Fuel cell stack assembly

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

[0001] Fuel cell stack assembly

[0002] Description:

[0003] The present invention relates to a fuel cell stack assembly.

[0004] Fuel cells allow a hydrogen-containing fuel gas and an oxygen-containing reactant gas such as air to electrochemically react with each other, so that electric power is produced. The fuel cell is basically structured with a membrane that selectively transports hydrogen ions and is sandwiched between two electrodes, i.e. an anode and a cathode. The assembly of membrane and the electrodes is usually referred to as membrane electrode assembly (“MEA”). A fuel cell stack usually comprises a plurality of stacked membrane electrode assemblies, which are separated by bipolar plates.

[0005] The bipolar plates are electrically conductive separators for mechanically clamping the MEA, and for establishing electrical connection in series between adjacent MEAs. Each bipolar plate comprises a plurality of gas flow channels for supplying the corresponding electrode with the fuel gas and the reactant gas and carrying away the generated water or excess gas. A structure body in which the MEAs are clamped between the bipolar plates is referred to as the unit fuel cell.

[0006] The fuel cell stack is provided with endplates at both ends, which sandwich the fuel cell stack and are clamped together by clamping means. Also, the stack is equipped with connecting elements that extend into the stack to supply different media such as hydrogen, air, coolant, and the like to and from the stack.

[0007] Generally, the stack is installed into a support structure or coupling unit having connection counter elements which interact with the connection elements of the fuel cell stack. The support structure is further adapted to support the fuel cell stack and other components of a fuel cell operation system. The support structure can be e.g. a media providing baseplate.

[0008] For installing the stack into the support structure, it is necessary that the connection and counter connection elements are connected to each other in a fluid tight manner, e.g. by inserting connection elements into connection counter elements or vice versa. In order to obtain the fluid tight connection between the connecting elements and connecting counter elements sealing elements are provided.

[0009] However, these sealing elements make it difficult to fully insert the connection elements into the connection counter elements or vice versa, since the sealing elements can create a lot of friction, and in order to bring the stack into position, a lot of feree has to be applied, wherein a weight of the stack and / or manual force is rarely enough.

[0010] It is therefore object of the present invention to provide a fuel cell stack assembly that allows for a quick and easy installation and removal of a fuel cell stack into a system while providing a secure leak tight seal that is not sensitive to vibration or thermal movements.

[0011] This object is solved by a fuel cell stack according to claim 1 .

[0012] In the following, a fuel cell stack assembly is provided that comprises at least an assembled fuel cell stack. The assembled fuel cell stack has at least a first endplate and a second endplate sandwiching a plurality of unit fuel cells, wherein each unit fuel cell comprises a membrane electrode assembly and a bipolar plate. Further, at least the first endplate, the second endplate and the plurality of unit fuel cells are clamped together by at least one clamping means for forming the assembled fuel cell stack. Additionally, the first end plate has at least one connection element through which a medium for operating the fuel cell stack is guided to or from the fuel cell stack. Preferably, the plurality of unit fuel cells is stacked in a stacking direction.

[0013] Furthermore, the fuel cell stack assembly further comprises a coupling unit for providing a fluid connection between a medium duct (and eventually a medium reservoir) and the first endplate, which has at least one connection counter element, which corresponds to the at least one connection element of the first endplate. Thereby, the connection element and the corresponding connection counter element are adapted to fit into each other in such a way that they are engaged by friction fit and / or form fit.

[0014] Thus, the connection element and the corresponding connection counter element are inserted into each other and are not arranged face to face as known form the state of the art, thereby fitting snuggly into each other and providing a fluid tight seal.

[0015] Preferably, the first endplate of the fuel cell stack comprises six connection elements, a hydrogen inlet connection element, a hydrogen outlet connection element, an oxidizing agent inlet connection element, an oxidizing agent outlet connection element, a coolant inlet connection element and a coolant outlet connection element. Correspondingly, there are also six connection counter elements, namely a hydrogen inlet connection counter element, a hydrogen outlet connection counter element, an oxidizing agent inlet connection counter element, an oxidizing agent outlet connection counter element, a coolant inlet connection counter element and a coolant outlet connection counter element.

[0016] However, inserting the connection element / s into the corresponding connection counter element / s or vice versa requires a lot of feree which cannot or cannot easily be provided manually, which in turn hampers the installation process of the fuel cell stack into the system. To provide a fuel cell stack assembly that allows for a quick and easy installation and removal of a fuel cell stack into a system while providing a secure leak tight seal that is not sensitive to vibration or thermal movements, at least one force receiving element and at least one force transmitting element is provided.

[0017] Further, the at least force receiving element and the at least one force transmitting element are configured to interact with one another to bring the at least one connection element and the at least one corresponding connection counter element in frictional or form fit engagement to provide a fluid tight connection between the connection element and the corresponding connection counter element.

[0018] Thereby, the at least one force receiving element may be arranged at the first endplate of the fuel cell stack, and the at least one force transmitting element may be arranged at the coupling unit. Alternatively, the at least one force transmitting element may be arranged at the first endplate of the fuel cell stack, and the at least one force receiving element may be arranged at the coupling unit. For example, the at least one force receiving element or the at least one force transmitting element may be arranged underneath the assembled fuel cell stack where there is a lot of mechanical rigidity.

[0019] According to a further preferred embodiment, the coupling unit is a media providing baseplate having at least one port as connection counter element for supplying media to and removing media from the fuel cell stack. Such a media providing baseplate may be part of a support structure which is adapted to support the fuel cell stack and the other components of a fuel cell operation system. The media providing baseplate may also be pre-installed in an application, e.g. in a vehicle, such as a ship, plane, train or automobile. The media providing baseplate may also be equipped with additional components for operating and controlling the fuel cell stack, e.g. valves for opening and closing the ports or electrical components for electrically coupling or decoupling of the fuel cell stack to a consumer. Alternatively, the coupling unit may be an adapter plate, which is adapted to connect the first endplate and thereby the assembled fuel cell stack to a medium reservoir, via a medium guiding device, e.g. a medium duct, or to a media providing baseplate having at least one port for supplying media to and removing media from the fuel cell stack as described above.

[0020] For that each connection counter element of the adapter plate has a first connection counter element part, a second connection counter element part and a third connection counter element part, wherein the first connection counter element part is adapted to engage with the connection element of the first endplate by friction fit and / or form fit, the second connection counter element part is adapted to be connected to the medium guiding device or the port of the media providing baseplate by friction fit and / or form fit, and the third connection counter element part is adapted to link the first and second connection counter element parts.

[0021] By means of the adapter plate, it is possible to connect a one-sized assembled fuel cell stack to different sized media providing baseplates. This allows for a one-size fuel cell stack, which can be mounted into different kinds of applications without amending the fuel cell stack. This also allows for retrofitting existing systems with improved fuel cell stacks without changing the application / system set up.

[0022] As mentioned above, the at least one connection element or the at least one connection counter element are adapted to fit into each other in such a way that they are fricti onally engaged or engaged by form fit. Thereby, the at least one connection counter element or the at least one connection element may be a nozzle, a tube, and the like that is fluidly connected to a fluid flow channel of the assembled fuel cell stack. Furthermore, the at least one connection counter element or the at least one connection element may be an opening or hole.

[0023] Preferably, the connection element and the corresponding connection counter element may be configured such that when the connection element engages with the corresponding connection counter element, a seal may be created that en- sures a fluid tight connection between the connection element and the corresponding connection counter element. For example, if the connection element is a nozzle and the corresponding connection counter element is a hole / opening, the nozzle may create a radial seal against the opening walls such that the connection between the nozzle and the opening is fluid tight. In addition, a seal element such as an O-ring may be provided on the at least one connection element and / or the at least one connection counter element.

[0024] Therefore, an embodiment is preferred, wherein at least one of the connection elements of the first endplate is a nozzle and the corresponding connection counter elements of the coupling unit is an opening, and / or wherein at least one of the connection elements of the first endplate is an opening and the corresponding connection counter elements of the coupling unit is a nozzle. Thereby, all connection elements of the first endplate may be designed as nozzles or openings, but it is also possible that only some of the connection elements of the same first endplate are nozzles, while the other remaining connection elements of the same first endplate are openings. The corresponding connection counter elements are designed so that they correspond to the respective connection element they are supposed to be connected to.

[0025] Furthermore, an embodiment is preferred, wherein the nozzle is provided with a sealing element which frictionally engages with an inner wall of the opening for providing the fluid tight friction engagement.

[0026] Additionally or alternatively, it is also preferred that the nozzle is equipped with a form element which engages by form fit with a complementary designed form element arranged at the inner wall of the opening for providing the fluid tight form fit engagement. For example, the form fit element at the nozzle may be a hook which snaps into a corresponding designed groove in the inner wall of the opening or vice versa. It should be further noted that it is also preferred that both a form fit element and a friction fit element are provided at the same connecting or connection counter element. This allows for an improved fluid tight engagement.

[0027] According to a further preferred embodiment, the at least force receiving element and the at least one force transmitting element interact such that a force is transmitted between the at least force receiving element and the at least one force transmitting element that causes the fuel cell stack to move in the stacking direction. This allows for a controlled force application to the fuel cell stack and therefore reduces any risks of damaging the fuel cell stack. Furthermore, due to the generated force in the stacking direction, the fuel cell stack may be pulled down, which also allows to insert the seals further down in the connection counter element, making a very robust seal.

[0028] Preferably, the at least force receiving element and the at least one force transmitting element are further configured interact such that a force can also be applied in a direction opposite the stacking direction for removal of the fuel cell stack. This also for a quick and easy removal of the fuel cell stack from the system.

[0029] According to a further embodiment, the at least one force receiving element and the at least one force transmitting element are configured to engage with one another. That is, the at least one force receiving element and the at least one force transmitting element may be configured to mate with each other when installed. For example, the at least one force receiving element and / or the at least one force transmitting element may be a gear, a threaded element, a gear rack, a leadscrew, a bayonet coupling, a hydraulic element, a pneumatic element, a lever, angled slide plane etc.

[0030] Preferably, the fuel cell stack assembly comprises a sensor unit detecting a position of the at least force receiving element and / or the at least one force transmitting element and / or the at least one connection element and / or the at least one connection counter element. Furthermore, the fuel cell stack assembly may com- prise at least one sensor detecting a fluid tightness between the connection element and the connection counter element.

[0031] For example, the sensor unit may be a switch that is actuated when the at least one connection element of the fuel cell stack and / or the at least one counter element reaches its final position. In particular, a part of the connection element may contact the switch that signals the system that the fuel cell stack is in place and a seal has been achieved to the outside. This also means that when a stack is removed, the system may receive a signal to close flow valves, disconnect electrical contacts, shine a warning light etc. Moreover, depending on a type of seal that is used between the connection element and the connection counter element, it may be possible for the fuel cell stack to be lifted significantly before the seal is broken, enabling switches and / or valves to actuate before the fluid ports are open to the outside. Preferably, if two or more fuel cell stacks are connected in the same fluid loop, the other ones may be not affected by this exchange.

[0032] According to a further embodiment, the fuel cell stack assembly comprises at least one locking unit configured to lock the at least force receiving element and the at least one force transmitting element. The at least one locking unit may provide an additional locking feature to further secure a position of the connection element and the connection counter element. The at least one locking unit has the advantage of adding a redundancy and may allow to separate the locking of the final position of the fuel cell stack from the moving of the fuel cell stack. For example, the at least one locking unit may be a lock that clamps on the at least one force receiving element, a pin lock, of the like. It is also possible that the at least one locking unit may be a separate component to both the force receiving element and the force transmitting element. Preferably, the at least one locking unit may be mechanically, pneumatically and / or hydraulically actuated. Additionally, or alternatively, the at least one locking unit may be actuated by the same movement that causes the fuel cell stack to move towards the fuel cell stack support unit. Preferably, the at least one force transmitting element is detachable. This has the advantage that the at least one force transmitting element may be removed from the fuel cell stack assembly when the fuel cell stack has been inserted in the system. Furthermore, the same force transmitting element may then be used to insert another fuel cell stack into the system.

[0033] According to a further embodiment, a plurality of feree receiving elements and / or a plurality of feree transmitting elements is provided. This allows to apply the force evenly on the fuel cell stack.

[0034] Preferably, the at least one force transmitting element is configured to act on a plurality of feree receiving elements. For example, several force receiving elements may be linked so that only one force transmitting element may be needed to apply an even force over the several force receiving elements. Moreover, the fuel cell stack assembly may include at least one driving unit configured to actuate the at least one force transmitting element. For example, only one driving unit and / or force transmitting element may be provided.

[0035] Alternatively, the at least one force transmitting element may include a driving unit configured to actuate the force transmitting element. In particular, each force transmitting element may include one driving unit.

[0036] According to a further aspect, a method for assembling a fuel cell stack assembly is provided, wherein the method comprises the following steps: providing an assembled fuel cell stack having at least a first endplate and a second endplate sandwiching a plurality of unit fuel cells, wherein each unit fuel cell comprises a membrane electrode assembly and a bipolar plate, and wherein at least the first endplate and the second endplate and the plurality of unit fuel cells are clamped together by at least one clamping means for forming the assembled fuel cell stack, wherein the first end plate has at least one connection element through which a medium for operating the fuel cell stack is guided to or from the fuel cell stack, providing a coupling unit for providing a fluid connection between a medium duct (and eventually a medium reservoir) and the first endplate and having at least one connection counter element, wherein the connection element and the connection counter element are adapted to fit into each other in such a way that they are engaged by friction fit and / or form fit, providing at least one force receiving element and at least one force transmitting element, wherein the at least one force receiving element is arranged at the first end plate of the fuel cell stack and the at least one force transmitting element is arranged at the coupling unit, or wherein the at least one force receiving element is arranged at the coupling unit and the at least one force transmitting element is arranged at the first endplate of the fuel cell stack, and operating the at least one force transmitting element such that a force is transmitted between the at least force receiving element and the at least one force transmitting element that causes the fuel cell stack to move such that the at least one connection element and the at least one connection counter element engage by friction fit and / or form fit with one another to form a fluid tight connection between the connection element and the connection counter element.

[0037] Further preferred embodiments are defined in the dependent claims as well as in the description and the figures. Thereby, elements described or shown in combination with other elements may be present alone or in combination with other elements without departing from the scope of protection.

[0038] In the following, preferred embodiments of the invention are described in relation to the drawings, wherein the drawings are exemplarily only, and are not intended to limit the scope of protection. The scope of protection is defined by the accompanied claims, only.

[0039] The figures show:

[0040] Fig. 1 a / b: schematic illustrations of a first embodiment of the fuel cell stack assembly, Fig. 2a / b: schematic illustrations of a second embodiment of the fuel cell stack assembly,

[0041] Fig. 3a / b: a schematic illustrations of an assembled fuel cell stack,

[0042] Fig. 4: a schematic illustration of a part of a fuel cell stack assembly according to a further embodiment,

[0043] Fig. 5: a schematic illustration of a first phase of an assembly of the fuel cell stack assembly,

[0044] Fig. 6: a schematic illustration of a second phase of the assembly of the fuel cell stack assembly according to the second embodiment,

[0045] Fig. 7: a schematic view of a force receiving element and a force transmitting element of a fuel cell stack assembly according to a further embodiment, Fig. 8: a cross section along the line A-A in Fig. 7,

[0046] Fig. 9: an exploded view of a part of a fuel cell stack assembly according to a further embodiment,

[0047] Fig. 10: a schematic illustration of a first phase of an assembly of the fuel cell stack assembly shown in Fig. 9,

[0048] Fig. 1 1 : a schematic illustration of a second phase of an assembly of the fuel cell stack assembly shown in Fig. 9, and

[0049] Fig. 12: a schematic illustration of a third phase of an assembly of the fuel cell stack assembly shown in Fig. 9.

[0050] In the following same or similar functioning elements are indicated with the same reference numerals.

[0051] Fig. 1 and 2 show two different preferred embodiments of a fuel cell stack assembly 1 , each comprising an assembled fuel cell stack 2 which is encased in a housing 3.

[0052] In general, the assembled fuel cell stack 2 is illustrated in Fig. 3 and comprises at least a first endplate 8-1 and a second endplate 8-2, which sandwich a plurality of unit fuel cells 4. Each unit fuel cell 4 comprises a bipolar plate 4-1 and a mem- brane electrode assembly 4-2, which are stacked such that two bipolar plates sandwich a multi-layer membrane electrode assembly 4-1 in a stacking direction.

[0053] For providing the assembled fuel cell stack 2, which can be handled as entity, the first and second endplate 8-1 , 8-2 are clamped together by a clamping device 5, e.g. clamping bands as illustrated in Fig. 3.

[0054] For operating the fuel cell stack 2 provision of reactants to the unit fuel cells 4 is necessary. Usually, as reactants hydrogen, an oxidizing agent, such as air, and a coolant are used. For supplying the reactants to and for removing the reactants from the fuel cell stack, each bipolar plate and / or membrane electrode assembly comprises a hydrogen inlet manifold 6-1 and a hydrogen outlet manifold 6-2, an air inlet manifold 6-3 and an air outlet manifold 6-4, and a coolant inlet manifold 6-5 and a coolant outlet manifold 6-6, wherein the manifolds form respective tubelike channel inlets and channel outlets (not shown). The channel inlets and channel outlets extend through the assembled fuel cell stack 2 and are fluidly connected to respective connection elements 10-1 - 10-6 arranged at the first endplate 8-1. The clamping device 5 ensures the fluid tightness of the assembled fuel cell stack 2.

[0055] For operating the fuel cell stack, the connection elements 10-1 - 10-6 in turn are adapted to be connected to respective media duct and eventually media reservoirs via a coupling unit 12, which comprise a corresponding number of ports 1 1 -1 - 11 - 6 as the first endplate 8-1 , which act as connection counter elements. Thereby, the coupling unit 12 may be designed as media providing baseplate 13, as is illustrated in the embodiment shown in Fig. 1 , wherein the connection counter elements 1 1 -1 - 1 1 -2 are provided by the ports arranged in the media providing baseplate 13.

[0056] Alternatively and as shown in Fig. 2, the coupling unit 12 may be designed as adapter plate 14, which is arranged intermittently between the first endplate 8-1 and a media guiding device so that the first endplate 8-1 is connected to the adapter plate 14, via connection counter elements 15-1 - 15-2. The media guiding device may by the media providing baseplate 13, as illustrated in Fig. 1. However, in case an adapter plate is provided, the ports 1 1 -1 - 1 1 -6 of the media providing baseplate 13 are connected to the connection counter elements 15-1 - 15-6 provided by the adapter plate 14.

[0057] Of course, it would also be possible to connect the connection counter elements 15 of the adapter plate 14 directly to media guiding hoses / tubes.

[0058] As can be further seen from Figs. 1 and 2, the connection elements 10 and the connection counter element 1 1 ; 15 are adapted to fit into each other in such a way that they are engaged by friction fit and / or form fit.

[0059] For that, in the illustrated embodiment of Fig. 1 , the connection elements 10 of the first endplate 8-1 are designed as nozzles and the ports 1 1 are designed as openings, wherein the nozzles are adapted to fit into ports 1 1 of the media providing baseplate 13.

[0060] In contrast to that, in the illustrated embodiment of Fig. 2, the connection elements 10 are designed as openings and the connection counter elements 15 of the adapter plate 14 are designed as nozzles, wherein the nozzles 15 are adapted to fit into openings 10 of the endplate 8-1.

[0061] As can be further seen from the embodiment illustrated in Fig. 2, each connection counter element 15 of the adapter plate 14 has a first connection counter element part 17, a second connection counter element part 19, and a third connection counter element part 20, linking the first and second connection counter element parts 17; 19.

[0062] When the connection element 10 is inserted in the connection counter element 14; 17 a seal is created that ensures a fluid tight connection between the connection element 10 and the connection counter element 1 1 ; 15. For increasing the fluid tightness, the nozzle may additionally be provided with a sealing element 21 , e.g. an O-ring which frictionally engages with an inner wall of the opening 14;17 for providing the fluid tight friction engagement, as can be seen in Fig. 2. Alternatively and or additionally, such a sealing element 21 may may also be provided at the inner wall of the opening 14; 17.

[0063] As can be further seen in the embodiment of Fig. 2, the connection counter elements 17, and particularly, the second connection counter element parts 19 are equipped with a form fit element 22, e.g. a hook, which engage with a groove (not illustrated) arranged in the inner wall of the opening 14; 17.

[0064] In order to pull the fuel cell stack 2 into position, that is, to insert the connection elements 10 into the connection counter elements 11 ; 15, a force needs to be applied that usually exceeds the weight of the fuel cell stack 2 and / or a force that can be manually generated. Thus, several force receiving elements 16 and force transmitting elements 18 are provided that interact with one another to generate a force that is large enough to insert connection elements 10 into the connection counter elements 11 ; 15 such that a fluid tight connection is established.

[0065] As can be seen from Fig. 2, the force receiving elements 16 in the first embodiment are rods with gears or screws that are fastened to the first endplate 8-1 of the fuel cell stack 2 to allow for even and controlled force application. The placement underneath the fuel cell stack 2 has the advantage that there is a lot of mechanical rigidity.

[0066] The force transmitting elements 18 in the first embodiment are corresponding gears as illustrated in Fig. 1 , such that, when the gears rotate, a force is transmitted between the force transmitting elements 18 and the force receiving elements 16 that causes the fuel cell stack 2 to move along the stacking direction 4. Advantageously, if the gears rotate in the opposite direction a force can also be applied in the opposite direction such that the fuel cell stack 2 can be easily removed from the that the fuel cell stack support unit 12. Moreover, the fuel cell stack assembly 1 comprises at least one locking unit (not illustrated) configured to lock the force receiving element 16 to further secure the final position of the connection element 10 and / or the connection counter element 11 ; 15. This may add a redundancy and may allow to separate the locking of the final position of the fuel cell stack 2 from the moving of the fuel cell stack 2. The at least one locking unit may be a clamp that clamps on at least one of the force receiving elements 16. The locking unit may be mechanically, pneumatically and / or hydraulically actuated. Additionally, or alternatively, the at least one locking unit may be actuated by the same movement that causes the fuel cell stack 2 to move towards the coupling unit 12.

[0067] In addition, the fuel cell stack assembly 1 is provided with a sensor unit 23 (see Fig. 2a) detecting a position of the connection element 10. For example, the sensor unit 23 may be a switch that is actuated when the at least one connection element of the fuel cell stack and / or the at least one counter element reaches its final position. In particular, a part of the connection element 10 may contact the switch that signals the system that the fuel cell stack 2 is in place and a seal has been achieved to the outside. This also means that when a stack is removed, the system may receive a signal to close flow valves, disconnect electrical contacts, shine a warning light etc. Moreover, depending on a type of seal that is used between the connection element 10 and the connection counter element 1 1 ; 15, it may be possible for the fuel cell stack 2 to be lifted significantly before the seal is broken, enabling switches and / or valves to actuate before the fluid ports are open to the outside.

[0068] Figs. 4 to 6 show a schematic illustration of a part of a fuel cell stack assembly 1 according to a further embodiment. In the illustrated embodiment, the first endplate 8-1 is equipped with two brackets 24, each having a hook 26 that is configured to interact with the force transmitting element 18 having two claws 28. Each claw 28 has a spiral shaped opening 30 in which the hook 26 of the bracket 24 engages (Fig. 5). When the force transmitting element 18 is then rotated, the hooks 26 and thereby the fuel cell stack 2 are pulled downward.

[0069] When the fuel cell stack 2 has reached its final position and the fluid tight connection between the connection element 10 and the connection counter element 1 1 ; 15 is established, the locking unit may be engaged to secure the position of the fuel cell stack 2. Moreover, it is possible to detach the force transmitting element 18 of the second embodiment once the final position has been reached and the position secured.

[0070] Figs. 7 to 8 show a schematic view of a force receiving element 16 and a force transmitting element 18 of a fuel cell stack assembly 1 according to a further embodiment. In the illustrated embodiment, the force receiving element 16 and the force transmitting element 18 interact via a bayonet coupling, wherein a male connector has a cylindrical shape with two pins 32 on its outer surface that are arranged opposite of each other, and a female connection has an internal pathway 34 with a helix-type shape.

[0071] In this embodiment, the force receiving element 16 is formed as the female connector having the internal pathway 34 and the force transmitting element 18 is formed as the male connector. When the force transmitting element 18 is rotated, the pins 32 move in the internal pathway 34 which causes the force receiving element 16 and the force transmitting element 18 to move towards each other until the surface 36 and the surface 38 contact each other.

[0072] When the fuel cell stack 2 has reached its final position and the fluid tight connection between the connection element 10 and the connection counter element 1 1 ; 15 is established, the locking unit may be engaged to secure the position of the fuel cell stack 2.

[0073] Figs. 9 to 12 show a schematic illustration of a fuel cell stack assembly 1 according to a further embodiment. In the illustrated embodiment, the first endplate 8-1 is quipped with a force receiving element 16 that having a mushroom like shape with a head 40 that has a larger diameter than a shaft 42 of the force receiving element 16. The force transmitting element 18 is a linear actuator 44 that couples to the force receiving element 16 via an elbow element 46 and a link 48 that are connected to a clamping system 50 that allows a gliding movement of the force receiving element 16. The clamping system includes two brackets 52, 54, a guiding part 56, and a block 58. When the linear actuator 44 starts to pull, the geometry of the parts 52, 54, 56, 58 of the clamping system 50 causes the fuel cell stack 2 to move towards the fuel cell stack support unit.

[0074] In summary, the fuel cell stack assembly 1 allows for a quick and easy installation and removal of the fuel cell stack 2 into a system while providing a secure leak tight seal that is not sensitive to vibration or thermal movements.

[0075] Reference numerals

[0076] 1 Fuel cell stack assembly

[0077] 2 assembled fuel cell stack

[0078] 3 housing

[0079] 4 unit fuel cell

[0080] 4-1 bipolar plate

[0081] 4-2 membrane electrode assembly

[0082] 5 clamping means

[0083] 6 inlet / outlet manifolds

[0084] 6-1 hydrogen inlet manifold

[0085] 6-2 hydrogen outlet manifold

[0086] 6-3 air inlet manifold

[0087] 6-4 air outlet manifold

[0088] 6-5 coolant inlet manifold

[0089] 6-6 coolant outlet manifold

[0090] 8-1 first endplate

[0091] 8-2 second endplate

[0092] 10 connection element

[0093] 11 connection counter element of media providing baseplate

[0094] 12 coupling unit

[0095] 13 media providing baseplate

[0096] 14 adapter plate

[0097] 15 connection counter element of adapter plate

[0098] 16 force receiving element

[0099] 17 first connection counter element part

[0100] 18 force transmitting element

[0101] 19 second connection counter element part

[0102] 20 third connection counter element part

[0103] 21 sealing device / friction fit element

[0104] 22 hook / form fit element

[0105] 23 sensor bracket hook claw opening pin internal pathway surface surface head shaft linear actuator elbow link clamping system bracket bracket guiding part block

Claims

Claims:

1. Fuel cell stack assembly (1 ) comprising at least an assembled fuel cell stack (2) having at least a first endplate (8-1) and a second endplate (8-2) sandwiching a plurality of unit fuel cells, wherein each unit fuel cell comprises a membrane electrode assembly and a bipolar plate, and wherein at least the first endplate and the second endplate and the plurality of unit fuel cells are clamped together by at least one clamping means for forming the assembled fuel cell stack, wherein further the first end plate (8-1) has at least one connection element (10) through which a medium for operating the fuel cell stack is guided to or from the fuel cell stack (2), characterized in that the fuel cell stack assembly further comprises a coupling unit for providing a fluid connection between a medium duct and the first endplate and having at least one connection counter element (14), wherein the connection element of the first endplate and the corresponding connection counter element of the coupling unit are adapted to fit into each other in such a way that they are engaged by friction fit and / or form fit, at least one force receiving element (16) and at least one force transmitting element (18), wherein the at least one force receiving element (16) is arranged at the first end plate (8) and the at least one force transmitting element (18) is arranged at the coupling unit (12), or wherein the at least one force receiving element (16) is arranged at the coupling unit (12) and the at least one force transmitting element (18) is arranged at the first endplate (8), and wherein the at least force receiving element (16) and the at least one force transmitting element (18) are configured to interact with one another to bring the at least one connection element (10) and the at least one corresponding connection counter element (14) in engagement by friction fit and / or form fit for providing a fluid tight connection between the connection element (10) and the corresponding connection counter element (14).

2. Fuel cell stack assembly (1) according to claim 1, wherein the coupling unit is a media providing baseplate having at least one port as connection counter element for supplying media to and removing media from the fuel cell stack.

3. Fuel cell stack assembly according to claim 1 , wherein the coupling unit is an adapter plate, wherein each connection counter element has a first connection counter element part, a second connection counter element part and a third connection counter element part, wherein the first connection counter element part is adapted to engage by friction fit and / or form fit with the connection element of the first endplate, the second connection counter element part is adapted to be connected to a medium guiding device, or to a media providing baseplate having at least one port, which is adapted to be connected to the second connection counter element part, for supplying media to and removing media from the fuel cell stack, and the third connection counter element part is adapted to link the first and second connection counter element parts.

4. Fuel cell stack assembly according to any one of the previous claims, wherein the connection element of the first endplate is a nozzle and the corresponding connection counter element of the coupling unit is an opening, and / or wherein the connection element of the first endplate is an opening and the corresponding connection counter element of the coupling unit is a nozzle.

5. Fuel cell stack assembly according to claim 4, wherein the nozzle is provided with a sealing element which frictionally engages with an inner wall of the opening for providing the fluid tight friction engagement, and / or wherein the nozzle is equipped with a form element which engages by form fit with a complementary designed form element arranged at the inner wall of the opening for providing the fluid tight friction engagement.

6. Fuel cell stack assembly according to any one of the previous claims, wherein force transmitting element is a gear device, a threaded element, a gearrack, a leadscrew, a bayonet coupling, a hydraulic element, a pneumatic element, a lever, angled slide plane and / or a linear actuator.

7. Fuel cell stack assembly (1) according to any one of the previous claims, wherein the fuel cell stack assembly (1 ) comprises a sensor unit (22) detecting a position of the at least force receiving element (16) and / or the at least one force transmitting element (18) and / or the at least one connection element (10) and / or the at least one connection counter element (14).

8. Fuel cell stack assembly (1) according to any one of the previous claims, wherein the fuel cell stack assembly (1 ) comprises at least one locking unit (20) configured to lock the at least force receiving element (16) and the at least one force transmitting element (18).Fuel cell stack assembly (1 ) according to claim 8, wherein the at least one locking unit (20) is mechanically, pneumatically and / or hydraulically actuated.

9. Fuel cell stack assembly (1) according to any one of the previous claims, wherein the at least one force transmitting element (18) is detachable.

10. Fuel cell stack assembly (1 ) according to any one of the previous claims, wherein a plurality of feree receiving elements (16) and a single force transmitting elements (18) are provided, wherein the single force transmitting element (18) is configured to act on the plurality of feree receiving elements (16).1 1 . Fuel cell stack assembly (1 ) according to any one of the previous claims, wherein the fuel cell stack assembly (1 ) includes at least one driving unit (44) configured to actuate the at least one force transmitting element (18), wherein preferably the driving unit (44) is included in the force transmitting element (18).

12. Method for assembling a fuel cell stack assembly (1 ), wherein the method comprises the following steps:providing an assembled fuel cell stack (2) having at least a first endplate (8-1 ) and a second endplate (8-2) sandwiching a plurality of unit fuel cells, wherein each unit fuel cell comprises a membrane electrode assembly and a bipolar plate, and wherein at least the first endplate and the second endplate and the plurality of unit fuel cells are clamped together by at least one clamping means for forming the assembled fuel cell stack, wherein the first end plate (8-1 ) has at least one connection element (10) through which a medium for operating the fuel cell stack is guided to or from the fuel cell stack (2), providing a coupling unit for providing a fluid connection between a medium duct and the first endplate and having at least one connection counter element (14), wherein the connection element and the connection counter element are adapted to fit into each other in such a way that they are engaged by friction fit and / or form fit, providing at least one force receiving element (16) and at least one force transmitting element (18), wherein the at least one force receiving element (16) is arranged at the first end plate (8) of the fuel cell stack (2) and the at least one force transmitting element (18) is arranged at the coupling unit (12), or wherein the at least one force receiving element (16) is arranged at the coupling unit (12) and the at least one force transmitting element (18) is arranged at the first endplate (8) of the fuel cell stack (2), and operating the at least one force transmitting element (18) such that a force is transmitted between the at least force receiving element (16) and the at least one force transmitting element (18) that causes the fuel cell stack (2) to move such that the at least one connection element (10) and the at least one connection counter element (14) engage by friction fit and / or form fit with one another to form a fluid tight connection between the connection element (10) and the connection counter element (14).