Gasket for a solid oxide fuel cell cell, arrangement and solid oxide fuel cell cell with

Abstract

The invention relates to a sealing gasket for sealing between a plurality of stacked electrochemical cells of solid oxide fuel cells and a base plate, having at least one metal sealing layer in which a sealing element is pressed, characterized in that the metal layer has at least one fastening point, the fixing point has a structure protruding from a surface of the metal layer, adjacent to a structure forming an outer side of the flat sealing gasket, and having at least one free edge in a protruding region.

Description

Technical Field

[0001] The invention relates to a sealing gasket for an arrangement between a base plate and a stack of electrochemical cells in a solid oxide fuel cell cell. Background Art

[0002] Solid oxide fuel cell cells are high temperature fuel cell cells whose electrolyte consists of solid ceramic material. This type of fuel cell cell has stacked electrochemical cells arranged on a base plate. The supply of reactants and the discharge of products and unused reactants are carried out via openings in the stacked electrochemical cells and the base plate, which extend in the stacking direction of the electrochemical cells.

[0003] Therefore, a seal is required between the base plate and the stack of electrochemical cells to prevent or minimize the leakage of products and precipitates through the gap between the base plate and the cell stack.

[0004] Solid oxide fuel cell cells operate at high temperatures ranging from 600°C to 1200°C, and due to the high temperatures, it is difficult for conventional seals to achieve such a seal. Even when a metal layer seal (MLS) is used, the strong temperature fluctuations between the operation and non-operation of the fuel cell cells can cause relative movement between the base plate and the seal, and between the seal and the battery cell stack, which affects the sealing effect.

[0005] Conventionally, relative movement is prevented by having such stud bolts on the base plate, which engage in openings in the seal and thus fix the seal. However, this solution is complex and costly.

[0006] Alternatively, in the prior art, the seal is completely inserted into a flat recess milled for this purpose into the base plate, the depth of which must be precisely determined so that the thickness of the seal is sufficient but does not extend too far beyond the depth of the milled recess. However, this requires a high degree of precision in the milling of the recess in the base plate and a very precisely dimensioned flat seal which is centrally arranged in the flat milled recess. Such a sealing gasket inserted in a milled recess is difficult to press into the main force connection between the base plate and the battery cell stack. This further impairs the sealing effect of the sealing gasket. Summary of the invention

[0007] Therefore, the object of the present invention is to provide a sealing gasket, an arrangement including a base plate and a battery cell stack end plate, and a solid oxide fuel cell cell, which can be produced at low cost, has a high sealing effect, and minimizes the relative movement between the base plate and the sealing gasket of the solid oxide fuel cell cell.

[0008] This object is achieved by a sealing gasket according to claim 1, an arrangement according to claim 9 and a solid oxide fuel cell cell according to claim 10. Advantageous further embodiments of the solution according to the invention are given in the dependent claims.

[0009] The sealing gasket according to the present invention is used for sealing between a plurality of stacked electrochemical battery cells and a base plate of a solid oxide fuel cell monomer. It has at least one metal sealing layer, in which a sealing element is convexly pressed. Such a metal seal is particularly suitable for sealing between two surfaces of two components under high temperature and high pressure.

[0010] According to the invention, the metal layer has at least one fixing point. The fixing point has a structure that protrudes from the surface of the metal layer adjacent to the structure that forms the outside of the gasket. In other words, this structure protrudes beyond the adjacent surface of the metal layer in the direction of one of the components between which the gasket is to seal. The structure has at least one free edge in the protruding area.

[0011] By means of the free edge of this structure, which can be, for example, a tab bent out of the metal layer, the gasket can be positively fixed in at least one direction in the plane of the metal layer of the gasket to an adjacent component, in particular to the base plate of the solid oxide fuel cell cell or also to the battery cell stack or another adjacent component. It is sufficient as long as the structure, for example the tab, engages in a recess in the surface of the adjacent component. If the seal is only fixed by one free edge, movement in other directions in the plane of the metal layer is still possible. By using such further structures that are appropriately designed and positioned, according to the present invention, the gasket can also be fixed to the adjacent component in other directions. It is always possible to fix the gasket to the adjacent component using a suitable design and with almost no play or with play in one, several or all directions.

[0012] The solution according to the invention avoids the need to mill a recess for the entire seal into an adjacent component, such as a base plate, and avoids the requirements for precision of the milled recess and the flat seal that are common in the prior art and are associated with this solution. Furthermore, the design of the sealing gasket according to the invention allows it to be arranged in the main force connection between adjacent components to be sealed against each other, thus achieving an improved seal. However, the sealing gasket is able to absorb sliding forces between the components without displacement in an impermissible manner relative to the adjacent components.

[0013] The structure according to the invention can provide to be not limited to fixing the sealing gasket to a (single) adjacent component. On the contrary, this structure according to the invention can also be arranged on both sides of the sealing gasket, thereby fixing the sealing gasket to the two components between which the sealing gasket is located.

[0014] It is also possible to arrange one or more of the structures according to the invention in the same or different orientations on one or both sides of the sealing gasket.

[0015] Solid oxide fuel cell cells usually do not have only a single stacked electrochemical cell per substrate, but two or more cell stacks can also be arranged adjacent to each other on the substrate. In this case, a separate gasket according to the invention can be arranged on the base plate for each stack, or a gasket with a continuous metal layer can be arranged for two or more stacks or even for all stacks. If several stacks are arranged on a common gasket, several structures according to the invention can also be arranged on the gasket, so that the gasket is fixed in different areas on the base plate, or the gasket is fixed independently on each individual stack or on each of the stacks.

[0016] Advantageously, the structure according to the invention can be a convex or bent structure. In this way, the structure can be formed cost-effectively in the metal layer using bending or convex techniques. In particular, the structure can be a convex flange that has a free edge at at least one of its longitudinal ends. It can also have free edges at both longitudinal ends of the flange, so that the flange is designed as a web (web) extending transversely to the direction of the flange.

[0017] Advantageously, the flange can be a complete flange. However, it can also be designed as a semi-flange. If the structure is designed as a semi-flange, which has free edges at its two ends in the direction of the flange and also has a free edge at one of its ends in a transverse direction relative to the direction of the flange, the semi-flange forms a tab bent out of the plane of the metal layer.

[0018] The structure may be an embossed or bent tab - also a possible design independent of a semi-convex edge as described above - which projects out of the plane of the metal layer and has a free edge at its protruding end.

[0019] Advantageously, whether as a full bead or as a half bead, the bead has a substantially or completely flat bead top, at least in certain areas, wherein advantageously the plane of the flat area of ​​the bead top is substantially or completely parallel to the plane of the metal layer adjacent to the bead.

[0020] Advantageously, however, the rim can also have, on both sides at least in some regions, a substantially or completely rounded rim top and / or a tapered rim top at least in some regions.

[0021] The invention also relates to an arrangement comprising a base plate and a stacking end plate, the stacking end plate being arranged on the base plate for stacking one or more electrochemical cells of a solid oxide fuel cell cell, wherein the base plate and / or the stacking end plate has at least one recess, and a sealing gasket according to the invention is arranged between the base plate and the stacking end plate. The sealing gasket having the structure according to the invention is arranged so that its protruding structure engages in the recess.

[0022] If there are several structures according to the invention in the gasket, which protrude from a plane in the direction of an adjacent component, a base plate or a stacked end plate, a recess must be arranged in the adjacent component for each of the structures, in which the structure can engage. A recess can be provided for each of the structures, or a common recess can be provided for several of the structures. Alternatively, one or more structures can also be fixed to the outer edge of the base plate.

[0023] The invention also relates to a solid oxide fuel cell cell with a base plate, at least one stack of one or more electrochemical cells and at least one stack end plate, which is arranged between the base plate and the stack at the end of the stack facing the base plate. The base plate and / or the stack end plate have at least one recess. The sealing gasket according to the invention is arranged between the base plate and the stack end plate. The sealing gasket having the structure according to the invention is arranged so that its protruding structure engages in the recess.

[0024] The gasket has at least one metal layer. However, the gasket may also have several metal layers. Any of the metal layers may comprise a structure according to the invention, but it is important that, when the structure according to the invention is arranged in one of the inner layers of the gasket, the structure must extend beyond the adjacent surface of the gasket so that it can engage a recess in an adjacent component. Preferably, however, the structure according to the invention is located in one or both of the outer or outermost layers of the gasket and protrudes beyond the outer surface of the corresponding layer adjacent to the corresponding structure in the plane of the layer.

[0025] The outer shape of the gasket is not subject to any restrictions; the outer dimensions of the gasket can be smaller entirely or only in certain areas than the outer dimensions of the adjacent components, in particular the base plate or one or both stack end plates. However, the gasket can also protrude entirely or only in certain areas beyond the outer dimensions of one or both adjacent components, in particular the base plate or the stack end plates. It is also possible to precisely match the outer dimensions of the gasket to the outer dimensions of one or both adjacent components entirely or only in certain areas.

[0026] One or more of the sealing elements of the sealing pad can be closed sealing ridges. For example, they can run around a through opening in the sealing pad or around the peripheral edge of the sealing pad.

[0027] The following materials are preferably used:

[0028] Spring steel, stainless steel or nickel-based alloys are used for the gaskets. The advantage of using nickel-based alloys is that they are particularly suitable for use at high temperatures. They are also characterized by high creep resistance.

[0029] Pressure casting, cast steel and stainless steel for base plates.

[0030] Stainless steel, titanium or high temperature alloys for stacking end plates.

[0031] Some examples of gaskets, arrangements and solid oxide fuel cell monomers according to the invention are given below. The same and similar reference numerals denote the same or similar elements. Therefore, the description of the same reference numerals is not always repeated. In the examples below, the requirements and optional features of the invention are shown together in each case. However, it is also possible to combine individual or several optional features of individual or several examples with each other without implementing further optional features. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the attached picture:

[0033] Figure 1 The arrangement of the base plate and the gasket is shown;

[0034] Figures 2 to 5 is each cross section of a sealing gasket according to the present invention in arrangement (partial diagram A) and in isolation (partial diagram B); and

[0035] Figure 6 The arrangement of the sealing gasket in the solid oxide fuel cell cell according to the present invention is shown. DETAILED DESCRIPTION

[0036] Figure 1 The arrangement of a solid oxide fuel cell cell 1 is shown in transverse section and in a section around a fixing point 20, with a base plate 2 and a sealing gasket 10, which in this example has a metal layer 11. Figure 6 An electrochemical cell 4 of a cell stack 3 of a fuel cell 1 is shown.

[0037] The bottom plate has a surface 7 facing the gasket 10. The gasket has a surface 14 facing the bottom plate 2 and - not necessarily, but in this case - resting directly on the surface 7 of the bottom plate 2. The gasket 10 also has a surface 15 facing away from the bottom plate 2. Since the gasket 10 has only one metal layer 11 in this example, the surfaces 14 and 15 are also the surfaces of the metal layer 11. Facing the gasket 10 and the surface 15 of the metal layer 11 is a stack end plate 8 with a surface 9 facing the gasket 10.

[0038] The base plate 2, the seal 10 and the stack end plate 8 each have through openings 5 ​​or 13 and 16 for the passage of screws 19 as fastening means, thereby fixing the stack end plate 8 and the seal 10 to the base plate 2. Despite this screw connection, lateral displacement of the seal 10 relative to the base plate 2 still occurs due to the high temperature in the solid oxide fuel cell monomer 1 and the resulting strong temperature changes.

[0039] In order to limit these lateral displacements and absorb the sliding forces, the base plate 2 has a flat recess 6 milled into its surface 7 facing the seal 10. The seal has a fixing point 20. This fixing point is designed as a web 21, which protrudes from the surface 14 of the seal 10 facing the base plate 2 in the direction of the base plate 2 and engages in the recess 6. In the transverse section shown, the web 21 is designed as a full bead with a substantially flat, uniform bead top. The web 21 is pressed or bent out of the plane of the seal 10. It has free edges running parallel to the drawing plane in front and behind the drawing plane, by which the web 21 and therefore the seal 10 are positively fixed relative to the base plate 2 in a direction perpendicular to the drawing plane, with or without play. This allows the web to absorb sliding forces in a direction perpendicular to the drawing plane and prevents excessive displacement of the seal 10 relative to the base plate 2 in this direction.

[0040] However, the web does not fix the seal 10 in the drawing plane in the horizontal direction relative to the base plate 2, but allows displacement in this direction. Such displacement can be prevented or limited by the arrangement of further fixing points designed according to the invention. For this purpose, duplicates of the fixing point 20 can be arranged at different locations on the seal 10 and the orientation of the web 21 can be rotated relative to the fixing point 6.

[0041] Figure 2 In part A, a cross-sectional view is shown. Figure 1 , and in the partial figure B an oblique plane view of the metal layer 11 of the sealing gasket 10 is shown without a cross-sectional view.

[0042] The fixing point 20 has a web 21 exposed between two through openings 23a and 23b, the web 21 being designed as a collar 21. The collar 21 extends in its longitudinal direction between the two openings 23a and 23b, so that the web forms free edges 22a and 22b as part of the peripheral edge of the openings 23a and 23b, which extend to both sides of the web 21. The collar 21 has a collar top 24 which is substantially flat and runs in the recess 6 when the gasket 10 is mounted on the base plate 2. The free edges 22a and 22b form stops on the adjacent edges of the recess 6 and thus limit the displacement of the web 21 and thus the metal layer 11 of the gasket 10 in a form-fitting manner in the direction of the longitudinal extension of the collar top 24.

[0043] Figure 3 Part A and Part B show the following Figure 2 The metal layer 11 of the sealing gasket 10 is designed to be Figure 2 However, with Figure 2 Differently, the recess in the base plate 2 is not designed as a flat cutout 6, but as a through hole 6 with a rounded transverse cross section that passes through the base plate 2. Now, the free edges 22a and 22b of the web 21 are positively engaged in the opening 6 of the base plate 2 and are in a manner similar to that of the web 21. Figure 2 The metal layer 11 of the sealing gasket 10 is fixed in the same manner as in FIG.

[0044] Figure 4 Part A and Part B show the following Figure 2 A and B parts of the figure show the fixing point 20 in a similar manner. The recess 6 of the bottom plate 2 is connected to the Figure 2 The substantially rectangular flat cutouts in the surface 7 of the bottom plate 2 are substantially of the same shape. Only the corners of the rectangular flat cutouts are rounded. Figure 2 Differently, Figure 4The web 21 in the embodiment of the present invention is not designed as a flange, the flange tip 24 of which projects furthest in the direction of the base plate 2 between the openings 23a and 23b perpendicularly to the longitudinal extent of the web 21 and engages in the recess 6. Instead, the web 21 is designed as a flange, the flange tip 24 of which runs in the plane of the metal layer 11 and the flange tip 24 of which runs to the metal layer 11 between the connection points of the web 21. The free edges 22a and 22b of the web 21 facing the openings 23a and 23b and partially forming the circumferential edges of the openings 23a and 23b are bent out of the plane of the metal layer 11 in the direction of the surface 7 of the base plate 2, in the adjacent region and in the plane of the flange tip 24. As a result, the region between the flange tip 24 and the free edges 22a and 22b each forms a tab 25a or 25b as a flank of the flange 21, which engages in the recess 6 of the base plate 2. This means that the free edges 22 a and 22 b also engage in the recess 6 in the surface 7 of the base plate 2 and limit the play of the sealing gasket 10 in a form-fitting manner in the extension direction between the two openings 23 a and 23 b .

[0045] Figure 5 Shown with Figure 4 Similar fixing points. However, the corners of the free edges 22a and 22b of the tabs 25a and 25b engage in the rounded recess 6 of the base plate 2. Since the recess 6 in the base plate 2 for fixing against displacement has a rounded transverse section, the free edges 22a and 22b do not contact the wall of the recess 6 over their entire length, but only the corners of the edges 22a' and 22a", and 22b' and 22b'" fix the sealing gasket 10. However, Figure 5 The sealing gasket 10 and Figure 4 The sealing gasket 10 in is designed in the same way.

[0046] Figure 6 The structure of a solid oxide fuel cell cell 1 is shown with a base plate 2, a sealing gasket 10 according to the invention, a stacking end plate 8 and electrochemical cells 4, which form a cell stack 3. The cell stack 3 is delimited at the upper end by an upper stacking end plate 17. The sealing gasket 10 according to the invention comprises sealing elements 12a and 12b, which surround a medium inlet 26 and a medium outlet 27, and two fixing points 20a and 20b according to the invention, which engage in recesses 6a and 6b of the base plate 2. The fixing elements 20a and 20b are symbolized here by boxes and, in this case, fix the sealing gasket 10 to the base plate 2 against displacement out of the drawing plane. As a result, the stacking end plate 8 can still move in all directions relative to the sealing gasket 10.

[0047] Reference numerals list

[0048] 1 Fuel cell monomer

[0049] 2 Bottom plate

[0050] 3 Battery Cell Stacking

[0051] 4 One or more electrochemical cells

[0052] 5 holes for fastening elements

[0053] 6 Recesses in the base plate to prevent movement

[0054] 7 The surface of the bottom plate is oriented toward the sealing gasket

[0055] 8 stacked end plates

[0056] 9 is oriented toward the surface of the stacked end plate of the gasket

[0057] 10 Gasket

[0058] 11 One or more metal layers

[0059] 12 Sealing element

[0060] 13 Through-opening for the sealing gasket of the fastening element

[0061] 14 The surface of the sealing gasket is oriented toward the bottom plate

[0062] 15 The surface of the sealing gasket is oriented toward the stacking end plate

[0063] 16 Through openings for stacked end plates

[0064] 17 Upper stacking end plate

[0065] 19 Fastening elements (screws, etc.)

[0066] 20 One or more fixed points

[0067] 21 One or more protrusions

[0068] 22 One or more free edges or their corners

[0069] 23 One or more recesses

[0070] 24 Convex top

[0071] 25 One or more flanges, one or more tabs

[0072] 26 Media inlet

[0073] 27 Media outlet

Claims

1. A sealing gasket for sealing between a plurality of stacked electrochemical battery cells of a solid oxide fuel cell and a base plate, the sealing gasket having at least one metal sealing layer, a sealing element convexly pressed into the metal sealing layer, It is characterized in that The metal layer has at least one fixing point, The fixing point has a structure that protrudes from the surface of the metal layer, is adjacent to a structure forming the flat outer side of the sealing gasket, and has at least one free edge in the protruding area.

2. The flat sealing gasket according to the preceding claim, characterized in that The structure is a convex pressed or curved structure.

3. The flat sealing gasket according to any one of the preceding claims, characterized in that The structure is an embossed bead having a free edge at at least one of its longitudinal ends.

4. The flat sealing gasket according to the preceding claim, characterized in that The flange is a full flange.

5. The flat sealing gasket according to any one of claims 3 and 4, characterized in that The flange has, at least in some areas, a substantially or completely flat flange top, wherein the plane of the flat area of ​​the flange top is advantageously substantially or completely parallel to the plane of the metal layer adjacent to the flange.

6. The flat sealing gasket according to any one of claims 3 and 4, characterized in that The ridge has, at least in some regions, a substantially or completely rounded ridge top and / or a tapered ridge top, optionally tapering from both sides to a point, at least in some regions.

7. The flat sealing gasket according to claim 1 or claim 2, characterized in that: The structure is a embossed or bent tab which protrudes from the metal layer out of the plane of the metal layer and has a free edge at the protruding end of the tab.

8. The flat sealing gasket according to any one of the preceding claims, characterized in that The metal layer has several fixing points with the structure as described above.

9. An arrangement consisting of a base plate and stacking end plates arranged on the base plate, for stacking one or more electrochemical cells of a solid oxide fuel cell cell, It is characterized in that The bottom plate and / or the stack end plate has at least one recess, and The flat sealing gasket according to any one of claims 1 to 8 is arranged between the bottom plate and the stack end plate such that the protruding structure of the sealing gasket engages in the recess.

10. A solid oxide fuel cell cell having a base plate, at least one stack of one or more electrochemical cells and at least one stack end plate, the stack end plate being arranged between the base plate and the stack at the end of the stack facing the base plate, It is characterized in that The bottom plate and / or the end plates of the stack have at least one recess, and The flat sealing gasket according to any one of claims 1 to 8 is arranged between the bottom plate and the stack end plate such that the protruding structure of the sealing gasket engages in the recess.

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