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] The media providing baseplate is usually constantly connected to respective media reservoirs via media guiding ducts. For removing or installing the fuel cell stack from / to the media providing baseplate, it is therefore necessary to first disconnect or reconnect the media ducts, which can be easily forgotten. This in turn result in serious explosion hazards as hydrogen might flow into a closed room.

[0009] 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.

[0010] This object is solved by a fuel cell stack according to claim 1 .

[0011] 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.

[0012] Additionally, the first endplate 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, a media providing baseplate is provided for providing a medium supply and removal between at least one medium duct and the first endplate. The media providing baseplate has at least one port for supplying media to and removing media from the fuel cell stack, wherein the first endplate and the media providing baseplate are connected to each other in fluid tight engagement. The media providing baseplate is further equipped with a control unit for determining a state of engagement between the first endplate and the media providing baseplate and for triggering at least one control action in the fuel cell stack assembly based on the state of engagement.

[0014] Such a media providing baseplate may be part of a fuel cell system 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 preinstalled in an application, e.g. in a vehicle, such as a ship, plane, train or automobile.

[0015] Usually, 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.

[0016] Thus, it is further preferred that for each medium, particularly hydrogen, oxidizing agent, e.g. air, and coolant, the media providing baseplate has corresponding connection counter element, namely corresponding inlet ports and corresponding outlet ports.

[0017] The triggering of control actions based on the state of engagement between the first endplate and the media providing baseplate allows for quick and automatic installations and / or deinstallations of the fuel cell stack into / from the media providing baseplate. This increases the safety of the operation of the fuel cell stack as e.g. media supply to the stack and / or electric power connections are only possible if the fuel cell stack is securely arranged and mounted into the media providing baseplate so that the first endplate and the media providing baseplate are in fluid tight connection.

[0018] For providing a fluid tight connection, an embodiment is preferred wherein the at least one connection element of the first endplate and the at least one corresponding port of the media providing baseplate are adapted to fit into each other in such a way that they are engaged by form fit and / or friction fit, and the control unit de- termines a state of engagement between the at least one connection element and the at least one port.

[0019] Alternatively, the fuel cell stack assembly further comprises an adapter plate which is arranged between the media providing baseplate and the first endplate, wherein the adapter plate includes at least one corresponding connection counter element, wherein each corresponding connection counter element comprises a first connection counter element part, second connection counter element part and third connection counter element part, wherein the first corresponding connection counter element part is configured to engage by form fit and / or friction fit with the connection element of the first endplate and the second corresponding connection counter element part is configured to be connected with the at least one port of the media providing baseplate, and the third connection counter element part is configured to link the first and the second connection counter element parts, and the control unit determines a state of engagement between the at least one second connection counter element and the at least one port.

[0020] 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.

[0021] It is further preferred that also the second connection counter element part is configured to be connected to the corresponding port of the media providing baseplate by form fit engagement and / or friction fit engagement for providing a fluid tight engagement between the adapter plate and the media providing baseplate.

[0022] Since there are inlet and outlet ports for the three media, the adapter plate comprises also six corresponding 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. Further, the connection counter element and the connection element and / or the port, respectively, 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.

[0023] As mentioned above, for ensuring that the fuel cell stack is securely arranged and mounted into the media providing baseplate so that the first endplate and the media providing baseplate are in fluid tight connection, a further embodiment is preferred, wherein the control action is an automatic closing and / or opening of the at least one port in the media providing baseplate. Thereby, a media supply to the stack is only possible if the fuel cell stack is securely arranged and mounted into the media providing baseplate.

[0024] According to a further preferred embodiment, the media providing plate may be equipped with a flow regulating valve, preferably a check valve, which interacts with the adapter plate and controls the automatic closing and / or opening of the ports. Thereby, the check valve is a normally closed check valve. The check valve provides a simple and cost effective way to open / close the ports in the media providing baseplate based on the state of engagement.

[0025] Thereby, it is possible that the check valve is opened by the connection counter element itself, particularly the second connection counter element part. However, it is also possible that the adapter plate is equipped with a mechanical device which mechanically opens the check valve. Further it is also possible that the open- ing / closing of the check valve, or of the ports in general, is triggered by an electric control command which is provided by the control unit, particularly by a sensor unit. Then, a mechanical interaction for opening and / or closing the ports between adapter plate and its parts and the media providing baseplate is not necessary.

[0026] According to a further preferred embodiment, the at least one port of the media providing baseplate is connected to a medium duct, for connecting the assembled fuel cell stack to the medium reservoir, and the check valve includes a backpressure regulation mechanism or is designed as back-pressure valve, which is con- figured to maintain a predetermined pressure in the assembled fuel cell stack and / or the medium duct.

[0027] Usually, such a back pressure regulation mechanism or a back-pressure valve maintains the predetermined pressure at its inlet side by opening to allow flow when the inlet pressure exceeds the predetermined value.

[0028] It differs from an over-pressure valve in that the over-pressure valve is only intended to open when the contained pressure is excessive, and it is not required to keep upstream pressure constant. It differs from pressure reducing regulators in that the pressure reducing regulator controls downstream pressure and is insensitive to upstream pressure.

[0029] It is a normally-closed valve which may be installed in parallel with sensitive equipment or after the sensitive equipment to provide an obstruction to flow and thereby maintain upstream pressure.

[0030] According to a preferred embodiment, the back pressure regulation mechanism uses the determined inlet pressure as input to the control mechanism and may be actuated by a spring loaded diaphragm or a piston reacting to changes in the inlet pressure to control the valve opening, wherein the valve is opened only enough to maintain the set regulated pressure.

[0031] Thus, the backpressure regulation mechanism is adapted to actively regulate the upstream pressure, while the check valve controls the opening and / or closing of the ports.

[0032] As mentioned above, it is further preferred that for each medium, particularly hydrogen, oxidizing agent, e.g. air, and coolant, the media providing baseplate has an inlet port and an outlet port.

[0033] The check valve may be arranged at either the respective inlet and outlet port or at both inlet and outlet ports. This allows for an embodiment, when the check valve closes the port based on the control command provided by the control unit, the back pressure regulation mechanism maintains the backpressure in the medium duct, in case the back pressure regulation mechanism is arranged at an inlet port of the media providing baseplate and / or in the fuel cell stack, in case the back pressure regulation mechanism is arranged at an outlet port of the media providing baseplate.

[0034] Consequently, the back pressure regulation mechanism ensures that the inlet and / or outlet ports should be able to be closed in such a way that pressure is retained in the stack to perform a hydrogen soak and air soak for recovery procedures, when the stack is disconnected.

[0035] Moreover, the backpressure regulation mechanism may also include features such as pressure-adjusting handles, outlet gauges, and inlet gauges, which may be also integrated into the check valve, and can be controlled by the control unit. A check valve with integrated back pressure mechanism may be a ball check valve, piston check valve, or wafer check valve.

[0036] According to a further preferred embodiment, the control action is a connection and / or disconnection of electrical contacts between the first endplate and the media providing baseplate. Thereby, providing electric power to a consumer is only possible if the fuel cell stack is securely arranged and mounted into the media providing baseplate.

[0037] Besides providing an automatic connection / disconnection between the first end- plate / adapter plate and the media providing baseplate, the control action may also be an auditory or visual warning signal that indicates the state of engagement between the first endplate / adapter plate and the media providing baseplate. This also allows for a safe attachment and fluid tight connection between the first endplate / adapter plate and the media providing baseplate which increases the operation safety of the fuel cell stack. It is further preferred that the control unit may comprise a mechanical switch and / or at least one sensor such as optical sensor, and / or electronic sensor for providing and / or triggering the respective control action as mentioned above.

[0038] As mentioned above, the connection counter element and the corresponding connection element and / or the corresponding port, respectively, are inserted into each other thereby fitting snuggly into each other and providing a fluid tight seal.

[0039] For that it is further preferred that at least one of the connection elements of the first endplate is a nozzle and the corresponding port of the media providing baseplate is an opening, and / or wherein at least one of the connection elements of the first endplate is an opening and the corresponding port of the media providing baseplate is a nozzle.

[0040] Alternatively, in case an adapter plate is arranged between the fuel cell stack and the media providing baseplate, it is preferred that at least one of the connection elements of the first endplate is a nozzle and the first corresponding connection counter element parts of the adapter plate is an opening, and / or wherein at least one of the connection elements of the first endplate is an opening and the corresponding first connection counter element parts of the adapter plate is a nozzle, and wherein at least one of the ports of the media providing baseplate is an opening and the corresponding second connection counter element parts of the adapter plate is a nozzle, or at least one of the ports of the media providing baseplate is a nozzle and the corresponding second connection counter element parts of the adapter plate is an opening.

[0041] Thereby, it should be noted that 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. Providing nozzles and openings as connection elements and / or connection counter elements has the advantage that introducing the nozzle into the corresponding opening 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 nozzle or in the opening which further increases the fluid tightness.

[0042] Therefore, an embodiment is preferred, wherein the nozzle is provided with a sealing element which frictional ly engages with an inner wall of the opening for providing the fluid tight friction engagement.

[0043] Additionally or alternative, for providing a secure engagement, which cannot come loose, the nozzle is equipped with a form fit element which engages by form fit with a complementary designed form fit element arranged at the inner wall of the opening for providing the fluid tight friction engagement.

[0044] It should be further noted that it is also preferred that both a form fit element and a friction fit element may be provided at the same connecting or connection counter element. This allows for an improved fluid tight engagement.

[0045] Regardless of form fit or friction fit engagement, inserting the connection element into the connection counter element or vice versa requires a lot of force which cannot or cannot easily be provided manually, which in turn hampers the installation process of the fuel cell stack into a system or into the media providing baseplate.

[0046] 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.

[0047] Thereby, the at least one 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 connection counter element in frictional engagement to provide a fluid tight connection between the connection element and the connection counter element.

[0048] 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 media providing baseplate. 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 media providing baseplate. Thereby, the at least one force receiving element or the at least one force transmitting element are arranged in an area where there is a lot of mechanical rigidity.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] According to a further preferred embodiment, the control unit of the media providing baseplate further comprises a sensor unit detecting a position of the at least force receiving element and / or the at least one force transmitting element . For example, the sensor unit may be a switch that is actuated when the at least force receiving element and the at least one force transmitting element reach their final position.

[0053] According to a further preferred embodiment, the control unit of the media providing baseplate further comprises a sensor unit detecting an operation of the at least force receiving element and / or the at least one force transmitting element . For example, the sensor unit may be a switch that is actuated when the at least force receiving element and the at least one force transmitting element are operated, which in turn triggers the respective control action.

[0054] 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 and / or the fuel cell stack into the media providing base plate, wherein the control unit is adapted to trigger the control action upon operation of the locking unit. 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.

[0055] According to a further aspect, a method for controlling a fuel cell stack assembly as mentioned above is provided, wherein the method comprises the following steps of: establishing a fluid connection between at least one medium reservoir via a medium guiding duct and a first endplate through a media providing baseplate connected to the medium duct, connecting the media providing baseplate with the first endplate by engaging a connection counter element located on the media providing baseplate with a connection element on the first endplate by force fit and / or friction fit, monitoring the state of engagement between the connection element and the connection counter element by using a control unit, which is provided at the media-providing baseplate, and triggering at least one control action in the fuel cell stack assembly based on the state of engagement between the connection element and the connection counter element, for regulating the supply and removal of medium into or from the fuel cell stack assembly.

[0056] 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.

[0057] 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.

[0058] The figures show:

[0059] Fig. 1a / b: schematic illustrations of a first embodiment of the fuel cell stack assembly,

[0060] Fig. 2a / b: schematic illustrations of a second embodiment of the fuel cell stack assembly,

[0061] Fig. 3: a schematic illustration of an assembled fuel cell stack,

[0062] Fig. 4: a schematic illustration of a first embodiment of a preferred media providing baseplate,

[0063] Fig. 5: a schematic illustration of a further embodiment of a preferred media providing baseplate, Fig. 6: a schematic illustration of a further embodiment of a preferred media providing baseplate,

[0064] Fig. 7: a schematic illustration of a further embodiment of a preferred media providing baseplate,

[0065] Fig. 8: a schematic illustration of a further embodiment of a preferred media providing baseplate, and

[0066] Fig. 9: a schematic illustration of a further embodiment of a preferred media providing baseplate.

[0067] In the following same or similar functioning elements are indicated with the same reference numerals.

[0068] 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.

[0069] 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 membrane 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.

[0070] 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.

[0071] 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.

[0072] For operating the fuel cell stack, the connection elements 10-1 - 10-6 in turn are adapted to be connected to respective media ducts via a coupling unit 12, which comprise a corresponding number of ports 11-1 - 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 11 -1 - 11-2 are provided by the ports arranged in the media providing baseplate 13.

[0073] 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 11 -1 - 11 -6 of the media providing baseplate 13 are also connected to the connection counter elements 15-1 - 15-6 provided by the adapter plate 14.

[0074] 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.

[0075] As can be further seen from Figs. 1 and 2, the connection elements 10 and the connection counter element 11 ; 15 are adapted to fit into each other in such a way that they are engaged by friction fit and / or form fit.

[0076] 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 are designed as openings, wherein the nozzles are adapted to fit into ports 11 of the media providing baseplate 13. 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 .

[0077] 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.

[0078] 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 11 ; 15.

[0079] For increasing the fluid tightness, the nozzle may additionally be provided with a sealing element 21 , e.g. an 0-ring which frictional ly 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.

[0080] 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.

[0081] 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. 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.

[0082] 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.

[0083] 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.

[0084] 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 11 ; 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.

[0085] Fig. 4 depicts a schematic illustration of the media providing baseplate 13, which is connected to the adapter plate 14 and the media guiding ducts 40. The inlet ports 11 -1 , 11 -3, and 11 -5 and outlet ports 11 -2, 11 -4, and 11 -6 of media providing baseplate 13 are connected to the corresponding connection counter element parts 15-1 to 15-6 of the adapter plate 14. The ports 11 -1 to 11 -6 are connected to the second connection counter element parts 19-1 to 19-6 of the connection counter element parts 15-1 to 15-6. Further, the first connection counter element parts 17-1 to 17-6 may engaged by friction fit and / or form fit with the corresponding connection elements 10-1 to 10-6 of the assembled fuel cell stack 2 to form a fluid- tight connection between the media providing baseplate 13 and the fuel cell stack 2, as shown in Fig. 1 .

[0086] As can see from the illustrated embodiment of Fig.4, to supply the necessary medium for the operation of the fuel cell stack 2 from the medium reservoir, the inlet ports 11 -1 , 11 -3, and 11 -5 of the media providing baseplate 13 are further connected to the corresponding media guiding duct 40, which in turn is connected to corresponding medium reservoirs (not shown). Consequently, the medium is supplied through the respective media guiding duct 40 from the medium reservoir, as indicated by the arrow in Fig. 4, to the corresponding inlet ports 11 -1 , 11 -3, and 11 -5 of the media providing baseplate 13 and subsequently to the assembled fuel cell stack 2. Thus, the media providing baseplate 13 and the adapter plate 14 act as an intermediate coupling unit to connect the fuel cell stack 2 with the medium reservoir.

[0087] Fig. 5 illustrate the further embodiment of media providing baseplate 13, in which the inlet ports 11 -1 , 11 -3, and 11 -5, as well as the outlet ports 11 -2, 11 -4, and 11 -6 of the media providing baseplate 13, are adapted to fit with the corresponding connection elements 10-1 to 10-6 of the first endplate 8-1 in such a way that they are engaged by friction fit and / or form fit. This direct engagement eliminates the need for an intermediary connection through the adapter plate 14 and facilitates the flow of medium from the media guiding duct40 into the connection elements 10-1 to 10-6 of the first endplate 8-1 .

[0088] Further, to regulate and control the flow of the medium from the medium reservoir to the fuel cell stack, the media providing baseplate 13 and / or the adapter plate 14 is equipped with a control unit 30 which can be an electronic and / or mechanical control mechanism.

[0089] Preferably, the control unit 30 may comprise a mechanical switch and / or at least one sensor 23 such as an optical sensor, and / or electronic sensor, which monitors the position of connection elements 10 of the first endplate 8-1 and the ports 11 of the media providing baseplate 13. This allows control unit 30 to automatically detect the position of connection element 10 in relation to ports 11 , determine the state of engagement between these components, and trigger necessary control actions. These control actions include, but are not limited to, the regulation of the medium's flow into and out of the fuel cell stack 2 or providing an auditory or visual warning signal that indicates the engagement status, i.e. , whether the connection element 10 is engaged with or disengage from the ports 11. Thus, the automatic control mechanism enhances the safe attachment or detachment of the fuel cell stack 2 mounted on the media providing baseplate 13.

[0090] Additionally or alternatively, the fuel cell stack 2 and / or media providing baseplate 13 may be provided with an electrical switch for electrically / connecting disconnecting the fuel cell stack 2 to / from a consumer. When connection element 10 fully engages or disengages with ports 11 , it activates the electrical switch. This signals the control unit 30 that the fuel cell stack is securely in place or completely. In response, the control unit 30 closes flow valves and / or disconnect electrical contacts between the fuel cell stack 2 and the media providing baseplate 13, and any consumer.

[0091] Figs. 6 and 7 illustrate a cross-sectional view of the fuel cell stack 2 and the media providing baseplate 13, which is provided with an electronic control unit 30 for regulating the flow of medium. As shown in Fig. 6, a flow regulation valve, preferably a check valve 34 is provided within ports 11 of the media providing baseplate 13 to regulate the supply and removal of medium into and out of the fuel cell stack 2. The media providing baseplate 13 is further equipped with an electronic control unit 3030, which controls the opening and / or closing of check valve 34 to regulate the flow of medium through port 11 into / out of the connection elements 10 based on an engagement state between the connection element 10 of the first endplate 8-1 and the ports 11 of media providing base plate 13. Generally, check valve 34 remains closed when the media providing baseplate 13 is not connected to the first endplate 8-1 , as shown in Fig. 6. Thus, the closed check valves within port 11 prevent further exposure of ports 11 to media guiding duct 40, thereby stopping the flow of medium from duct 10 into port 11 .

[0092] Alternatively, or additionally, a check valve 34 may be positioned at the connection element 10 of the first endplate 8-1 , which may (also) be controlled by the control unit 30 in the media providing baseplate 13 to automatically opening closing the connection elements 10 once stack 2 is engaged / disengaged in / from the media providing baseplate 13.

[0093] As illustrated in Fig. 6, various sensors 23 are arranged at the fuel cell stack assembly, e.g. a sensor 23 is located at the control unit 30, and / or the media providing baseplate 13, and / or the fuel cell stack 2. Additionally, sensors 23 may be positioned at ports 11 , and / or at connection element 10, and / or the adapter 14 (not shown) for monitoring the position of the connection element 10 of the first endplate 8-1 and the counter connection element 11 , i.e., ports 11 of the media providing baseplate 13. When the connection element 10 engages with port 11 of the media providing baseplate 13, sensor 23 signals this state of engagement to the control unit 30. Upon receiving the signal from sensor 23, the control unit 30 commands the check valve 34 to open, which facilitates the flow of medium from media guiding duct 40 through port 11 and into connection element 10. Preferably, the sensor 23 transmits the signal to the control unit after the fluid tight connection between the ports 11 and the connection element 10, is achieved. Further, Fig. 7 depicts the closed state of check valve 34 following the disengagement between ports 11 and connection element 10. Here, the sensors 23 transmit a signal to control unit 30 indicating this state of disengagement, prompting the control unit to command the check valves 34 to close. In response, the check valves 34 closes, thereby sealing the ports 11 of the media providing baseplate 13 and preventing any further medium flow from duct 40 into / from connection element 10. Thus, the control unit 30 automatically opens and / or closes the check valves 34 and ports 11 based on the stated of engagement between the connection element 10 of the first endplate 8-1 and the corresponding ports 11 of the media providing baseplate 13. Thus, the supply of fluid of medium from the medium reservoir into and out of the fuel cell stack 2 is automatically regulated while preventing the loss of medium, preferably when the fuel cell stack 2 is disengaged from the medium reservoir.

[0094] Figs. 8 and 9 illustrate a cross-sectional view of the media providing baseplate 13 provided with the mechanical control mechanism.

[0095] As shown in Fig. 8, the ports 11 of the media providing baseplate 13 is equipped with a mechanical device 38 that opens or closes the check valves 34 mechanically based on the state of engagement between the connection element 10 of the first endplate 8-1 and the ports 11 of the media providing base plate 13 to regulate the flow of medium into and out of the fuel cell stack 2.

[0096] When the first end plate 8-1 of the fuel cell stack 2 is mounted onto the media providing baseplate 13, the mechanical device 38 located at the media providing baseplate 13 is actuated by the pressure resulting from the engagement between the media providing baseplate 13 and the fuel cell stack 2. This pressure pushes the mechanical device 38 against check valve 34, resulting in the opening of check valve 34 and allowing the flow of medium into port 11 and thereby to the connection element 10.

[0097] However, as shown in Fig. 9, when the fuel cell stack 2 is detached from the media providing baseplate 13, the pressure applied to the mechanical device 38 is reduced. This, in turn, releases the mechanical device 38 from check valve 34, causing the check valve 34 to close and thereby preventing further flow of medium from duct 40 into the fuel cell stack 2 through ports 11 of the media providing baseplate 13.

[0098] Alternatively, in a non-i I lustrated embodiment, the mechanical device 38 may be controlled by an electronic control unit 30 provided at the media providing baseplate 13 based on the state of engagement between connection element 10 and port 11. Further, the connection element 10 of stack 2 may be equipped with mechanical device 38 to open or close the check valve mechanically either controlled by the control unit or through the interaction between the connection element 10 and the media providing baseplate 13.

[0099] Reference numerals

[0100] 1 Fuel cell stack assembly

[0101] 2 assembled fuel cell stack

[0102] 3 housing

[0103] 4 unit fuel cell

[0104] 4-1 bipolar plate

[0105] 4-2 membrane electrode assembly

[0106] 5 clamping means

[0107] 6 inlet / outlet manifolds

[0108] 6-1 hydrogen inlet manifold

[0109] 6-2 hydrogen outlet manifold

[0110] 6-3 air inlet manifold

[0111] 6-4 air outlet manifold

[0112] 6-5 coolant inlet manifold

[0113] 6-6 coolant outlet manifold

[0114] 8-1 first endplate

[0115] 8-2 second endplate

[0116] 10 connection element

[0117] 11 connection counter element of media providing baseplate

[0118] 12 coupling unit

[0119] 13 media providing baseplate

[0120] 14 adapter plate

[0121] 15 connection counter element of adapter plate

[0122] 16 force receiving element

[0123] 17 first connection counter element part

[0124] 18 force transmitting element

[0125] 19 second connection counter element part

[0126] 20 third connection counter element part

[0127] 21 sealing device / friction fit element

[0128] 22 hook / form fit element

[0129] 23 sensor

Claims

Claims:1 . Fuel cell stack assembly (1 ) comprising at least, an assembled fuel cell stack having at least a first endplate and at least 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 at least one clamping means configured to clamp the first endplate, the second endplate, and the plurality of unit fuel cells together to form the assembled fuel cell stack, wherein further the first endplate 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, characterized in that the fuel cell stack assembly further comprises, a media providing baseplate for providing a medium supply and removal between at least one medium duct and the first endplate, and having at least one port for supplying media to and removing media from the fuel cell stack, wherein the first endplate and the media providing baseplate are connected to each other in fluid tight engagement, and wherein the media providing baseplate is further equipped with a control unit for determining a state of engagement between the first endplate and the media providing baseplate and for triggering at least one control action in the fuel cell stack assembly based on the state of engagement.

2. Fuel cell stack assembly according to claim 1 , wherein the at least one connection element of the first endplate and the at least one port of the media providing baseplate are adapted to fit into each other in such a way that they are engaged by form fit and / or friction fit, and the control unit determines a state of engagement between the at least one connection element and the at least one port.

3. Fuel cell stack assembly according to claim 1 , further comprises an adapter plate which is arranged between the media providing baseplate and the first endplate, wherein the adapter plate includes at least one connection counter element, wherein each connection counter element comprises a first connection counter element part, second connection counter element part and third connection coun-ter element part, wherein the first connection counter element part is configured to engage by form fit and / or friction fit with the connection element of the first endplate and the second connection counter element part is configured to be connected with the at least one port of the media providing baseplate, and the third connection counter element part is configured to link the first counter and the second connection counter element parts, and the control unit determines a state of engagement between the at least one second connection counter element part and the at least one port.

4. Fuel cell stack assembly according to any one of the preceding claims, wherein the control action is an automatic closing and / or opening of the at least one port in the media providing baseplate.

5. Fuel cell stack assembly according to claim 4, wherein the automatic closing and / or opening of the at least on port is regulated by a flow regulating valve, preferably a check valve, in the fuel cell stack assembly.

6. Fuel cell stack assembly according to claim 5, wherein the at least one port of the media providing baseplate is connected to a medium guiding duct for connecting the assembled fuel cell stack to the medium reservoir, and the check valve includes a backpressure regulation mechanism, which is configured to maintain a predetermined pressure in the medium guiding duct.

7. Fuel cell stack assembly according to any one of the preceding claims, wherein the control action is an automatic connection and / or disconnection of electrical contacts between the first endplate and the media providing baseplate.

8. Fuel cell stack assembly according to any one of the preceding claims, wherein the control action is providing an auditory or visual warning signal that indicates the state of engagement.

9. Fuel cell stack assembly according to any one the preceding claims, wherein the control unit comprises a mechanical switch and / or at least one sensor such as optical sensor, and / or electronic sensor.

10. Fuel cell stack assembly according to claim 2, wherein at least one of the connection elements of the first endplate is a nozzle and at least one of the ports of the media providing baseplate is an opening, and / or wherein at least one of the connection elements of the first endplate is an opening and at least one of the ports of the media providing baseplate is a nozzle.11 . Fuel cell stack assembly according to claim 3, wherein at least one of the connection elements of the first endplate is a nozzle and at least one of the first connection counter element parts of the adapter plate is an opening, and / or wherein at least one of the connection elements of the first endplate is an opening and at least one of the first connection counter element parts of the adapter plate is a nozzle, and wherein at least one of the ports of the media providing baseplate is an opening and at least one of the second connection counter element parts of the adapter plate is a nozzle, or at least one of the ports of the media providing baseplate is a nozzle and at least one of the second connection counter element parts of the adapter plate is an opening.

12. Fuel cell stack assembly according to claim 10 or 11 , 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.

13. Fuel cell stack assembly according to any of the preceding claims, wherein the first endplate comprise at least one force receiving element and the media providing baseplate comprises at least one force transmitting element, or wherein the first endplate comprise at least one force transmitting element and the media providing baseplate comprises at least one force receiving element, and wherein the at least force receiving element and the at least one force transmitting element are configured to interact with one another to bring the first endplate and / or the adapter plate and the media providing baseplate into fluid tight engagement by friction fit and / or form fit.Fuel cell stack assembly according to any one the preceding claims, wherein the control unit detects a position of the at least one connection element, and / or at least one connection counter element, and / or at least one least one force transmitting element and / or at least one force receiving element.

14. Method for controlling a fuel cell stack assembly, wherein the fuel cell stack assembly is provided according to any one of the preceding claims, the method comprises the following steps of: establishing a fluid connection between at least one medium duct and a first endplate through a media providing baseplate connected to the medium duct, connecting the media providing baseplate with the first endplate by engaging a connection counter element located on the media providing baseplate with a connection element on the first endplate by force fit and / or friction fit, monitoring the state of engagement between the connection element and the connection counter element by using a control unit, which is provided at the media-providing baseplate, and triggering at least one control action in the fuel cell stack assembly based on the state of engagement between the connection element and the connection counter element, for regulating the supply and removal of medium into or from the fuel cell stack assembly.