DE10330478B9 - Fuel cell unit and method for manufacturing a fuel cell unit - Google Patents

Abstract

A fuel cell unit comprising a cathode-anode electrolyte unit (138) having a cathode (144) of an electrically conductive ceramic material, an oxygen ion conductive solid electrolyte (142), and an anode (140) of an electrically conductive ceramic material and a substrate (136) on which the cathode-anode-electrolyte unit (138) is arranged, the fuel-cell unit (100) having at least one fluid passage opening (114, 116, 122, 124) through which a fluid passes through the fuel cell unit (100). wherein the substrate (136) comprises a sintered body (148) extending around the at least one fluid passage opening (114, 116, 122, 124), and wherein the sintered body (148) is disposed around the at least one fluid passage opening (114, 116, 122, 124) extending around area provided with an insulating layer of an electrically insulating material.

Description

The present invention relates to a fuel cell unit comprising a cathode-anode-electrolyte unit and a substrate on which the cathode-anode-electrolyte unit is disposed, the fuel-cell unit having at least one fluid passage opening through which a fluid passes through the fuel cell unit can pass through.

Such fuel cell units are known from the prior art.

In known fuel cell units of the aforementioned type, the substrate is arranged in a central region of the fuel cell unit, which is not penetrated by the fluid passage openings through which the fluids required for the operation of the fuel cell unit can enter or exit the fuel cell unit. Therefore, it is necessary that the portions of the fuel cell unit surrounding these fluid passage openings are provided with separate sealing members for sealing the fuel gas space of the fuel cell unit from the oxidant space of the fuel cell unit and / or separate support members for establishing the required mechanical stability of the fluid passage areas of the fuel cell unit.

The US 6 051 330 A discloses an SOFC fuel cell unit fabricated by providing an unsintered ceramic anode, an unsintered ceramic electrolyte, a non-sintered ceramic cathode, and an unsintered ceramic interconnector each having fluid passage holes, and then stacked, laminated, and sintered together become.

The DE 41 04 839 A1 discloses a support for a fuel cell made by extruding a mass of ceramic powder and extrusion additives, ducted in the green state and then sintered.

The DE 102 07 743 A1 discloses a dividing wall for a polymer electrolyte fuel cell having at least one channel for gas and water, wherein the dividing wall is made of a material obtained by die-casting a mixture, the carbon powder, such as natural graphite, artificial graphite, expanded graphite and / or amorphous carbon, and a phenol resin, or a mixture obtained by sintering the thus-obtained casting at a temperature of 300-1200 ° C. The partition wall is provided with electrically insulating sealing elements made of elastomer.

The present invention has for its object to provide a fuel cell unit of the type mentioned, which is simple and easy to manufacture.

This object is achieved by a fuel cell unit according to claim 1.

By extending the sintered body around the at least one fluid passage opening, it is possible to use the sintered body as a supporting member for producing sufficient mechanical strength of the fuel cell unit. In particular, such a sintered body can prevent the fuel cell unit from being compressed in the area of the fluid passage opening along the stacking direction of a fuel cell stack in which the fuel cell unit is arranged.

Furthermore, the sintered body itself can serve as a sealing element for sealing the fluid passage opening or as a carrier for such a sealing element. It is therefore no longer necessary to provide a sealing element separate from the sintered body and to be installed separately from the sintered body at the fluid passage opening in the production of the fuel cell unit according to the invention.

In particular, the sintered body may have at least one passage opening for the passage of a fluid through the sintered body.

Preferably, the cathode-anode-electrolyte unit also has at least one passage opening for the passage of a fluid through the cathode-anode-electrolyte unit.

In a particular embodiment of the fuel cell unit according to the invention it is provided that the cathode-anode-electrolyte unit is arranged directly on the sintered body.

The fluid passing through the fuel cell unit may be, for example, a fuel gas, an exhaust gas, or an oxidizer.

Thus, in particular, it may be provided that the fuel cell unit has at least one fuel gas passage opening through which a fuel gas can pass through the fuel cell unit, and that the sintered body extends around the at least one fuel gas passage opening.

Alternatively or additionally, it can be provided that the fuel cell unit has at least one exhaust gas passage opening through which an exhaust gas can pass through the fuel cell unit, and that the sintered body extends around the at least one exhaust gas passage opening around.

Alternatively or additionally, it can further be provided that the fuel cell unit has at least one oxidant through-opening, through which an oxidizing agent can pass through the fuel cell unit, and that the sintered body extends around the at least one oxidant through-opening.

The sintered body may have at least one fuel gas passage opening for passing fuel gas through the sintered body, at least one exhaust gas passage opening for passing exhaust gas through the sintered body, and / or at least one oxidant passage opening for passing oxidizing agent through the sintered body.

The cathode-anode-electrolyte unit can at least one fuel gas passage opening for the passage of fuel gas through the cathode-anode-electrolyte unit, at least one exhaust gas passage opening for passage of exhaust gas through the cathode-anode-electrolyte unit and / or at least one oxidant passage opening for passage of oxidant through the cathode-anode-electrolyte unit.

In a preferred embodiment of the fuel cell unit according to the invention, it is provided that the fluid passage opening of the fuel cell unit as a portion of a substantially perpendicular to the main surfaces of the cathode-anode-electrolyte unit through the fuel cell unit extending fluid channel, ie in particular a fuel gas channel, an exhaust passage or an oxidant channel , is trained.

The sintered body may extend to immediately adjacent to the respective fluid passage opening, so that the sintered body in this case forms a lateral boundary of at least one fluid passage opening of the fuel cell unit.

Alternatively, it may be provided that the sintered body is provided in a region extending around the at least one fluid passage opening with a sealing layer of a substantially gas-impermeable material. In this case, the sintered body thus does not extend as far as directly to the fluid passage opening, but is separated from the fluid passage opening by the sealing layer of the essentially gas-impermeable material.

In the fuel cell unit according to the invention, it is provided that the sintered body is provided with an insulating layer of a substantially electrically insulating material in a region extending around the at least one fluid passage opening.

This electrically insulating insulating layer may in particular be formed by the electrolyte of the cathode-anode-electrolyte unit, which extends around the at least one fluid passage opening.

This makes it possible to dispense with additional sealing elements of electrically insulating material in the region of the fluid passage opening.

In a particular embodiment of the fuel cell unit according to the invention, it is provided that a support element which is different from the sintered body is arranged on the at least one fluid passage opening in order to further increase the mechanical strength of the fuel cell unit in the area of the fluid passage opening.

Such a support element can serve, in particular, to receive the sealing surface pressure applied to the fuel cell unit during installation in a fuel cell stack and to serve as a spacer, which prevents compression of the fuel cell unit during assembly and / or during operation of the fuel cell stack.

Such a support element may be formed in particular substantially annular.

Furthermore, it can be provided that the support element is formed from a metallic material, in particular from a steel sheet.

It is particularly easy and time-saving to produce a support element, which is designed as a sheet metal part. In this case, a support element preform from a suitable sheet, in particular a steel sheet, cut out, in particular punched or cut, and be brought by forming operations in the final shape of the support element.

The support element can be connected to the sintered body after its production, for example by welding or soldering.

Alternatively or additionally, it can also be provided that the support element is sintered to the sintered body.

In particular, it can be provided that the support element during the formation of the Sintered body has been sintered from a sintered body precursor to the sintered body. In this case, in particular, the support member may serve as part of a mold into which the sintered body precursor is filled prior to the sintering operation to form the sintered body by a subsequent sintering process.

Furthermore, it is provided in a preferred embodiment of the fuel cell unit according to the invention that the support element is provided in a region extending around the fluid passage opening around area with a sealing layer of a substantially gas-impermeable material.

Alternatively or additionally, it can also be provided that the support element is provided in an area extending around the fluid passage opening around an area with an insulating layer of a substantially electrically insulating material.

In particular, it can be provided that the electrolyte of the cathode-anode-electrolyte unit at least partially covers the support element. In this way, it is ensured that the region of the support element adjoining the sintered body and the region of the sintered body adjoining the support element are provided with an electrically insulating and substantially gas-impermeable layer, so that at this point the fuel cell unit does not provide an additional seal made of an electrically insulating material and gas impermeable material must be provided.

In a preferred embodiment of the fuel cell unit according to the invention it is further provided that the sintered body is formed by sintering from a starting material containing particles, and that the mean grain size in a first layer of the sintered body, which faces the cathode-anode-electrolyte unit, is smaller than in a second layer of the sintered body, which has a greater distance from the cathode-anode-electrolyte unit than the first layer of the sintered body.

In this embodiment of the invention, a sintered body is thus used as the substrate for the cathode-anode-electrolyte unit, which has areas which differ in terms of the mean grain size in these areas. A first layer of the substrate facing the cathode-anode-electrolyte unit has a smaller average grain size to create a closed surface of the sintered body facing the cathode-anode-electrolyte unit, which is particularly well suited for the deposition of the cathode anodes -Electrolyte unit is suitable. A second layer of the substrate farther from the cathode-anode-electrolyte unit has a larger average grain size and thus provides sufficient porous nature of the substrate to provide the required gas permeability of the substrate and sufficient gas supply to the cathode-anode electrolyte Unit through the substrate to allow.

In this case, the first layer and the second layer of the substrate can adjoin one another along a sharp boundary surface; but it is also possible that the properties of the sintered body with increasing distance from the cathode-anode-electrolyte unit change substantially continuously, so that the first layer and the second layer without sharp separation surface merge into each other.

In a preferred embodiment of the invention, it is provided that the mean grain size in the sintered body increases substantially monotonically with increasing distance from the cathode-anode-electrolyte unit, that is with increasing distance from the cathode-anode-electrolyte unit in each area of the sintered body increases or at least remains the same, wherein the monotonous increase can be stepped or substantially continuous.

In particular, it may be provided that the mean grain size in the sintered body varies substantially continuously as a function of the distance from the cathode-anode-electrolyte unit, in particular increases continuously with increasing distance.

Alternatively or additionally, it may be provided that the mean grain size in the sintered body in dependence on the distance from the cathode-anode-electrolyte unit step-like, with one or more stages varies, in particular gradually increases with increasing distance.

It has proved to be particularly favorable when the sintered body comprises at least one first layer facing the cathode / anode / electrolyte unit, in which the average grain size is at most approximately 160 μm, preferably at most approximately 80 μm, in particular at most approximately 50 μm.

It is particularly advantageous if the first layer contains substantially no grains which are larger than about 160 μm, preferably substantially no grains which are larger than about 80 μm, in particular substantially no grains which are larger than about 50 μm ,

Furthermore, it is advantageous if the first layer of the sintered body has an essentially uniform particle size distribution over the thickness of the layer.

In order to ensure sufficient gas permeability of the substrate, it is also advantageous if the first layer of the sintered body has a thickness of at most approximately 300 μm.

Further, it is advantageously provided that the first layer of the sintered body is immediately adjacent to the cathode-anode-electrolyte unit, so that this first layer of the sintered body can serve as a base for the production of the cathode-anode-electrolyte unit.

In order to ensure a sufficient porous nature and thus gas permeability of the second layer of the sintered body, it is advantageous if in the second layer of the sintered body, the mean grain size is at least about 50 .mu.m, preferably at least about 80 .mu.m, in particular at least about 160 .mu.m.

It is particularly favorable if the second layer of the sintered body contains substantially no grains which are smaller than approximately 50 μm, preferably substantially no grains which are smaller than approximately 80 μm, in particular essentially no grains which are smaller than approximately 160 μm.

Furthermore, it is advantageous if the second layer of the sintered body has an essentially uniform particle size distribution over the thickness of the layer.

In order to ensure sufficient mechanical stability of the sintered body, it is favorable if the second layer has a thickness of at least approximately 150 μm.

Furthermore, it has proved to be advantageous if the first layer of the sintered body has a smaller thickness than the second layer of the sintered body.

In order to ensure sufficient gas supply to the cathode-anode-electrolyte unit, it is advantageous if the sintered body has a thickness of at most about 5000 μm, preferably at most about 1600 μm, in particular at most about 400 μm.

On the other hand, in order to ensure sufficient mechanical stability of the sintered body, it is advantageous if the sintered body has a thickness of at least approximately 100 μm, preferably of at least approximately 200 μm.

In a preferred embodiment of the fuel cell unit according to the invention it is provided that the sintered body contains a metallic material, in particular iron, chromium, aluminum, yttrium and / or nickel in metallic form.

By the presence of the metallic material in the sintered body, it is ensured that the sintered body has sufficient electric conductivity required because the electrode of the cathode-anode-electrolyte unit facing the sintered body is electrically contacted via the sintered body to be conductive during the electrochemical Reaction in the fuel cell unit to provide the necessary charge compensation.

After its manufacture, the sintered body of the substrate can be introduced into a housing of the fuel cell unit and subsequently connected to the housing, for example by welding or soldering.

In a preferred embodiment of the fuel cell unit according to the invention, however, it is provided that the fuel cell unit comprises a housing which comprises at least one housing part which is connected by sintering with the sintered body of the substrate.

It is preferably provided that the housing part has been connected to the sintered body during the formation of the sintered body from a sintered body starting material.

In this embodiment of the invention, the sintered body is sintered in situ, that is, at the location of the housing of the fuel cell unit where it is disposed during operation of the fuel cell unit, so that the otherwise required operations of introducing the sintered body in the housing part and the connecting omitted sintered body and housing part.

In a preferred embodiment of the fuel cell unit according to the invention it is provided that the housing part is sintered to a surface of the sintered body remote from the cathode-anode-electrolyte unit.

In order to produce a sufficient electrical contact with the respectively adjacent fuel cell unit in a fuel cell stack, it can be provided that the housing part is provided with at least one contact element for contacting the cathode-anode-electrolyte unit of an adjacent fuel cell unit.

In order to arrange the sintered body in a simple and safe manner in the housing of the fuel cell unit, it can be provided that the housing part forms a trough for receiving the sintered body.

The housing part of the fuel cell unit can be produced in a particularly simple and time-saving manner if the housing part is designed as a sheet metal shaped part.

In particular, the housing part may be formed from a steel sheet, from which a housing part preform, for example by punching or cutting, is separated out, which is then brought by forming and / or embossing operations in the final shape of the housing part.

Another object of the present invention is to provide a method for manufacturing a fuel cell unit comprising a cathode-anode-electrolyte unit and a substrate on which the cathode-anode-electrolyte unit is disposed be carried out quickly.

This object is achieved by a method according to claim 42.

Further features and advantages of the invention are the subject of the following description and the drawings of exemplary embodiments.

In the drawings show:

1 a schematic plan view of a housing part of a fuel cell unit with fuel gas passage openings, an exhaust gas passage opening, oxidant through-holes and contact elements;

2 a schematic section through a fuel cell unit with the housing part 1 and a substrate for a cathode-anode-electrolyte unit accommodated therein taken along the line 2-2 in FIG 1 ;

3 one of the 2 corresponding schematic section through a plurality along a stacking direction stacked fuel cell units;

4 a schematic section through a fuel cell unit with the housing part 1 and a substrate received therein along the line 4-4 in FIG 1 ;

5 one of the 4 corresponding schematic section through a plurality along a stacking direction stacked fuel cell units;

6 a schematic section through a fuel cell unit with the housing part 1 and a substrate received therein along the line 6-6 in FIG 1 ;

7 one of the 6 corresponding schematic section through a plurality along a stacking direction stacked fuel cell units;

8th an enlarged view of the area I from 6 ;

9 a schematic section through a cathode-anode-electrolyte unit at the top of the substrate of the fuel cell unit from the 1 to 8th ;

10 one of the right side of the 2 corresponding schematic section through a second embodiment of a fuel cell unit whose housing part has horizontally oriented edge flanges;

11 one of the right side of the 4 corresponding schematic section through the second embodiment of a fuel cell unit, the housing part has horizontally oriented edge flanges;

12 one of the 6 corresponding schematic section through the second embodiment of a fuel cell unit, the housing part has horizontally oriented edge flanges;

13 a schematic plan view of a housing part of a third embodiment of a fuel cell unit having fuel gas passage openings, an exhaust gas passage opening, oxidant through holes and contact elements;

14 a schematic section through the third embodiment of a fuel cell unit with the housing part 13 and a substrate for the cathode-anode-electrolyte unit received therein, taken along the line 14-14 in FIG 13 ;

15 one of the 14 corresponding schematic section through a plurality along a stacking direction stacked fuel cell units;

16 a schematic section through the third embodiment of a fuel cell unit with the housing part 13 and a substrate received therein along the line 16-16 in FIG 13 ;

17 one of the 16 corresponding section through a plurality along a stacking direction stacked fuel cell units;

18 a schematic section through the third embodiment of a fuel cell unit with the housing part 13 and a substrate received therein along the line 18-18 in FIG 13 ;

19 one of the 18 corresponding schematic section through a plurality along a stacking direction stacked fuel cell units;

20 an enlarged view of the area II from 18 ;

21 one of the 16 corresponding schematic section through a fourth embodiment of a fuel cell unit with the housing part 13 and annular support members surrounding the fuel gas and exhaust gas passages of the fuel cell unit;

22 a schematic plan view from above on the annular support element 21 ; and

23 a schematic plan view of a support element preform from which in the 21 and 22 shown supporting element is formed by folding operations.

Identical or functionally equivalent elements are denoted by the same reference numerals in all figures.

One in the 1 to 9 illustrated first embodiment of a whole as 100 designated fuel cell unit comprises a housing 102 that from the in 1 shown housing part 104 is formed.

The housing part 104 has the shape of a substantially flat, substantially rectangular plate, which in its center with a substantially rectangular contact field 106 which is how best 6 can be seen, is formed by a corrugated contact structure, the downwardly facing and in the longitudinal direction 108 the contact field extending crests each have a contact element 110 of the contact field 106 form.

In a left of the contact field 106 arranged first end portion 112 of the housing part 104 are two substantially circular fuel gas passage openings 114 and one between the two fuel gas passage openings 114 lying oxidant passage opening 116 arranged.

The number of fuel gas passage openings 114 and the oxidant passage holes in the end portion 112 can also take any other value.

Preferably follow in the transverse direction 118 of the housing part 104 each a fuel gas passage opening 114 and an oxidant passage opening 116 alternately on each other.

In the right of the contact field 106 lying right end 120 of the housing part 104 are two substantially circular oxidant ports 122 and one between the two oxidant passageways 122 lying, also substantially circular exhaust passage opening 124 arranged.

The number of oxidant ports 122 and the exhaust passage openings 124 in the right end area 120 of the housing part 104 can also accept any other value.

Preferably follow in the transverse direction 118 of the housing part 104 alternately one oxidant through-opening 122 and an exhaust passage opening 124 each other.

How best 2 As can be seen, the oxidant ports are 116 . 122 each with a bent and substantially parallel to one of the main surfaces of the housing part 104 vertical stacking direction 126 aligned vertical, the respective oxidant passage opening 116 . 122 ring-shaped enclosing ring wall 128 surround.

Furthermore, the housing part 104 with a likewise parallel to the stacking direction 126 bent over, along the outer edge of the housing part 104 ring-shaped peripheral edge wall 130 Mistake.

On its underside is the housing part 104 with a substantially parallel to the edge wall 130 circumferential, annularly closed edge seal 132 Mistake.

The edge seal 132 is formed of a substantially gas impermeable material.

The edge seal 132 can be electrically insulating, but it does not have to be.

The edge seal 132 For example, a flat gasket made of mica or a gas-tight coating, which can be applied as a paste by screen printing or by roller coating on the underside of the housing part 104 has been applied.

Furthermore, the housing part 104 on its underside in the region of the exhaust gas passage opening 124 (please refer 4 ) and in the area of the fuel gas passage openings 114 each with a gas channel seal 134 provided, which the respective exhaust gas passage opening 124 or fuel gas passage opening 114 surrounds annularly.

The gas can seal 134 is formed of a substantially gas impermeable material.

The gas can seal 134 may consist of an electrically insulating material, but it does not have to.

As material for the gas channel sealing 134 come the same materials as for the edge seal already described above 132 of the housing part 104 in question.

The top of the housing part 104 with the ring walls 128 and the peripheral edge wall 130 forms a tub, in which one as a whole with 136 designated substrate for the cathode-anode-electrolyte unit 138 (in the following: KAE unit) of the fuel cell unit, which in detail in 9 is shown, is arranged.

How out 9 can be seen, includes the KAE unit 138 a directly on the substrate arranged plate-shaped anode 140 of an electrically conductive ceramic material, for example Ni-ZrO ₂ cermet (ceramic-metal mixture), which is porous to which through the substrate 136 fuel gas passed through the anode 140 adjacent, substantially plate-shaped electrolyte 142 to enable.

As fuel gas, for example, a hydrocarbon-containing gas mixture or pure hydrogen can be used.

The electrolyte 142 is preferably formed as a solid electrolyte and formed for example of yttrium-stabilized zirconia.

On the anode 140 opposite side of the electrolyte 142 adjacent to the same a plate-shaped cathode 144 which is formed of an electrically conductive ceramic material such as LaMnO ₃ and has a porous nature, to an oxidizing agent, such as air or pure oxygen, from a to the cathode 144 adjacent oxidant space 146 the passage to the electrolyte 142 to enable.

The electrolyte 142 is substantially gas-tight, so that no oxidant from the oxidant space 146 through the electrolyte 142 in the substrate 136 and no fuel gas from the substrate 136 through the electrolyte 142 into the oxidant room 146 can get.

Furthermore, the electrolyte acts 142 electrically insulating.

The KAE unit 138 extends over the entire top of the substrate 136 and the tops of the edge wall 130 as well as the ring walls 128 of the housing part 104 so that the electrolyte 142 that in the housing part 104 absorbed substrate 136 gastight from that above the KAE unit 138 lying oxidant space 146 separates.

Alternatively, it can also be provided that only the electrolyte 142 over the entire top of the substrate 136 extends and that the anode 140 and / or the cathode 144 just over the contact field 106 of the housing part 104 corresponding area of the top of the substrate 136 extend as the anode 140 and the cathode 144 only for carrying out the electrochemical reactions in the fuel cell unit 100 but not needed as a gas seal and electrical insulation.

The substrate 136 It has two main tasks: First, it must provide a closed, smooth as possible and even top layer on which the KAE unit 138 For example, by a vacuum plasma spraying method, can be generated. On the other hand, the substrate must 136 have a sufficient porous nature to the fuel gas to access the anode 140 to enable.

In order to fulfill these two functions as optimally as possible, is the substrate 136 as a sintered body 148 formed with a construction of at least two layers, the best from the schematic representation of 8th can be seen. The sintered body 148 includes an upper, the KAE unit 138 (in the 8th due to their small thickness is not visible) facing cover layer 150 with a smaller average grain size and one on the KAE unit 138 opposite underside of the cover layer 150 to the same subsequent carrier layer 152 having a larger average grain size than the cover layer 150 ,

The cover layer 150 and the carrier layer 152 are both formed from a metal-containing powder, the chemical composition of the Powder for the topcoat 150 the same as the powder for the carrier layer 152 or the composition of the powder for the carrier layer 152 can be different.

In particular, the cover layer 150 and the carrier layer 152 both are formed from a FeCrAlY powder sold under the designation FE-151 by the company PRAXAIR in Indianapolis, Illinois, USA. The approximate composition of this FeCrAlY powder is as follows: 30% by weight Cr, 5% by weight Al, 0.5% by weight Y, balance Fe.

The mean grain size in the topcoat 150 is preferably about 20 μm to about 50 μm.

The mean grain size in the carrier layer 152 is preferably about 160 μm to about 250 μm.

The thickness of the cover layer is preferably about 30 μm to about 300 μm.

The thickness of the carrier layer 152 is preferably about 150 μm to about 1500 μm.

The total thickness of the sintered body 148 (perpendicular to the main surfaces of the KAE unit 138 measured) is preferably about 180 μm to about 1800 μm.

As best of the representations of 2 to 5 can be seen forms the sintered body 148 an integrally formed unit, which surrounds the fluid passage openings of the fuel cell unit 100 ie, around the fuel gas passage openings 114 , the exhaust passage opening 124 and the oxidant passages 116 . 122 extends around and that of the housing part 104 essentially completes the formed pan.

In the area of the fuel gas passage openings 114 , the exhaust passage opening 124 and the oxidant passages 116 . 122 has the sintered body 148 in each case a fuel gas passage opening, exhaust gas passage opening or oxidant passage opening, which is substantially perpendicular to its main surfaces through the sintered body 148 extends through.

Likewise, the KAE unit points 138 in the area of the fuel gas passage openings 114 , the exhaust passage opening 124 and the oxidant passages 116 . 122 in each case one fuel gas passage opening, exhaust gas passage opening or oxidant passage opening, which extends through the KAE unit essentially perpendicular to its main surfaces.

Like from the 2 and 3 can be seen, is the side edge 154 of the sintered body 148 in the area of the oxidant through openings 116 . 122 through the ring walls 128 of the housing part 104 from the oxidant passages 116 . 122 separated, so that no oxidizing agent through the lateral edge 154 in the substrate 136 can get.

Like from the 4 and 5 can be seen, is the side edge 154 of the sintered body 148 in the area of the exhaust gas passage opening 124 and the fuel gas passage openings 114 however, to the exhaust passage opening 124 or to the fuel gas passage openings 114 open and forms a lateral boundary of these passage openings, so that fuel gas from the fuel gas passage openings 114 through the side edge 154 in the substrate 136 can pass or exhaust gas from the substrate 136 through the side edge 154 in the exhaust passage opening 124 can get.

The fuel cell unit described above 100 is made as follows:
First, the housing part 104 made by a housing part preform, for example by punching and / or cutting, is separated from a suitable metallic sheet, for example from a steel sheet, whose outer contours the outer contours of the housing part 104 correspond. Subsequently, from the housing part preform by suitable forming operations, in particular Umbiege- and embossing operations, the housing part 104 produced with the shape described above.

Subsequently, the from the top of the housing part 104 , from the ring walls 128 and the border wall 130 formed tub filled with a sintered body material.

The sintered body precursor comprises a first sintered body precursor having a larger average grain size, which is used to form the carrier layer 152 is provided. This first sintered body precursor is first filled into the trough in the desired layer thickness. In particular, this first sintered body precursor may be a metal powder, for example, the above-mentioned FeCrAlY metal powder in a proportion of, for example, about 200 parts by weight and a binder in a suitable solvent, for example, an acrylate polymer dissolved in an ester, in a weight ratio of, for example, about 50 parts by weight include. In particular, a 20% solution of an acrylate resin, for example methacrylate, in butoxyl can be used. Instead of the acrylate resin, an acrylate rubber may also be used.

The mean grain size of the metal powder used for the first sintered body precursor is preferably about 160 μm to about 250 μm. By sieving with sieve elements having through holes of appropriate size, the particles having a size below 160 microns and above 250 microns are substantially completely removed before the production of the sintered body starting material from the metal powder used.

The sieved metal powder is then processed into a dispersion with the solvent and the binder, and the dispersion is introduced into the housing part as a first sintered body starting material, for example by knife coating, spraying or pouring 104 brought in.

Subsequently, the second sintered body precursor material is applied to the first sintered body precursor in the desired layer thickness.

The second sintered body precursor, like the first sintered body precursor, comprises a metal powder which has been made into a dispersion with a solvent and a binder.

As the metal powder, a metal powder having the same chemical composition as the metal powder used for the first sintered body precursor but having a different grain size distribution may be used.

In particular, the above-mentioned FeCrAlY metal powder having an average grain size of about 20 μm to about 50 μm can be used.

This mean grain size is adjusted by sieving the metal powder. Further, particles having a size below about 20 microns or a size above 50 microns are substantially removed by sieving from the metal powder.

As the solvent and binder for the second sintered body precursor, as with the first sintered body precursor, a 20% solution of an acrylate polymer in an ester, for example, an acrylate resin (such as methacrylate) in butoxyl may be used. Instead of the acrylate resin, an acrylate rubber may also be used.

For example, 200 parts by weight of the metal powder are processed with, for example, 50 parts by weight of the binder dissolved in the solvent to a dispersion, which then in a suitable manner, for example by knife coating, spraying or casting, on the already introduced first sintered body starting material in the housing part 104 is applied.

After incorporation of the sintered body materials, the solvent is removed from the sintered body materials by a drying process.

The drying process may include, for example, heating to a temperature in the range of about 80 ° Celsius to about 140 ° Celsius for a period of, for example, about 20 minutes to about 60 minutes.

After the drying process, the sintered body becomes 148 formed from the sintered body materials by a sintering process.

The sintering process can in particular be a heating of the housing part 104 with the sintered body materials contained therein at a temperature of about 1150 ° Celsius during a heating period of, for example, about 5 hours, then maintaining the final temperature of about 1150 ° Celsius over a period of, for example, about 3 hours followed by cooling to ambient temperature.

This sintering process is preferably carried out in an inert gas atmosphere, for example in a nitrogen and / or noble gas atmosphere.

Further, the sintered body precursor is preferably applied during the sintering operation with a pressing force which is generated by means of a suitable press ram.

In the fuel gas passage openings 114 and the exhaust passage opening 124 the fuel cell unit 100 are during filling of the housing part 104 with the sintered body materials and during the sintering process, moldings, which may be formed in particular of an oxide ceramic material, arranged to prevent penetration of the sintered body Vormaterials in the respective through holes.

In the manner described above, the sintered body 148 by sintering in situ, ie within the housing part 104 , in which the sintered body 148 during operation of the fuel cell unit 100 is arranged generates.

In this case, the housing part 104 during the sintering process with its upper side and with the inner sides of the ring walls 128 and the border wall 130 to the sintered body 148 sintered and in this way cohesively with the sintered body 148 connected.

Subsequent connection processes, for example a welding or soldering of the housing part 104 with the sintered body 148 , can therefore be omitted.

After the production of the sintered body 148 becomes the housing part 104 at its bottom with the gas duct seals 134 and the edge seal 132 Mistake.

Then it is at the top of the sintered body 148 the KAE unit 138 in a suitable manner, for example by a vacuum plasma spraying process.

This is the production of the fuel cell unit 100 completed.

To form a functional fuel cell stack are more of the fuel cell units 100 along the stacking direction 126 stacked and braced against each other by means of a suitable clamping device. The fuel cell stack produced in this way is connected to a fuel gas supply, an oxidant supply, an exhaust gas removal and an oxidant removal.

The fuel cell stack produced in this way works as follows:
The fuel gas passage openings 114 the stacked fuel cell units 100 form a fuel gas supply channel 156 by which fuel gas the individual fuel cell units 100 is supplied. The fuel gas passes through lateral edges 154 of the sintered body 148 in the substrate 136 a fuel cell unit 100 and flows along the longitudinal direction 108 of the contact field 106 , From the substrate 136 the fuel gas reaches the anode 140 the fuel cell unit concerned 100 where it is at least partially oxidized.

The oxidation product (water) comes out of the substrate together with excess fuel gas 136 through the side edge 154 of the sintered body 148 in the exhaust passage opening 124 the fuel cell unit concerned 100 ,

The exhaust passage opening 124 the stacked fuel cell units together form a Abgasabführkanal 158 through which the exhaust gas of the fuel cell units 100 is discharged to a (not shown) exhaust treatment unit.

The oxidant passages 116 in the left end areas 112 the housing parts 104 the fuel cell units 100 together form an oxidant feed channel 160 by which the oxidizing agent is the fuel cell units 100 is supplied. In this case, the oxidizing agent passes out of the Oxidationsmittelzuführkanal 160 through the spaces between the ring walls 128 stacked fuel cell units 100 in each case between a KAE unit 138 and the housing part 104 an adjacent fuel cell unit 100 arranged oxidant rooms 146 , in which the oxidizing agent along the longitudinal direction 108 of the contact field 106 flows along. From the oxidant are at the cathodes 144 every KAE unit 138 Oxygen ions are formed by the electrolyte 142 to the anode 140 the respective KAE unit 138 hike. Excess oxidant passes out of the oxidant spaces 146 into the oxidant passageway 122 in the right end areas 120 the housing parts 104 the fuel cell units 100 which together multiple Oxidationsmittelabführkanäle 162 form. Through these Oxidationsmittelabführkanäle 162 the excess oxidant is removed from the fuel cell stack.

The flow direction of the fuel gas and the exhaust gas through the fuel cell stack is shown in the drawings with simple arrows 164 , the flow direction of the oxidant by means of double arrows 166 specified.

One in the 10 to 12 illustrated second embodiment of a fuel cell unit 100 differs from the first embodiment described above in that the ring walls 128 and the border wall 130 not only comprise a vertically oriented portion, but in addition with a substantially horizontal (ie, substantially perpendicular to the stacking direction 126 ) aligned edge flange 168 respectively. 170 are provided.

The edge flanges 168 . 170 are at their top substantially flush with the top of the substrate 136 ,

The edge flanges 168 . 170 are at their top with the KAE unit 138 but at least with the electrolyte 142 the KAE unit 138 , provided and thus completed upwards both gas-tight and electrically insulating.

By the edge flanges 168 . 170 is guaranteed that the KAE unit 138 or the electrolyte 142 from the top of the sintered body 148 from over a further distance away on areas of the housing part 104 can extend, so that a more reliable sealing of the transition between the sintered body 148 and the housing part 104 can be achieved, as is the case in the first embodiment described above.

In this second embodiment is thus particularly reliably prevents fuel gas from the substrate 136 into the oxidant room 146 can get.

Otherwise, the second embodiment of a fuel cell unit is correct 100 in terms of structure and function with the first embodiment, to the above description, reference is made in this regard.

One in the 13 to 20 illustrated third embodiment of a fuel cell unit 100 differs from the first embodiment described above in that the sintered body 148 of the substrate 136 not in situ in the housing part 104 has been sintered, but rather outside of the housing part 104 manufactured and only then in the housing part 104 has been used and connected to the same.

In the production of this embodiment, the sintered body materials for producing the sintered body become 148 not in the housing part 104 but applied to a suitable external carrier, in particular by spraying, pouring or knife coating.

This carrier can be formed, for example, from an oxide ceramic material, in particular from an aluminum oxide ceramic material.

The sintered ceramic precursor material can, as in the first embodiment, comprise at least two layers with different particle size distribution.

After application of the sintered body ceramics, the solvent is removed by a drying process.

For example, the drying process may include heating to a temperature in the range of about 80 ° Celsius to about 140 ° Celsius for a drying period of, for example, about 20 minutes to about 60 minutes.

After drying, the sintering of the sintered body takes place 148 by a sintering process comprising heating the sintered body precursor and the support from room temperature to a temperature of, for example, about 1150 ° Celsius during a heating period of, for example, about 5 hours, maintaining the achieved final temperature during a holding period of, for example, about 3 hours, and a subsequent Cool to room temperature.

The sintering process is preferably carried out under an inert gas atmosphere, for example a nitrogen and / or noble gas atmosphere.

Further, the sintering process is preferably carried out by pressurizing the sintered body precursor at a pressing pressure of, for example, about 10,000 Pa, which is produced by means of a suitable press die.

The sintered body formed by the sintering process 148 is in the housing part 104 used and at welds 171 along the inner edges of the ring walls 128 and the border wall 130 of the housing part 104 welded to the housing part, for example by laser welding or electron beam welding.

After the connection of the sintered body 148 with the housing part 104 becomes the housing part 104 with the edge seal 132 and the gas duct seals 134 Mistake.

Subsequently, the KAE unit 138 at the top of the sintered body 148 , for example by a vacuum plasma spraying process.

This is the production of the third embodiment of a fuel cell unit 100 completed.

Like from the 14 to 17 can be seen corresponds to the outer shape of the sintered body 148 the third embodiment of a fuel cell unit 100 not completely the outer shape of the sintered body 148 the first embodiment. Rather, the sintered body 148 the third embodiment on its underside in the outside of the contact field 106 lying areas with recesses 172 provided during operation of the fuel cell unit 100 with the fuel cell unit 100 supplied fuel gas or with the from the fuel cell unit 100 discharged exhaust gas are filled. This recess 172 have a lower flow resistance than the substrate 136 and thus facilitate the distribution of the fuel gas in the fuel cell unit 100 or the discharge of the exhaust gas from the fuel cell unit 100 ,

The recesses 172 become in the production of the sintered body 148 produced by the fact that the carrier, on which the sintered body pre-material is applied, with the recesses 172 appropriate surveys is provided.

In a variant of the manufacturing method of the third embodiment of a fuel cell unit 100 the sintered body-starting material is initially not on the carrier, which for the Sintering process is used, applied, but first applied to the drying process on a drying support made of a paper with an anti-adhesion coating or of a plastic material. The order can be done for example by spraying, pouring or knife coating, preferably by casting or knife coating.

After application of the sintered ceramic precursor, a drying process is carried out.

For example, the drying process may include heating to a temperature of, for example, about 80 ° Celsius to 140 ° Celsius for a drying period of, for example, about 20 minutes to about 60 minutes.

After the drying process, the dried layer of the sintered body starting material is removed from the drying carrier and placed on a sintered carrier made of a ceramic material, for example of aluminum oxide. Subsequently, a sintering process, as already described above.

The finished sintered sintered body 148 is in the housing part 104 introduced and connected to the same, for example by welding.

Otherwise, the third embodiment of a fuel cell unit is correct 100 in terms of structure, function and method of manufacture with the first embodiment, to the description of which reference is made.

One in the 21 to 23 illustrated fourth embodiment of a fuel cell unit 100 differs from the third embodiment described above in that the sintered body 148 in the area of the fuel gas passage openings 114 and the exhaust passage opening 124 with its side edge 154 not directly adjacent to the respective passage opening, but at a distance from the respective passage opening on the outside of an annular support member 174 is present, which surrounds the respective passage opening annularly and with radially aligned to the respective passage opening gas passageways 176 is provided.

Each of these support elements 174 will be from an in 23 shown, substantially planar support element preform 178 formed, which from a starting material, for example of a metallic material, preferably from a steel sheet, separated out, for example, punched or cut, is.

The support element preform 178 comprises two substantially annular support elements 180 whose ring inner diameter d each have the diameter of one of the fuel gas passage openings 114 or the exhaust passage opening 124 corresponds, depending on whether the support element to be produced from the preform 174 at a fuel gas passage opening 114 or an exhaust passage opening 124 should be arranged.

From the outside of each ring carrier element 180 are several, for example, eight, tabs 182 radially outward. How out 23 can be seen, the tabs are rejuvenated 182 to her the support element 180 facing away from the free end.

Further, adjacent tabs are 182 along the circumference of the carrier element 180 spaced apart.

One of the tabs 182a of the first carrier element 180a is at her the support element 180a opposite end with the second support element 180b opposite end of a tab 182b the second carrier element 180b connected so that the from the support elements 180 and tabs 182 formed support element preform 178 is formed in one piece as a whole.

Before installing the fuel cell unit 100 is made by bending or folding operations from the in 23 illustrated support element preform 178 that in the 21 and 22 illustrated finished support element 174 educated.

For this purpose, the tabs 182 of the first carrier element 180a along the tantential to the outer edge of the support element extending bending lines 184 in which these tabs on the first support element 180a adjoin, bent at an angle of about 180 ° down and on the bottom 186a of the first carrier element 180a folded back.

Likewise, the tabs 182 the second carrier element 180b along the bending lines 184 to which these tabs on the second support element 180b adjoin, bent at an angle of about 180 ° down and on the bottom 186b the second carrier element 180b folded back.

Then the tab 182a of the first carrier element 180a around the bend line 184a at which the tab 182a to the first carrier element 180a adjoins, bent at an angle of about 180 ° down and on the bottom 186a of the first carrier element 180a folded back, with the tab too 182b and the second support member 180b rotated by about 180 °.

Then the tab 182b along the bend line 188 at which the tab 182b to the tab 182a adjoins, bent at an angle of about 180 ° and on the tab 182a folded back, wherein also the second carrier element 180b is rotated through an angle of about 180 °.

Finally, the second carrier element 180b around the bend line 184b at which the second carrier element 180b to the tab 182b adjoins, bent at an angle of about 180 ° down and on the tab 182b folded back, so that the second carrier element 180b vertically below the first carrier element 180a comes to rest and the tabs 182 both support elements 180 are arranged between them, as in 21 shown.

In this assembled state of the support element 174 the margins run 190 the tabs 182 substantially radially to the central axis 192 the support element 174 ,

Like from the 21 and 22 can be seen, are between the adjacent tabs 182 the support elements 180 Gas transit channels 176 with substantially rectangular, to the outside of the support element 174 formed cross-sections widening whose height of the sum of the heights of two abutting tabs 182 and whose width is the distance between two adjacent tabs 182 along the circumferential direction of the carrier elements 180 equivalent.

The annular support elements thus formed 174 be during assembly of a fuel cell unit 100 in the area of the fuel gas passage openings 114 or in the region of the exhaust gas passage opening 124 so on the top of the housing part 104 arranged that the top 194b the carrier element 180b at the top of the housing part 104 lies flat.

The top 194a of the first carrier element 180a lies in the assembled state of the fuel cell stack surface at the bottom of a gas channel seal 134 an adjacent fuel cell unit 100 at.

Because the tabs 182 a support element 180 flat on the tabs 182 an adjacent support element 180 the support element 174 abut and that the tabs 182 in each case flat on one of the support elements 180 abut, is a homogeneous as possible Dichtpressungsverteilung on the support 174 achieved in the installed state.

The gas passageways 176 between the tabs 182 are formed, allow gas exchange between the ring inner side and the ring outer side of the support element 174 with only a small flow resistance.

By choosing the thickness of the starting material from which the support element preform 178 punched or cut, the total height of the finished support element 174 be set to any desired value.

Furthermore, it would also be possible, the tabs 182 each fold several times, so a higher installation thickness of the support 174 to achieve.

In addition, several support elements could 180 , which are not integrally connected to each other, are arranged one above the other to the support element 174 to build.

After insertion of the annular support elements 174 and the sintered body 148 in the housing part 104 become the sintered body 148 and the annular support elements 174 along the upper outer edge of the support elements 174 , for example, by a weld 196 , connected with each other.

Otherwise, the fourth embodiment of a fuel cell unit is correct 100 in terms of structure, function and method of manufacture with the third embodiment, to the above description of which reference is made.

Claims (42)

A fuel cell unit comprising a cathode-anode electrolyte unit ( 138 ) with a cathode ( 144 ) of an electrically conductive ceramic material, with an oxygen-ion-conducting solid electrolyte ( 142 ) and with an anode ( 140 ) of an electrically conductive ceramic material and a substrate ( 136 ) on which the cathode-anode-electrolyte unit ( 138 ), wherein the fuel cell unit ( 100 ) at least one fluid passage opening ( 114 . 116 . 122 . 124 ), through which a fluid through the fuel cell unit ( 100 ), whereby the substrate ( 136 ) a sintered body ( 148 ), which surrounds the at least one fluid passage opening ( 114 . 116 . 122 . 124 ), and wherein the sintered body ( 148 ) in a about the at least one fluid passage opening ( 114 . 116 . 122 . 124 ) is provided with an insulating layer of an electrically insulating material. Fuel cell unit according to claim 1, characterized in that the cathode-anode-electrolyte unit ( 138 ) directly on the sintered body ( 148 ) is arranged. Fuel cell unit according to one of claims 1 or 2, characterized in that the fuel cell unit ( 100 ) at least one fuel gas passage opening ( 114 ), through which a fuel gas through the fuel cell unit ( 100 ), and that the sintered body ( 148 ) around the at least one fuel gas passage opening ( 114 ) extends around. Fuel cell unit according to one of claims 1 to 3, characterized in that the fuel cell unit ( 100 ) at least one exhaust gas passage opening ( 124 ), through which an exhaust gas through the fuel cell unit ( 100 ), and that the sintered body ( 148 ) around the at least one exhaust gas passage opening ( 124 ) extends around. Fuel cell unit according to one of claims 1 to 4, characterized in that the fuel cell unit ( 100 ) at least one oxidant passage ( 116 . 122 ), by which an oxidizing agent through the fuel cell unit ( 100 ), and that the sintered body ( 148 ) around the at least one oxidant passage ( 116 . 122 ) extends around. Fuel cell unit according to one of claims 1 to 5, characterized in that the fluid passage opening ( 114 . 116 . 122 . 124 ) a portion of a perpendicular to the major surfaces of the cathode-anode-electrolyte unit ( 138 ) through the fuel cell unit ( 100 ) extending fluid channel ( 156 . 158 . 160 . 162 ). Fuel cell unit according to one of claims 1 to 6, characterized in that the sintered body ( 148 ) a lateral boundary of at least one fluid passage opening ( 114 . 124 ) of the fuel cell unit ( 100 ). Fuel cell unit according to one of claims 1 to 7, characterized in that the sintered body ( 148 ) in a about the at least one fluid passage opening ( 114 . 116 . 122 . 124 ) is provided with a sealing layer of a gas impermeable material. Fuel cell unit according to one of claims 1 to 8, characterized in that the electrolyte ( 142 ) of the cathode-anode-electrolyte unit ( 138 ) around the at least one fluid passage opening ( 114 . 116 . 122 . 124 ) extends around. Fuel cell unit according to one of claims 1 to 9, characterized in that at the at least one fluid passage opening ( 114 . 124 ) one of the sintered body ( 148 ) various support element ( 174 ) is arranged. Fuel cell unit according to claim 10, characterized in that the supporting element ( 174 ) is annular. Fuel cell unit according to one of claims 10 or 11, characterized in that the supporting element ( 174 ) is formed of a metallic material. Fuel cell unit according to one of claims 10 to 12, characterized in that the supporting element ( 174 ) is formed as a sheet metal part. Fuel cell unit according to one of claims 10 to 13, characterized in that the support element ( 174 ) to the sintered body ( 148 ) is sintered. Fuel cell unit according to claim 14, characterized in that the supporting element ( 174 ) during the formation of the sintered body ( 148 ) from a sintered body precursor to the sintered body ( 148 ) has been sintered. Fuel cell unit according to any one of claims 10 to 15, characterized in that the supporting element ( 174 ) in a to the fluid passage opening ( 114 . 124 ) is provided with a sealing layer of a gas impermeable material. Fuel cell unit according to one of claims 10 to 16, characterized in that the supporting element ( 174 ) in a to the fluid passage opening ( 114 . 124 ) is provided with an insulating layer of an electrically insulating material. Fuel cell unit according to one of claims 10 to 17, characterized in that the electrolyte ( 142 ) of the cathode-anode-electrolyte unit ( 138 ) the supporting element ( 174 ) at least partially covered. Fuel cell unit according to one of claims 1 to 18, characterized in that the sintered body ( 148 ) is formed by sintering from a starting material, which contains metallic particles, and that the mean grain size in a first layer ( 150 ) of the sintered body ( 148 ), which the cathode-anode-electrolyte unit ( 138 ) is smaller than in a second layer ( 152 ) of the sintered body ( 148 ) located a greater distance from the cathode-anode-electrolyte unit ( 138 ) than the first layer ( 150 ) of the sintered body ( 148 ). Fuel cell unit according to claim 19, characterized in that the middle Grain size in the sintered body ( 148 ) with increasing distance from the cathode-anode-electrolyte unit ( 138 ) increases monotonously. Fuel cell unit according to one of claims 19 or 20, characterized in that the mean grain size in the sintered body ( 148 ) with increasing distance from the cathode-anode-electrolyte unit ( 138 ) increases continuously. Fuel cell unit according to one of claims 19 or 20, characterized in that the mean grain size in the sintered body ( 148 ) with increasing distance from the cathode-anode-electrolyte unit ( 138 ) stepwise, with one or more steps, increases. Fuel cell unit according to one of claims 19 to 22, characterized in that the sintered body ( 148 ) at least one of the cathode-anode-electrolyte unit ( 138 ) facing first layer ( 150 ), in which the mean grain size is at most 160 μm, preferably at most 80 μm, in particular at most 50 μm. Fuel cell unit according to one of claims 19 to 23, characterized in that the first layer ( 150 ) contains no grains which are larger than 160 microns, preferably no grains which are larger than 80 microns, in particular no grains which are larger than 50 microns. Fuel cell unit according to one of claims 19 to 24, characterized in that the first layer ( 150 ) of the sintered body ( 148 ) has a constant grain size distribution across the thickness of the layer. Fuel cell unit according to one of claims 19 to 25, characterized in that the first layer ( 150 ) of the sintered body ( 148 ) has a thickness of at most 300 microns. Fuel cell unit according to one of claims 19 to 26, characterized in that the first layer ( 150 ) of the sintered body ( 148 ) directly to the cathode-anode-electrolyte unit ( 138 ) adjoins. Fuel cell unit according to one of claims 19 to 27, characterized in that in the second layer ( 152 ) of the sintered body ( 148 ) the average particle size is at least 50 μm, preferably at least 80 μm, in particular at least 160 μm. Fuel cell unit according to one of claims 19 to 28, characterized in that the second layer ( 152 ) of the sintered body ( 148 ) contains no grains which are smaller than 50 microns, preferably no grains which are smaller than 80 microns, in particular no grains which are smaller than 160 microns. Fuel cell unit according to one of claims 19 to 29, characterized in that the second layer ( 152 ) of the sintered body ( 148 ) has a constant grain size distribution across the thickness of the layer. Fuel cell unit according to one of claims 19 to 30, characterized in that the second layer ( 152 ) has a thickness of at least 150 microns. Fuel cell unit according to one of claims 19 to 31, characterized in that the first layer ( 150 ) of the sintered body ( 148 ) has a smaller thickness than the second layer ( 152 ) of the sintered body ( 148 ). Fuel cell unit according to one of claims 1 to 32, characterized in that the sintered body ( 148 ) has a thickness of at most 5000 μm, preferably of at most 1600 μm, in particular of at most 400 μm. Fuel cell unit according to one of claims 1 to 33, characterized in that the sintered body ( 148 ) has a thickness of at least 100 μm, preferably of at least 200 μm. Fuel cell unit according to one of claims 1 to 34, characterized in that the sintered body ( 148 ) contains a metallic material, in particular iron, chromium, aluminum, yttrium and / or nickel in metallic form. Fuel cell unit according to one of claims 1 to 35, characterized in that the fuel cell unit ( 100 ) a housing ( 102 ), which at least one housing part ( 104 ) obtained by sintering with the sintered body ( 148 ) of the substrate ( 136 ) connected is. Fuel cell unit according to claim 36, characterized in that the housing part ( 104 ) with the sintered body formed during sintering in situ from a sintered body precursor material ( 148 ) of the substrate ( 136 ) connected is. Fuel cell unit according to one of claims 36 or 37, characterized in that the housing part ( 104 ) to one of the cathode-anode-electrolyte unit ( 138 ) facing away from the surface of the sintered body ( 148 ) is sintered. Fuel cell unit according to one of claims 36 to 38, characterized in that the housing part ( 104 ) with at least one contact element ( 110 ) for contacting the cathode-anode-electrolyte unit ( 138 ) of an adjacent fuel cell unit ( 100 ) is provided. Fuel cell unit according to one of claims 36 to 39, characterized in that the housing part ( 104 ) a trough for receiving the sintered body ( 148 ). Fuel cell unit according to one of claims 36 to 40, characterized in that the housing part ( 104 ) is formed as a sheet metal part. Method for producing a fuel cell unit comprising a cathode-anode-electrolyte unit ( 138 ) with a cathode ( 144 ) of an electrically conductive ceramic material, with an oxygen-ion-conducting solid electrolyte ( 142 ) and with an anode ( 140 ) of an electrically conductive ceramic material and a substrate ( 136 ) on which the cathode-anode-electrolyte unit ( 138 ), comprising the following method steps: - generating at least one layer ( 150 . 152 ) a sintered body starting material, which at least one fluid passage opening ( 114 . 116 . 122 . 124 ) around which the layer of sintered body precursor extends; Producing a sintered body ( 148 ) from the sintered body precursor by a sintering process; Generating the cathode-anode-electrolyte unit ( 138 ) on the sintered body; the sintered body ( 148 ) in a about the at least one fluid passage opening ( 114 . 116 . 122 . 124 ) is provided with an insulating layer of an electrically insulating material.

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