Connection element for an electrically conductive connection of an electrical stack connection of an SOFC fuel cell stack in an SOFC fuel cell tower

Abstract

The present invention relates to a connection element (10) for an electrically conductive connection of an electrical stack connection (122) of an SOFC fuel cell stack (120) in an SOFC fuel cell tower (100) in which at least two SOFC fuel cell stacks (120) are placed one above the other in a stacking direction (SR), the connection element comprising an electrically conductive connection body (20) having a first body connection (22) and a second body connection (24) spaced apart therefrom, wherein the connection body (20) has at least one compensation portion (26) between the first body connection (22) and the second body connection (24) for elastic length compensation of the connection distance (AA) between the two body connections (22, 24) in a compensation direction (AR).

Description

[0001] Connection element for an electrically conductive connection of an electrical stack connection of a SOFC fuel cell stack in a SOFC fuel cell tower

[0002] The present invention relates to a connection element for an electrically conductive connection of an electrical stack connection of a SOFC fuel cell stack in a SOFC fuel cell tower, to an SOFC fuel cell tower of a SOFC fuel cell system having such a connection element, and to an assembly method for assembling an SOFC fuel cell tower using such a connection element.

[0003] It is known that fuel cell stacks are stacked on top of each other in fuel cell towers to provide electrical power. Large and complex fuel cell systems can also have multiple fuel cell towers in order to provide correspondingly large amounts of electrical power. During assembly, the individual fuel cell stacks are usually arranged one above the other in a housing of the fuel cell tower along a stacking direction. For operational functionality, it is necessary to electrically connect the individual fuel cell stacks to one another. Likewise, it is also necessary to provide electrical contact between the interconnected fuel cell stacks from the fuel cell tower. Such connections can also be referred to as contact connections or, in English, as "busbars" or "electrical busbars".

[0004] A disadvantage of the solutions known to date is that they require considerable effort to take into account the thermal load on the fuel cell stack. This is due to the fact that the electrical contacts are usually located inside the housing, where high operating temperatures of up to 1000 degrees Celsius prevail during operation of the fuel cell tower. This integration in the hot part leads to a high level of effort, particularly with regard to the assembly process, but also with regard to the design of the individual connections. The corresponding connecting cables and contact elements must therefore be designed to be electrically conductive and, at the same time, resistant to high temperatures. This is usually not possible with simple connecting cables, or only possible with considerable effort.

[0005] It is therefore an object of the present invention to at least partially remedy the disadvantages described above. In particular, the object of the present invention is to combine an electrically conductive connecting section with a thermal compensation option in the stacking direction in a cost-effective and simple manner.

[0006] The above object is achieved by a connection element having the features of claim 1, an SOFC fuel cell tower having the features of claim 13, and an assembly method having the features of claim 15. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the connection element according to the invention naturally also apply in connection with the SOFC fuel cell tower according to the invention and the assembly method according to the invention, and vice versa, so that reference is always made to the disclosure of the individual aspects of the invention.

[0007] The core idea of ​​the invention is to provide a connection element for an electrically conductive connection of an electrical stack connection of an SOFC fuel cell stack in the SOFC fuel cell tower. In this SOFC fuel cell tower, at least two SOFC fuel cell stacks are arranged one above the other along a stacking direction. For the electrically conductive connection, the connection element has an electrically conductive connection body with a first body connection and a second body connection spaced apart from the first body connection. The connection element is characterized in that the connection body has at least one compensation section between the first body connection and the second body connection for elastic length compensation of the connection distance between the two body connections along a compensation direction.

[0008] The core concept of the invention is based on combining two functionalities in the connection element. The main functionality is the electrically conductive connection between two components connected to the body connections. This can be two SOFC fuel cell stacks arranged side by side and thus adjacent to one another, each having a stack connection. Each of these stack connections is then electrically conductively connected to one of the two body connections, and the connection body establishes the electrically conductive connection between these two stack connections and thus between the two adjacent SOFC fuel cell stacks. Alternatively, as explained later, an electrically conductive connection to a tower connection, i.e. from the housing of the SOFC fuel cell tower, can also be provided through one of the body connections within the scope of the present invention.The connection from the housing is particularly important, as the electrical connection must be combined with gas tightness and electrical insulation from other conductive components. Further details on the specific embodiments will be provided later. However, the basic concept of geometric compensation according to the invention brings the aforementioned advantages to all embodiments.

[0009] An SOFC fuel cell system is a solid oxide fuel cell system that operates at temperatures of up to 600 °C, in particular 800 °C, particularly preferably up to 1000 °C.

[0010] A second functionality provided within the scope of the present invention is thermal length compensation. As already indicated, SOFC fuel cell stacks are operated particularly in high temperature ranges. This can involve operating temperatures of up to 1000 degrees Celsius. In the idle state, the SOFC fuel cell stacks are at ambient temperature in the range of approximately 20 degrees Celsius. Due to the large temperature differences between the idle state and the operating state, which can amount to up to a temperature difference of approximately 1000 degrees Celsius, correspondingly high temperature expansions are to be expected. In the operating state, the SOFC fuel cell stacks will accordingly exhibit a greater longitudinal expansion along the stack direction than in the idle state.However, it should be ensured that the electrically conductive connection between the SOFC fuel cell stacks is maintained in each of these states and, in particular, is not damaged if a thermally induced movement of the SOFC fuel cell stacks is generated by a longitudinal expansion of the stacks. This length compensation is now ensured according to the invention by the compensation section of the connection body. The compensation function is ensured by elastic deformability. It is crucial that the compensation direction provides the length compensation with regard to a compensation distance for the body connections of the connection distances. In other words, when the SOFC fuel cell tower heats up, the connection distance between the body connections will increase due to the corresponding electrically conductive contact, for example with stack connections.In order to compensate for this increase in the connection distance during operation at high temperatures, the compensation section can now deform elastically so that the connection distance between the two body connections also increases. If the SOFC fuel cell tower is put into a rest state, the temperature drops over time to the ambient temperature of, for example, approximately 20 degrees Celsius. The thermal expansion decreases, and the distance between the stack connections of the adjacent SOFC fuel cell stacks is reduced again to the situation at room temperature. Accordingly, the compensation section also deforms elastically back to its original state, so that the connection distance between the two body connections also follows the reduced distances between the stack connections of the adjacent SOFC fuel cell stacks and thus reduces itself.

[0011] According to the invention, it is now possible to provide the connector body in a simple and cost-effective manner, for example, through a metallic design. The electrically conductive functionality is thus provided by the material selection of the connector body. Through a preferably clever geometric design, elastic deformability is ensured, firstly, by the material selection, but especially by the shape of the connector body in the compensation section, which will be explained in more detail later. In other words, it is now possible to ensure the electrically conductive connection with a high degree of reliability, even across different thermal expansion states of the SOFC fuel cell stack.At the same time, it becomes possible, in particular through the geometric provision of the compensation functionality, to provide a sufficiently large cable cross-section at the connection body and in particular also at the compensation section in order to transmit even high electrical currents via the compensation body between the adjacent SOFC fuel cell stacks.

[0012] Last but not least, the integration of the compensation section further reduces the mechanical stress on the stack connections and thus on the SOFC fuel cell stack. This compensation option reduces the forces acting on the stack connections and, in particular, limits them to a minimum. Mechanical stress and, in particular, bending moments acting on the SOFC fuel cell stacks can thus be largely avoided, significantly increasing the longevity of the entire SOFC fuel cell stack.

[0013] It can be advantageous if, in a connecting element according to the invention, the compensating section is designed to be symmetrical at least in sections, in particular symmetrical about a plane of symmetry transverse to the compensating direction. This can be, for example, the curved design explained later. However, other symmetrical designs, such as spring-like or similar geometric shapes, are also conceivable in principle. The symmetrical design ensures that symmetrical elastic and thus bilaterally symmetrical deformation can take place. Undesirable inequalities and the resulting introduction of bending moments on the adjacent stack connections of the SOFC fuel cell stack can thus be further reduced. Transverse loads on the body connections as well as shear loads are also reduced to a minimum.

[0014] It is furthermore advantageous if, in a connection element according to the invention, the first body connection and the second body connection are arranged symmetrically, at least in sections, in particular symmetrically to a plane of symmetry transverse to the compensation direction. This applies in particular if the connection element is a connection element integrated in the housing between two adjacent SOFC fuel cell stacks. Since the stack connections on the SOFC fuel cell stacks are usually also arranged laterally parallel to one another, a correspondingly parallel design of the body connections can ensure surface contact between both stack connections by the two body connections. The connection distance between the body connections thus extends perpendicular or essentially perpendicular to the body connections, so that the compensation direction can also be aligned along this perpendicular.

[0015] Furthermore, it can be advantageous if, in a connection element according to the invention, the compensation section has a compensation extension along the compensation direction that is greater than the connection distance between the two body connections. This applies in particular at least for a temperature in the idle state, for example at ambient temperature. In other words, the compensation extension is selected to be larger than the connection section in order to provide a correspondingly compact and yet sufficiently large compensation functionality. The compensation function is therefore significantly increased with respect to the resulting smaller connection distance. In the case of a flat extension, in particular as a flat and curved extension, this brings with it the aforementioned advantages with regard to the geometric compensation functionality.Last but not least, this increased compensation extension further reduces the mechanical impact on the two body connections.

[0016] It can also be advantageous if, in a connecting element according to the invention, the two body connections overlap at least partially, in particular completely or essentially completely, viewed along the compensation direction. With the curved design of the compensation section explained later, this leads to a C-shape in the side view for the connecting body. This also means that when connecting means or connecting bolts are used, the center lines of the corresponding connection openings in the body connections are congruent and thus, in particular, coaxial. This increases the symmetry and, due to the increased symmetry, leads to the already repeatedly explained further reduction, in particular a minimization of the forces acting on the body connections and the components of the SOFC fuel cell tower connected to them.

[0017] It is also advantageous if, in a connection element according to the invention, at least one of the two body connections, in particular both body connections, have a flat and / or planar extension. This correlates in particular with a flat and / or planar extension of the components to be connected, for example a tower connection and / or a stack connection of the SOFC fuel cell stack. The flat contacting option accordingly makes it possible to provide a large contact area in order to transmit even high currents via this contact area. Last but not least, a flat and in particular planar design of the body connections also ensures secure contact, since, for example, with the help of contact bolts, flat contact and even flat pressing against the mating connection in the form of the stack connection and / or the tower connection is possible.The flat design can be provided alternatively or in addition to a connecting thread in order to correlate the connection functionality and also the contacting surface with a connecting bolt and a connecting thread.

[0018] Further advantages can also be achieved if, in a connection element according to the invention, the first body connection is designed for an electrically conductive connection to a stack connection of an SOFC fuel cell stack and the second body connection is designed for an electrically conductive connection to a tower connection. If, for example, four SOFC fuel cell stacks are arranged one above the other in the stacking direction in an SOFC fuel cell tower, these four SOFC fuel cell stacks are electrically conductively connected to one another. However, the bottom and top SOFC fuel cell stacks must be led to a tower connection in order to make the entire subsystem of the SOFC fuel cell tower electrically conductively contactable to the outside. In other words, each SOFC fuel cell stack is now equipped with two stack connections.The directly adjacent SOFC fuel cell stacks are electrically connected to one another by the previously described, particularly C-shaped, design of the connecting element. The SOFC fuel cell stack arranged at each end has a connecting element of this present embodiment to provide a connection to an external tower connection, thus enabling external electrical contacting of the entire SOFC fuel cell tower.

[0019] Further advantages can be achieved if, in the connection element according to the preceding paragraph, the connecting body has a bridging section between the compensation section and the second body connection for geometrically bridging a tower insulation. As already explained, the SOFC fuel cell tower is in operation at high operating temperatures, for example, in the range of approximately 1000 degrees Celsius. To ensure that these operating temperatures are maintained efficiently and that no undesirable heat loss, and thus a resulting minimization of efficiency, can occur, the housing of such an SOFC fuel cell system is usually at least thermally, and in particular also electrically, insulated.The bridging section, for example in the form of a bridging bolt, serves to conduct the electrically conductive connection over this insulation, in particular through an insulating layer of the tower insulation. The outer surface is therefore sufficiently cooler to be contacted by a correspondingly simpler external, electrically conductive contact, for example, the tower connection. The connection between the compensating section and the bridging section can be made, for example, by welding.

[0020] It is also advantageous if, in a connection element according to the preceding paragraph, the bridging section is at least partially, in particular completely or substantially completely, surrounded by a thermal insulation material. In other words, this bridging section is thus longer, so that a cooling length can be provided in this way to make the second body connection even cooler and thus even easier to connect, for example, to the tower connection. The lateral and surrounding thermal insulation with a thermal insulation material is also designed, in particular, for electrical insulation.

[0021] Further advantages can be achieved if, in a connection element according to the invention, at least one cooling section is arranged between the bridging section and the second body connection, for an additional cooling section to the second body connection. For example, a plate-shaped or sheet-metal configuration can be provided outside a bolt-shaped bridging section in order to provide an even larger cooling section. Starting from a first body connection that can reach temperatures of up to 1000 degrees Celsius, this now means that the second body connection can be brought to a significantly reduced temperature of, for example, below 300 degrees Celsius, preferably below 100 degrees Celsius. The requirements for the contacting components, for example of a tower connection, are thus further reduced.

[0022] It is further advantageous if, in a connecting element according to the invention, the compensation section has at least one curved curvature section for elastic length compensation, wherein the at least one curvature section has, in particular, a curvature center line that is oriented transversely or substantially transversely to the stacking direction and / or to the fastening axis of at least one body connection. The design as a curved section is a particularly simple and cost-effective design option for a desired geometric length compensation. The integration of a curvature center line in the aforementioned design transversely to the stacking direction means that the maximum length compensation can be provided in the compensation direction parallel to and thus along the stacking direction.

[0023] It is further advantageous if, in a connection element according to the invention, the connection body is formed in layers, at least in the compensation section. In principle, the connection body can be formed, for example, from metal, in particular from nickel or a nickel-based metal or a nickel-based metal alloy, or an alloy of different materials. The layered design, particularly in the compensation section, results in, on the one hand, very good and, above all, mechanically stable compensation functionality with elastic deformability. On the other hand, the layered structure simultaneously provides a sufficiently large overall cross-section for the desired electrical transmission option for electrical current.The individual layers can be welded together at least at the ends in order to provide the combination of a high cable cross-section and the desired elastic flexibility.

[0024] The present invention also relates to an SOFC fuel cell tower of an SOFC fuel cell system, comprising a housing having a housing space. At least one SOFC fuel cell stack, in particular at least two SOFC fuel cell stacks, are arranged one above the other in a stacking direction within this housing space. Such an SOFC fuel cell tower is characterized in that the at least one SOFC fuel cell stack has at least one connection element according to the present invention. Thus, such an SOFC fuel cell tower offers the same advantages as those explained in detail with reference to a connection element according to the invention.

[0025] It may be advantageous if, in an SOFC fuel cell tower according to the invention, the at least one connection element is arranged on a side of the SOFC fuel cells that is free from flows of supply and / or discharge gases from the SOFC fuel cell stacks. Thus, the SOFC fuel cell stacks can be designed with free flow of the cathode gases and / or anode gases. The side free of such supply and discharge gases can also be referred to as the passive side of the SOFC fuel cell stacks with regard to gas flow. This side is thus particularly advantageously available for the aforementioned electrically conductive connection with the thermal compensation functionality of the compensation section.

[0026] Furthermore, the present invention provides an assembly method for assembling an SOFC fuel cell system according to the invention. Such an assembly method comprises the following steps:

[0027] - Stacking at least two SOFC fuel cell stacks in a housing space of the housing,

[0028] - electrically conductively connecting the at least two SOFC fuel cell stacks by means of at least one connecting element according to the present invention,

[0029] - Closing the housing.

[0030] By assembling an SOFC fuel cell tower according to the invention and using a connecting element according to the invention, an assembly method according to the invention also brings about the same advantages as have been explained in detail with reference to a connecting element according to the invention and an SOFC fuel cell tower according to the invention.

[0031] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. They show schematically:

[0032] Fig. 1 shows an embodiment of a SOFC fuel cell tower,

[0033] Fig. 2 is a detailed view of the embodiment of Figure 1 with a first embodiment of a connecting element,

[0034] Fig. 3 the connection element of Figure 2 in an isolated representation,

[0035] Fig. 4 shows a further illustration of a connecting element at one end of the SOFC fuel cell tower,

[0036] Fig. 5 an alternative to the embodiment of Figure 4 and

[0037] Fig. 6 shows an alternative to the embodiments of Figures 4 and 5.

[0038] Figure 1 schematically shows an SOFC fuel cell tower 100. Within a housing 130 and thus in the housing space 132, four SOFC fuel cell stacks 120 are arranged one above the other along a stacking direction SR. For the operation of the SOFC fuel cell system and thus of the SOFC fuel cell tower 100, the SOFC fuel cell stacks 120 must be supplied with the necessary operating gases, and the resulting exhaust gases must be removed. For electrical operability, electrical contact between the individual SOFC fuel cell stacks 120 and to the outside, and thus electrical contact of the entire SOFC fuel cell tower 100, is necessary. With regard to these two necessary electrical contacts, a connection element 10 according to the invention is used multiple times, as will now be explained in more detail in Figures 2 to 6.

[0039] Figure 2 shows a detailed illustration of how an electrically conductive connection between two adjacent SOFC fuel cell stacks 120 within the SOFC fuel cell tower 100 can be ensured. The upper SOFC fuel cell stack 120, as well as the lower SOFC fuel cell stack 120 in Figure 2, each have a stack connection 122, which can also be referred to as a connection tab. Each of these stack connections 122 is shown here along a center line with a connection opening in which a connection bolt (not shown in more detail) can ensure an electrically conductive contact. To form the electrically conductive contact, these two stack connections 122 are not directly conductively connected to one another; rather, this electrically conductive connection runs via a connection body 20 of the connection element 10.This connecting element 10 is designed here with a substantially C-shaped cross-section, open to the left, and has a first body connection 22 and a second body connection 24. Both body connections 22 and 24 are flat and planar here and overlap essentially completely along the compensation direction AR. Thus, they can be brought into planar contact with the respective stack connection 122 using the bolt, thus securing them in this electrically conductive connection.

[0040] Figure 2 now shows that the connecting body 22 has a curved compensation section 26 as a curved section 27 in direct electrically conductive connection to the two body connections 22 and 24. This is curved around a curvature center line KM and accordingly represents a compensation option in the compensation direction AR.

[0041] If, starting from the illustration in Figure 2, which can represent the situation in the resting state and thus at ambient temperature, for example, heating to an operating temperature of approximately 1000 degrees Celsius is carried out, the SOFC fuel cell stacks 120 expand. The distance between the two stack connections 122 increases, and the two body connections 22 and 24 are, so to speak, pushed apart.

[0042] Figure 3 shows that the connection distance AA along the compensation direction AR between the two body connections 22 and 24 also increases. In order to ensure this compensation possibility and this change in the connection distance AA, an elastic deformation of the compensation section 26 along the compensation direction AR must take place. For this purpose, as Figure 3 clearly shows, a compensation extension AE is provided, which here is even greater than the compensation distance AA. The mechanical load on the two body connections 22 and 24 is minimized because an elastic compensation function is provided by the elastic deformation of the geometric design of the curved section 27 of the compensation section 22.

[0043] Figures 4, 5, and 6 show the connection options for the two SOFC fuel cell stacks 120 at the top and bottom ends in Figure 1. These must now provide an electrical connection to the outside for a tower connection 102. In other words, as shown in Figure 4, for example, it is now possible to connect the stack connection 122 of the lower SOFC fuel cell stack 120 to a tower connection 102 through the housing 130 and a tower insulation 110. Here, the second body connection 24 is provided for electrically conductive contact with the tower connection 102. The compensation functionality is provided here with the aid of a compensation section 26 with two different curved sections 27, wherein the compensation direction AR again extends along the stack direction SR.In addition, a bridging section 28 is provided, which here is welded directly to the compensating section 26 in a bolt-like manner. The bridging section 28 extends through the tower insulation 110 in a bolt-like manner and is electrically and securely fastened to the tower connection 102 by means of a further contacting bolt.

[0044] Figure 5 shows a further development of the embodiment of Figure 4. Here, a cooling section 29 is additionally provided, which further reduces the temperature at the connection point of the second body connection 24 with respect to the increased operating temperature of approximately 1000 degrees Celsius in the housing space 132. To achieve even further improved thermal decoupling between the first body connection 22 and the second body connection 24, Figure 6 shows an extended bolt as a bridging section 28. This is further surrounded by an insulating material 30, which in particular can also provide electrical insulation.

[0045] Important in the embodiments of Figures 4 to 6 is the combination of electrical and thermal insulation with a gas-tight feedthrough through the housing 130. In particular, in Figure 6, additional sealing means are shown as black blocks. The insulating material 30 serves here in particular to provide electrical insulation to the housing 130, which is made of metal and is therefore conductive. In this variant, the thermal tower insulation can also be electrically conductive, since the electrical insulation function is provided by the insulating material 30.

[0046] As can be seen from Figure 6, the feedthrough through the housing 130 was designed to be rigid and thus locally separated from the compensation option of the compensation section 26. Such a rigid feedthrough design is significantly simpler and also more reliably gas-tight.

[0047] In particular, the variant in Figure 6 combines the functions of the electrical connection to the outside, the gas-tight feedthrough, the electrical insulation, the mechanical compensation and the further thermal decoupling.

[0048] The above explanation of the embodiments describes the present invention exclusively by way of examples.

[0049] List of reference symbols

[0050] 10 connecting element

[0051] 20 connecting bodies

[0052] 22 first body connection

[0053] 24 second body connection

[0054] 26 Compensation section

[0055] 27 Curvature section

[0056] 28 Bridging section

[0057] 29 Cooling section

[0058] 30 insulation material

[0059] 100 SOFC fuel cell towers

[0060] 102 tower connection

[0061] 110 Tower insulation

[0062] 120 SOFC fuel cell stacks

[0063] 122 Stacking connection

[0064] 130 housings

[0065] 132 housing space

[0066] SR stacking direction

[0067] AR compensation direction

[0068] AE compensation extension

[0069] AA connection distance

[0070] KM Curvature centerline

Claims

Patent claims 1. Connection element (10) for an electrically conductive connection of an electrical stack connection (122) of a SOFC fuel cell stack (120) in an SOFC fuel cell tower (100), in which at least two SOFC fuel cell stacks (120) are arranged one above the other along a stacking direction (SR), comprising an electrically conductive connection body (20) with a first body connection (22) and a second body connection (24) spaced therefrom, characterized in that the connection body (20) has at least one compensation section (26) between the first body connection (22) and the second body connection (24) for an elastic length compensation of the connection distance (AA) of the two body connections (22, 24) along a compensation direction (AR).

2. Connection element (10) according to claim 1, characterized in that the compensating section (26) is formed at least in sections symmetrically, in particular symmetrically about a plane of symmetry transverse to the compensating direction (AR).

3. Connection element (10) according to one of the preceding claims, characterized in that the first body connection (22) and the second body connection (24) are arranged at least in sections symmetrically, in particular symmetrically to a plane of symmetry transverse to the compensation direction (AR).

4. Connection element (10) according to one of the preceding claims, characterized in that the compensation section (26) has a compensation extension (AE) along the compensation direction (AR) which is greater than the connection distance (AA) between the two body connections (22, 24).

5. Connecting element (10) according to one of the preceding claims, characterized in that the two body ends (22, 24) overlap at least in sections, in particular completely or substantially completely, as seen along the compensation direction (AR).

6. Connection element (10) according to one of the preceding claims, characterized in that at least one of the two body connections (22, 24), in particular both body connections (22, 24) have a flat and / or planar extension.

7. Connection element (10) according to one of the preceding claims, characterized in that the first body connection (22) is designed for an electrically conductive connection to a stack connection (122) of a fuel stack (120) and the second body connection (24) is designed for an electrically conductive connection to a tower connection (102).

8. Connection element (10) according to claim 7, characterized in that the connection body (20) has a bridging section (28) between the compensation section (26) and the second body connection (24) for geometrically bridging a tower insulation (110).

9. Connection element (10) according to claim 8, characterized in that the bridging section (28) is at least partially, in particular completely or substantially completely surrounded by a thermal insulation material (30).

10. Connection element (10) according to one of claims 8 or 9, characterized in that at least one cooling section (29) is arranged between the bridging section (28) and the second body connection (24), for an additional cooling section to the second body connection (24).

11. Connection element (10) according to one of the preceding claims, characterized in that the compensation section (26) has at least one curved curvature section (27) for the elastic length compensation, wherein the at least one curvature section (27) has in particular a curvature center line (KM) which is aligned transversely or substantially transversely to the stacking direction (SR) and / or to the fastening axis of at least one body connection (22, 24).

12. Connecting element (10) according to one of the preceding claims, characterized in that the connecting body (20) is formed in layers at least in the compensating section (26).

13. SOFC fuel cell tower (100) of an SOFC fuel cell system, comprising a housing (130) which has a housing space (132) in which at least two SOFC fuel cell stacks (120) are arranged one above the other along a stacking direction (SR), characterized in that the at least two SOFC fuel cell stacks (120) have at least one connection element (10) with the features of one of claims 1 to 12.

14. SOFC fuel cell tower (100) according to claim 13, characterized in that the at least one connection element (10) is arranged on a side of the SOFC fuel cell stack (120) which is free from flows of supply and / or discharge gases of the SOFC fuel cell stack (120).

15. Assembly method for assembling an SOFC fuel cell tower (100) having the features of one of claims 13 or 14, characterized by the following steps: - stacking at least two SOFC fuel cell stacks (120) in a housing space (132) of a housing (130), - Electrically conductive connection of the at least two SOFC fuel cell stacks (120) by means of at least one connection element (10) having the features of one of claims 1 to 12, Closing the housing (130).

Images