Manufacturing arrangement for a fuel cell stack and method for manufacturing a fuel cell stack
Patent Information
- Authority / Receiving Office
- HK · HK
- Patent Type
- Patents
- Current Assignee / Owner
- POWERCELL SWEDEN AB
- Filing Date
- 2021-04-28
- Publication Date
- 2026-07-17
AI Technical Summary
In the existing technology, the manufacturing process of fuel cell stacks is costly and time-consuming, and the alignment features of MEA and bipolar plates are required to be extremely narrow, which makes the stacking process complex and prone to misalignment and performance degradation.
At least two independent alignment stations and handling devices are used to align and fasten the MEA and bipolar plates respectively. By pre-assembling the fuel cell unit, the spatial orientation of the MEA and bipolar plates is fixed, avoiding the risks of direct contact and bending. Fastening methods such as ultrasonic welding are used to achieve a fast and reliable stacking process.
It reduces manufacturing costs, improves stacking efficiency, reduces alignment requirements for MEAs and bipolar plates, ensures alignment accuracy and performance stability of fuel cell stacks, allows the use of softer or thinner MEA materials, and increases the power output of the stack.
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Abstract
Description
Technical Field
[0001] The present invention relates to a manufacturing arrangement for a fuel cell stack, a method for manufacturing a fuel cell stack, and a fuel cell stack having been manufactured by said arrangement and / or method. Background Technology
[0002] Fuel cell stacks typically consist of two monopolar plates with multiple membrane electrode assemblies (MEAs) arranged between them, which are then separated by bipolar plates. Each MEA itself includes at least a cathode, an anode, and a membrane located between the anode and cathode to react hydrogen and oxygen to generate electricity and water. Regarding the supply of reactants (hydrogen and oxygen) to the respective electrodes, the bipolar plates positioned on either side of the MEA have a fluid flow field that guides the fluid flow of reactants to the corresponding electrodes.
[0003] Because the reaction in a single MEA typically produces insufficient voltage to operate most applications, multiple MEAs need to be stacked and electrically connected in series to achieve the desired voltage. Current is harvested from the fuel cell stack and used to drive the load.
[0004] The efficiency of a fuel cell stack depends on the flow of reactants across the MEA surface and the integrity of the various contact and sealing interfaces within the individual fuel cells of the stack. These contact and sealing interfaces include those associated with the delivery of fuel, coolant, and effluents within and between the fuel cells in the stack. Therefore, proper alignment of the fuel cell components and assemblies within the fuel cell stack is crucial for ensuring the effective operation of the fuel cell system.
[0005] Regarding alignment and stacking, alignment tools are typically used, such as alignment frames with at least one guiding element, which ensure a predefined arrangement of the MEA and bipolar plates during the stacking process. After the desired amounts of MEA and bipolar plates have been stacked, the resulting fuel cell stack is compressed (e.g., screwed) together or otherwise bonded so that the fuel cell stack is usable for the desired application.
[0006] Regarding ensuring proper alignment of the MEA and bipolar plate, existing technologies have proposed providing alignment features to both the MEA and bipolar plate, such as alignment frame guide elements that can be inserted into or integrated into recesses therein.
[0007] The known drawback of alignment is that both the MEA and the bipolar plate must provide corresponding alignment features, which makes the manufacturing cost of the MEA and bipolar plate extremely high, and the manufacturing can only tolerate very narrow tolerances. In addition, the stacking process is extremely time-consuming, and the entire stack will inevitably fall apart if even a single bipolar plate or MEA is not properly aligned. Summary of the Invention
[0008] Therefore, the object of the present invention is to provide a manufacturing arrangement for a fuel cell stack and a method for manufacturing a fuel cell stack that allows for rapid, reliable and cost-effective stacking of fuel cell stacks.
[0009] The following describes a manufacturing arrangement for a fuel cell stack, comprising at least a first alignment station having a first alignment structure and a second alignment structure. The first alignment structure receives bipolar plates, and the second alignment structure arranges a membrane electrode assembly (MEA) in a predetermined orientation on one side of the bipolar plates, preferably on top of the bipolar plates. Thus, the bipolar plates and the MEA are aligned, and a so-called pre-assembled fuel cell unit is provided.
[0010] Therefore, it should be noted that the "first" and "second" designations of the alignment structure do not necessarily relate to the order in which the fuel cell components are handled. Thus, it is also possible that the MEA is placed first in the second alignment structure, and only in a subsequent step is the bipolar plate placed on top of the MEA.
[0011] This arrangement also includes a fastening station for securing the membrane electrode assembly (MEA) to the bipolar plates, thereby providing an assembled fuel cell unit. This ensures that the spatial orientation of the components of the pre-assembled fuel cell unit is preserved. It should be noted that at the fastening station, only the spatial orientation of the bipolar plates and MEA needs to be ensured. The fluid tightness of the MEA and bipolar plates is typically achieved by compressing the fully assembled fuel cell stack.
[0012] The arrangement also includes a second alignment station having at least one third alignment structure for aligning the assembled fuel cell units to provide a fuel cell stack.
[0013] Advantageously, the stacking process can be accelerated and automated by providing a manufacturing arrangement with at least two independent alignment stations. This is due to the fact that stacking fuel cell stacks in such a manner (second alignment) allows the use of pre-assembled fuel cell units in which the bipolar plates and MEAs are aligned and secured. Furthermore, the stacking process is facilitated because the MEAs are arranged only on one side of the bipolar plates.
[0014] Specifically, when fuel cell units are stacked onto a fuel cell stack at the second manufacturing station, the fuel cell units can be gripped by bipolar plates (e.g., by vacuum gripping) and then placed upside down (i.e., with bipolar plates on top of the MEA) in the third alignment structure. During this process, the MEA maintains its pre-assembled spatial orientation through the fixation provided by the fastening station, such that in the third alignment structure, the alignment of the fuel cell units can be based solely on the spatial orientation of the MEA.
[0015] When stacking fuel cell units, it is important to have bipolar plates on top of the MEA. This reduces the risk of the MEA tearing off the bipolar plates, and it also reduces the risk of bending the MEA during stacking. Bending of the MEA is always a risk, especially when stacking unassembled components, because the MEA is more flexible than a rigid bipolar plate. Bending of the MEA can lead to misalignment and performance degradation in the fuel cell stack during the stacking process.
[0016] Another advantage is that even if the MEA is placed only on one side of the bipolar plate, the rigidity of the bipolar plate will enhance the rigidity of the MEA to the point that the MEA can be used independently as the basis for the alignment of the fuel cell unit. Regarding the alignment of the fuel cell stack, the bipolar plate itself can be completely ignored. In the prior art, fuel cell units typically include an MEA sandwiched between two flow field plates. This always results in undesirable but inevitable contact between the flow field plates during the stacking process.
[0017] The proposed manufacturing arrangement has another advantage: even softer materials can be used in the MEA and / or thinner MEAs can be fabricated. This allows for the use of materials capable of providing higher power output and / or the stacking of more fuel cell units into a stack with the same dimensions as known fuel cell stacks. This is due to the fact that the MEA is stabilized by bipolar plates, which are then fastened to the MEA to maintain proper alignment.
[0018] According to yet another preferred embodiment, the manufacturing arrangement further includes at least a first transport device for conveying the pre-assembled fuel cell unit to a fastening station, wherein the first transport device is preferably a movable element (particularly a rotary table) including first and second structures for aligning the bipolar plates and membrane electrode assembly. Alternatively, the movable element is a movable alignment structure (e.g., a fixing device) that securely holds the bipolar plates and / or MEA.
[0019] By utilizing a transport device, the first alignment station and the fastening station do not need to be located in the same position. This allows for a faster stacking process because the alignment station is already operational, even if the bipolar plates and MEA have not yet been fastened to provide for assembling the fuel cell unit.
[0020] Therefore, this is preferred, as the predefined spatial orientation may be lost if the pre-assembled fuel cell unit is not handled in this manner. This can be ensured, for example, by a movable element or turntable that moves / rotates the pre-assembled fuel cell unit to a securing position without compromising the spatial orientation of the MEA and bipolar plates.
[0021] In addition to moving the pre-assembled fuel cell unit from the alignment station to the fastening station, it is also possible to combine the first alignment station and the fastening station into a fuel cell unit assembly station, where the bipolar plates and MEA are first aligned and then fastened. For this purpose, the combined fuel cell assembly station may include an alignment manipulator for aligning the bipolar plates and MEA, and a fastening manipulator for fastening the membrane electrode assembly to the bipolar plates. Instead of a welding manipulator, any other fastening operation can be used; for example, the bipolar plates may also be glued, thermally assembled using thermoplastics, or soldered to the MEA.
[0022] The assembly station offers even higher reliability for maintaining the pre-defined orientation between the bipolar plate and the MEA.
[0023] According to yet another embodiment, the fastening station and / or assembly station includes an ultrasonic welding manipulator. Instead of using an ultrasonic welding manipulator, any other fastening manipulator / operation can be used; for example, the bipolar plates can also be glued, thermally assembled via thermoplastic, or soldered to the MEA.
[0024] Further preferably, the manufacturing arrangement also includes a second transport device for conveying the assembled fuel cell unit to a second alignment station, wherein the second transport device is preferably adapted to contact only the assembled fuel cell unit at the membrane electrode assembly.
[0025] By providing a second handling device, the fastening station or assembly station and the second alignment station do not need to be arranged in the same location. This allows for a faster stacking process because the first alignment / fastening station or assembly station is already operationally free, even if the fuel cell stack is not yet fully completed. Furthermore, independent alignment stations can be precisely adapted to the corresponding alignment requirements. Since contact with the bipolar plates is undesirable, the first and second alignment structures can be optimized for aligning the bipolar plates and MEA, while a third alignment structure can be optimized for aligning the assembled fuel cell unit (specifically, the MEA of the assembled fuel cell unit).
[0026] According to another preferred embodiment, the membrane electrode assembly may extend over at least one region above the bipolar plates. This ensures that the bipolar plates are electrically isolated from each other, thereby allowing for the avoidance of any short circuits in the fuel cell stack. In the case of overlapping bipolar plates with the MEA, proper alignment of the bipolar plates and the MEA is extremely challenging. In the prior art, specific alignment features exist that enable proper alignment of the bipolar plates and the MEA, such as recesses in the bipolar plates and openings in the MEA. However, the provision and use of these alignment features are time-consuming and costly. Furthermore, proper alignment of the MEA and bipolar plates requires that, at least in the region of the alignment features, the MEA and bipolar plates be flush with each other to ensure alignment, which in turn increases the risk of short circuits.
[0027] By utilizing two alignment stations in the manufacturing arrangement, it is even possible to overlap bipolar plates in various locations within the MEA. Because the alignment of the bipolar plates and MEA is achieved by fastening the MEA and bipolar plates in a predefined spatial orientation, the alignment of the bipolar plates in the second alignment step / station may be completely ignored, and the alignment of the fuel cell unit may only relate to the MEA. Therefore, preferably, the protruding periphery of the membrane electrode assembly is used for alignment, and at least one third alignment structure in the second alignment station is adapted to align the fuel cell unit by aligning the protruding periphery of the membrane electrode assembly in said at least one region.
[0028] Another aspect of the present invention relates to a method for manufacturing a fuel cell stack, the method comprising at least the following steps:
[0029] — A pre-assembled fuel cell unit is provided by arranging the membrane electrode assembly on one side of a bipolar plate in a predefined spatial orientation, preferably on the top of the bipolar plate, and preferably by utilizing a first alignment station having a first structure for receiving the bipolar plate and a second structure for arranging the membrane electrode assembly on one side of the bipolar plate.
[0030] — By fastening the membrane electrode assembly to the bipolar plates, an assembled fuel cell unit is provided; and
[0031] — By aligning and assembling fuel cell units, preferably in a second alignment station having at least one third alignment structure, a fuel cell stack is provided.
[0032] The features and advantages described above with respect to the apparatus also apply to this method.
[0033] Therefore, the method may also include the step of ultrasonically welding the membrane electrode assembly to the bipolar plate.
[0034] According to yet another preferred embodiment, the method includes the step of aligning the assembled fuel cell unit in a second alignment station by contacting only the membrane electrode assembly of the assembled fuel cell unit.
[0035] Advantageously, the method further includes the steps of: providing a membrane electrode assembly extending over at least one region above a bipolar plate, arranging the membrane electrode assembly on the bipolar plate such that the periphery of the membrane electrode assembly protrudes above the bipolar plate in the at least one region, and aligning the fuel cell unit by aligning the protruding periphery of the membrane electrode assembly in the at least one region.
[0036] According to another aspect, the present invention relates to a fuel cell stack comprising a plurality of fuel cell units, each of which includes a membrane electrode assembly preferably ultrasonically welded to a bipolar plate, wherein the fuel cell stack has been manufactured by the arrangement and / or by the methods discussed above.
[0037] According to yet another embodiment, the fuel cell stack also includes at least one fuel cell unit, wherein the MEA extends at least one region above the bipolar plate.
[0038] Other advantages and preferred embodiments are disclosed in the claims, description, and drawings. It should also be noted that those skilled in the art may consider or use these features individually, or combine them in ways other than those shown, without extending the scope of the invention.
[0039] In the following description, the invention will be illustrated with reference to the embodiments shown in the accompanying drawings. The illustrated embodiments are merely exemplary and are not intended to limit the scope of protection. The scope of protection is defined only by the appended claims. Attached Figure Description
[0040] The attached diagram shows:
[0041] Figure 1 A schematic perspective view of a first embodiment of the manufacturing arrangement for a fuel cell stack;
[0042] Figure 2 A schematic diagram showing the details of assembling a fuel cell unit; and
[0043] Figure 3 A schematic perspective view of a second embodiment of the manufacturing arrangement. Detailed Implementation
[0044] In the following text, the same or similar functional elements are indicated by the same reference numerals.
[0045] Figure 1A perspective view of a manufacturing arrangement 1 is shown, which manufactures a fuel cell stack 2 by stacking multiple assembled fuel cell units 4. As shown, the manufacturing arrangement includes a first alignment station 6 and a second alignment station 8. In the illustrated embodiment, two manipulators 10 and 12 are provided for handling the fuel cell elements. The manufacturing arrangement 1 also includes a fastening station 14 and a conveying device 16 for transferring the fuel cell elements from the alignment station 6 to the fastening station 14. Figure 1 The conveying device 16 in the illustrated embodiment is a rotatable table.
[0046] like Figure 1 As further shown, the fastening station 14 includes a welding manipulator 18, which is adapted to fasten or weld the membrane electrode assembly 26 to the bipolar plate 22. Additionally, the manufacturing arrangement 1 includes an alignment manipulator 20 for aligning the membrane electrode assembly 26 to the bipolar plate 22.
[0047] The operation of manufacturing arrangement 1 will be described below. In a first step, the transport manipulator 10 transfers the bipolar plate 22 to a first alignment structure 24 (e.g., a fixing device) arranged on a rotary table 16. The table 16 then rotates such that the bipolar plate 22 (arranged in the alignment structure 24) is conveyed to a first alignment station 6, where the alignment manipulator 20 places the membrane electrode assembly (MEA) 26 on one side of the bipolar plate 22, i.e., in Figure 1 In the illustrated embodiment, the MEA is placed on top of the bipolar plate 22. However, it is also possible that the MEA is placed below the bipolar plate and / or the first alignment structure is subsequently arranged to the second alignment structure.
[0048] Aligning the MEA 26 on one side of the bipolar plate 22 can be performed by any suitable alignment method, regardless of whether the MEA or the bipolar plate is handled first. For example, it is possible that the alignment manipulator 20 includes a camera that serves as a second alignment structure and determines the position of the bipolar plate 22, and based on the determined position, the manipulator places / orients the MEA 26 on the bipolar plate. Alternatively or additionally, it is also possible that a second mechanical alignment structure exists; when the MEA 26 is placed on top of the bipolar plate 22, this second mechanical alignment structure provides the MEA 26 with a predetermined spatial orientation relative to the bipolar plate 22. Of course, any other alignment process is also possible.
[0049] After the MEA 26 is placed on top of the bipolar plate 22, a so-called pre-assembled fuel cell unit 28 is provided, which is conveyed to the fastening station 14 by a rotary table 16. At the fastening station 14, the MEA 26 is fastened to the bipolar plate 22. This fastening can be performed by ultrasonic welding, but any other suitable fastening method can also be used, such as adhesive bonding, thermoplastic thermal bonding, soldering, etc. However, ultrasonic welding provides a fast and inexpensive fastening method because it does not require the addition of special materials.
[0050] After fastening station 14, the spatial orientation of MEA 26 relative to bipolar plate 22 is fixed, allowing the now-assembled fuel cell unit 4 to be removed from the first alignment station for further processing.
[0051] In the illustrated embodiment, the assembled fuel cell unit 4 is removed from the rotary table 16 by a second handling manipulator 12 and transported to a second alignment station 8 (stacking). It should be noted that the second alignment station 8 does not necessarily need to be located close to the first alignment station 6. Because the spatial orientation of the MEA 26 and bipolar plates 22 is fixed by the fastening step, the assembled fuel cell unit 4 can be transported to a remote location for the stacking process. Alternatively, the assembled fuel cell unit 4 can be placed in a warehouse and the stacking process performed later.
[0052] However, in Figure 1 In the illustrated embodiment, the second alignment station 8 is arranged close to the first alignment station, allowing the assembled fuel cell unit 4 to be directly conveyed to the third alignment structure 30, which is adapted to align the fuel cell unit 4 to provide the fuel cell stack 2. Thus, the third alignment structure 30 can be adapted to align only the periphery of the fuel cell unit 4, allowing for rapid but precise placement of the fuel cell unit 4. This is due to the fact that the spatial orientation of the bipolar plate 22 and the MEA 26 is fixed by fastening the MEA 26 to the bipolar plate 22.
[0053] Therefore, this allows MEA 26 to be in at least one region 34 (see Figure 2 A fuel cell unit design with overlapping bipolar plates 22 is provided, wherein region 34 is used for aligning fuel cell unit 4. This simultaneously ensures that any contact between the third alignment structure and the bipolar plates is avoided. Alternatively, a fuel cell unit design is possible in which the MEA 26 overlaps the bipolar plates 22 in various locations. In this embodiment, the third alignment structure 30 is adapted to align the fuel cell unit 4 based solely on the periphery of the MEA 26. Thus, a fuel cell stack 2 can be provided in which the risk of short circuits arising from contact with adjacent bipolar plates 22 is avoided because the membrane of the MEA 26 reliably isolates the adjacent bipolar plates 22.
[0054] Figure 2 A detailed view shows an assembled fuel cell unit 4 having bipolar plates 22 and MEA 26 fastened together by ultrasonic welds 32. It can also be seen that the MEA 26 overlaps the bipolar plates 22 in at least the region 34, such that only the MEA 26 contacts the third alignment structure 30.
[0055] Another advantage is that the bipolar plate 22 remains untouched by any device during the alignment of the fuel cell units in the fuel cell stack, which allows for rapid but precise alignment of the fuel cell units.
[0056] Figure 3 Another embodiment of manufacturing arrangement 1 is shown. As can be seen, in the alternative embodiment, alignment and fastening are performed at the assembly station 36, where two manipulator arms 38 and 40 are transporting, aligning, and fastening bipolar plates 22 and MEA 26 for providing the assembled fuel cell unit 4. Compared to Figure 1 The manufacturing arrangement does not have a rotating stage, so the risk of misalignment of bipolar plates 22 and MEA 26 due to the rotational movement of the stage is reduced.
[0057] After fastening, the assembled fuel cell unit 4 is conveyed to the second alignment station 8, which includes an alignment structure 30 for stacking the fuel cell unit 4 onto the fuel cell stack 2.
[0058] By separating the alignment of individual fuel cell elements and the stacking of fuel cell units into at least two distinct steps or stations, the alignment and stacking processes can be accelerated and automated. Furthermore, by securing the MEA to the bipolar plates at separate fastening stations and steps, the spatial orientation of the fuel cell elements can be preserved. This, in turn, allows for a fuel cell unit design in which the MEA overlaps with the bipolar plates, and because stacking (or a second alignment) can be performed solely based on the orientation of the MEA, a fast and precise stacking process is equally permitted. Therefore, the spatial orientation of the bipolar plates themselves is negligible, as it is defined by the orientation of the MEA. It is also advantageous that by placing the MEA on one side of the bipolar plates and handling only the MEA in other steps, the bipolar plates do not need to contact each other during other assembly processes, ensuring a rapid and precise stacking process.
[0059] Figure Labels
[0060] 1 Manufacturing layout
[0061] 2 Fuel Cell Stack
[0062] 4 fuel cell units
[0063] 6 First Alignment Station
[0064] 8 Second Alignment Station
[0065] 10,12 conveying devices
[0066] 14 Fastening Stations
[0067] 16 rotating platforms
[0068] 18 Fastening Manipulator
[0069] 20 Alignment Manipulator
[0070] 22 bipolar plates
[0071] 24 First Alignment Structure
[0072] 26. Membrane Electrode Assembly (MEA)
[0073] 28 pre-assembled fuel cell units
[0074] 30 Third Alignment Structure
[0075] 32 welds
[0076] 34. The region where MEA extends above the bipolar plate.
[0077] 36 assembly stations
[0078] 38,40 manipulator arms
Claims
1. A manufacturing arrangement (1) for a fuel cell stack (2) having a plurality of assembled fuel cell units (4), wherein each fuel cell unit includes a membrane electrode assembly (26) fixed on a bipolar plate (22), wherein the manufacturing arrangement (1) includes at least: — A first alignment station (6) is used to align the bipolar plate (22) and the membrane electrode assembly (26). The first alignment station (6) has a first alignment structure (24) and a second alignment structure. The first alignment structure (24) is used to receive the bipolar plate (22). The second alignment structure is used to arrange the membrane electrode assembly (26) in a predefined spatial orientation on one side of the bipolar plate (22) such that the membrane electrode assembly (26) extends at least one region (34) above the bipolar plate (22). The at least one region (34) is used to align the fuel cell unit (4) thereby providing a protruding periphery of the membrane electrode assembly in the at least one region (34), thereby providing a pre-assembled fuel cell unit (28). — Fastening station (14), the fastening station (14) includes an ultrasonic welding manipulator for fastening the membrane electrode assembly (26) to the bipolar plate (22) by applying an ultrasonic weld in at least one region (34), thereby fixing the spatial orientation of the membrane electrode assembly (26) and the bipolar plate (22), thereby providing an assembled fuel cell unit (4). — A second alignment station (8), located at a different position from the first alignment station (6), the second alignment station (8) having at least one third alignment structure (30), wherein the at least one third alignment structure (30) is adapted to align the assembled fuel cell unit (4) by aligning the protruding periphery of the membrane electrode assembly (26) in the at least one region (34) to provide the fuel cell stack (2); and — A second transport device (12) adapted to contact the assembled fuel cell unit (4) only at the membrane electrode assembly (26) for transporting the assembled fuel cell unit (4) to the second alignment station (8).
2. The manufacturing arrangement (1) according to claim 1 further includes at least a first transport device (16) for transporting the pre-assembled fuel cell unit (28) to the fastening station (14), wherein the first transport device (16) is a movable element, the movable element is a rotary table and includes a first alignment structure (24) and a second alignment structure for aligning the bipolar plate (22) and the membrane electrode assembly (26).
3. The manufacturing arrangement (1) according to claim 1, wherein the first alignment station (6) and the fastening station (14) are combined in a fuel cell unit assembly station (36), the fuel cell unit assembly station (36) including an alignment manipulator (20) and an ultrasonic welding manipulator (18), the alignment manipulator (20) being used to align the bipolar plate (22) and the membrane electrode assembly (26); the ultrasonic welding manipulator (18) being used to weld the membrane electrode assembly (26) to the bipolar plate (22) in at least one region (34).
4. A method for manufacturing a fuel cell stack (2) having a plurality of assembled fuel cell units (4), wherein each fuel cell unit includes a membrane electrode assembly (26) fixed to a bipolar plate (22), wherein the method includes at least the following steps: — By arranging the membrane electrode assembly (26) in a predefined spatial orientation on one side of the bipolar plate (22) to provide a pre-assembled fuel cell unit (28) at a first alignment station (6), such that the membrane electrode assembly (26) extends at least one region (34) above the bipolar plate (22), the at least one region (34) being used for alignment of the fuel cell unit (4), thereby providing a membrane electrode assembly protruding peripheral in the at least one region (34); — After the pre-assembled fuel cell unit (28) is provided, the pre-assembled fuel cell unit (28) is transferred to the fastening station (14). — The membrane electrode assembly (26) is fixed to the bipolar plate (22) using an ultrasonic welding manipulator, providing an assembled fuel cell unit (4) at the fastening station (14), wherein an ultrasonic weld is applied in at least one region (34) to fix the spatial orientation of the membrane electrode assembly (26) and the bipolar plate (22); and — After the assembled fuel cell unit (4) is provided, the assembled fuel cell unit (4) is transferred to a second alignment station (8), wherein the second alignment station (8) is located at a different position from the first alignment station (6), and a second transport device (12) is used to contact the assembled fuel cell unit (4) only at the membrane electrode assembly (26). — By utilizing the membrane electrode assembly (26) on the protruding periphery in at least one region (34), a plurality of assembled fuel cell units (4) are aligned to provide a fuel cell stack (2) at the second alignment station (8).
5. A fuel cell stack (2) comprising a plurality of assembled fuel cell units (4), each of the assembled fuel cell units (4) comprising a membrane electrode assembly (26) secured to a bipolar plate (22) by ultrasonic welding, wherein the fuel cell stack (2) is manufactured in the arrangement (1) according to any one of claims 1 to 3 and / or the method according to claim 4.
6. The fuel cell stack (2) according to claim 5, wherein the at least one assembled fuel cell unit (4) includes a membrane electrode assembly (26) extending at least one region (34) above the bipolar plate (22) to provide a peripheral protrusion of the membrane electrode assembly, and wherein, An ultrasonic weld is arranged in at least one region (34).