tight electrolyte gas-tight

Form process gas chamber. For electrolyte-supported cells, attachment may be by sintered connections or by application of sealant (e.g., glass solder).

In the context of the present invention, "gas-tight" means in particular that the leak rate with sufficient gas-tightness is by default <10 ³ hPa ^* dm ³ / cm ² s (hPa: hectopascal, dm ³ : cubic decimeter, cm ² : square centimeter, s: second) ( measured under air with pressure rise method with the measuring instrument of Dr. Wiesner, Remscheid, type: Integra DDV at a pressure difference dp = 100 hPa).

The housing extends on at least one side of the electrochemical cell unit beyond the region of the electrochemical cell unit and forms a subspace of the process gas space as a

electrochemical cell unit open process gas guidance room. Of the

Process gas space is therefore subdivided (thought) into two subregions, into an inner region directly below the layer structure of the

electrochemical cell unit and in a, surrounding the inner region process gas guiding space.

In the area of the process gas guidance space are in the housing

Gas passage openings formed, which serve to supply and / or discharge of the process gases. The gas passage openings, for example, in Edge area of the interconnector and in housing parts such as circumferential

Be integrated frame plates.

The supply of the electrochemical cell unit in the inner region of the process gas space by means of distribution structures, which are preferably integrated into the interconnector. Preferably, the interconnector is embodied by a correspondingly shaped metallic sheet metal part, which is, for example, knob-shaped or wavy.

In operation of the electrochemical module as SOFC, the anode becomes fuel (eg, hydrogen or conventional hydrocarbons, such as

Methane, natural gas, biogas, etc., possibly completely or partially pre-reformed) fed through the gas passage opening and distribution structures of the interconnector and there oxidized catalytically with release of electrons. The electrons are derived from the fuel cell and flow via an electrical load to the cathode. At the cathode becomes an oxidizing agent

(For example, oxygen or air) reduced by receiving the electrons. The electrical circuit is closed by flowing in an oxygen ion conductive electrolyte flowing at the cathode oxygen ions to the anode via the electrolyte and to the corresponding

Interfaces react with the fuel.

In the operation of the electrochemical module as a solid oxide electrolysis cell (SOEC), a redox reaction is forced using electric current, for example a conversion of water into hydrogen and oxygen. The structure of the SOEC substantially corresponds to the structure of an SOFC outlined above, in which the role of cathode and anode is reversed. A reversible solid oxide fuel cell (R-SOFC) is operable as both SOEC and SOFC.

According to the present invention, a gas guide member is provided, which is preferably produced by powder metallurgy and therefore porous or at least partially porous, if it is post-treated by pressing or local melting, for example, at the edge or on the surface. The gas guide part is arranged in the region of the process gas guiding space. The porous structure of the gas guide part serves to increase the surface with which the process gas in the area of

Process gas guiding space can interact. The surface of the gas guide part is at least partially functionalized, whereby a reactive or catalytically active surface is ready for manipulation of the process gases. With the aid of the functionalized surface, gases can be treated on the educt side, in particular cleaned and / or reformed, and gases can be post-processed on the product side, in particular cleaned. The gas guide part is functionalized by a with the

Process gas catalytically and / or reactively acting material introduced into the material of the gas guide part and / or applied as a superficial coating. The catalytic and / or reactive material can therefore already be added to the starting powder for the production of the sintered gas guide part ("alloyed") and / or after the sintering process by a coating process on the surface of the gas guide member, which comes into contact with the process gas, are applied . Of the

Coating process can be carried out by conventional methods known in the art, for example by means of different deposition processes from the gas phase (physical vapor deposition, chemical

Gas phase deposition), by means of dip coating (in which the component is infiltrated with a melt or solution with the appropriate functional material) or by application of suspensions or pastes (in particular for the functionalization with ceramic

Materials). For surface enlargement, it is advantageous if the porous surface structure is preserved in the coating process, i. The porous surface should not be overlaid with a cover layer, but primarily only the (inner) surface of the porous structure should be coated. A functionalization by means of a superficial coating is particularly advantageous on the whole because comparatively less catalytically and / or reactive material is required than if the catalytically and / or reactive material is added to the material for the gas-conducting part.

Due to the arrangement of the functionalized gas guide part in the region of the process gas guidance space, the chemical reactions for manipulating the process gases proceed separately from the electrochemical reactions that occur directly take place at the electrochemical cell unit. This separation has

decisive advantages: any deposits or degradations on the

Gas guide part have no immediate negative impact on the

Reactions in the electrochemical cell unit. In addition, are

Different functionalizations for the field of gas supply and the field of gas discharge possible and can be optimized independently for each requirement.

In a preferred embodiment, the gas guide part is designed as a separate component of the electrochemical cell unit and the housing. The gas guide part is to be arranged within the

Adapted process gas guiding space, in other words, its shape is adapted to the interior of the process gas guiding space. Preferably, the gas guide part is formed flat and has a flat body with a main extension plane. In an advantageous variant that is

Gas guide part as a support element in the vertical direction (in the stacking direction of the electrochemical modules) executed. In this case, its thickness is selected according to the internal space height of the process gas guiding space, so that it rests with its upper side on an upper housing part of the process gas guiding space and with its lower side on a lower housing part of the process gas guiding space and therefore compression of the housing edge area is prevented when applying a contact pressure. In a planar configuration of the gas guide part also the bending and torsional rigidity of

Enclosure edge area increases and so the enclosure edge area before

Bends or other deformations protected. This can be done in the

Edge of the module additional stresses of the welds or other, for example, soldered or sintered joints between the individual housing parts or the electrochemical cell unit, which in practice often represent weak points in terms of gas tightness avoided.

During operation of the electrochemical module, the separately executed

Gas guide part within the process gas guide space, advantageously completely in the process gas guidance space, ie in the process gas space completely outside the area directly below the layer structure of the

electrochemical cell unit, arranged.

Instead of a separate component in the interior of the

Process gas guide space is arranged, the functionalized

Gas guide part in a further embodiment as a demarcation of

Process gas management space or a portion thereof (that is, as part of the housing of the process gas guide space) to be executed. The

Functionalization of the surface is carried out by alloying or on the interior of the process gas guide space facing surface of the gas guide part. In MSCs, the gas guide part is preferably formed by the edge region of the metallic carrier substrate, which extends beyond the region of the electrochemical cell unit. The

Gas guide part is thus through the edge part of the metallic

Carrier substrate, on which no electrochemically active layers are arranged formed. The gas guide part is shared with the

Carrier substrate preferably monolithic, i. made in one piece. The functionalization is preferably carried out by means of an element or a compound which is not yet contained in the base material of the carrier substrate. In particular, in the case of a Fe and / or Cr-containing

Carrier substrate still provided an additional element or an additional compound as a functionalization. So that the gas guide part in this

Of course, to fulfill its function as a housing, of course, the porous gas guide part must be made gas-tight, which, for example, by

Pressing and / or local superficial melting on the

Process gas guidance space remote from the side can be achieved. In a preferred variant, the gas guide part as an integral part of

Carrier substrate carried out, wherein the functionalization is not through

Alloying, but by coating the surface, in particular by means of vapor deposition, dip coating or application process of suspensions or pastes done. Flexibility is thereby gained since the functionalization can be configured differently and comparatively cost-effectively for different areas and optimized for the respective requirement. For example, the edge region of the carrier substrate, via whose Gas passage openings the process gas is fed, different from the edge region of the carrier substrate, through the gas passage openings, the process gas is derived, be functionalized. In addition to the manipulation of the process gases and mechanical tasks (primarily in a separately executed gas guide part), the gas guide part has an important task in improving the gas flow within the process gas guide space. In order to optimize the gas flow, gas line structures may be formed on the gas guide part, which gas flows into the inner region of the gas flowing through the gas passage openings

Process gas space to the gas line structures of the interconnector

forward or outflowing gas from the inner region of the

Remove the process gas space to the discharging gas passage openings. The gas line structures can be designed differently, depending on whether the gas guide part a gas distributor or a

Gas collector task has to fulfill. The functionalization of the

Gas guide member may be coupled to the shape of the gas routing structures, i. it can be specifically designed to be more intensive in those surface areas that have a more intensive contact with the process gas.

In the following, possible optimizations of the gas line structures will be discussed using the example of a separately designed gas guide section. If appropriate, individual aspects can of course be attributed to gas guide parts

transferred, which are designed as part of the housing, and in which the functionalized, the process gas guide space facing surface is provided with corresponding gas line structures. In the gas guide part continuous gas passage openings may be integrated, wherein in the arrangement in the electrochemical module, the gas passage openings of the gas guide part with the gas passage openings of the

Process gas guide chamber (housing) are aligned with each other, so that a vertically continuous gas channel is formed within the stack. The gas guide member is at least in one direction in the main plane of extension of the gas passage opening to a lateral, the inner

Process gas chamber facing edge permeable to gas. This can do that Gas guide part generally or at least in this direction have an open, continuous porosity, in which case in particular the inner surface, where the process gas flows past, is functionalized. In order to optimize the gas flow, the gas permeability (porosity) of the gas-conducting part can vary spatially (for example by grading the porosity or locally different compression of the gas-conducting part, in particular by inhomogeneous pressing) or for a higher one

Gas flow rate, the gas guide member may alternatively or additionally along the main plane of extension at least one channel or a plurality of channels. The one or more channels whose surface are advantageously functionalized, are preferably formed on the surface and can, for example by milling, pressing or rolling with appropriate

Structures in the surface of the gas guide part (both designed as a housing part gas guide part as well as separately executed component) are incorporated. In the context of the present application, a porous gas guide part with a closed porosity and a superficial channel structure, which runs from the gas passage opening to a lateral edge, is also considered to be gas-permeable from the gas passage opening to the lateral edge. It is also conceivable that the channel or channels extend at least in sections over the entire thickness of the gas guide part, that is, that the channels are not only superficially formed. The advantage of this embodiment is a higher gas flow rate, but care must be taken that the component remains integral and not

falling apart. To prevent this, the channels extending over the entire thickness can be superficial over their course

Pass channel structures or porous structures. The number and shape of the channels is optimized in terms of flow characteristics and desired reactions. The gas guide part according to the invention is produced by powder metallurgy, wherein the material for the functionalization is added to the starting powder already during the production of the sintered component and / or the surface of the component is at least partially occupied by it after the sintering process. As starting material for the production of the gas guide part is a preferably metal-containing powder, preferably a powder of a corrosion-resistant alloy such as a powder of a Cr (chromium) and / or Fe (iron) based material combination, ie the Cr and Fe content is in total at least 50 wt.% , preferably in total at least 80% by weight, preferably at least 90% by weight. The

Gas guide part consists in this case of a ferritic alloy. The preferably powder-metallurgical production of the gas-conducting part takes place in a known manner by pressing the starting powder (optionally with addition of the material for the functionalization), optionally with the addition of organic binders, and subsequent sintering process.

When using the gas-conducting part as a separately formed component in an MSC, the gas-conducting part preferably consists of the same or a substantially identical (that is, only with the addition of the material to the

Functionalization) material such as the carrier substrate of the MSC. This is advantageous because in this case the thermal expansion is the same and no temperature-induced stresses occur.

As already mentioned, the gas guide part according to the invention is used in an electrochemical module, in particular in an MSC. In a preferred embodiment, the electrochemical module for the

Supply line and discharge of the process gases in each case differently formed gas guide parts. The gas guide parts may differ in terms of the material used, their shape, porosity, the shape of the formed gas line structures such as the channel structures, etc.

In particular, the functionalization of the gas guide parts used for the supply and discharge of the process gases may differ and be optimized for the different tasks. While that

Gas guide part, which is used in the supply of process gases (educt gases), adapted for the treatment of educt gases, is the

Gas guide part, which is used for the discharge of process gases (product gases), adapted for post-processing of the product gases.

In particular, when used in a SOFC, the gas-conducting part can be functionalized for the catalytic reforming of the educt gas. For catalytic reforming, the following materials have been proven (Especially when using a gas guide part of a

powder-metallurgically produced alloy based on iron and / or chromium): nickel (Ni), platinum (Pt), palladium (Pd) and / or oxides of these metals such as NiO. In the case of a homogeneous alloy, the proportion of these metals or metal oxides should total at least 1% by weight, preferably at least 2% by weight. This functionalization generates additional hydrogen for the electrochemical reaction while maintaining the reactant gas stream. For the preferred effect, these materials can be alloyed into the base material or applied by coating processes to the surface streamed by the process gas (for example by means of dip coating (suspension dipping) or different deposition processes from the gas phase), whereby alloying or gas phase separation processes are based on a dipping process

Wetting effects, which are detrimental to the porous structure, are preferable.

The gas-conducting part can be further functionalized to purify the educt gas against impurities such as sulfur, chlorine, oxygen and / or carbon. The impurities react with the introduced materials, whereby the risk of possible

Damage to the electrochemically active layers of the cell unit is reduced. As elements (getter atoms) for purifying the educt gas of sulfur and / or chlorine are used: Ni, cobalt (Co), chromium (Cr), scandium (Sc) and / or cerium (Ce), Ni due to its above mentioned Properties in terms of catalytic reforming and Ce are preferred. Preferred elements for the purification of the reactant gas

Oxygen is Cr, copper (Cu) and / or titanium (Ti), with Ti being particularly advantageous for carbon because of its retentive effect and thus because of its simultaneous action to prevent soot formation. Although these getter atoms typically can only retain residual amounts in the ppm range, this will increase the performance and lifetime of the getter

Electrochemical module measurably positively influenced. The introduction of the materials is also done here by alloying in the base material,

Dip coating with suspensions or separation methods from the Gas phase, with preference given to the flexibility of gas phase deposition method.

Similarly, functional centers for post-processing of the product gas can be introduced. The product gas (exhaust gas) can be purified by a correspondingly functionalized gas-conducting part, especially with regard to impurities with volatile Cr ions. A corresponding

Functionalization against Cr impurities can be carried out by oxide ceramics such as Cu-Ni-Mn spinels of the structure AB2O4 (where A is an element from the group Cu or Ni and B is the element manganese (Mn)), which by means of vapor deposition, dipping or

Application method can be done with suspensions or pastes or by conversion of the metallic elements.

To prevent back diffusion of oxygen from the exhaust pipes, the gas guide part may be functionalized with oxygen getter. These should prevent oxidation of the anode. Suitable oxygenated getters are: Ti, Cu or substoichiometric spinel compounds, preference being given to using Ti and / or Cu. These two metals are preferably applied to the porous surface of the gas guide member by a vapor deposition method. Optionally, suppression of back diffusion may be further assisted by suitable gas routing structures.

In summary, especially for use in a SOFC, the gas-conducting part on the educt gas side can be functionalized with Ni, Pt, Pd (and / or oxides of these metals), Co, Cr, Sc, Cer, Cu and / or Ti. Possible functionalizations of the gas-conducting part on the product side include Ti, Cu and / or oxidic ceramics, in particular Cu-Ni-Mn spinels.

Preferred combinations for the functionalization of the gas guide parts on the educt gas side and product gas side comprise Ni or NiO on the

Educt gas side and Ti on the product gas side, as well as Ni or NiO on the educt gas side and Cu on the product gas side, etc.

Further advantages of the invention will become apparent from the following description of embodiments with reference to the attached figures, in which for purposes of illustrating the present invention, the size ratios are not always given to scale. In the various figures, the same reference numerals are used for matching components.

From the figures show:

Fig. 1a: a first embodiment of a functionalized

Gas guide part for use in an electrochemical module in perspective view;

1b: the gas guide part of Fig. 1a in plan view and

Fig. 1c: the gas guide part of Figure 1a in a side view.

Fig. 2: a first embodiment of the electrochemical module, each with a gas guide part according to Fig. 1a-c for the process gas supply space for supply and discharge of the process gases in an exploded view (it should be noted that the electrochemical module in Fig. 2 in Compared to the modules in Fig. 3 for better visibility of the channels upside down);

3 shows a stack with three electrochemical modules according to FIG. 2 in FIG

Cross-section;

4 shows a second embodiment of the electrochemical module in an exploded view and

5 shows a stack with three electrochemical modules according to FIG. 4 in FIG

Cross-section.

1a shows a perspective view of a first embodiment of the functionalized gas-conducting part (10), which is designed as a separate component and is arranged in the electrochemical module, in particular in a SOFC, within the process gas-guiding space. A possible arrangement in the process gas guidance space will be apparent from the following FIGS. 2 and 3. Fig. 1b shows the gas guide part (10) in plan view and in Fig. 1c in a side view from the side (A), in the arrangement in

electrochemical module (20) facing the interior of the process gas space. The gas guide member (10) became powder metallurgical of an Fe base Alloy with Fe> 50 wt.% And 15 to 35 wt.% Cr produced. It was a powder with a particle size <150 μηι, in particular <100 μιτι chosen so that after the sintering process, the porous gas guide member has a porosity of preferably 20 to 60%, in particular 40 to 50%. The particle size is the smaller to choose, the thinner the gas guide member is to be formed. Preferably, an open porosity is set (ie gas exchange between individual adjacent pores is possible). It preferably has a thickness in the range from 170 μm to 1.5 mm, in particular in the range from 250 μm to 800 μm. The planar gas guide part has a plurality of gas passage openings (11), in the illustrated variant three central gas passage openings (11) through which the process gas is supplied or discharged during operation of the electrochemical module. The process gas stream is additionally directed by gas line structures, in the present

Embodiment by star-shaped, superficially formed channels (12) extending from the gas passage openings to the lateral edge (A). Channels which branch off from the gas passage opening (1 1) originally in a direction away from the inner process gas chamber direction, are thereby deflected arcuately to the lateral edge (A) in the direction of the inner process gas space. At the remaining lateral edges (13) (except lateral edge (A)), the gas guide member is gas-tight compressed. In operation of the

electrochemical module, the process gas flows from the

Gas passage openings (1 1) through the channels (12) and the pores on the lateral edge (A) of the gas guide part, from where it in the inner

Process gas space continues to flow, which is supplied by the many channels as evenly as possible. When using the gas guide part for discharging the process gases, the gas flows in the reverse direction.

For functionalization, the surface of the gas-conducting part was coated on the side with the channels in a PVD system with a functional layer (14) with a thickness of <1 μm. Care was taken to ensure that the porous

Surface structure of the gas guide part is maintained during the coating process, ie. the open porous surface is not overlaid by a cover layer, so that a large compared to a smooth surface

functionalized surface remains. It was also ensured that in particular the surface of the channels, which by the process gas is overflowed and therefore is in a relatively intensive contact with the process gas has been adequately coated.

There were several gas guide parts with different functionalization for the preparation or post-processing of the process gases produced, the

Gas guide parts are intended for use in an SOFC. A first embodiment of the gas-conducting part was coated with Ni, a second with NiO. Both gas guide parts are used in the treatment of fuel gases; the functionalized surface of both embodiments serves as a catalyst for the reforming of the fuel gas and also has a getter effect against chlorine and sulfur. For the gas guide part for the exhaust aftertreatment, a Ti coating was chosen, which causes a filtration of the exhaust gas flow to Cr ions.

In Fig. 2 and Fig. 3, the arrangement of the gas guide parts (10,10 ') is illustrated in the electrochemical module. Fig. 2 shows in one

Exploded view of an electrochemical module (20) with correspondingly functionalized gas guide parts (10,10 '), Fig. 3 in a

It should be noted that in Figure 2 the electrochemical module is inverted compared to the modules in Figure 3 for better visibility of the channels (12) is shown. The electrochemical modules (20) each have an electrochemical

Cell unit (21), which consists of a powder metallurgically produced, porous, metallic carrier substrate (22) on which in a gas-permeable region, a layer structure (23) is applied with at least one electrochemically active layer. The carrier substrate (22) with the layer structure (23) is gas-tight pressed at the edge and has a plate-shaped basic structure, which may also be locally curved, for example, wave-shaped embodiments in order to increase the surface on a smaller scale. On the opposite side of the layer structure of the

Carrier substrate (22) is in each case an interconnector (24), which in

Area where it rests against the carrier substrate (22), a rib structure (24a). The longitudinal direction of the rib structure extends in the

Cross-sectional plane in Fig. 3. The interconnector (24) extends on two opposite sides over the region of the electrochemical cell unit (21) and is located at its outer edge on a the electrochemical cell unit encircling frame plate (25). The peripheral frame plate (25) is gas-tight at the inner edge with the electrochemical cell unit (21) and connected at the outer edge via a circumferential weld gas-tight with the interconnector (24). The frame plate (25) and the

Interconnector (24) thus form part of a metallic, gas-tight

Housing, which defines a gas-tight process gas space (26) with the electrochemical cell unit (21). The process gas space (26) is (thought) in two opposing subspaces - the two

Process gas guide spaces (27, 27 ') - subdivided, wherein the subspaces each extend over a region outside the range of the electrochemical cell unit (21) and in the direction of electrochemical cell unit (21) are open. In this case, a first process gas guiding space (27) serves

corresponding gas inlet openings (28) in the housing (frame plate and interconnector) of the supply line of the process gases, during the

opposite process gas guide space (27 ') via corresponding

Gas outlet openings (28 '), the discharge of the process gases accomplished (the gas passage openings are not shown in Fig. 3, since the section is located laterally of the gas passage openings). Within the stack, the gas flow in the vertical direction (stacking direction of the stack (B)) by corresponding channel structures, which are usually formed in the gas passage openings by separate depositors (29), seals and by targeted application of sealant (such as glass solder).

Within the process gas guide space (27) for the supply line is a

Gas guide member (10) arranged whose surface is functionalized for the treatment of the educt gas (reforming, purification). That for the

Post-processing of the product gases functionalized gas guide part (10 ') is disposed within the opposite process gas guide space (27') for the discharge of the product gases. The gas guide parts (10, 10 ') used for the supply line and discharge therefore preferably have one

different functionalization. Of course, the gas guide parts can also differ with regard to other properties (base material, shape, porosity, geometry of the channels, etc.) and be optimized independently of each other for their intended use. Preferably, the gas guide parts (10,10 ') as a supporting element in

Stacking direction (B) of the electrochemical modules executed. For this purpose, the shape of the gas guide part in each case to the interior of the respective

Adjusted process gas management room. The gas guide parts (10,10 ') are each with their top on the frame plate (25), the upper delimitation of the respective process gas guide space (27, 27'), and with its underside on the interconnector (24), the lower boundary of the respective

Process gas management room, on. Particularly advantageous is a flat system, at the top and / or on the underside of the respective

Gas guide member. The thickness of the gas guide part therefore corresponds to the interior space height of the respective process gas guide space (27, 27 '). The superficially formed channels (12) are located at the bottom of the gas guide parts (0,10 '). Due to the planar design of the gas guide parts, the bending and torsional stiffness of the housing edge region, which consists of a thin frame plate (25) and thin interconnector (24),

significantly increased and so the risk of cracking in the

Weld seams reduced under mechanical loads. In an advantageous embodiment, the functionalized gas guide parts are spot welded to the housing and fixed so.

FIGS. 4 and 5 show a second embodiment of the invention

electrochemical module (20 ') in which the gas guide members (10 ", 10"') form part of the housing and are integral with the support substrate (22 '). The porous carrier substrate (22 ') is gas-tight pressed on two opposite sides in each case at the edge region, in each of which gas passage openings (11, 11') are integrated. The edge region can also be made gas-tight on the side facing the layer structure (23) by a reflow process, for example by means of laser beam melting. These

opposite edge regions of the carrier substrate are outside the gas-permeable region with the layer structure (23). They each represent a gas guide part (10 ", 10" ') and border the two

Process gas guide spaces (27,27 ') upwards. During the pressing process, gas line structures (12) can optionally be attached to the underside (the interior of the

Process gas guiding space facing side) of the edge region of the Be integrated carrier substrate. In the variant implemented, the edge region (10 ") of the carrier substrate assigned to the feed line of the fuel gas is coated on its underside with Ni; the edge region (10"') associated with the discharge of the exhaust gas is coated on its underside with Ti. An analogous to the embodiment of Fig. 1 to Fig. 3 preparation of the fuel gases and cleaning of the exhaust gases is achieved.

Both for the embodiment shown in Fig. Ibis Figure 3 with a separately formed gas guide member as well as for the illustrated in Fig. 4 and Fig. 5 embodiment with the integrated gas guide part are of course other functionalizations than the Ni or NiO and the Ti

Coating conceivable. For use in a SOFC, the

Gas guide part on the educt gas side next Ni or NiO with Pt, Pd (and / or oxides of these two metals), Co, Cr, Sc, cerium, Cu and / or Ti are functionalized. Possible functionalizations of the gas guidance part on the

Product side include Ti, Cu and / or oxide ceramics, in particular Cu-Ni-Mn spinels.

Claims

claims

Porous or at least partially porous gas guide part (10, 10 ') for an electrochemical module (20),

wherein the electrochemical module (20)

at least one electrochemical cell unit (21) having a layer structure (23) with at least one electrochemically active layer, and a metallic, gas-tight housing (24; 25) which forms a gas-tight process gas space (26) with the electrochemical cell unit (21),

wherein the housing (24; 25) extends beyond the region of the electrochemical cell unit (21) on at least one side, forming a process gas guide space (27; 27 ') open to the electrochemical cell unit and in the region of the process gas guide space (27; 27'). at least one

Has gas passage opening (28, 28 ') for supply and / or discharge of the process gases,

characterized in that the gas guide part (10,10 ') for

Arrangement within the process gas guide space (27, 27 ') is adapted and the surface of the gas guide part is functionalized to interact with the process gas.

Gas guide part according to claim 1, characterized in that the gas guide part (10,10 ') is formed as a separate component of the electrochemical cell unit (21).

Gas guide part according to claim 1 or 2, characterized in that the gas guide part (10,10 ') is adapted to support the housing to both sides along a stacking direction of the electrochemical module.

Porous or at least partially porous gas guide part (10 ", 10" ') for an electrochemical module (20'),

the electrochemical module (20 ') at least one electrochemical cell unit (21) having a layer structure (23) with at least one electrochemically active layer, and a metallic, gas-tight housing which forms a gas-tight process gas space (26) with the electrochemical cell unit,

wherein the housing extends on at least one side beyond the region of the electrochemical cell unit (21), thereby open to the electrochemical cell unit

Process gas guiding space (27, 27 ') forms and in the area of the process gas guiding space at least one

characterized in that the gas guide part (10 ", 10" ') as

Housing part of the process gas guide space (27, 27 ') is formed and the process gas guide inner space facing surface of the gas guide part is functionalized to interact with the process gas.

Gas guide part according to claim 4, characterized in that the gas guide part (10 ", 10" ') is formed integrally with a metallic carrier substrate (22) of the electrochemical cell unit (21).

Gas guide part according to one of the preceding claims, characterized in that the gas guide part (10, 10 ', 10 ", 10"') for

catalytic reforming of a reactant gas is functionalized.

Gas guide part according to claim 6, characterized in that the functionalization for the catalytic reforming by introducing nickel, platinum and / or palladium and / or oxides of these metals takes place.

Gas guide part according to one of claims 1 to 5, characterized

in that the gas-conducting part (10, 10 '; 10 ", 10"') is functionalized for purifying the educt gas, in particular for purification with respect to sulfur, chlorine, oxygen and / or carbon. 9. Gas guide part according to claim 8, characterized in that the functionalization for purifying the educt gas to sulfur and / or chlorine by introducing nickel, cobalt, chromium and / or cerium takes place.

10. Gas guide part according to claim 8, characterized in that the

Functionalization to purify the educt gas to oxygen by introducing chromium, copper and / or titanium takes place. 11. Gas guide part according to claim 8, characterized in that the

Functionalization to purify the educt gas against carbon (soot) by introducing titanium takes place.

12. Gas guide part according to one of claims 1 to 5, characterized

in that the gas-conducting part (10, 10 '; 10 ", 10"') is functionalized for purifying the product gas, in particular for purifying it against chromium and / or oxygen.

13. Gas guide part according to claim 12, characterized in that the functionalization for the purification of the product gas against chromium by introducing oxidic ceramics, in particular by Cu-Ni-Mn spinels takes place.

14. Gas guide part according to claim 12, characterized in that the functionalization for purification against oxygen by introducing Ti and / or Cu or substoichiometric spinel compounds.

15. Gas guide part according to one of claims 7, 9, 10, 11, 13 or 14,

characterized in that the introduction by alloying or a

Coating method, in particular by means of a

Gas phase deposition, dip coating or a

Application process of suspensions or pastes takes place. 16. Gas guide part according to one of the preceding claims, characterized in that the base material for the gas guide part (10, 10 ', 10 ", 10"') is a powder metallurgy produced on iron and / or chromium-based ferritic alloy.

Gas guide part according to one of the preceding claims, characterized in that the gas guide part (10,10 '; 10 ", 10"') has at least one gas line structure (12).

Electrochemical module (20; 20 '), comprising:

a substantially plate-shaped electrochemical cell unit (21) having a layer structure (23) with at least one

electrochemically active layer, and a metallic, gas-tight

A housing (24; 25) which forms a gastight process gas space (26) with the electrochemical cell unit (21), the housing (24; 25) extending beyond the area of the electrochemical cell unit (21) on at least one side, the housing (24; 25) forms a process gas guide space (27; 27 ') open to the electrochemical cell unit and at least one gas passage opening (28; 28') in the region of the process gas guide space (27; 27 ') for supplying and / or discharging the process gases,

characterized in that within the process gas guide space (27, 27 ') in the region of the gas passage openings at least one

Gas guide member (10,10 ') according to claim 1 or one of the dependent of claim 1 claims 2, 3, 6 to 17 is arranged, which is the

Supporting the housing along the stacking direction (B) of

electrochemical module (20; 20 ') is used

and / or the housing of the process gas guide space is formed at least in sections by at least one gas guide part (10 ", 10" ') according to claim 4 or one of claims 4 to 5 dependent on claim.

An electrochemical module according to claim 18, characterized in that the housing (24; 25) extends on at least two sides beyond the area of the electrochemical cell unit (21), whereby a first process gas guiding space (27) with at least one

Gas inlet opening (28) for a reactant gas, the at least a first A second process gas guide space (27 ') is formed with at least one gas outlet opening (28') for a product gas to which at least one second gas guide part (10 ', 10 "') is assigned the functionalization of the first, the first process gas guide room assigned

Gas guide part (10; 10 ") of the functionalization of the second, the second process gas guide space associated gas guide part (10 ', 10"') differs. 20. An electrochemical module according to claim 19, characterized in that the first gas guide part (10; 10 ") for the preparation of

Educt gas and / or the second gas guide part (10 ', 10 "') for

Post-processing of the product gas is functionalized.