Unit fuel cell, fuel cell stack, and manufacturing device and method for unit fuel cell or fuel cell stack

Abstract

The present invention relates to an apparatus for manufacturing a fuel cell stack or one or more unit fuel cells (1) of said fuel cell stack, comprising a pre-positioning station for arranging at least a membrane electrode assembly (2) and a bipolar plate (4) in a predefined orientation relative to each other, wherein said bipolar plate (4) has one or more openings (12) and / or one or more specific contours, and said membrane electrode assembly (2) covers one or more openings in said bipolar plate (4) and / or extends over said bipolar plate (4) in one or more areas. ) are oriented relative to each other, and the manufacturing apparatus further includes one or more cutting sites having a cutting device (6) configured to cut the membrane electrode assembly (2) at a predetermined region so that the membrane electrode assembly (2) has cutting openings (12) similar to the one or more openings in the bipolar plate (4) and / or one or more cutting contours (10) similar to the one or more contours of the bipolar plate (4) and / or one or more cutting alignment structures (10) for aligning the unit fuel cell (1) of a fuel cell stack, and a manufacturing method corresponding to the manufacturing apparatus.

Description

[Technical field]

[0001] The present invention relates to Unit fuel cell or The present invention relates to an apparatus and method for manufacturing a fuel cell stack, and to a unit fuel cell and a fuel cell stack manufactured by the apparatus and / or the method. [Background technology]

[0002] A fuel cell stack typically consists of two monopolar plates with multiple membrane electrode assemblies between them separated by a bipolar plate. The membrane electrode assembly (MEA) itself consists of at least a cathode, an anode, and a membrane between them, which reacts hydrogen and oxygen to produce electrical energy and water. To deliver the reactants (hydrogen and oxygen) to each electrode, bipolar plates on either side of the membrane electrode assembly contain fluid flow fields that direct the reactant fluid streams to each electrode.

[0003] The voltage generated by the reaction in a single membrane electrode assembly is usually insufficient for operation in most applications, so multiple membrane electrode assemblies and bipolar plates are stacked and electrically connected in series to achieve the desired voltage. Current is collected from the fuel cell stack and used to drive a load. Various approaches are known for manufacturing fuel cell stacks. For example, in US Pat. No. 5,999,233, the bipolar plates and membrane electrode assemblies are designed as endless tapes, which are placed against each other. To provide the fuel cell stack, the endless tapes are cut to length to form unit fuel cells, and the unit fuel cells are stacked.

[0004] The efficiency of a fuel cell stack depends on the flow of reactants across the surfaces of the membrane electrode assemblies and the integrity of the various contact and sealing interfaces within the individual fuel cells of the fuel cell stack. Such contact and sealing interfaces include those associated with the transport of fuel, coolant, and effluent within and between the unit fuel cells of the stack. Therefore, proper alignment of fuel cell components and assemblies within a fuel cell stack is critical to ensure efficient operation of the fuel cell system.

[0005] Furthermore, the stack itself must ensure that adjacent bipolar plates are electrically isolated from each other to avoid short circuits. For that purpose, membrane electrode assemblies or parts of membrane electrode assemblies are usually used. However, if the membrane electrode assemblies and the bipolar plates are misaligned, parts of the bipolar plates will be exposed and the exposed parts of adjacent bipolar plates may come into contact with each other, increasing the risk of short circuits. Therefore, accurate alignment of the membrane electrode assemblies and the bipolar plates is very important to ensure the proper operation of the fuel cell stack.

[0006] The alignment and stacking typically involves the use of an alignment tool, such as an alignment framework having one or more guide elements, to ensure a predetermined positioning of the membrane electrode assemblies and bipolar plates during the stacking process. After a desired amount of membrane electrode assemblies and bipolar plates are stacked, the resulting fuel cell stack is compressed and, for example, screwed or otherwise joined so that the fuel cell stack is ready for use in a desired application.

[0007] Previously, to ensure proper alignment of the membrane electrode assemblies and bipolar plates, it has been proposed in the art to provide the membrane electrode assemblies and / or bipolar plates with alignment features, such as recesses, into which guide elements of an alignment framework can be inserted or incorporated.

[0008] A drawback of known alignment methods is that both the membrane electrode assemblies and the bipolar plates must have their own alignment features, which is very costly and the tolerances allowed in the manufacture of the membrane electrode assemblies and the bipolar plates are very narrow. Furthermore, the stacking step is very time consuming and the entire stack must be rejected if even one bipolar plate or membrane electrode assembly is not properly aligned. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] China Patent Application Publication No. 106876756 Summary of the Invention [Problem to be solved by the invention]

[0010] It is therefore an object of the present invention to provide an apparatus and method for manufacturing fuel cell stacks that allows for fast, reliable and cost-effective building of fuel cell stacks.

[0011] This object is solved by a manufacturing device according to claim 1 and a manufacturing method according to claim 11.

[0012] The basic idea of ​​the present invention is to improve the alignment between the membrane electrode assembly and the bipolar plate by cutting the openings and / or shapes of the membrane electrode assembly and / or alignment structures in the membrane electrode assembly after the membrane electrode assembly and the bipolar plate are positioned or oriented relative to each other, so that problems such as short circuits caused by misalignment of the membrane electrode assembly and the bipolar plate can be avoided.

[0013] Disclosed below is a manufacturing apparatus for manufacturing a fuel cell stack having a plurality of stacked unit fuel cells or one or more unit fuel cells of a fuel cell stack, the unit fuel cell including one or more bipolar plates and a membrane electrode assembly.

[0014] In general, a membrane electrode assembly usually has an active area with electrodes and membranes (a three-layer membrane electrode assembly), and a so-called subgasket that encompasses the active area, thereby forming a five-layer membrane electrode assembly. Furthermore, a gas diffusion layer may be placed between the bipolar plate and the membrane electrode assembly, which may be attached to the membrane electrode assembly itself to form a seven-layer membrane electrode assembly, or may be attached to the bipolar plate. Regardless of the exact arrangement or layer structure, all types of membrane electrode assemblies will be addressed by the expression "membrane electrode assembly" in this application.

[0015] A bipolar plate generally includes three main regions: an active area having flow fields for distributing reactants to each electrode of a membrane electrode assembly, a distribution region for distributing reactants to the flow fields, and a feed region for feeding reactants to the distribution region from a main feed of the fuel cell stack. It is further noted that a bipolar plate in this context may be either a cathode plate and / or an anode plate, or a bipolar plate assembly including both joined anode and cathode plates.

[0016] The proposed manufacturing apparatus further includes a number of sites, e.g., a pre-positioning site and a cutting site. In the pre-positioning site, one or more membrane electrode assemblies and one or more bipolar plates are placed in a predefined orientation relative to each other, with the one or more bipolar plates having one or more openings and / or one or more specific contours. Furthermore, the membrane electrode assemblies and the bipolar plates are oriented such that the membrane electrode assemblies cover one or more openings in the bipolar plates and / or extend over the bipolar plates in one or more regions.

[0017] To provide a unit fuel cell that allows for rapid and accurate manufacturing and subsequent stacking of fuel cells, the manufacturing apparatus further includes a cutting site having a cutting device for cutting the membrane electrode assembly. Cutting the membrane electrode assembly after the bipolar plate and the membrane electrode assembly are oriented relative to each other ensures that the membrane electrode assembly covers the bipolar plate at all places, thereby avoiding the risk of short circuits.

[0018] The cutting device further includes a cutting element adapted to cut the membrane electrode assembly at a predetermined area, such that the membrane electrode assembly has cutting openings similar to the openings in the bipolar plates and / or one or more cutting contours similar to the contours of the bipolar plates and / or one or more cutting alignment structures for aligning the unit fuel cells.

[0019] Therefore, the basic idea of ​​the present invention is to improve the alignment between the membrane electrode assembly and the bipolar plate by orienting the membrane electrode assembly and the bipolar plate relative to each other and then cutting the openings and / or shapes and / or alignment structures in the membrane electrode assembly, so that problems such as short circuits caused by misalignment of the membrane electrode assembly and the bipolar plate can be avoided.

[0020] Preferably, the portion of the membrane electrode assembly that extends over the contours and / or openings of the bipolar plates is the subgasket and / or the gas diffusion layer, which is made of an easily cuttable material(s), such as plastic and / or carbon paper. Thus, the cutting element is preferably adapted to cut the material of the subgasket and / or the gas diffusion layer. Since the subgasket is usually used to separate the bipolar plates from each other and resembles the shape of the bipolar plates, any misalignment of the subgasket increases the risk of the bipolar plates contacting each other, resulting in a short circuit, which must be avoided under all circumstances. Even if misalignment of the electrodes does not necessarily lead to a short circuit, it reduces the efficiency of the fuel cell stack and must be avoided.

[0021] According to another preferred embodiment, the cutting element is a cutting punch having a shape similar to the shape of one or more openings in the bipolar plate and / or one or more specific contours of the bipolar plate and / or one or more alignment structures and / or the shape of the bipolar plate itself. The use of a cutting punch allows high-precision and high-speed cutting of the membrane electrode assembly. Furthermore, the cutting punch can be provided in a wide variety of shapes so that any kind of shape or opening can be opened in the membrane electrode assembly.

[0022] According to another embodiment, the manufacturing apparatus further comprises one or more fastening devices for fastening the membrane electrode assemblies to the bipolar plates, so that a fitted unit fuel cell is provided. The fastening devices may be part of the pre-positioning site or may be arranged in a separate fastening site. Before the membrane electrode assemblies are cut, the membrane electrode assemblies and the bipolar plates received in the receiving unit are preferably fastened to each other by gluing, welding, in particular ultrasonic or laser welding, and / or soldering. To that end, the fastening devices may comprise an adhesive unit and / or a welding unit. This allows a fast and reliable fastening process.

[0023] By cutting the membrane electrode assembly after fixing the membrane electrode assembly to the bipolar plate, the manufacturing and alignment tolerances can be balanced. The region of the membrane electrode assembly having a predefined shape can be used as a cutting alignment structure when stacking the unit fuel cells. Since the shape is created after fixing the bipolar plate and the membrane electrode assembly, very accurate alignment of the unit fuel cells can be achieved almost automatically.

[0024] As mentioned above, the cutting device can be used, besides cutting the alignment structures, to cut other structures for the membrane electrode assembly, for example the openings required for the main feed channels of the reactants. In other words, a shape of the membrane electrode assembly similar to that of the bipolar plate is provided after the membrane electrode assembly is fixed to the bipolar plate. Thus, according to another preferred embodiment, the membrane electrode assembly to be fixed to the bipolar plate is a sheet element without openings, and the cutting device is further adapted to cut one or more required openings in the one or more membrane electrode assemblies. This simplifies the manufacturing steps and also improves the precision and avoids the risk of short circuits. This is due to the fact that less finesse is required during the orientation of the membrane electrode assembly to the bipolar plate and / or during the fixing of the membrane electrode assembly to the bipolar plate. The subgasket and / or the gas diffusion layer surrounding the active part of the membrane electrode assembly may be cut to shape after the fixing process. Furthermore, the cutting after fixing ensures that the membrane electrode assembly, or indeed the subgasket, separates the bipolar plate in all areas, so that the risk of short circuits can be eliminated.

[0025] According to another embodiment, the pre-positioning site of the manufacturing apparatus further comprises a holding unit adapted to receive and hold one or more membrane electrode assemblies and bipolar plates or a plurality of bipolar plates and membrane electrode assemblies in a pre-positioned orientation, and the cutting device adapted to cut one or more membrane electrode assemblies, so that, for example, after the unit fuel cells are aligned by the cutting alignment structure and corresponding alignment features, e.g., guiding elements such as guide racks, openings can be made in the membrane electrode assemblies of a subset of aligned unit fuel cells or of a complete fuel cell stack.

[0026] According to another preferred embodiment, the manufacturing apparatus further comprises one or more handling devices for handling the membrane electrode assemblies and / or the bipolar plates and / or the installed unit fuel cells and / or the unit fuel cells at one or more of the sites and / or for transporting the membrane electrode assemblies and / or the bipolar plates and / or the installed unit fuel cells and / or the unit fuel cells from one of the sites to another one of the sites.

[0027] The expressions "installed unit fuel cell" and "ready-to-use unit fuel cell" are used to distinguish unit fuel cells that are ready to be used in a fuel cell stack from unit fuel cells that are not yet finished. Thus, an installed unit fuel cell may lack necessary elements such as reactant openings, special alignment features for aligning the unit fuel cell with a stack or with a unit fuel cell in which the membrane electrode assembly and the bipolar plates are not fixed to each other. However, the term "ready-to-use unit fuel cell" is intended to describe a unit fuel cell that is ready to be used in a fuel cell stack and that comprises all the elements, structures, openings and contours as in a final fuel cell stack. When such a distinction is not necessary, the simple phrase "unit fuel cell" refers to both "installed" and "ready-to-use" unit fuel cells.

[0028] The manufacturing apparatus preferably includes at least a first operating unit for receiving a bipolar plate and a second operating unit for receiving a membrane electrode assembly at the pre-positioning site, the first operating unit and the second operating unit being adapted to position the membrane electrode assembly and the bipolar plate in a predefined orientation relative to each other.

[0029] Furthermore, the second operational unit for receiving the membrane electrode assembly and the first operational unit for receiving the bipolar plate are preferably adapted to position the bipolar plate on the membrane electrode assembly, and the first operational unit is preferably adapted to carefully position the bipolar plate with a theoretical midpoint of the bipolar plate at the center of the second operational unit, thereby ensuring that the active portion of the membrane electrode assembly is positioned in the fluid flow field of the bipolar plate.

[0030] In order to avoid short circuits, it is more preferred to stack a plurality of unit fuel cells first and then cut the necessary openings. Therefore, an embodiment in which the cutting device is further adapted to cut a plurality of membrane electrode assemblies is preferred.

[0031] Furthermore, it may be advantageous to use a two-stage cutting process, first cutting the alignment structure, then aligning a plurality of so-called mounted unit fuel cells using the alignment structure, and finally drilling the necessary openings to provide a correctly aligned subgroup of a plurality of so-called ready-to-use unit fuel cells. These subgroups of ready-to-use unit fuel cells can then be stacked in turn to provide the final fuel cell stack. Of course, it is also possible to drill the necessary openings for the final stacked fuel cell stack.

[0032] According to another preferred embodiment, the manufacturing apparatus further comprises an alignment and / or stacking site adapted to receive, align and / or stack a plurality of unit fuel cells. Thereby, it is advantageous that the alignment and / or stacking site further comprises alignment features adapted to align the plurality of unit fuel cells based on one or more cut alignment structures of the membrane electrode assembly. Thereby, the one or more alignment features of the alignment and stacking site preferably have a shape complementary to the alignment structures of the membrane electrode assembly.

[0033] As mentioned above, the predefined shape of the cut membrane electrode assemblies resembles the contour of the bipolar plates, which allows the predefined shape to be used as an alignment structure for both the membrane electrode assemblies and the bipolar plates. Furthermore, short circuits can be avoided and the overall dimensions of the fuel cell stack can be optimized.

[0034] According to another preferred embodiment, the membrane electrode assemblies are cut in areas that are located at the periphery of the assembled fuel cell unit, preferably at one or more corners, preferably at two diagonally opposite corners, so that the unit fuel cells can be stacked and / or aligned using a diagonal working arrangement, which ensures a simplified and fast stacking and alignment process, so that the diagonally opposite corners of the unit fuel cells can be used for stacking / alignment.

[0035] As a result, it is further preferred that the alignment and / or stacking site adapted to receive, align and / or stack a plurality of unit fuel cells comprises guide elements arranged at diagonally opposite corners. As mentioned above, the alignment features of the alignment and / or stacking site are advantageously further adapted to align the plurality of unit fuel cells based on the cut area of ​​the membrane electrode assembly.

[0036] It is further preferred that the alignment and / or stacking site further comprises a first alignment structure and a second alignment structure adapted to accommodate a plurality of unit fuel cells. The alignment and stacking site may further comprise a handling unit adapted to rotate one or more of the unit fuel cells by 180° and place the rotated unit fuel cell on one or more other, preferably non-rotated, unit fuel cells, thereby avoiding oblique stacking. It is also possible to rotate every other unit fuel cell.

[0037] According to another preferred embodiment, the sites in the manufacturing device are arranged in a certain manufacturing sequence, where the pre-positioning site is arranged upstream of the cutting site, which in turn is arranged upstream of the alignment site. An optional fixation site is preferably arranged downstream of the pre-positioning site, but upstream of the cutting site. It should also be noted that the sites do not have to be physically separated from each other and may be realized as binding sites.

[0038] Another aspect of the invention relates to a method for manufacturing a fuel cell stack, comprising the steps of: (a) providing a fuel cell stack;

[0039] In a pre-positioning step, the bipolar plate and the membrane electrode assembly are arranged in a predefined orientation relative to each other, the bipolar plate having one or more openings and / or one or more specific contours, and the membrane electrode assembly and the bipolar plate are oriented relative to each other such that the membrane electrode assembly covers one or more openings in the bipolar plate and / or extends over the bipolar plate in one or more areas; Cutting the membrane electrode assembly at one or more predefined regions so that the membrane electrode assembly has cut openings similar to one or more openings in the bipolar plate and / or one or more cut contours similar to one or more contours of the bipolar plate and / or one or more cut alignment structures for aligning unit fuel cells of a fuel cell stack.

[0040] The method may further comprise a so-called fastening step of fastening the membrane electrode assemblies to the bipolar plates, preferably by gluing, welding and / or soldering, to provide a mounted unit fuel cell. The fastening step is preferably performed after the positioning step and before the cutting step.

[0041] Other steps of the method may include: Providing a bipolar plate, i.e. a cathode plate, an anode plate, or a pre-assembled bipolar plate assembly; Providing a pre-assembled membrane electrode assembly; A step of fixing a membrane electrode assembly to a bipolar plate, thereby providing a pre-assembled unit fuel cell, the membrane electrode assembly extending over the contour of the bipolar plate in one or more areas.

[0042] According to another embodiment, the method further comprises the step of aligning the unitary fuel cells by at least one of the cutting structures cut into the membrane electrode assembly of the installed unitary fuel cells.

[0043] It should be noted that the features described for the device also apply to the claimed method.

[0044] Further preference is given to using a manufacturing device as described above, which is adapted to carry out the corresponding method steps.

[0045] Another aspect of the present invention relates to a ready-to-use unit fuel cell for a fuel cell stack, the ready-to-use unit fuel cell being manufactured by the above-mentioned manufacturing apparatus and / or the above-mentioned manufacturing method.

[0046] Another aspect of the invention relates to a fuel cell stack comprising a plurality of unit fuel cells as described above, manufactured by an apparatus as described above and / or a method as described above.

[0047] Further preferred embodiments are defined in the dependent claims as well as in the description and figures, whereby an element described or shown in combination with other elements can also be present alone or in combination with other elements without departing from the scope of protection.

[0048] In the following, preferred embodiments of the invention will be described with reference to the drawings, which are exemplary and are not intended to limit the scope of protection, which is defined solely by the appended claims.

[0049] The diagram shows the following: [Brief description of the drawings]

[0050] [Figure 1a] 2A to 2C are schematic diagrams illustrating the steps of manufacturing a unit fuel cell according to the first embodiment. [Figure 1b] 2A to 2C are schematic diagrams illustrating the steps of manufacturing a unit fuel cell according to the first embodiment. [Figure 1c] 2A to 2C are schematic diagrams illustrating the steps of manufacturing a unit fuel cell according to the first embodiment. [Figure 1d] 2A to 2C are schematic diagrams illustrating the steps of manufacturing a unit fuel cell according to the first embodiment. [Diagram 2] FIG. 4 is a schematic diagram of a cutting device according to a second embodiment. [Figure 3a] 11A to 11C are schematic diagrams illustrating the steps of manufacturing a unit fuel cell according to a third embodiment. [Figure 3b] 11A to 11C are schematic diagrams illustrating the steps of manufacturing a unit fuel cell according to a third embodiment. [Figure 3c] 11A to 11C are schematic diagrams illustrating the steps of manufacturing a unit fuel cell according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] In the following, identical or similar functional elements are designated by the same reference numbers.

[0052] Furthermore, in the following, the phrases "installed unit fuel cell" and "ready-to-use unit fuel cell" are used to distinguish unit fuel cells ready for use in a fuel cell stack from unit fuel cells that are not yet finished. Thus, an installed unit fuel cell may lack necessary elements such as reactant openings, special alignment features for aligning the unit fuel cell with a stack or with a unit fuel cell in which the membrane electrode assembly and the bipolar plate are not fixed to each other. However, the term "ready-to-use unit fuel cell" is intended to refer to a unit fuel cell ready for use in a fuel cell stack, including all elements, structures, openings and contours as in the final fuel cell stack. The simple expression "unit fuel cell" refers to both "installed" unit fuel cells and "ready-to-use" unit fuel cells. For example, stacking and alignment of unit fuel cells can be performed not only on installed fuel cells but also on ready-to-use unit fuel cells.

[0053] FIG. 1 shows diagrammatically the steps of manufacturing a unitary fuel cell 1 according to a first embodiment of the invention, comprising at least a membrane electrode assembly 2 and a bipolar plate 4. It is thereby noted that the membrane electrode assembly 2 comprises one or more membranes sandwiched by two electrodes (a three-layer membrane electrode assembly) and may be surrounded by a subgasket, thus forming a five-layer membrane electrode assembly. Furthermore, the membrane electrode assembly 2 may comprise a gas diffusion layer attached to the five-layer membrane electrode assembly, thus forming a seven-layer membrane electrode assembly. Of course, other configurations and more or less layers are possible. For the sake of simplicity, in the following, all types of membrane electrode assemblies will be addressed by the expression membrane electrode assembly 2.

[0054] Figure 1a illustrates the membrane electrode assembly 2 at a pre-positioning site of a manufacturing apparatus (not shown) placed on a bipolar plate 4. Thereby, the membrane electrode assembly 2 and the bipolar plate 4 are oriented relative to each other to provide a so-called pre-mounted unit fuel cell. As shown in Figure 1a, in a pre-mounted unit fuel cell, the membrane electrode assembly 2 overlaps the bipolar plate 4 and does not have openings and / or contours similar to the shape of the bipolar plate 4. The membrane electrode assembly 2 is preferably attached to the bipolar plate 4 by any suitable fastening procedure, such as gluing, welding, in particular ultrasonic welding, soldering, etc.

[0055] It should be noted that there are multiple possible ways to fasten the membrane electrode assembly 2 to the bipolar plate 4. For example, when using a 5-layer membrane electrode assembly 2, the gas diffusion layer may be a separate element and fastened to the bipolar plate 4 before the membrane electrode assembly is fastened to the bipolar plate 4. Alternatively, the gas diffusion layer may be fastened to the 5-layer membrane electrode assembly and then the 7-layer membrane electrode assembly may be fastened to the bipolar plate 4. Furthermore, it is also possible to fasten the 5-layer membrane electrode assembly 2 to the bipolar plate 4 and then position and fasten the gas diffusion layer, for example during stacking.

[0056] It goes without saying that the step of fixing the membrane electrode assemblies 2 to the bipolar plates 4 may also be performed after the membrane electrode assemblies 2 have been cut to shape.

[0057] In a next step, as shown in Figure 1b, the membrane electrode assembly 2 and the bipolar plate 4 are inserted into a cutting device 6. The cutting device may be part of the cutting section of a manufacturing apparatus. Of course, it is also possible that the above-mentioned orientation step is performed in the cutting device 6 itself, whereby a combined prepositioning site and cutting site is used. To that end, the cutting device 6 may for example comprise one or more holding units (not shown), which are adapted to receive the membrane electrode assemblies 2 and the bipolar plates 4 and to orient them relative to one another. Of course, the holding units may also be adapted to receive the mounted unit fuel cells themselves.

[0058] Furthermore, the cutting device 6 includes one or more cutting punches 8, which are adapted to cut the membrane electrode assembly 2 in a predetermined area. In the embodiment illustrated in FIG. 1b, there are two cutting punch elements 8-1 and 8-2, which are adapted to cut the edges 10-1 and 10-2 of the membrane electrode assembly 2. Thereby, all the installed unit fuel cells 1 are provided with the same edges 10-1 and 10-2, which can be used to align the unit fuel cells 1 in the subsequent stacking step. Since the cut edges 10-1 and 10-2 are identical for each unit fuel cell 1, it is possible to improve the alignment accuracy and thus the operation of the fuel cells. An installed unit fuel cell 1 having only alignment structures, i.e. cut edges 10-1 and 10-2, is shown in FIG. 1c. These alignment structures can interact with corresponding but complementary shaped alignment features during stacking of the fuel cell stack.

[0059] Besides cutting the alignment structures, i.e. cutting edges 10-1, 10-2, it is also possible to open the openings 12 for reactants and coolants with a correspondingly shaped cutting punch element 8-3, as shown in Fig. 1d. The openings 12 may be opened in a subsequent step of cutting the alignment structures 10, but it is also possible to cut all structures, openings 12, alignment structures 10 etc. with a single correspondingly shaped cutting element 8, as shown in Fig. 2.

[0060] Furthermore, the openings 12 may already be drilled before the membrane electrode assembly 2 and the bipolar plate 4 are oriented relative to one another, or the membrane electrode assembly 2 may have openings already fabricated, as shown in Figures 3a-c. In the illustrated embodiment, the edge cuts may be used to provide identical alignment structures 10-1 and 10-2 in the unit fuel cells that match corresponding alignment features 14 (see Figure 3c) so that the unit fuel cells can be stacked accurately.

[0061] However, by cutting both the openings 12 and the alignment structures 10, the risk of short circuits or misalignment of the membrane electrode assembly 2 to the bipolar plate 4 may be reduced if the cutting of the membrane electrode assembly 2 is performed after orienting the membrane electrode assembly 2 to the bipolar plate 4, ensuring that the membrane electrode assembly 2 covers the bipolar plate 4 at all places, thereby isolating two adjacent bipolar plates 4. Accidental exposure of the bipolar plate 4 by a misaligned membrane electrode assembly 2 may be avoided.

[0062] In another embodiment, not shown, a subset of the installed unit fuel cells are first aligned and fixed relative to each other, and only after the subset of installed unit fuel cells is aligned are the openings in the membrane electrode assemblies opened.

[0063] In the embodiment shown in Figure 3, all of the structures such as openings, alignment structures, contours, etc. are performed before the now-ready-to-use unit fuel cells are transferred to an alignment site (see Figure 3c) which includes an alignment unit 16 shown diagrammatically in Figure 3c. The alignment unit 16 has alignment features 14 having shapes corresponding to the alignment structures 10-1 and 10-2, allowing very precise alignment of the unit fuel cells.

[0064] In summary, very precise alignment of the unit fuel cells is possible by cutting the membrane electrode assemblies 2 to shape after they have been placed or preferably attached to the bipolar plates 4. Furthermore, the risk of short circuits is avoided, as the membrane electrode assemblies reliably cover the bipolar plates 4 at all places, so that no part of the bipolar plates 4 is exposed and can come into contact with adjacent bipolar plates 4. [Explanation of symbols]

[0065] 1 unit fuel cell 2. Membrane Electrode Assembly 4 Bipolar Plates 6 Cutting device 8 Cutting punch 10 Cutting edge (alignment structure) 12 aperture 14 Alignment Features 16 Alignment unit

Claims

1. A manufacturing apparatus for manufacturing a fuel cell stack having a plurality of stacked unit fuel cells or one or more unit fuel cells (1) of the fuel cell stack, the unit fuel cell (1) including one or more bipolar plates (4) and membrane electrode assemblies (2), and the manufacturing apparatus includes at least a receiving unit for receiving a membrane electrode assembly (2) and one or more bipolar plates (4) having one or more openings (12) and / or one or more alignment structures, said receiving unit of the cutting device being further adapted to orient said membrane electrode assembly (2) and said bipolar plate (4) such that said membrane electrode assembly (2) covers said one or more openings and / or said one or more alignment structures of said bipolar plate (4) and / or extends over said bipolar plate (4) in one or more regions, and a cutting device (6) for cutting the membrane electrode assembly (2) including a cutting element (8) adapted to cut the membrane electrode assembly (2) at a predetermined area, so that the membrane electrode assembly (2) has one or more cutting openings (12) similar to the one or more openings (12) of the bipolar plate (4) and / or one or more cutting alignment structures similar to the one or more alignment structures of the bipolar plate (4) and / or one or more cutting alignment structures (10) extending on a periphery of the bipolar plate for aligning the unit fuel cell (1) with the membrane electrode assembly.

2. 2. The manufacturing device according to claim 1, wherein the cutting element (8) is a cutting punch (8) having a shape similar to the shape of one or more openings in the bipolar plate (4) and / or one or more specific contours of the bipolar plate (4) and / or one or more alignment structures (10) and / or the shape of the bipolar plate (4) itself.

3. 3. The manufacturing apparatus according to claim 1 or 2, further comprising a fixing device adapted to fix the membrane electrode assembly (2) and the bipolar plate (4) received in a holding unit to each other by gluing, welding or soldering.

4. 4. The manufacturing apparatus according to claim 1, wherein the receiving unit is further adapted to receive a plurality of bipolar plates and membrane electrode assemblies, and the cutting element is adapted to cut a plurality of membrane electrode assemblies.

5. 5. The manufacturing apparatus according to claim 1, further comprising a first operating unit for handling a bipolar plate (4) and a second operating unit for handling a membrane electrode assembly (2), the first operating unit and the second operating unit being adapted to position the membrane electrode assembly (2) and the bipolar plate (4) in a predefined orientation relative to each other in a receiving unit.

6. The manufacturing apparatus of any one of claims 1 to 5, further comprising an alignment and / or stacking unit (16) adapted to receive, align and / or stack a plurality of unit fuel cells (1) and including one or more alignment elements (14) adapted to align the plurality of unit fuel cells (1) based on the cut area of ​​the membrane electrode assembly (2).

7. The manufacturing apparatus of claim 6 , wherein the one or more cutting alignment structures are cutting areas and the one or more alignment elements have a complementary shape to the cutting alignment structures.

8. The manufacturing apparatus of claim 6 or 7, wherein the alignment and / or stacking unit further includes a handling unit that rotates one or more of the unit fuel cells (1) by 180° and places the rotated unit fuel cell (1) on one or more unit fuel cells (1) that are not rotated, whereby the first alignment element is used to align the non-rotated unit fuel cell and the second alignment element is used to align the rotated unit fuel cell.

9. A method for manufacturing a fuel cell stack having a plurality of stacked unit fuel cells or one or more unit fuel cells of a fuel cell stack (1), comprising the steps of: the step of orienting the bipolar plate (4) and the membrane electrode assembly (2) relative to each other in a predefined orientation, wherein the bipolar plate (4) has one or more openings (12) and / or one or more alignment structures, and the membrane electrode assembly (2) covers the one or more openings and / or the one or more alignment structures of the bipolar plate (4) and / or extends over the bipolar plate (4) in one or more regions; fixing the membrane electrode assembly to the bipolar plate by gluing, welding, and / or soldering; and cutting the membrane electrode assembly (2) at one or more predefined regions so that the membrane electrode assembly (2) has one or more cut openings (12) similar to the one or more openings in the bipolar plate (4) and / or one or more cut alignment structures (10) similar to the one or more alignment structures in the bipolar plate (4) and / or one or more cut alignment structures (10) extending over a periphery of the bipolar plate for aligning the unit fuel cell (1) with the membrane electrode assembly in a fuel cell stack.

10. 10. The method according to claim 9, wherein the step of fixing the membrane electrode assembly (2) to the bipolar plate (4) is performed after the cutting step.

11. 11. The method according to claim 9 or 10, further comprising an alignment step of aligning unit fuel cells (1) using one or more of the cut alignment structures of the membrane electrode assemblies (2).

12. The method of claim 11 , wherein the aligning step further comprises the step of rotating every other unit fuel cell 180 degrees.

13. A method according to any one of claims 9 to 11, using a manufacturing device according to any one of claims 1 to 8.

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