GB2511930A

GB2511930A - Separator plate assembly, fuel cell stack, vehicle and method for manufacturing a separator plate assembly

Info

Publication number: GB2511930A
Application number: GB1402154.7A
Authority: GB
Inventors: Michael Medina; Alan Parkin
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2014-02-07
Filing date: 2014-02-07
Publication date: 2014-09-17
Also published as: GB201402154D0

Abstract

A separator plate assembly 10 for a fuel cell is disclosed, comprising a first plate 14 with a flow field 16 for an anode of the fuel cell, a second plate 18 with a flow field 20 for a cathode of the fuel cell and a frame member 22, preferably made of plastic, arranged between the first plate and the second plate, both preferably made of metal. The frame member comprises a substantially flat region in which the frame member is in contact with the first plate and the second plate. The flat region provides support for at least one first sealing member (40, 42) arranged on the first plate and for at least one second sealing member (40, 42) arranged on the second plate. Further disclosed is a fuel cell stack with a plurality of such separator plate assemblies, a vehicle with a fuel cell stack and a method for manufacturing a separator plate assembly. The frame member may further comprise several openings for reactants (28, 30, 32, 34) and for coolants (36, 38). Preferably, the first and second plate are fixed to the frame member using an adhesive.

Description

Separator Plate Assembly, Fuel Cell Stack, Vehicle and Method for manufacturing a Separator Plate Assembly The invention relates to a separator plate assembly for a fuel cell. The assembly comprises a first plate with a flow field for an anode of the fuel cell, a second plate with a flow field for a cathode of the fuel cell and a frame member arranged between the first plate and the second plate. The invention further relates to a fuel cell stack for a fuel cell system, wherein the fuel cell stack comprises a plurality of the separator plate assemblies. Another aspect of the invention relates to a vehicle with a fuel cell stack and to a method for manufacturing a separator plate assembly for a fuel cell.

Document JR 2005 050 584 A describes a separator plate assembly for a fuel cell, wherein a first plate and a second plate are made of thin metal. The plates each comprise a channel structure for distributing a reactant to a membrane electrode assembly. A frame assembly is arranged between the thin metal plates, which comprises a cooling water frame arranged between a first frame and a second frame. These frames are made of a resin such as a glass epoxy resin. A first sealing ring surrounds an external perimeter of the plates and the frames. Other sealing rings are lining openings for reactants and the cooling water, which are provided in the frames and in the plates.

A similar structure is described in JR 2005 310 633 A. Here, gas passage forming members are separate elements which are arranged in recessed parts of metal plates, between which two frame members made of a resin are arranged. Here again sealing rings circumferentially surround openings in the metal plates and in the frames.

However, placing the sealing rings in their respective locations within these separator plate assemblies is rather laborious.

It is therefore an object of the present invention to provide a separator plate assembly, a fuel cell stack, a vehicle and a method for manufacturing a separator plate assembly of the initially mentioned kind, which is particularly simple and economic in manufacturing.

This object is solved by a separator plate assembly having the features of claim 1, a fuel cell stack having the features of claim 8, a vehicle having the features of claim 9 and a method having the features of claim 10. Advantageous configurations with convenient further developments of the invention are specified in the dependent claims.

According to the invention the frame member comprises a substantially flat region in which the frame member is in contact with the first plate and the second plate. The flat region provides support for at least one first sealing member arranged on the first plate and for at least one second sealing member arranged on the second plate. This is based on the finding that in such a configuration the frame member enables having a flat sealing surface provided on the first plate and on the second plate respectively, onto which sealing members can be easily arranged. The sealing members can be provided on the plates by for example injection molding prior to assembling the separator plate assembly.

Such a flat surface is not easy to provide on a pure metal plate assembly, especially if the flow field plates are comparatively thin. On such pure metal plate assemblies the seal landing typically has no support underneath.

The flat sealing surface enables to use a variety of processes for placing sealing members on the first plate and on the second plate respectively in a robust manner, and also a wide choice of sealing member materials is possible. Especially high pressure and high temperature injection molding can be utilized to arrange the sealing members on the plates. The flat sealing surface also provides for a uniform seal profile. This results in uniform pressures on the sealing members in a fuel cell stack comprising a plurality of the separator plate assemblies. The support provided by the frame member for the sealing members also allows for particularly high seal forces in the fuel cell stack.

Furthermore, arranging the frame member between the first plate and the second plate enables the integration of functionalities in the frame member which conventionally need to be integrated into the anode plate and/or the cathode plate. This allows a high degree of formability, and still the plate assembly fabrication is simple as there is a reduced design complexity. Also near independent development streams allow for different material combinations to be tested simultaneously.

For example, the optimum seal material and process development as well as the optimum material for the plate and/or a coating of the plate can be investigated separately as well as the material and the process development for the frame member. This increases chances of finding the right combination in a timely manner. Consequently, multiple backups are produced, and the best possible material combinations can be determined.

The frame member with the flat region serves to provide mechanical stability to the separator plate assembly in areas which are otherwise mechanically instable, for example in pure metal plate assemblies, and which are thus prone to rupture when assembled into a fuel cell stack. Therefore, the separator plate assembly allows for a particularly simple and economic manufacturing.

Advantageously, the frame member can comprise openings for reactants, wherein a passage between the openings and the respective flow field is provided by a plurality of slots which are separated from each other by web elements. The dimension of the slots has an influence on the pressure drop which occurs when the reactants flow from the respective inlet opening to the flow field and from the flow field to the outlet opening. As these slots or vias are provided in the frame member, a particularly low flow restriction can be provided by the frame member. The slots thus provide for a performance enhancement when the separator plate assembly is utilized in a fuel cell stack.

In a like manner the frame member can comprise openings for a coolant, wherein a passage between the openings and coolant channels established between the first plate and the second plate is provided by a plurality of slots which are separated from each other by web elements. In such a configuration a coolant flow trough the coolant channels can be achieved, which is very efficient in carrying away the heat produced by the fuel cell reaction.

Also the web elements can be coated, for example, with a hydrophobic coating, in order to enhance the flow rate. This is particularly helpful during a start up procedure, especially during a freeze start up.

In a further advantageous embodiment the frame member comprises at least one groove adjacent to the flat region. The at least one groove is configured to accommodate an adhesive utilized to fix the first plate and the second plate to the frame member. Such grooves or spill grooves allow for a particularly even contact between the frame member and the two plates.

The plates are preferably made of metal, wherein a maximum thickness of each one of the metal plates is advantageously at least about five times smaller than a thickness of the frame member in the flat region. This allows for a particularly flat design of the separator plate assembly leading to a particularly thin unit cell. A unit cell with a small pitch results in a high power to volume ratio of a fuel cell stack comprising a plurality of the separator plate assemblies.

As the frame member provides efficient robustness to the separator plate assembly, particularly thin metal plates can be utilized, in particular plate material with a thickness of less than 0.1 mm. As a division between the functions of the metal plates and the frame member serving as support frame is achieved, the separator plate assembly can have a particularly small form factor. Also metal plates are particularly easy in fabrication.

It has further proven advantageous if the frame member is made of plastics, wherein an outer dimension of the frame member is larger than an outer dimension of each one of the plates. Thus, an electrical isolation can be achieved in a fuel cell stack comprising a plurality of such separator plate assemblies. Also an isolation between the plates can be achieved.

Further advantageously the frame member can comprise a recess, wherein the recess is configured to accommodate a conductive element for monitoring the voltage of the fuel cell. With a frame member made of plastics, the integration of such a cell voltage monitoring feature can be particularly easily achieved.

The fuel cell stack according to the invention is a component of a fuel cell system and comprises a plurality of the separator plate assemblies according to the invention. Such a fuel cell stack and a corresponding fuel cell system can in particular be utilized for a vehicle. The invention therefore further relates to a vehicle with a fuel cell stack according to the invention.

In the method for manufacturing a separator plate assembly for a fuel cell according to the invention a frame member is arranged between a first plate with a flow field for an anode of the fuel cell and a second plate with a flow field for a cathode of the fuel cell.

Herein a substantially flat region of the frame member is brought in contact with the first plate and the second plate. At least one first sealing member is arranged on the first plate and at least one second sealing member is arranged on the second plate, wherein the flat region provides support for the sealing members.

The advantages and preferred embodiments described with respect to the separator plate assembly also apply to the fuel cell stack and the vehicle according to the invention as well as to the method for manufacturing the separator plate assembly.

The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the 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 not explicitly shown in the figures or explained, but which result and can be generated by separated feature combinations of the explained implementations are also to be considered encompassed and disclosed by the invention.

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.

Therein show: Fig. 1 in an exploded view a separator plate assembly comprising a first plate and a second plate made of thin metal, wherein a support frame made of plastics is arranged between the two metal plates; Fig. 2 a top view of the separator plate assembly according to Fig. 1; Fig. 3 a section view along a line Ill -Ill in Fig. 2; Fig. 4 an enlarged view of a part of the section shown in Fig. 3; Fig. 5 the support frame in a top view; Fig. 6 an enlarged, perspective view of a part of the support frame shown in Fig. 5; Fig. 7 a reactant inlet region of the separator plate assembly according to Fig. 2; Fig. 8 a section view of a coolant channel within the separator plate assembly according to Fig. 2; Fig. 9 a side view of the section shown in Fig. 8; Fig. 10 a flow chart indicating steps in manufacturing the separator plate assembly according to Fig. 2; and Fig. 11 an exploded view of a fuel cell stack comprising a plurality of the separator plate assemblies shown in Fig. 2.

Fig. 1 is an exploded view of a separator plate assembly in the form of a bipolar plate 10 as they are stacked together in a fuel cell stack 12 shown in Fig. 11. The fuel cell stack 12 is preferably a component of a fuel cell system of a vehicle.

The bipolar plate 10 comprises a first plate 14 with a flow field 16 for distributing a reactant, for example hydrogen. The first plate 14 is made of metal and can have a thickness of less than 0.1 mm. The bipolar plate 10 further comprises a second plate 18 which also comprises a flow field 20 for the distribution of an oxidizing agent as reactant, for example air. The second plate 18 is also made of thin metal. The thickness of the metal plates 14, 18 can in particular be about 0.075 mm.

Between the two metal plates 14, 18 a frame member in the form of a support frame 22 is arranged. This support frame 22 has a central cut out region 24 in an area where the flow fields 16, 20 and transition regions 26 of the metal plates 14, 18 are located. The support frame 22 provides stability to the bipolar plate 10 in particular in regions where the thin metal plates 14, 18 are prone to rupture when assembled into the fuel cell stack 12. The support frame 22 is preferably of engineered plastics and may comprise a liquid crystal polymer (LOB) and/or a polyphenylene sulfide (PPS).

Preferably, the metal plates 14, 18 are coated to provide for corrosion resistance and a low contact resistance. They can be made of stainless steels such as 316SS. For forming the features of the metal plates 14, 18, i.e. the flow fields 16, 20 and the structures in the transition zones 26, stamping, hydro forming and adiabatic forming are possible processes. However, forming of these structures is preferably only done in the active areas, i.e. in the flow fields 16, 20, and in the transition zones 26. In the areas outside the flow fields 16, 20 and the transition zones 26 the plates 14, 18 are configured as flat sheet metal plates, where preferably no other structures than simple cutouts are present.

As shown in Fig. 2, the plates 14, 18 and the support frame 22 have a number of openings or ports which function as inlets and outlets. For example, a fuel inlet 28 is located in a corner region of the bipolar plate 10 and a fuel outlet 30 in a corner which is diagonally opposite to the fuel inlet 28. In like manner an oxidant inlet 32 is located in another corner of the bipolar plate 10 and an oxidant outlet 34 in another corner which is diagonally opposite to the oxidant inlet 32. On a side where the oxidant inlet 32 and the fuel inlet 28 are located, there is also a coolant inlet 36, wherein a coolant outlet 38 is located on the opposite side of the bipolar plate 10.

The aforementioned openings for reactants and the openings for the coolant are each surrounded by a sealing member 40 placed on each one of the metal plates 14, 18.

Another sealing member 42 encloses the an area of each metal plate 14, 18, in which the transition zone 26 and the flow field 16, 20 is located. The support frame 22 also has holes 44 through which tie rods 46 pass in the assembled fuel cell stack 12 (see Fig. 11).

Also there are alignment holes 48 which facilitate the assembly of the fuel cell stack 12.

As can be further seen from Fig. 2, an outer dimension of the support frame 22 is larger than the outer dimensions of the metal plates 14, 18. In other words, an edge 50 of the support frame 22 protrudes over the metal plates 14, 18 in a plane which coincides with the flow fields 16, 20 of the plates 14, 18. This plastic edge 50 around the entire perimeter of the metal plates 14, 18 electrically isolates the fuel cell stack 12. Thus, isolation sheets around the fuel cell stack 12 are no longer necessary. Rather the edges 50 of the plurality of bipolar plates 10 in the fuel cell stack 12 constitute a plastic cover around the metal plates 14, 18 within the fuel cell stack 12. The support frame 22 also has an aperture 52 through which a bus bar passes in the fuel cell stack 12.

The section view in Fig. 3 shows the channel structures or flow fields 16, 20 on the opposite sides of the first plate 14 and the second plate 18. Also a membrane electrode assembly 54 is shown which is located between the flow fields 20, 16 of adjacent bipolar plates 10. Fig. 3 further shows coolant channels 56 which are formed by the two metal plates 14, 18 of each bipolar plate 10 assembly.

As can be particularly well seen in the enlarged view in Fig. 4, the support frame 22 of each bipolar plate 10 comprises a flat region 58 in an area where the sealing member 42 is located. Due to this flat region 58 which is in contact with the flat parts of the metal plates 14, 18 the bipolar plate 10 can easily withstand the compressive forces which are exerted when the bipolar plates 10 are compressed in the fuel cell stack 12. Thus, there is no deformation of the metal plates 14, 18 or the support frame 22, even though very thin metal plates 14, 18 are preferably utilized for the bipolar plates 10.

As can be derived from Fig. 4 the sealing members 40, 42 on the second plate 18 are arranged at the same locations as shown for the first plate in Fig. 2 but on the side which faces towards the membrane electrode assembly 54. Thus there are sealing members 40 sealing the ports or openings for the reactants and the coolant. And there is another sealing member 42 around the active area or flow field 20 of the second plate 18, wherein this sealing member 42 also conforms around the transition zone 26 of the second plate 18.

The sealing members 4042 on the plates 14, 18 are shown to have a simple D-shape, but other designs of the sealing members 40,42 can be utilized. As material for the sealing members 40, 42 in particular silicone can be utilized. A process for applying the sealing members 40, 42 to the metal plats 14, 18 can include injection molding, injection molding with ultraviolet curing or an indirect seal transfer process.

The metal plates 14, 18 are capable of supporting a wide range of processing conditions without damage. For example high temperature injection molding can be utilized for applying the sealing members 40, 42. In particular standard metal insert molding can be utilized, and due to the flat sealing surface and the capability to be fully supported from underneath, no damage occurs during processing. The metal plates are preferably processed prior to final assembly of bipolar plate 10.

A thickness 62 of the support frame 22 in the flat region 58 can in particular be about 0.5 mm. Together with an utilization of thin metal plates 14, 18 this preferably results in a particularly low height 60 of a unit cell comprising the bipolar plate 10 (see Fig. 3). For example, when utilizing very thin metal plates 14, 18 a thickness of the bipolar plate 10 of only 0.07 mm to 0.08 mm can be achieved.

The sealing members 40, 42 which are supported by the flat region 58 can in particular be formed on the metal plates 14, 18 by injection molding, for example, liquid injection molding.

Adjacent to the flat region 58 the support frame 22 has spill grooves 64. These spill grooves 64 are part of a glue joint 66 in which the metal plates 14, 18 of each bipolar plate 10 are fixed to the support frame 22. Glue or such an adhesive which is applied in excess can thus be accommodated in the spill grooves 64 upon the assembly of the bipolar plate 10. As an adhesive for fixing the metal plates 14, 18 to the support frame 22 in particular a fast cure glue can be utilized, wherein ultraviolet radiation or heat may be utilized for curing. The adhesive can be applied by inkjet printing, engraved roller printing, screen printing or the like. The processing temperature and pressure for the application of the adhesive is chosen to be compatible with the materials of the support frame 22 and the sealing members 40, 42.

As can well be seen in Fig. 4, the membrane electrode assembly 54 comprises a catalyst coated membrane 68, a cathode gas diffusion layer 70 and an anode gas diffusion layer 72. With a catalyst coated membrane 68 of about 0.035 mm, a cathode gas diffusion layer 70 of about 0.2 mm and an anode gas diffusion layer 72 of about 0.14 mm, an overall height 60 of the unit cell of about 1.27 mm can be obtained (see Fig. 3). The unit cell comprises the bipolar plate 10 and the membrane electrode assembly 54.

Fig. 5 shows the support frame 22 in a top view. It can be seen from this view that there are specific structures between the openings for the reactants and the coolant and the central cutout region 24 of the support frame 22. These structures comprise a backfeed support 74 for the reactant inlets and outlets and a coolant support 76 adjacent to the coolant inlet 36 and the coolant outlet 38 respectively.

As can be seen from Fig. 6, the backfeed support 74 comprises a plurality of slots 78 which are separated from each other by web elements 80 or ribs. Through the slots 78, for example anode exhaust gas can pass from the transition zone 26 into the fuel outlet 30. On this flow path the fuel passes underneath a region of the metal plate 14, in which the sealing members 40, 42 are located. As the backfeed support 74 is provided by the support frame 22, there is no need of integrating such features into the metal plates 14, 18.

In a like manner the coolant support 76 comprises slots 82 between webs 84 or ribs, wherein the coolant passes from the coolant channels 54 to the coolant outlet 38 through the slots 82. A height 86 of the webs 84 can be about 0.5 mm. As can be further seen in Fig. 6, the glue joint 66 may comprise glue joint vents 88. Further, Fig. 6 shows a recess in the support frame 22, which allows to place a conductive element for cell voltage monitoring wherein the conductive element is electrically isolated by the plastics material of the support frame 22. As the support frame 22 is made of plastics, cell voltage monitoring elements can be molded into the support frame 22 particularly easily.

The support frame 22 can in particular be produced by injection molding or compression injection molding. The coefficient of thermal expansion of the support frame 22 is preferably similar to the coefficient of thermal expansion of the metal plates 14, 18.

By choosing a plastic material for the support frame 22, the vias or slots 78, 82 and the ports or openings for the reactants or the coolant can be molded in a great variety of forms. Also interchangeable inserts can be used in molding for the development of the most appropriate design of the support frame 22. By integrating the slots 76, 82 in the support frame 22, flow enhancement of the coolant and the reactants can be achieved.

This is in particular advantageous for a freeze start up of the fuel cell stack 12.

As can be seen from Fig. 7, the height of the webs 80 between the slots 78 facilitates the backfeed entrance of a reactant into the transition zone 26 and from there further to the flow field 16. This results in an improved pressure drop as a larger volume of fluid per time unit flows trough the transition zone 26 and from there further to the flow field 16. An arrow 92 illustrates the backfeed entrance of the reactant through the slots 78 underneath the seal 42 located on the metal plate 14.

Fig. 8 visualizes by another arrow 94 a coolant flow through one of the coolant channels 56 between the two metal plates 14, 18. Spaced apart from an end of the anode gas diffusion layer 72 there is a notch 96 provided in the first plate 14, which narrows the diameter of the coolant channel 56. As these notches 96 can be produced individually for each coolant channel 56, a flow restriction can be achieved which results in a very even coolant flow along the active areas of the metal plates 14, 18. Fig. 9 shows how the notch 96 provides for a flow control at the level of the individual coolant channel 56. Thus, the coolant flow is controlled and flow sharing can be mitigated.

A flow chart 98 in Fig. 10 illustrates a simplified process flow for the manufacturing the bipolar plate 10. In a first step 100 steel sheet blanks are provided for the first plate 14 and the second plate 18. Anode stamping 102 and cathode stamping 104 is subsequently performed to form the flow fields 16, 20 and the transition zones 26 respectively. In a next step 106 a final cut is performed which may be followed by coating 108 of at least parts of the metal plates 14, 18.

By injection molding 110, in particular liquid injection molding, the sealing members 40, 42 can be applied to the metal plates 14, 18. Glue application 112 can be performed by applying an adhesive to the metal plates 14, 18 and/or to the support frame 22 in the region of the glue joint 66.

In parallel the support frame 22 can be manufactured, wherein in a first step 114 plastic pellets are provided. By injection molding 116 or compression molding the features or structures of the support frame 22 can be created. This is preferably followed by a step of def lashing 118 of the support frame 22. Subsequently, the assembly 120 of the bipolar plate 10 takes place which may be followed by a step of curing 122.

In the bipolar plate 10 the support frame 22 constitutes a sort of a bone structure, wherein the thin metal plates 14, 18 correspond to a skin on this bone. By providing the support frame 22, functionalities which have in prior art been integrated into the plates can now be integrated into the support frame 22. This allows for enhancements of those functionalities, for particularly thin bipolar plates 10 and for a simplification of the bipolar plate 10 design. This facilitates the overall bipolar plate 10 manufacturing.

As only the flow fields 16, 20 and the transition zones 26 of the metal plates 14, 18 are produced by stamping, there is also a considerable simplification of the manufacturing of the metal plates 14, 18. By gluing the metal plates 14, 18 to the support frame 22 there is no need for welding of metal plates. As welding typically causes warping of plates in metal plate assemblies, an improved dimensional stability and simplified stacking can be achieved with the bipolar plates 10 according to Fig. 2. Also in the area of the flat region 58 there are no structures present in the metal plates 14, 18, which may be deformed due to the compressive forces present in the assembled fuel stack 12 (see Fig. 11).

Fig. 11 shows the fuel cell stack 12 in an exploded view. The simplification of some of the stack hardware which is possible with the bipolar plate 10 can thus be illustrated. For example, as the edges 50 of support frames 22 form a plastic cover, no separate isolation sheets are needed for electrical isolation of this part of the fuel cell stack 12. Also no straps around the fuel cell stack 12 are necessary, as there are several tie rods 46 passing through the tie rod holes 44 in the support frame 22 and the metal plates 14, 18.

The tie rods 46 are fastened with barrel nuts 124.

As there is a multitude of tie rods 46, in particular ten tie rods 46 utilized, no deformation due to the natural frequency of the fuel cell stack 12 occurs. This ensures a highly stable fuel cell stack 12. The fuel cell stack 12 further comprises a cathode end plate 126, an isolation plate 128 and a bus plate 130 at one side of the stack and another bus plate 132 and an anode end plate 134 on the other side of the stack. Due to the plastic material of the frame members 22, an electrical isolation between the frame members 22 and the bus plates 130, 132 is achieved as well as an electrical isolation between the frame members 22 and the tie rods 46.

Preferably there are springs 136 adjacent to the anode end plate 134 and a spring plate 138 which covers the springs 136. Furthermore on the cathode end plate 126 there are cell row assembly mounting locations 140 and mounting points 142 for a fluid connector.

The unit cells of the fuel cell stack 12 can have a current density of 1.3 A/cm2 and an active area of 275 cm2. The total active area can be 11.825 m2. With a number of unit cells of 430 and a cell voltage of 0.65 V a stack voltage of 280 V can be achieved. The fuel cell stack 12 may in particular be designed to provide a current of 357.5 A and a power of 100 kW.

The thickness of the membrane electrode assembly 54 can be 0.375 mm. The bipolar plate 10 can have a thickness or height of 0.9 mm, and the pitch or height 60 of the unit cell can be 1.275 mm. Furthermore, the length of a cell row in the fuel cell stack 12 can be 548.25 mm.

List of reference signs bipolar plate 12 fuel cell stack 14 first plate

16 flow field

18 second plate

flow field

22 support frame 24 cutout region 26 transition region 28 fuel inlet fuel outlet 32 oxidant inlet 34 oxidant inlet 36 coolant inlet 38 coolant outlet sealing member 42 sealing member 44 hole 46 tie rod 48 alignment hole edge 52 aperture 54 membrane electrode assembly 56 coolant channel 58 flat region height 62 thickness 64 spill groove 66 glue joint 68 catalyst coated membrane cathode gas diffusion layer 72 anode gas diffusion layer 74 backfeed support 76 coolant support 78 slot web 82 slot 84 web 86 height 88 glue joint vent recess 92 arrow 94 arrow 96 notch 98 flow chart step 102 anode stamping 104 anode stamping 106 final cut 108 coating injection molding 112 glue application 114 step 116 injection molding 118 del lashing assembly 122 curing 124 barrel nut 126 cathode end plate 128 isolation plate bus plate 132 bus plate 134 anode end plate 136 spring 138 spring plate mount location 142 mounting point

Claims

Claims Separator plate assembly for a fuel cell, comprising a first plate (14) with a flow field (16) for an anode of the fuel cell, a second plate (18) with a flow field (20) for a cathode of the fuel cell and a frame member (22) arranged between the first plate (14) and the second plate (18), characterized in that the frame member (22) comprises a substantially flat region (58) in which the frame member (22)is in contact with the first plate (14) and the second plate (16), wherein the flat region (58) provides support for at least one first sealing member (40, 42) arranged on the first plate (14) and for at least one second sealing member (40, 42) arranged on the second plate (18).
2. Separator plate assembly according to claim 1, characterized in that the frame member (22) comprises openings (28, 30, 32, 34) for reactants, wherein a passage (74) between the openings (28, 30, 32, 34) and the respective flow field (16, 20) is provided by a plurality of slots (78) which are separated from each other by web elements (SO).
3. Separator plate assembly according to claim 1 or 2, characterized in that the frame member (22) comprises openings (36, 38) for a coolant, wherein a passage (76) between the openings (36, 38) and coolant channels (56) established between the first plate (14) and the second plate (18) is provided by a plurality of slots (82) which are separated from each other by web elements (84).
4. Separator plate assembly according to any one of claims 1 to 3, characterized in that the frame member (22) comprises at least one groove (64) adjacent to the flat region (58), configured to accommodate an adhesive utilized to fix the first plate (14) and the second plate (18) to the frame member (22).
5. Separator plate assembly according to any one of claims 1 to 4, characterized in that the plates (14, 18) are made of metal, wherein a maximum thickness of each one of the metal plates is, in particular about five times, smaller than a thickness of the frame member (22) in the flat region (58).
6. Separator plate assembly according to any one of claims 1 to 5, characterized in that the frame member (22) is made of plastics, wherein an outer dimension of the frame (22) member is larger than an outer dimension of each one of the plates (14, 18).
7. Separator plate assembly according to claim 6, characterized in that the frame member (22) comprises a recess (90) configured to accommodate a conductive element for monitoring a voltage of the fuel cell.
8. Fuel cell stack for a fuel cell system, in particular of a vehicle, comprising a plurality of the separator plate assemblies (10) according to any one of claims 1 to 7.
9. Vehicle with a fuel cell (12) stack according claim 8.
10. Method for manufacturing a separator plate assembly (10) for a fuel cell, in which a frame member (22) is arranged between a first plate (14) with aflowfield (16) for an anode of the fuel cell and a second plate (18) with a flow field (20) for a cathode of the fuel cell, characterized in that a substantially flat region (58) of the frame member (22) is brought in contact with the first plate (14) and the second plate (18), wherein at least one first sealing member (40, 42) is arranged on the first plate (14) and at least one second sealing member (40, 42)is arranged on the second plate (18), and wherein the flat region (28) provides support for the sealing members (40, 42).