GB2524353A

GB2524353A - Separator plate assembly for a fuel cell stack, injection molding tool, fuel cell system and vehicle

Info

Publication number: GB2524353A
Application number: GB1420429.1A
Authority: GB
Inventors: Jonas Stoll; Stephan Wade; Christian Martin Erdmann; David Kassebaum
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2014-11-18
Filing date: 2014-11-18
Publication date: 2015-09-23
Also published as: GB201420429D0; DE102015014679A1

Abstract

A separator plate assembly (10, fig 4) for a fuel cell stack comprises at least one plate 12, 14 and at least one sealing element 18 applied to the at least one plate. The at least one sealing element 18 encloses an edge 30 of the at least one plate 12, 14. The at least one sealing element 18 comprises at least one alignment element (42, 50; fig 4), which may be in the form of recesses, configured to cooperate with a corresponding alignment element (48, 52; fig 4) of an injection moulding tool 44. A positioning of the at least one plate 12, 14 within a cavity of the injection moulding tool 44 can be effected by the cooperation of the alignment elements (42, 48, 50, 52; fig 4). Further aspects of the invention also relate to the injection moulding tool 44, to a fuel cell system and to a vehicle with a fuel cell system.

Description

Separator plate assembly for a fuel cell stack, injection molding tool, fuel cell system and vehicle The invention relates to a separator plate assembly for a fuel cell stack, the assembly comprising at least one plate and at least one sealing element applied to the at least one plate. The at least one sealing element encloses an edge of the at least one plate. The invention further relates to an injection molding tool with a cavity configured to accommodate such a separator plate assembly, to a fuel cell system with a fuel cell stack comprising a plurality of such separator plate assemblies and to a vehicle with such a fuel cell system.

In a fuel cell system fuel cells such as proton exchange membrane (REM) fuel cells create electricity through the electro-chemical reaction that takes place when a fuel such as hydrogen and an oxidant such as oxygen are passed across opposing sides of an electrolyte membrane. Further a coolant or cooling fluid is typically used to remove the heat generated from this reaction.

The proton exchange membrane fuel cell comprises a membrane electrode assembly (MEA) which comprises an anode, a cathode and the proton exchange membrane arranged between these electrodes. This membrane electrode assembly is arranged between two separator plates, wherein one separator plate comprises channels for the distribution of the fuel and the other separator plate channels for the distribution of the oxidant. The respective channels facing the membrane electrode assembly build a

channel structure which is called a flow field.

In a fuel cell stack a plurality of such unit cells comprising two separator plates and the membrane electrode assembly arranged between the separator plates are often connected in series. In such a fuel cell stack instead of monopolar separator plates bipolar plates can be utilized, which are electrically conductive and which act as an anode for one unit cell and as a cathode for the adjacent unit cell.

In a bipolar plate assembly a first plate acting as an anode for a first unit cell and a second plate acting as a cathode for the adjacent unit cell can be bonded together, for example by welding. As the reactants in form of the fuel and the oxidant and the coolant need to be kept separated from each other, a separator plate assembly or a bipolar plate assembly typically comprises sealing elements which maintain these gases and fluids within their respective areas.

Document US 2004/0180255 Al describes a fuel cell arrangement comprising two stacked plates which are joined to one another to form a module. Between such modules membranes are arranged with an anode catalyst on one side and a cathode catalyst on the other side. The plates are joined to one another by a common seal element of polymer material which is injected onto the plates. To accomplish this the sealing element can encompass the end faces of the two plates.

Document US 2003/0127806 Al describes a membrane electrode assembly for a fuel cell, wherein a gasket is secured around the perimeter of two gas diffusion layers of the membrane electrode assembly. A membrane with catalyst material is sandwiched between the two gas diffusion layers provided with the gasket.The gaskets include flaps which allow an alignment pin to be inserted through holes provided in the membrane and in two separator plates between which the membrane electrode assembly is arranged.

Upon insertion of the alignment pin the flap moves aside. After removal of the pin the flap moves back into its original position. Such an alignment feature shall provide proper alignment during a subsequent molding process or assembly process.

However, in order to assure the alignment the gasket with the flap must already be present on the membrane electrode assembly prior to the subsequent molding process.

Further, document US 2012/0122009 Al describes a method for manufacturing a frame gasket comprising a frame having a certain stiffness and thus stabilizing the frame gasket.

The frame is placed in an injection molding tool with an upper mold and a lower mold, wherein each of the molds comprises a projection projecting towards the frame located in a cavity of the injection molding tool. The projections assure that the frame does not move during the injection of the gasket material in the cavity.

Providing complex components of the fuel cell stack such as separator plates or bipolar plates with sealing elements remains however quite challenging. In particular it is rather laborious and costly to apply sealing elements to such plates by injection molding. This is due to the low rigidity and stability of such components and due to the presence of projections and the like, for example in the area of ports for media such as reactants or a coolant.

It is therefore an object of the present invention to provide a separator plate assembly of the initially mentioned kind, a injection molding tool configured to apply a sealing element on at least one plate of such a separator plate assembly, a fuel cell system with such separator plate assemblies and a vehicle with such a fuel cell system, which provides for an improved application of the sealing element to the plate.

This object is solved by a separator plate assembly having the features of claim 1, by an injection molding tool having the features of claim 7, by a fuel cell system having the features of claim 9 and by a vehicle having the features of claim 10. Advantageous configurations with convenient developments of the invention are specified in the dependent claims.

The separator plate assembly according to the invention comprises at least one plate and at least one sealing element applied to the at least one plate. The at least one sealing element encloses an edge of the at least one plate. The at least one sealing element further comprises at least one alignment element configured to cooperate with a corresponding alignment element of an injection molding tool. Herein a positioning of the at least one plate within a cavity of the injection molding tool can be effected by the cooperation of the alignment elements of the at least one sealing element on the one hand and of the injection molding tool on the other hand.

As the sealing element which is applied to the at least one plate in the injection molding process encompasses the at least one plate along its perimeter, the sealing element is particularly well fixed to the at least one plate. Further, the alignment elements provided in the separator plate assembly assure, in cooperation with the alignment elements provided by the injection molding tool, a very accurate positioning or alignment of the plate within the cavity of the injection molding tool during the injection molding process. As the alignment elements of the separator plate assembly cooperate or interact with the corresponding alignment elements of the injection molding tool a reliable and reproducible positioning of the at least one plate within the cavity of the injection molding tool is therefore achieved. This assures that the least one sealing element is applied at the correct location on the plate The separator plate assembly thus provides for an improved and simplified application of the sealing element on the plate in the injection molding process.

Further the at least one sealing element can be directly, and with particularly little effort and cost, applied to the at least one plate. With such accurately positioned sealing elements securely fixed to the at least one plate an improved separation of reactants and/or a coolant from each other can be achieved and thus an improved isolation of ports, manifolds, channels and the like within a fuel cell stack comprising a plurality of such separator plate assemblies.

With such separator plate assemblies fuel cell systems with particularly agile fuel cell stacks can be provided, which can be utilized in automotive applications for example.

In an advantageous embodiment a first alignment element of the at least one sealing element is located on a first edge of the at least one plate and a second alignment element of the at least one sealing element is located on a second edge of the at least one plate. By providing at least two alignment elements on different edges of the plate the correct positioning of the plate within the cavity of the injection molding tool is further improved.

The alignment elements of the sealing element can in particular be formed as recesses.

Thus, such recesses can cooperate with protrusions or projections provided on at least one mold of the injection molding tool. Further, by forming the alignment elements of the sealing element as recesses and not as protrusions avoids the presence of protrusions on the edge of a separator plate assembly. This facilitates the stacking of such separator plates with membrane electrode assemblies in a fuel cell stack and also reduces the volume occupied by such a fuel cell stack.

Further, by forming the alignment element as recesses the protrusions or projections provided in the injection molding tool can be brought into direct contact with the at least one plate. This further facilitates the desired alignment or positioning of the at least one plate within the cavity of the injection molding tool.

The first edge and the second edge of at least one plate can form an angle, in particular a substantially right angle. Thus corresponding protrusions or projections provided on at least one mold of the injection molding tool contact the at least one plate from different narrow sides. This assures an easily producible alignment of the at least one plate within the cavity.

A particularly good positioning of the at least one plate within the cavity can further be achieved, if according to an additional or alternative embodiment the first edge and the second edge are opposite narrow sides of the at least one plate or at least of a region of the at least one plate. Also with such an arrangement of the alignment elements an accurate alignment of the at least one plate within the cavity of the injection molding tool can be achieved.

It has further proven advantageous, if a first alignment element of the at least one sealing element is configured to receive a pin as the corresponding alignment element of the injection molding tool. Herein a second alignment element of the at least one sealing element is configured to receive a spring element or such a moveable feature as the corresponding alignment element of the injection molding tool. With such an arrangement of alignment elements a clamping force provided by the spring element or such a moveable feature securely holds the at least one plate in place during the injection of the sealing element material into the cavity of the injection molding tool.

A dimension of the second alignment element which is configured to receive the spring element can be greater than a dimension of the first alignment element. Thus, a relatively large contact area for the spring element can be provided which allows a good distribution of the contact pressure which holds the at least one plate in place within the cavity of the injection molding tool.

In particular providing an alignment element for a pin on one edge of the separator plate assembly and another alignment element for the moveable spring element on an opposite edge of the separator plate assembly results in the spring element pushing the at least one plate into the correct position within the cavity.

A portion of the at least one sealing element, which covers an upper side and/or a lower side of the at least one plate can have at least one opening and/or at least one depression configured to receive a knob of the injection molding tool. Thus with at least one knob applying pressure to the at least one plate from the upper side and preferably also from the lower side the plate is not only held in place. Rather the distortion of the at least one plate during the injection molding process can be effectively avoided. To accomplish this, the at least one knob is preferably configured to fix the at least one plate within the cavity of the injection molding tool during the injection of sealing element material into the cavity.

It is therefore particularly advantageous if the portion of the at least one sealing element has openings that allow a direct contact of the knobs with the at least one plate.

The separator plate can in particular comprise a cathode plate and an anode plate, wherein these plates are bonded to each other by bonding means such as welds. This accounts for an enhanced rigidity of the separator plate assembly which then constitutes a bipolar plate assembly.

Herein a portion of the at least one sealing element can be located in a space between the cathode plate and the anode plate, wherein the space is limited by the bonding means to at least one side. Thus, during injection of the sealing element material in the cavity of the injection molding tool the material can flow into the space and thus anchor or fix the sealing element to the plates in a particularly secure and robust manner.

Alternatively or additionally a portion of the at least one sealing element can extend from an edge of the two plates beyond an elevation of at least one of the plates. This also leads to a reliable fixing of the sealing element to the plates.

The elevation can in particular form a closed profile, wherein one plate cooperates with the other one of the plates. This can for example be accomplished by welding an embossed structure of one plate to a flat structure of the other plate. Thus a hollow elevation feature is created which is easy to manufacture and which does not increase the weight of the separator plate assembly.

The sealing element can in particular be made of an injection moldable plastics such as silicone or silicone rubber. The at least one plate of the separator plate assembly can in particular be a thin metal sheet.

The injection molding tool according to the invention has a cavity which is configured to accommodate the separator plate assembly according to the invention. The injection molding tool comprises a first mold and a second mold. At least one of the molds comprises an alignment element which is configured to cooperate with a corresponding alignment element of the at least one sealing element of the separator plate assembly.

Such an injection molding tool enables an improved application of the sealing element to the at least one plate when the at least one plate is accommodated in the cavity.

The at least one mold can comprise at least one alignment element formed as a pin.

Herein the pin is configured to be inserted in the corresponding alignment element of the at least one sealing element. Such alignment elements in the form of pins can be provided on the mold particularly easily and at low cost.

Alternatively or additionally at least one mold can comprise at least one second alignment element which is moveable into the corresponding alignment element of the at least one sealing element. Thus, the insertion of the at least one plate into the cavity can be easily accomplished, and upon insertion the moveable alignment element can be moved into a desired position in which it fixes the at least one plate. Such a moveable alignment element can particularly well bring the at least one plate received in the cavity into the desired position before an injection of the sealing element material. To move the moveable alignment element in particular a spring can be utilized, but other means such as hydraulic or pneumatic means may also be employed.

A dimension of the second alignment element of the mold can be greater than a dimension of the first alignment element. This is in particular advantageous if the moveable second alignment element applies a force to the at least one plate in order to position the at least one plate correctly in the cavity. Then the force exerted by the moveable alignment element can be particularly well distributed over a contact area of this moveable element, in which it is in contact with the at least one plate.

The first alignment elements and/or the second alignment elements can in particular extend in a direction which is parallel to an upper side and/or a lower side of the at least one plate. Thus, such alignment elements contact narrow sides or front faces of the at least one plate. By such laterally arranged alignment elements the at least one plate can be particularly well fixed in a desired position within the cavity.

Alternatively but preferably additionally the at least one mold comprises at least one knob configured to create an opening and/or a depression in a portion of the at least one sealing element covering an upper side and/or a lower side of the at least one plate after the injection of the sealing element material into the cavity. The at least one knob is configured to fix the at least one plate within the injection molding tool during the injection of sealing element material. This can particularly well be accomplished if a plurality of knobs are in contact with the upper side and the lower side of the at least one plate arranged within the at least one cavity.

S

Still further the at least one mold can comprise at least one injection passage for the application of sealing element material to the at least one plate. The at least one injection passage can be oriented towards an upper side and/or towards a lower side of the at least one plate once the plate is received in the cavity of the injection molding tool. Alternatively or additionally the at least one injection passage can be orientated towards a narrow side or front face of the at least one plate. As the sealing element material injected into the cavity can flow around the edge of the at least one plate in order to enclose or encompass the edge, a limited number of injection passages is sufficient for the application of the sealing element onto the at least one plate.

However, injecting the sealing element material from above, from below and from the front side or narrow side of the at least one plate can be an option to evenly fill the cavity with the sealing element material particularly easily. Still the number of injection passages or injection nozzles utilized during injection molding can be reduced.

The fuel cell system according to the invention, which in particular can be employed in a vehicle, includes a fuel cell stack with a plurality of separator plate assemblies according to the invention. Herein a membrane electrode assembly is arranged between a pair of separator plate assemblies of the fuel cell stack.

Such a fuel cell system can include a plurality of further components usual in particular for fuel cell systems of vehicles, which presently do not have to be explained in detail.

The vehicle according to the invention includes a fuel cell system according to the invention.

The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of figures and/or shown in the figures alone are usable not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the invention.

Thus, implementations are also to be considered as encompassed and disclosed by the invention, which are not explicitly shown in the figures or explained, but arise from and can be generated by separated feature combinations from the explained implementations.

Further advantages, features and details of the invention are apparent from the claims, the following description of preferred embodiments as well as based on the drawings in which features having analogous functions are designated with the same reference signs.

Therein show: Fig. 1 in a plane view a section of a bipolar plate assembly comprising a cathode plate and an anode plate bonded to each other by welding, the bipolar plate assembly comprising a sealing element which continuously encompasses the bonded plates along their perimeter, wherein alignment recesses are provided along the perimeter of the plates, which are intended for interaction with corresponding alignment features of an injection molding tool; Fig. 2 a section view along a line Il-Il in Fig. 1; Fig. 3 a section view along a line Ill-Ill in Fig. 1; Fig. 4 the bipolar plate assembly according to Fig. 1 in the injection molding tool after application of sealing element material to the plates; Fig. 5 schematically the injection molding tool in an area configured to form the sealing element shown in Fig. 2, wherein the mold is shown in an open state; Fig. 6 the injection molding tool according to Fig. 5 in a closed state, wherein the bipolar plate assembly is arranged in a cavity of the injection molding tool; Fig. 7 another schematic and perspective view of the injection molding tool in its open state, wherein knobs are visible which fix and support the bonded plates during the injection molding process; and Fig. 8 the injection molding tool according to Fig. 7 in its closed state in which the bonded plates are fixed by the knobs.

Fig. 1 shows a part of a separator plate assembly for a fuel cell stack, which can in particular be a component of a fuel cell systems employed in a vehicle. In the example shown the separator plate assembly 10 is configured as a bipolar plate assembly comprising a cathode plate 12 and an anode plate 14 (see Fig. 2). The two plates 12, 14 can in particular be bonded to each other by welds 16, which are schematically shown in Fig. 6.

In a (not shown) fuel cell stack of a fuel cell system which can in particular be utilized for a vehicle, the cathode plate 12 faces a cathode of a membrane electrode assembly of a first unit cell and the anode plate 14 faces an anode of another membrane electrode assembly of an adjacent unit cell of the fuel cell stack.

The separator plate assembly 10 comprises a sealing element 18 which assures that the reactants provided to the fuel cell stack, i.e. a fuel and an oxidant for example in the form of hydrogen as the fuel and air as the oxidant are kept separated from each other. The sealing element 18 further avoids leakage of a coolant from a coolant flow field which can be provided in a space 20 between the plates 12, 14 (see Fig. 2).

The sealing element 18 comprises a sealing lip 22 in the form of a bulge in an area, where the sealing element 18 surrounds openings or ports 24, 26 provided in the two plates 12, 14. Such ports 24, 26 can be utilized as fuel inlet or as fuel outlet, as oxidant inlet or oxidant outlet, or as coolant inlet or coolant outlet. In the fuel cell stack these ports 24, 26 form manifolds for the aforementioned reactants and the coolant respectively.

The sealing lip 22 can be arranged in an elevated region 28 of the sealing element 16, as can be seen from the section view in Fig. 2. From this section view it is further evident that the sealing element 18 encloses an edge 30 of the two plates 12, 14 which in their welded or otherwise bonded state constitute a bipolar plate. Thus, the sealing element 16 does not only cover an upper side 32 of the cathode plate 12 and a lower side 34 of the anode plate 14 but also a narrow side of the bipolar plate comprising these two plates 12, 14 bonded together.

The sealing element 18 which is present on the upper side 32 of the cathode plate 12 and on the lower side 34 of the anode plate 14 assures the sealing function on the cathode side and the anode side of the separator plate assembly 10 respectively.

However, the sealing element 18 does not only encompass or enclose this first edge 30 of the two plates 12, 14 but also a second edge 36 forming an angle with the first edge 30 and a third edge 38 which is another narrow side of the two plates 12, 14 located opposite of the first edge 30 in a corner region 40 of the separator plate assembly 10 (see Fig. 1).

By enclosing these edges 30, 36, 38 of the plates 12, 14 the sealing element is securely fixed to the plates 12, 14. The sealing element 18 is preferably present all around the entire perimeter of the two plates 12, 14, i.e. along the outer narrow sides of the separator plate assembly 10.

The sealing element 18 consists of an injection moldable plastics such as a silicone or a silicone rubber. Along the edges 30, 36, 38 of the separator plate assembly 10, the sealing element 18 has alignment elements or alignment features which are formed as recesses 42 in the example shown in Fig. 1. In the area of these recesses 42 alignment features or alignment elements which are provided by an injection molding tool 44 are in contact with the narrow sides or edges 30, 36 of the separator plate assembly 10 during the injection of sealing element material into a cavity 46 of the injection molding tool 44 (see Fig. 4 and Fig. 5).

The alignment elements of the injection molding tool 44 can for example be formed as pins 48 which are in contact with the narrow sides of the plates 12, 14 and which thus create the recesses 42 along the edges 30, 36 of the separator plate assembly 10 during the injection molding process (see Fig. 4). The pins 48 are thus alignment elements which correspond to the recesses 42 in the sealing element 18, which are provided along the edges 30, 36 of the separator plate assembly 10. The cooperation or interaction of these alignment elements assures a correct alignment or positioning of the plates 12, 14 placed within the cavity 46 of the injection molding tool 44 prior to and during the injection of the sealing element material.

In addition to the smaller recesses 42 created by the pins 48 (see Fig. 4) the separator plate assembly 10 shown in Fig. 1 has a larger recess 50 which is in the present example located along the third edge 38, i.e. opposite the first edge 30 (see Fig. 1). This recess 50 is configured to receive a corresponding alignment element in the form of moveable pin or bolt, which can in particular be a spring element 52. In Fig. 4 an arrow 54 indicates a force which moves this moveable alignment element towards the first edge 30 once the two plates 12, 14 are arranged within the cavity 46 of the injection molding tool 44. The pressure which can for example be exerted by a spring leads to a correct positioning of the two plates 12, 14 within the cavity 46 during the injection molding process. The alignment features of the separator plate assembly 10 can also be referred to as alignment docks, wherein the broader recess 50 is an alignment dock where the plates 12, 14 are in contact with the moveable alignment element shown in Fig. 4, which can in particular be formed as the spring element 52.

Through the interaction of the pins 48 and the spring element 52 with the corresponding alignment features provided along the perimeter of the separator plate assembly 10 an accurate alignment of the separator plate assembly 10 within the cavity 46 of the injection molding tool 44 is achieved.

As can be seen from Fig. 2 and Fig. 3, a portion 56 of the sealing element 18 can enter the space between the two plates 12, 14 from the edge 30. The space between the two plates 12, 14 which receives this portion 56 is limited by the welds 16. Such portions 56 of the sealing element 18 which enter the space between the two plates 12, 14 lead to a particularly good fixing of the sealing element 18 to the plates 12, 14.

As can further well be seen from Fig. 2, a further portion 58 of the sealing element 18 can extend from the edge 30 beyond an elevation 60 of one of the two plates 12, 14, in the example shown of the cathode plate 12. This elevation 60 forms a closed profile 62 in cooperation with the anode plate 14 and the welds 16. As the sealing element 16 covers the elevation 60 or step in the cathode plate 12 a slipping off of the sealing element 18 from the two plates 12, 14 is efficiently avoided.

Fig. 5 shows an upper mold 64 and a lower mold 66 of the injection molding tool 44 which form the cavity 46 for the separator plate assembly 10. In Fig. 5 a portion of the injection molding tool 44 is shown which is configured to receive an area of the separator plate assembly 10 which comprises the sealing lip 22.

The upper mold 64 and the lower mold 66 each have knobs 68 which fix and support the plates 12, 14 arranged in the cavity 46 during the injection molding process. These knobs 68 create openings 70 in the portions of the sealing element 18 which cover the upper side 32 of the cathode plate 12 and the lower side 34 of the anode plate 14 (see Fig. 1).

The knobs 68 are in contact with the welded plates 12, 14 and thus fix and support the plates 12, 14 during the injection molding process. Therefore the knobs 68 prevent a distortion of the plates 12, 14 during the injection molding process. This is in particular relevant as pressure is exerted on the plates 12, 14 during the injection of the sealing element material into the cavity 46.

Fig. 6 shows the knobs 68 contacting the plates 12, 14 during the injection molding process. From Fig. 6 it can further be seen that one of the plates 12, 14 or both plates 12, 14 can have at least one hole 72 which allows the sealing element material to flow into a space 74, limited to both sides by the welds 16. In the area of the space 74 one of the plates 12, 14, for example the anode plate 14, can have a depression which allows more material to get into the space 74 between the two plates 12, 14.

As can be further seen from Fig. 6, there can be an injection passage 76 provided in the upper mold 64, which is oriented towards the upper side 32 of the cathode plate 12, and which thus allows injection of the sealing element material from above the cathode plate 12. Additionally or alternatively the lower mold 66 can have an injection passage 78 which is oriented towards the lower side 34 of the anode plate 14. This injection passage 78 or injection nozzle thus allows an injection of sealing element material from below the anode plate 14.

Further additionally or alternatively an injection passage 80 can be provided in at least one of the molds 64, 66, which is oriented towards the narrow side or edge 30 of the plates 12, 14 and which thus allows injection of the sealing element material from a front side or front face of the separator plate assembly 10. As the sealing element material can flow around the edge 30 of the two plates 12, 14 either one of these injection passages 76, 78, 80 can be utilized to apply the sealing element 18 to the plates 12, 14.

Alternatively more than one or all the injection passages 76, 78, 80 can be utilized in particular to apply the injection moldable sealing material from different sides to the plates 12, 14 simultaneously.

Fig. 7 shows the injection molding tool 44 in its open state in which the two plates 12, 14 which are bonded together or such a bipolar plate 82 is arranged in the cavity 46 between the upper mold 64 and the lower mold 66. However, in this open state the knobs 68 are not yet in contact with the upper side 32 or the lower side 34 of the bipolar plate 82.

In the closed state of the injection molding tool 44, which is shown in Fig. 8, the knobs 68 firmly fix the bipolar plate 82 in place in the cavity 46, and the injection of the sealing element material does not lead to a distortion of the bipolar plate 82. However, it is not mandatory that the knobs 68 firmly hold the bipolar plate 82, but, instead, could be kept back very slightly to allow for any thickness tolerances of the piece (e.g. a metal piece) inserted into the injection molding tool 44.

The knobs 68 described above are illustrated in the figures, in particular in Fig. 7 and 8, as cubes. However, it is to be understood that the knobs 68 can have different shapes, such as round or dome shapes, as needed to e.g. for material flow, tooling manufacturing, tool durability, etc. List of reference signs separator plate assembly 12 cathode plate 14 anode plate 16 weld 18 sealing element space 22 scaling lip 24 port 26 port 26 elevated region edge 32 upper side 34 lower side 36 edge 38 edge corner region 42 recess 44 injection molding tool 46 cavity 48 pin recess 52 spring element 54 arrow 56 portion 58 portion elevation 62 profile 64 upper mold 66 lower mold 68 knob opening 72 hole 74 space 76 injection passage 78 injection passage injection passage 82 bipolar plate

Claims

Claims Separator plate assembly for a fuel cell stack, comprising at least one plate (12, 14) and at least one sealing element (18) applied to the at least one plate (12, 14), wherein the at least one sealing element (18) encloses an edge (30, 36, 38) of the at least one plate (12, 14), characterized in that the at least one sealing element (18) comprises at least one alignment element (42, 50) configured to cooperate with a corresponding alignment element (48, 52) of an injection molding tool (44), wherein a positioning of the at least one plate (12, 14) within a cavity (46) of the injection molding tool (44) can be effected by the cooperation of the alignment elements (42, 48, 50, 52).
2. Separator plate assembly according to claim 1, characterized in that a first alignment element (42), in particular formed as a recess, of the at least one sealing element (18) is located on a first edge (30) of the at least one plate (12, 14) and a second alignment element (42, 50), in particular formed as a recess, of the at least one sealing element (18) is located on a second edge (36, 38) of the at least one plate (12, 14).
3. Separator plate assembly according to claim 2, characterized in that the first edge (30) and the second edge (36) form an angle, in particular a substantially right angle, and/or the first edge (30) and the second edge (38) are opposite narrow sides of at least of a region (40) of the at least one plate (12, 14).
4. Separator plate assembly according to any one of claims 1 to 3, characterized in that a first alignment element (42) of the at least one sealing element (18) is configured to receive a pin (48) as the corresponding alignment element of the injection molding tool (44) and a second alignment element (50) of the at least one sealing element (18) is configured to receive a spring element (52) as the corresponding alignment element of the injection molding tool (44), wherein a dimension of the second alignment element (50) is greater than a dimension of the first alignment element (42).
5. Separator plate assembly according to any one of claims 1 to 4, characterized in that a portion of the at least one sealing element (18), which covers an upper side (32) and/or a lower side (34) of the at least one plate (12, 14) has at least one opening (70) and/or at least one depression configured to receive a knob (68) of the injection molding tool (44), configured to fix the at least one plate (12, 14) within the cavity (46) of the injection molding tool (44) during an injection of sealing element material.
6. Separator plate assembly according to any one of claims 1 to 5, characterized in that the separator plate assembly (10) comprises a cathode plate (12) and an anode plate (14) bonded to each other by bonding means (16), in particular by welds, -wherein a portion (56) of the at least one sealing element (18) is located in a space between the cathode plate (12) and the anode plate (14), the space being limited by the bonding means (16) to at least one side, and/or -wherein a portion (58) of the at least one sealing element (18) extends from an edge (30) of the two plates (12, 14) beyond an elevation (60) of at least one of the plates (12, 14), in particular forming a closed profile (62) in cooperation with the other one of the plates (12, 14).
7. Injection molding tool with a cavity (46) configured to accommodate the separator plate assembly (10) according to any one of claims ito 6, the injection molding tool (44) comprising a first mold (64) and a second mold (66), wherein at least one of the molds (64, 66) comprises an alignment element (48, 52) configured to cooperate with a corresponding alignment element (42, 50) of the at least one sealing element (18) of the separator plate assembly (10).
8. Injection molding tool according to claim 7, characterized in that the at least one mold (64, 66) comprises, -at least one first alignment element formed as a pin (48) configured to be inserted in the corresponding alignment element (42) of the at least one sealing element (18) and/or -at least one second alignment (52) element which is movable, in particular by a spring, into the corresponding alignment element (50) of the at least one sealing element (18), wherein a dimension of the second alignment (52) element is greater than a dimension of the first alignment (48) element and/or wherein the alignment element (48, 52) extends in a direction which is parallel to an upper side (32) and/or a lower side (34) of the at least one plate (12, 14), and/or -at least one knob (68) configured to create an opening (70) and/or a depression in a portion of the at least one sealing element (18) covering an upper side (32) and/or a lower side (34) of the at least one plate (12, 14), the at least one knob (68) being configured to fix the at least one plate (12, 14) within the injection molding tool (44) during an injection of sealing element material and/or -at least one injection passage (76, 78, 80) for the application of sealing element material to the at least one plate (12, 14), the at least one injection passage (76, 78, 80) being oriented towards an upper side (32) and/or towards a lower side (34) and/or towards a narrow side (30) of the at least one plate (12, 14) which can be received in the cavity (46) of the injection molding tool (44).
9. Fuel cell system, in particular for a vehicle, with a fuel cell stack comprising a plurality of separator plate assemblies (10) according to any one of claims 1 to 6, wherein a membrane electrode assembly is arranged between a pair of the separator plate assemblies (10) of the fuel cell stack.
10. Vehicle with a fuel cell system according to claim 9.