DE102018219200A1 - Fuel cell device - Google Patents

Abstract

The invention relates to a fuel cell device (1) with a fuel cell stack (12), which is formed from a plurality of unit cells (11) stacked one above the other in a stacking direction, each of which has one or more media channels (8) and a membrane electrode arrangement (2), which comprises a cathode, an anode and a membrane arranged between the cathode and the anode, and with a media guide (22) running essentially parallel to the stacking direction, which can be connected or connected to the fuel cell stack (12) without a tie rod in order to hold a medium in the To be guided essentially laterally to the stacking direction into or out of the media channels (8) of the unit cells (11) of the fuel cell stack (12). The media guide (22) has one or more media connections (33) for supplying or removing a medium into or from the media guide (22).

Description

The invention relates to a fuel cell device with a fuel cell stack which is formed from a plurality of unit cells stacked one above the other in a stacking direction, each of which has one or more media channels and a membrane electrode arrangement which have a cathode, an anode and a membrane arranged between the cathode and the anode comprises, as well as with a substantially parallel to the stack direction, in particular stack-external, media guide, which can be connected or connected to the fuel cell stack without tie rods in order to guide a medium essentially laterally to the stack direction in or out of the media channels of the unit cells of the fuel cell stack.

In the WO 2010/054647 A2 describes a fuel cell stack without bipolar plates, the connections for oxygen, hydrogen and coolant being arranged on both sides of the stack in order to enable media to be fed laterally into the fuel cell stack. In the US 2004/0023089 A1 A fuel cell stack is shown in which the coolant is guided laterally to the fuel cell stack between the fuel cells, for which purpose a corresponding free space is realized between the fuel cells. The media is also fed in laterally US 2005/0130019 A1 described, with the media guides running in the stacking direction. Opposing media guides are clamped in the sense of end plates of a fuel cell stack by means of tie rods or tie rods.

In the DE 103 15 601 A1 A fuel cell device is shown according to the features of the preamble of claim 1, in which the media guides are attached to the fuel cell stack outside the stack.

It is therefore the object of the present invention to provide a fuel cell device which can be easily adapted to the given installation space.

This object is achieved by a fuel cell device with the features of claim 1. Advantageous refinements with expedient developments of the invention are specified in the dependent claims.

The fuel cell device is characterized in that the media guide has one or more media connections for supplying or removing a medium into or out of the media guide. A connection for the medium is therefore not provided on the end plates that are usually present, but rather on the media guides themselves. This means that there can be a supply or discharge at any point on the media guides in order to be adapted to the given installation space requirements. The end cells of the fuel cell stack that enclose the unit cells between them are thus preferably formed without a media connection.

The media guides, the external headers, are produced separately from the rest of the stack and are only connected to the stack after the stack has been completed. The geometry of the media connection can thus be selected independently of the stack geometry, which makes it possible in particular to design the connection direction independently of the stack direction.

In this context, it has therefore proven to be advantageous if the media connection is designed to supply or remove a medium from the media guide in a direction that deviates from the stacking direction.

A particularly space-saving design can be achieved in that the media connection on the media guide is arranged laterally with respect to the stacking direction.

Due to the space, it is also possible that the media connection of a first media guide is designed to feed or discharge a medium from a first direction, and that the media connection is designed of a second media guide to feed a medium from a second direction that deviates from the first direction or dissipate. With a suitable geometry and arrangement of the media connection, it is also possible that the media do not experience any changes in their flow direction, which can directly lead to less turbulence and thus to a lower pressure loss and ultimately to a higher system efficiency.

The media guide can itself represent a functional component that can be coupled directly to the fuel cell stack. There is also the possibility that the media connection of the media guide is formed on its side facing away from the fuel cell stack as an interface for the fluid-mechanical connection of a functional component. The direct connection of a functional component or the formation of interfaces results in a reduced number of components, a reduced number of connection points and an even better use of installation space.

For the functional component, it has proven to be advantageous if it is selected from a group that includes a humidifier, a Includes ion exchanger, an ion trap, a particle filter, an air filter and a water separator.

In addition, it is useful if the functional component which is connected to the flow of media is designed such that a medium can be supplied or removed in a direction deviating from the stacking direction, in particular laterally to the stacking direction. This also ensures that the flow of the medium is deflected as little as possible in order not to have to accept pressure losses.

In order to facilitate the assembly of the fuel cell device, it has proven to be advantageous if the fuel cell stack, in particular the unit cells, has leg receptacles which are designed in such a way that they each hold one guide leg of the media guides, the guide legs preferably being connected directly to one another.

In particular, the guide limbs of the media guide are inserted in leg receptacles of the fuel cell stack that run essentially parallel to the stacking direction.

The guide legs of the media guides on the side can be positioned on the fuel cell stack with a predetermined stop on the fuel cell stack. This reduces the effort of installing the media guides in the right place. In addition, the assembly time for the assembly of the media guides is minimized due to the leg receptacles formed on the fuel cell stack.

Such an arrangement is also advantageous since a different material can be selected for the media guidance than for the unit cells or for the bipolar plates of the unit cells. In addition, the number of sealing traces that have to be made to seal the media guides can be reduced. This also reduces manufacturing complexity.

It has proven to be useful if the leg receptacles of the fuel cell stack are formed as grooves that run essentially parallel to the stack direction. Such grooves are very simple to manufacture.

Furthermore, it is advantageous if the media guide is designed to be elastically resilient, such that the guide legs are held in the leg receptacles under a pretension. By means of such a preload, the media guides can be fixed in a self-locking manner during assembly on the fuel cell stack, wherein preferably a material connection between the guide leg and the fuel cell stack, in particular with its leg receptacles, can also be formed in order to establish a firm connection.

The restoring force is preferably directed outwards, because the pressure generated by the medium likewise brings about an outward force on the guide legs. Due to the formation of the sum of the force of the flowing medium and the restoring force given by the elasticity, an even firmer and thus even more secure connection of the media guide to the fuel cell stack is achieved.

An additional securing of the guide legs within the leg receptacles can be achieved in that the leg receptacles have an undercut, preferably running essentially parallel to the stacking direction, which is designed in such a way that one formed or arranged on one and / or on the other guide leg Guide member is receivable.

In order to additionally strengthen the fixation of the guide legs, it has proven to be advantageous if the guide member can be positively received in the undercut.

In this context, it can also be useful if the guide member is made of a different material than the guide leg. For example, the guide member can be formed from a material with adhesive properties, so that - if necessary in addition to a positive fit - the guide member is additionally glued within the undercut and thus an integral connection is additionally formed.

Due to the pressure prevailing in the media guide or in the fuel cell stack due to the medium carried therein, the connection of the media guide to the fuel cell stack faces a challenge with regard to maintaining a tightness. In order to meet this requirement, it has therefore proven to be useful if the guide member is also formed from a sealing material.

In one embodiment of the media guide, the guide legs are indirectly connected to one another via a guide web. This can be used to describe a U-shape, with the open end of the " U “Points to the fuel cell stack and thus the media are brought to the fuel cell stack from the outside. The media therefore flow essentially parallel to the stacking direction within the media guides. They get into the fuel cell stack in a lateral or lateral direction (xy direction) with respect to the stacking direction (z direction).

Alternatively, the guide limbs can also be connected directly to one another, so that the media guides have a C-shaped cross section with an open end of the “ C. “For the fuel cell stack. Here, too, the media flow essentially parallel to the stacking direction within the media guides and reach the fuel cell stack in a lateral or lateral direction with respect to the stacking direction.

A fuel cell device that is easy to manufacture is also characterized in that several media guides are provided. These are preferably subdivided into a first media feed for feeding a first reaction medium on a first side of the fuel cell stack and a first media discharge on a second side of the fuel cell stack opposite the first side for removing the at least partially used first reaction medium. Furthermore, the plurality of media guides are subdivided into a second media feed for feeding a second reaction medium on a third side of the fuel cell stack and a second media discharge for removing the at least partially used second reaction medium on a fourth side of the fuel cell stack opposite the third side. Thus, the two reaction media are laterally along the fuel cell stack, i.e. out of the stack, guided in the media guides, wherein they can enter or exit from the unit cells of the fuel cell stack perpendicular to the stacking direction, thus laterally.

In order to additionally guide a coolant outside the stack along the fuel cell stack, and to guide the coolant laterally into the unit cells or between two unit cells in the fuel cell stack, it has proven to be useful if the media guides also extend into a coolant supply on the third side of the fuel cell stack and subdivide a coolant discharge on the fourth side of the fuel cell stack.

• 1a eine Brennstoffzellenvorrichtung in einer Perspektivansicht,
• 1b eine weitere Brennstoffzellenvorrichtung in einer Perspektivansicht,
• 1c eine Brennstoffzellenvorrichtung in einer Perspektivansicht mit einem an einer der Medienführungen montierten Funktionsbauteil in Form eines Befeuchters,
• 1 d eine Brennstoffzellenvorrichtung in einer Perspektivansicht bei der die Medienführung selbst das Funktionsbauteil (vorliegend in Form eines Befeuchters), an welches ein weiteres Funktionsbauteil in Form eines Luftfilters angeschlossen ist.
• 2 eine (erste) Bipolarplatte einer Einheitszelle in einer Draufsicht,
• 3 den Schnitt III-III aus 2,
• 4 die (erste) Bipolarplatte aus 2 mit aufgebrachter Verbundschicht, in einer Draufsicht gezeigt,
• 5 den Schnitt V-V aus 4 (unverpresster Zustand),
• 6 die (erste) Bipolarplatte aus 4 mit einer darauf aufgelegten Brennstoffzellenanordnung,
• 7 den Schnitt VII-VII aus 6 (unverpresster Zustand),
• 8 die Konfiguration aus 6 mit einer aufgebrachten Verbindungsschicht,
• 9 den Schnitt IX-IX aus 8 (unverpresster Zustand),
• 10 eine Einheitszelle des Brennstoffzellenstapels mit einer (zweiten) Bipolarplatte, in einer Draufsicht gezeigt,
• 11 die (zweite) Bipolarplatte in einer Unteransicht, d.h. in einer Ansicht auf die der Membranelektrodenanordnung zugewandten Fläche der zweiten Bipolarplatte,
• 12 ein aus mehreren Einheitszellen entsprechend 10 gebildeter Brennstoffstoffzellenstapel in einer Perspektivansicht,
• 13 die Schnittansicht XIII-XIII aus 10 durch eine Mehrzahl an übereinander gestapelten Einheitszellen (verpresster Zustand),
• 14 die Schnittansicht XIV-XIV aus 10 durch eine Mehrzahl an übereinander gestapelten Einheitszellen (verpresster Zustand),
• 15 einen senkrecht zur Stapelrichtung verlaufenden Querschnitt durch den Brennstoffzellenstapel aus 1a mit daran angebrachten Medienführungen,
• 16 einen senkrecht zur Stapelrichtung verlaufenden Querschnitt durch die Brennstoffzellenvorrichtung aus 1b,
• 17 eine perspektivische Detailansicht der Brennstoffzellenvorrichtung nach 1b,
• 18 eine Detailansicht auf die Schenkelaufnahme und das Ende eines Führungsschenkel, und
• 19 eine weitere Detailansicht auf die Schenkelaufnahme mit darin eingesetzten Führungsschenkel.

Further advantages, features and details of the invention result from the claims, the following description of preferred embodiments and with reference to the drawings. Show:

• 1a a fuel cell device in a perspective view,
• 1b another fuel cell device in a perspective view,
• 1c 1 shows a fuel cell device in a perspective view with a functional component in the form of a humidifier mounted on one of the media guides,
• 1 d a fuel cell device in a perspective view in which the media guide itself the functional component (here in the form of a humidifier), to which a further functional component in the form of an air filter is connected.
• 2nd a (first) bipolar plate of a unit cell in a plan view,
• 3rd the cut III-III out 2nd ,
• 4th the (first) bipolar plate 2nd with applied composite layer, shown in a top view,
• 5 the cut VV out 4th (unpressed state),
• 6 the (first) bipolar plate 4th with a fuel cell arrangement placed on it,
• 7 the cut VII-VII out 6 (unpressed state),
• 8th the configuration 6 with an applied connection layer,
• 9 the cut IX-IX out 8th (unpressed state),
• 10th a top view of a unit cell of the fuel cell stack with a (second) bipolar plate,
• 11 the (second) bipolar plate in a bottom view, ie in a view of the surface of the second bipolar plate facing the membrane electrode arrangement,
• 12th one from several unit cells accordingly 10th formed fuel cell stack in a perspective view,
• 13 the sectional view XIII-XIII out 10th by a plurality of unit cells stacked one above the other (compressed state),
• 14 the sectional view XIV-XIV out 10th by a plurality of unit cells stacked one above the other (compressed state),
• 15 a cross-section running perpendicular to the stacking direction through the fuel cell stack 1a with attached media guides,
• 16 a cross-section running perpendicular to the stacking direction through the fuel cell device 1b ,
• 17th a detailed perspective view of the fuel cell device according to 1b ,
• 18th a detailed view of the leg receptacle and the end of a guide leg, and
• 19th a further detailed view of the leg receptacle with the guide leg inserted therein.

It should be pointed out in advance that the dimensions, the proportions and the scale of the illustrations shown are not fixed and can vary. In particular in the sectional representations, the individual layers are shown in such a way that it is understandable in which mutual position and in which order the individual layers are stacked on top of one another.

In the 1a , 1b , 1c and 1d is a fuel cell device 1 with a fuel cell stack 12th shown. The fuel cell stack 12th is composed of a plurality of unit cells stacked one above the other in a stacking direction (z-direction) 11 is formed. The unit cells 11 each have one or more media channels 8th ( 2nd ) and a membrane electrode arrangement 2nd ( 6 ) on. Each of the membrane electrode assemblies 2nd in the unit cells 11 comprises a cathode, an anode and an ion-conductive membrane arranged between the cathode and the anode.

The fuel cell device 1 also has media guides that run parallel to the stacking direction 22 on that with the fuel cell stack 12th are connected to a medium substantially laterally to the stacking direction in or out of the media channels 8th of the unit cells 11 of the fuel cell stack 12th respectively. The present fuel cell device 1 includes several media tours 22 that result in a first media feed 22a on a first side of the fuel cell stack 12th for feeding a first reaction medium (eg hydrogen) to the anodes and into a first media outlet 22b on a second side of the fuel cell stack opposite the first side 12th to dissipate the in the unit cells 11 break down unused first reaction medium. The media tours are also subdivided 22 into a second media feed 22c on a third side of the fuel cell stack 12th for supplying a second reaction medium (eg oxygen or air) to the cathodes and into a second medium discharge 22d on a fourth side of the fuel cell stack opposite the third side 12th to dissipate the in the unit cells 11 unused second reaction medium. Ultimately, the media tours are subdivided 22 also in a coolant supply 22e on the third side of the fuel cell stack 12th for supplying a coolant (e.g. liquid water) and into a coolant outlet 22f on the fourth side of the fuel cell stack 12th for the removal of (partially) heated coolant.

Based on 1a and 1b it can be seen that the media tours 22 with a media connection 33 are formed to the media guides 22 supply or discharge a medium. Accordingly, the end plates of the fuel cell stack, not shown, are 12th formed without media connection, the stack of unit cells between them 11 mounting. Through the media connections 33 can the media guides 22 a medium is supplied or removed in a direction deviating from the stacking direction. The media connections are present 33 on the respective media management 22 arranged laterally with respect to the stacking direction in order to utilize the available installation space. There is a possibility that the media connection 33 a first media tour 22 is configured to feed or discharge a medium from a first direction, and that the media connection 33 a second media tour 22 is configured to feed or discharge a medium from a second direction that deviates from the first direction.

There is also the possibility that the media connection 33 the media management 22 at their the fuel cell stack 12th opposite side as an interface 34 for fluid mechanical connection of a functional component 35 is formed. The fuel cell device shows such a configuration 1 to 1c , at the first media feed 22a the functional component 35 is connected in the form of a humidifier, which in turn has a connection, with which the functional component 35 is designed such that a medium can be supplied or removed in turn in a direction deviating from the stacking direction, in this case in a direction oriented laterally to the stacking direction.

In 1d the possibility is also shown that one of the media tours 22 even as one of the functional components 35 , in the form of a humidifier. Thus the humidifier is directly with the unit cells 11 of the fuel cell stack 12th can be coupled and thus forms the media guide 22 . There is also the possibility opened and in 1d shown that on this functional component 35 an additional functional component of the humidifier 35 , can be connected in the form of an air filter. This configuration makes the fuel cell device very compact 1 educated.

The manufacture or construction of the unit cells shown is exemplified below 11 of the fuel cell stack 12th based on 2nd to 11 explained.

In 2nd is a bipolar plate 7 from one of the unit cells 11 shown. This first bipolar plate 7a has an inner active area shown in dashed lines 3rd and an outer edge region shown in dashed lines 5 on. At the edge 5 are multiple media channels 8th trained in the first media entry channels shown on the left in the drawing 8a and the first media outlet channels shown in the drawing on the right 8b break down. The media channels 8th a pair of leg receptacles is surrounding each 26 trained, which will be discussed in more detail below. More thigh shots 26 are on the long edges 17a the bipolar plate 7 educated.

Five of the first media entry channels are available 8a and five of the first media exit channels 8b in the first bipolar plate 7a educated. A different number is possible. The first media entry channels 8a are with the first media outlet channels 8b over a first river field 13a fluidly connected with each other. This river field 13a is in the active area 3rd and can be an adjacent membrane electrode assembly 2nd provide a reaction medium. In the example after 2nd points the river field 13a several guides or walls 14 on to evenly distribute a reaction medium over the surface of the membrane electrode assembly 2nd . However, it is also possible to have different types of river fields 13a to be used, for example those in which the flow of the reaction medium is meandering over the area of the active surface. In addition, the distance between the walls 14 , the walls or the webs vary. Also the depth of through neighboring walls 14 The channel formed can be of different depths and can vary.

How out 3rd , the cut III-III out 2nd results is also on that of the membrane electrode assembly 2nd opposite side of the first bipolar plate 7a a river field 13c formed, which serves to flow through another medium, for example a coolant.

How 4th shows is on the first bipolar plate 7a at the edge 5 a composite layer 15 , in particular a joint layer applied. This composite layer 15 is formed in several parts or points in the area of the media channels 8a , 8b Recesses 16 on. The cutouts 16 ensure that the media entry channels 8a and the media exit channels 8b are not sealed and later allow media to pass through.

The edge area 5 attached composite layer 15 extends along the long edge 17a the first bipolar plate 7a so that it is flush with the dimensions of the bipolar plate 7 given edge area 5 arises. Even on the composite layer 15 there remain areas for the thigh shots 26 free. Through this composite layer 15 becomes the active area or area 3rd sealed from the environment, choosing the material of the composite layer 15 It is to be ensured that this sealing function is guaranteed. In 5 , the cut VV out 4th , is the flush completion of the composite layer 15 or the joining material with the bipolar plate 7 along their long edges 17a to recognize. Also the sections of the composite layer 15 that are on the short edges 17b are preferably flush with the bipolar plate 7 from. The selected representation of the composite layer 15 is exemplary. It can be much thinner than the first bipolar plate 7a be designed.

At 6 was a fuel cell assembly with a membrane electrode assembly 2nd to the one with the composite layer 15 covered first bipolar plate 7a to 4th applied or hung up. It essentially becomes the active area 3rd by the dimensions of the membrane electrode assembly 2nd predetermined, which in turn is sketched in the figure by the inner dashed line. The active area 3rd extends not only in one plane (xy plane) but also in the stacking direction (z direction), which is directed out or in from the paper plane.

The active area 3rd is the area in which the electrochemical reaction occurs through the membrane electrode assembly 2nd fuel cell formed. In the electrochemical reaction, a fuel (eg hydrogen) is fed to the anode, where it is catalytically oxidized to protons with the release of electrons. These protons are transported to the cathode through the ion exchange membrane. The electrons derived from the fuel cell flow via an electrical consumer, preferably to an electric motor for driving a vehicle or to a battery. Then the electrons are led to the cathode. At the cathode, the oxidation medium (eg oxygen or air containing oxygen) is reduced to anions by the absorption of the electrons, which react directly with the protons to form water.

The membrane electrode arrangement is used to ensure that the fuel reaches the anode directly or that the oxidation medium reaches the cathode directly 2nd a sealing structure 4th laterally assigned ( 6 , 8th ). The combination of the membrane electrode arrangement 2nd and the sealing structure 4th forms a common fuel cell arrangement. The sealing structure 4th includes components that are in the marginal area 5 extend or even over the Edge area 5 protrude. These components are therefore outside the active area 3rd arranged. In other words, the edge area delimits 5 the active area 3rd in the radial or lateral direction or circumferentially.

It is in the 6 and 8th to recognize that the sealing structure 4th one in or over the edge area 5 extending sealing tongue 6 for the axial gastight covering of one in an adjacent bipolar plate 7 trained and in the marginal area 5 located media channel 8th includes. The fuel cell arrangement shown here has a total of four sealing tongues 6 on. Two of the sealing tongues 6 are on the shorter edge 9a the membrane electrode assembly 2nd arranged opposite each other. The other two sealing tongues 6 are on the long edge 9b the membrane electrode assembly 2nd arranged opposite and offset from each other. The sealing tongues 6 all have a rectangular shape in the present case. However, polygonal shapes of the sealing tongues are possible, including rounded sealing tongues 6 be considered.

The sealing structure 4th and especially the sealing tabs 6 are dimensionally stable with regard to a compressive and / or tensile load acting axially on them. It can also be seen that the sealing tongues 6 over the edge area 5 extend out. However, it is also possible that one or more of the sealing tongues 6 just in the edge area 5 extend into it, but do not cover it completely or protrude laterally beyond it.

It can also be seen that the sealing structure 4th one the membrane electrode assembly 2nd laterally sealing edge of the seal 10th having. That through the sealing edge 10th formed sealing line seals the membrane electrode assembly 2nd against the lateral leakage of media.

The sealing tongue 6 The fuel cell arrangement on the left side covers the left media channels 8th the first bipolar plate 7a axially gas-tight. The right sealing tongue 6 the fuel cell arrangement covers the right media channels 8th the first bipolar plate 7a axially gas-tight. In other words, it is the left sealing tongue 6 as a first entry sealing tongue 6a for the axial gas-tight covering of the first media inlet channel 8a formed on the left. The right sealing tongue is accordingly 6 as a first exit sealing tongue 6b for the axial gastight cover of the right first media outlet channel 8b shaped. The one on the long edge 17a the bipolar plate 7a provided sealing tongues 6 lie on the composite layer 15 on. They can be subdivided into a second inlet sealing tongue 6c and a second exit seal tab 6d .

As the material of the composite layer 15 a plastic or a plastic mixture can be used, which preferably has a lower thermal stability compared to the plastic or plastic mixture of the sealing structure 4th or the sealing tongues 6 having. So the sealing tongues can 6 in a (hot) pressing process in the composite layer 15 sink and preferably merge with it, the sealing tongues 6 maintain their dimensional stability. In other words, the melting point of the material of the sealing structure is 4th above the melting point of the material of the composite layer 15 .

In the central area, i.e. where the active area is 3rd is the sealing structure 4th the fuel cell arrangement adapted in terms of its outer contour to that of the composite layer 15 given inner contour. The tongue-free sections form the sealing structure 4th Contact points, contact lines 18th or contact surfaces with the composite layer 15 off, so that a sealing function is additionally guaranteed.

7 , the cut VII-VII out 6 , shows an unpressed sectional view of the partial unit cell 11 . It can be seen that the first sealing tongues 6a , 6b the composite layer 15 tower and supernatants 19th train with this. This ensures the necessary sealing in the lateral direction. Here too, the selected representation is not to be understood to scale. The thicknesses of the individual layers can vary, especially after a joining process or joining process (hot pressing process), after which they can appear or act like a single common layer. Also the one between the inlet sealing tongue 6a and the channels 8th lying area of the recess 16 is then minimized so that the inlet sealing tabs 6a the channels 8th cover axially. A medium can be the membrane electrode assembly 2nd laterally and in the stacking direction below the first inlet sealing tongue 8a respectively. (Part) Used medium can then laterally and in the stacking direction below the first outlet sealing tongue 8b the unit cell 11 of the fuel cell stack 12th leave.

In 8th is on the first inlet sealing tongue 6a and on the first outlet sealing tongue 6b a tie layer 20th applied, which is to be understood as a further joining layer. The composite layer 15 and the tie layer 20th ensure a secure connection of a first bipolar plate 7a in the stacking direction with a second bipolar plate 7b . The composite layer 15 forms overlaps 21st with the tie layer 20th out, such that the two layers have a contact area in the stacking direction. This ensures a sealing function. The overlaps 21st are 9 , the cut IX-IX out 8th to take closer. Here, too, an unpressed condition is shown, which is not to scale, but which is intended to clarify the stacked arrangement of the individual layers.

On the composite layer 15 and the connection layer connected to it 20th can now have a second bipolar plate 7b to complete the unit cell 11 be applied. This is 10th refer to. The first bipolar plate 7a and the second bipolar plate 7b can be joined together by the joining layers in such a way that a unit cell made from the first bipolar plate is provided with little protrusions 7a , Fuel cell arrangement and second bipolar plate 7b arises. However, the individual layers of the unit cell are preferably 11 edge-free or offset-free in the stacking direction.

Like the first bipolar plate 7a also owns the in 10th and 11 shown second bipolar plate 7b on their membrane electrode assembly 2nd opposite side of a river field 13c for guiding a cooling medium. This river field 13c is essentially in the active area 3rd . It is fluidly connected to coolant inlet channels 8e and with coolant outlet channels 8f . The second bipolar plate also includes 7b recessed areas that the thigh shots 26 form.

On their membrane electrode assembly 2nd facing side has the second bipolar plate 7b but one or more second media entry channels 8c and one or more second media exit channels 8d on ( 11 ). It also includes one with the second media entry channel 8c and the second media outlet channel 8d flow-related second river field 13b , via which one of the reaction media of the membrane electrode assembly 2nd can be supplied.

In 12th is one of several unit cells 11 formed fuel cell stack 12th shown. This fuel cell stack 12th has the advantage that the bipolar plate 7 Compared to known bipolar plates can be designed with smaller dimensions, so that the manufacturing costs of the fuel cell stack 12th are reduced. The bipolar plates are present 7 basically shaped rectangular, the present invention does not apply to a rectangular shape of the bipolar plates 7 is instructed, but can also be used without restriction in any shape with, for example, round or curved lines. In any case, it is important in this context that the fuel cell stack 12th a plurality of leg receptacles formed parallel to the stacking direction 26 are present on which the media tours 22 can be fixed.

13 shows an exemplary sectional view along the section XIII-XIII out 10th through a fuel cell stack 12th . It can be seen that the composite layer 15 after the joining or hot pressing process, both the first bipolar plate 7a as well as the second bipolar plate 7b touched or contacted, the bipolar plates 7 over the composite layer 15 are connected or joined together. It can also be seen that the second media entry channels 8c through which in or over the edge area 5 extending second inlet sealing tongues 6c are covered axially gas-tight. The same applies to the opposite side on the second bipolar plate 7b where in or over the edge area 5 extending second outlet sealing tongues 6d are provided for the axial gas-tight covering of the second media outlet channels 8c . In 13 can also be seen that a second reaction medium laterally and in the stacking direction above the sealing structure 4th to the membrane electrode assembly 2nd to be led. The same applies in the stacking direction above the sealing structure 4th the (partially) used second reaction medium laterally again from the unit cells 11 or from the fuel cell stack 12th led out.

The second bipolar plate 7b a first unit cell 11 forms with a first bipolar plate 7a another unit cell 11 then the complete channel cross section for the passage of the cooling medium. In other words, these then also form the coolant inlet channels 8e and the coolant outlet channels 8f out. The second bipolar plate 7b the first unit cell 11 and the first bipolar plate 7a the further unit cell 11 can also be joined together with a joining agent or joining medium.

Alternatively, there is a one-piece design of the adjacent bipolar plates 7 possible.

14 shows an exemplary sectional view along the section XIV-XIV out 10th through a fuel cell stack 12th . It can be seen that the second bipolar plate in the stacking direction 7a on the connection layer 20th and the composite layer 15 is applied. It can also be seen that a first reaction medium in the stacking direction below the sealing structure 4th to the membrane electrode assembly 2nd to be led. The first media entry channels 8a are here through the first inlet sealing tongues 6a covered axially gastight. A first reaction medium is supplied laterally or in the lateral direction with respect to the Stacking direction. The same applies in the stacking direction below the sealing structure 4th the (partially) used first reaction medium again from the unit cell 11 or from the fuel cell stack 12th led out laterally or laterally.

In 15 is a sectional view through the fuel cell device 1 to 1b shown, which is essentially the top view of the unit cells 11 to 10th corresponds. It can be seen that now, however, the media tours 22 with their guide legs 24a , 24b in the thigh shots 26 are used. The media tours shown here 22 have a guide bridge 23 on the the two terminal guide legs 24a , 24b connects with each other. Each of the guide legs 24a , 24b is in one of the thigh shots 26 which extend parallel to the stacking direction of the fuel cell stack 12th added. The open side of the media tours 22 points to the fuel cell stack 12th , so that a medium flowing through them laterally into the unit cells 12th can reach. The media tours 22 are essentially rectangular in cross section, but a different shape is possible. The media channels are preferred 22 formed from a, in particular dimensionally stable, plastic.

16 shows a different shape of the media guides 22 , here a cross section through the fuel cell stack 12th the 1b you can see. Here are the media tours 22 semicircular or C-shaped, so that the guide leg 24a , 24b are directly connected to each other without a guide bar 23 .

From the detailed view 17th it can be seen that in the present case the media guides 22 are formed resiliently. This makes the guide legs 24a , 24b in a - in particular outward - preload in the leg receptacles 26 of the fuel cell stack 12th held. So it is a restoring force (indicated by the force arrows 29 ) effective and the media tours 22 are due to this restoring force within the leg receptacles 26 secured. In addition, the guide legs are additionally secured 24a , 24b due to the pressure of one in the media guides 22 flowing medium. This medium also creates an outward force, which - added to the restoring force - creates an even stronger connection between the media guides 22 and the fuel cell stack 12th to lead.

Alternatively or in addition, the leg receptacles can 26 also according to the in 18th detail shown be formed. Here, the leg receptacles 26 an undercut 27th on the one on the guide leg 24a , 24b trained or arranged guide member 28 is recordable. Inside the thigh receptacle 26 is - the undercut 27th opposite - an inclined insertion surface 30th trained the insertion of the guide leg 24a , 24b in the thigh receptacle 26 facilitated. The insertion area 30th is both regarding the long edge 17a as well as the short edge 17b the bipolar plate 7 arranged inclined. The insertion area 30th goes into a (lateral) contact surface aligned parallel to the plate edge 31 about that the depth of penetration of the guide leg 24a , 24b in the thigh receptacle 26 specifies and / or limited. Starting from the contact area 31 goes the thigh shot 26 then into a groove-shaped contact surface 32 about that preferably the undercut 27th trains.

While in the example after 17th the leader 28 in one piece with the guide leg 24a , 24b is formed in the example 19th the leader 28 made of a different material than the guide leg 24a , 24b shaped. This other material can, for example, be an (additional) sealing material to ensure the tightness of the fuel cell stack 12th to ensure in addition.

The present design of the fuel cell device 1 allows a precise positioning of the media guides 22 on the fuel cell stack 12th . The fixation of the guide leg 24a , 24b inside the thigh receptacles 26 of the fuel cell stack 12th by means of the non-positive and / or positive and / or material coupling holds a large force from the fuel cell stack 12th is facing away, which was caused by the pressure of the media guides 22 flowing media is exercised. The media tours 22 are characterized by their excellent self-locking function.

Due to the present design, the outward force secures the media guides 22 additionally on the fuel cell stack 12th . This also means the greater the pressure generated by the media within the media guides 22 the stronger the connection between the guide leg 24a , 24b inside the thigh receptacle 26 of the fuel cell stack 12th .

Reference symbol list

1

Fuel cell device

2nd

Membrane electrode arrangement (MEA)

3rd

active area

4th

Sealing structure

5

Edge area

6

Sealing tongue

6a

first entry sealing tongue

6b

first outlet sealing tongue

6c

second inlet sealing tongue

6d

second outlet sealing tongue

7

Bipolar plate

7a

first bipolar plate

7b

second bipolar plate

8th

Media channel

8a

first media entry channel

8b

first media exit channel

8c

second media entry channel

8d

second media exit channel

8e

Coolant inlet duct

8f

Coolant outlet channel

9a

short edge of the membrane electrode assembly

9b

long edge of the membrane electrode assembly

10th

Sealing ring

11

Unit cell

12

Fuel cell stack

13a

first river field

13b

second river field

13c

Flow field (cooling medium)

14

wall

15

Composite layer

16

Recess

17a

long edge of the bipolar plate

17b

short edge of the bipolar plate

18th

Contact lines

19th

Got over

20th

Link layer

21

Overlaps

22

Media guidance

22a

first media feed

22b

first media discharge

22c

second media feed

22d

second media outlet

22e

Coolant supply

22f

Coolant discharge

23

Boardwalk

24a

Guide leg (left)

24b

Guide leg (right)

26

Thigh receptacle

27th

Undercut

28

Leader

29

Power arrow

30th

Insertion surface

31

(lateral) contact surface

32

(groove-shaped) contact surface

33

Media connection

34

interface

35

Functional component

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• WO 2010/054647 A2 [0002]
• US 2004/0023089 A1 [0002]
• US 2005/0130019 A1 [0002]
• DE 10315601 A1 [0003]

Claims (10)

Fuel cell device (1) with a fuel cell stack (12), which is formed from a plurality of unit cells (11) stacked one on top of the other in a stacking direction, each of which has one or more media channels (8) and a membrane electrode arrangement (2), which have a cathode, a Anode and a membrane arranged between the cathode and the anode, as well as with a media guide (22) which runs essentially parallel to the stacking direction and which can be connected or connected to the fuel cell stack (12) without tension rods in order to create a medium essentially laterally to the stacking direction to lead into or out of the media channels (8) of the unit cells (11) of the fuel cell stack (12), characterized in that the media guide (22) one or more media connections (33) for supplying or removing a medium into or out of the Media guide (22). Fuel cell device (1) Claim 1 , characterized in that the media connection (33) is designed to supply or remove a medium in a direction deviating from the stacking direction to the media guide (22). Fuel cell device (1) Claim 2 , characterized in that the media connection (33) on the media guide (22) is arranged laterally with respect to the stacking direction. Fuel cell device (1) according to one of the Claims 1 to 3rd , characterized in that the media connection (33) of a first media guide (22) is designed to feed or discharge a medium from a first direction, and that the media connection (33) of a second media guide (22) is designed to remove a medium to supply or to discharge a second direction deviating from the first direction. Fuel cell device (1) according to one of the Claims 1 to 4th characterized in that the media connection (33) of the media guide (22) is formed on its side facing away from the fuel cell stack (12) as an interface (34) for the fluid mechanical connection of a functional component (35). Fuel cell device (1) Claim 5 , characterized in that the functional component (35) is selected from a group comprising a humidifier, an ion exchanger, an ion trap, a particle filter, an air filter and a water separator. Fuel cell device (1) Claim 5 or 6 , characterized in that the functional component (35) connected to the flow with the media guide (22) is designed such that a medium can be supplied or removed in a direction deviating from the stacking direction. Fuel cell device (1) according to one of the Claims 1 to 7 , characterized in that the fuel cell stack (12) has leg receptacles (26) which are designed to each receive a guide leg (24a, 24b) of the media guides (22). Fuel cell device (1) Claim 8 , characterized in that the leg receptacles (26) have undercuts (27), that at least one guide member (28) is assigned to the guide legs (24a, 24b), and that the guide member (28) is positively and / or non-positively and / or cohesively in the undercut (27) is receivable. Fuel cell device (1) according to one of the Claims 1 to 9 , characterized in that several of the media guides (22) are provided, which act as a first media feed (22a) for feeding a first reaction medium on a first side of the fuel cell stack (12) and as a first media drain (22b) for removing the at least partially used first Reaction medium are formed on a second side of the fuel cell stack (12) opposite the first side, and which act as a second media feed (22c) for feeding a second reaction medium on a third side of the fuel cell stack (12) and as a second media discharge (22d) for discharge of the at least partially used second reaction medium are formed on a fourth side of the fuel cell stack (12) opposite the third side.

Images