Fuel cell device

Abstract

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 having one or more media channels (8) and a membrane electrode arrangement (2) arranged between two bipolar plates (7), which comprises a cathode, an anode and a membrane arranged between the cathode and the anode, and with a plurality of media guides (22) running essentially parallel to the stacking direction, the media guide (22) is joined to the bipolar plates (7) of the fuel cell stack (12) in such a way as to guide media substantially laterally to the stacking direction into or out of the media channels (8) of the unit cells (11) of the fuel cell stack (12), wherein the media guides (22) comprise a coolant supply (22e) joined to a first long edge (17a) of the bipolar plates (7) and a second media discharge (22c) joined to the first long edge (17a) of the bipolar plates (7) for discharging an at least partially used second reaction medium, and wherein the media guides (22) comprise a coolant outlet (22f) joined to a second long edge (17a) of the bipolar plates (7) and a second media supply (22c) joined to the second long edge (17a) of the bipolar plates (7) for supplying the second reaction medium, characterized in that the media guides (22) have a first media feed (22a) joined to a first short edge (17b) of the bipolar plates (7) for feeding a first reaction medium and comprise a media discharge (22) joined to a second short edge (17b) of the bipolar plates (7) for discharging the at least partially consumed first reaction medium.

Description

[0001] The invention relates to a fuel cell device comprising a fuel cell stack formed from a plurality of unit cells stacked one above the other in a stacking direction. Each of the unit cells has one or more media channels and a membrane electrode assembly (MEA). The membrane electrode assembly comprises a cathode, an anode, and a membrane arranged between the cathode and the anode. The fuel cell device also has a media guide running substantially parallel to the stacking direction.

[0002] Known fuel cell devices have channels formed within the fuel cell stack along the stacking direction. To ensure that the reaction media do not mix, a complex sealing structure is required. During operation of the fuel cell stack, it is also necessary to ensure that the media do not escape to the outside environment.

[0003] DE 10 2007 023 544 A1 shows a fuel cell device. Collecting lines for the operating media and / or for the cooling medium are enclosed by a circumferential seal. It must be ensured that each of the unit cells of the fuel cell stack seals the collecting line accordingly or provides a corresponding passage for the medium to be supplied to the active area. Such a sealing structure is complex to manufacture.

[0004] DE 103 15 601 A1 discloses a fuel cell device according to the preamble of claim 1, comprising a plurality of unit cells stacked one above the other in a stacking direction, in which media inlets and outlets are formed laterally, i.e., perpendicular to the stacking direction. Furthermore, external media guides are attached to the sides of the fuel cell stack by means of a silicone bead, which can supply a plurality of unit cells with a medium simultaneously.

[0005] It is therefore the object of the present invention to provide a fuel cell device in which the media supply to the fuel cell stack is simplified and which has a more compact, lighter construction.

[0006] This object is achieved by a fuel cell device having the features of claim 1. In particular, the media guide is connectable or connected to the fuel cell stack in such a way as to guide a medium into or out of the media channels of the unit cells of the fuel cell stack substantially laterally to the stacking direction.

[0007] Such an arrangement is advantageous because a different material can be selected for the media guide than for the unit cells or the bipolar plates of the unit cells. Furthermore, the number of sealing tracks that must be manufactured to seal the media guides can be reduced. This also reduces manufacturing complexity.

[0008] It is advantageous if the media guide comprises a guide web and guide legs connected to it. The guide legs are connectable or connected to the fuel cell stack. This allows a U-shape to be described, with the open end of the "U" facing the fuel cell stack, thus guiding the media from the outside to the fuel cell stack. The media therefore flows within the media guides essentially parallel to the stack direction. They enter the fuel cell stack in a lateral or sideways direction (xy direction) relative to the stack direction.

[0009] For improved sealing, it has proven advantageous to connect the media guide to the fuel cell stack using joining lines. These joining lines run essentially in the stacking direction and are arranged on both sides of the media channels. Preferably, the joining lines—like the media guide—extend in the stacking direction (z-direction) over the entire length of the fuel cell stack. The joining lines provided on the outer edge of the fuel cell stack allow the media guide to be sealed from the environment.

[0010] Preferably, the material of the joining lines is selected to bond the media guide to the fuel cell stack; thus, to bond the media guide to the fuel cell stack.

[0011] To realize a fuel cell stack with a high level of efficiency, it is useful if the unit cells have an active region and an edge region located outside the active region, in which the one or more media channels are formed for guiding the at least one medium into or out of the active region. The active region is essentially the region in which the electrochemical reaction of a fuel cell takes place. In particular, the active region is delimited on the circumference by the non-active edge region. The edge region is essentially intended to create a seal between two adjacent bipolar plates and in particular to provide the media channels for supplying media, such as reaction media or cooling media.

[0012] In this context, it has proven advantageous for the unit cells to comprise a first bipolar plate with a first media inlet channel and a first media outlet channel, as well as a first flow field connecting the first media inlet channel to the first media outlet channel. This flow field can, for example, be used to supply a reaction medium to a membrane electrode assembly located in the active region.

[0013] To supply a second medium to the membrane electrode assembly, it is useful for the unit cells to comprise a second bipolar plate with a second media inlet channel and a second media outlet channel. The second media inlet channel and the second media outlet channel are connected to each other via a second flow field.

[0014] For additional sealing of the cathode relative to the anode of the membrane electrode assembly, it is advantageous if the sealing structure has a sealing edge that laterally seals the membrane electrode assembly.

[0015] A fuel cell device that is easy to manufacture is further characterized in that a plurality of media guides are provided. These are preferably subdivided into a first media supply for supplying a first reaction medium and a first media discharge for discharging the at least partially used first reaction medium. Furthermore, the plurality of media guides are subdivided into a second media supply for supplying a second reaction medium and a second media discharge for discharging the at least partially used second reaction medium. Thus, the two reaction media are guided laterally along the fuel cell stack, i.e. external to the stack, in the media guides, wherein they can enter or exit the unit cells of the fuel cell stack perpendicular to the stack direction, i.e. laterally.

[0016] 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 into the fuel cell stack, it has proven useful if the media guides are also divided into a coolant supply and a coolant discharge.

[0017] In the following, the invention is explained in more detail using exemplary embodiments shown in the drawing; in which: Fig. 1 a fuel cell device in a perspective view, Fig. 2 a (first) bipolar plate of a unit cell in a top view, Fig. 3 section III-III Fig. 2, Fig. 4 the (first) bipolar plate from Fig. 2 with applied composite layer, shown in a plan view, Fig. 5 the section VV from Fig. 4 (unpressed condition), Fig. 6 the (first) bipolar plate from Fig. 4 with a fuel cell arrangement placed thereon, Fig. 7 section VII-VII Fig. 6 (unpressed condition), Fig. 8 the configuration Fig. 6 with an applied bonding layer, Fig. 9 section IX-IX Fig. 8 (unpressed condition), Fig. 10 a unit cell of the fuel cell stack with a (second) bipolar plate, shown in a plan view, Fig. 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, Fig. 12 one of several unit cells corresponding Fig. 10 formed fuel cell stack in a perspective view, Fig. 13 the sectional view XIII-XIII from Fig. 10 by a plurality of unit cells stacked on top of each other (compressed state), Fig. 14 the section view XIV-XIV from Fig. 10 by a plurality of unit cells stacked on top of each other (compressed state), Fig. 15 a cross-section through the fuel cell stack perpendicular to the stacking direction Fig. 12 with joining lines attached, and Fig. 16 a cross section through the fuel cell device perpendicular to the stacking direction Fig. 1,

[0018] Please note in advance that the dimensions, proportions, and scale of the images shown are not fixed and may vary. Especially in the cross-sectional views, the individual layers are depicted in such a way that it is clear in which position and in what order the individual layers are stacked.

[0019] In Fig. 1 shows a fuel cell device 1 with a fuel cell stack 12. The fuel cell stack 12 is formed from a plurality of unit cells 11 stacked one above the other in a stacking direction (z-direction). The unit cells 11 each have one or more media channels 8 and a membrane electrode assembly 2. Each of the membrane electrode assemblies 2 in the unit cells 11 comprises a cathode, an anode, and an ion-conductive membrane arranged between the cathode and the anode.

[0020] The fuel cell device 1 also has media guides 22 running parallel to the stacking direction, which are connected to the fuel cell stack 12 in such a way as to guide a medium 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 present fuel cell device 1 comprises for this purpose a plurality of media guides 22, which are subdivided into a first media supply 22a for supplying a first reaction medium (e.g., hydrogen) to the anodes and a first media discharge 22b for discharging the first reaction medium (partially) consumed in the unit cells 11. Furthermore, the media guides 22 are subdivided into a second media supply 22c for supplying a second reaction medium (e.g., oxygen or air) to the cathodes and a second media discharge 22d for discharging the second reaction medium (partially) consumed in the unit cells 11.Finally, the media guides are also subdivided into a coolant supply 22e for supplying a coolant (e.g. liquid water) and a coolant discharge 22f for discharging (partially) heated coolant.

[0021] By way of example, the production or construction of the unit cells 11 of the fuel cell stack 12 shown is shown below with reference to the Fig. 2 to 11 explained.

[0022] In Fig. 2 shows a bipolar plate 7 of one of the unit cells 11. This first bipolar plate 7a has an inner active region 3, shown in dashed lines, and an outer edge region 5, shown in dashed lines. Formed in the edge region 5 are several media channels 8, which can be subdivided into the first media inlet channels 8a, shown on the left in the drawing, and the first media outlet channels 8b, shown on the right in the drawing.

[0023] In the present case, five of the first media inlet channels 8a and five of the first media outlet channels 8b are formed in the first bipolar plate 7a. A different number is possible. The first media inlet channels 8a are fluidly connected to the first media outlet channels 8b via a first flow field 13a. This flow field 13a is located in the active region 3 and can provide a reaction medium to an adjacent membrane electrode arrangement 2. In the example according to Fig. 2, the flow field 13a has several guides or walls 14 for uniformly distributing a reaction medium over the surface of the membrane electrode assembly 2. However, it is also possible to use other types of flow fields 13a, for example, those in which the flow of the reaction medium is guided in a meandering pattern over the area of ​​the active surface. Furthermore, the spacing of the walls 14, the walls, or the webs can also vary. The depth of the channel formed by adjacent walls 14 can also be designed and vary.

[0024] As can be seen from Fig. 3, section III-III from Fig. 2, a flow field 13c is also formed on the side of the first bipolar plate 7a facing away from the membrane electrode arrangement 2, which flow field serves for the flow through of another medium, for example a coolant.

[0025] How Fig. As shown in Figure 4, a composite layer 15, in particular a bonding layer, is applied to the first bipolar plate 7a in the edge region 5. This composite layer 15 is formed in several parts and has recesses 16 in the area of ​​the media channels 8a, 8b. The recesses 16 ensure that the media inlet channels 8a and the media outlet channels 8b are not sealed and allow the passage of media later.

[0026] The composite layer 15 applied in the edge region 5 extends along the long edge 17a of the first bipolar plate 7a, creating a flush finish with the edge region 5 defined by the dimensions of the bipolar plate 7. This composite layer 15 seals the active area or active region 3 from the environment, with the material of the composite layer 15 being selected to ensure this sealing function. Fig. 5, the section VV from Fig. 4 shows the flush termination of the composite layer 15 or the joining material with the bipolar plate 7 along its long edges 17a. The sections of the composite layer 15 located at the short edges 17b also preferably terminate flush with the bipolar plate 7. The selected representation of the composite layer 15 is exemplary. It can be configured much thinner than the first bipolar plate 7a.

[0027] At Fig. 6, a fuel cell assembly with a membrane electrode assembly 2 was placed on the first bipolar plate 7a covered with the composite layer 15 according to Fig. 4. Essentially, the active region 3 is defined by the dimensions of the membrane electrode assembly 2, which is again outlined in the figure by the inner dashed line. However, the active region 3 extends not only in one plane (xy plane) but also in the stacking direction (z direction), which is directed out of or into the paper plane.

[0028] The active region 3 is the region in which the electrochemical reaction of the fuel cell formed by the membrane electrode assembly 2 takes place. During the electrochemical reaction, a fuel (e.g. hydrogen) is fed to the anode, where it is catalytically oxidized to protons with the release of electrons. These protons are transported through the ion exchange membrane to the cathode. 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. The electrons are then fed to the cathode. At the cathode, the oxidation medium (e.g. oxygen or oxygen-containing air) is reduced to anions by absorbing the electrons, which then react directly with the protons to form water.

[0029] To ensure that the fuel reaches the anode directly, or that the oxidation medium reaches the cathode directly, a sealing structure 4 is laterally assigned to the membrane electrode assembly 2. The combination of the membrane electrode assembly 2 and the sealing structure 4 forms a common fuel cell assembly. The sealing structure 4 comprises components that extend into the edge region 5 or even protrude beyond the edge region 5. These components are thus arranged outside the active region 3. In other words, the edge region 5 delimits the active region 3 in the radial or lateral direction, or circumferentially.

[0030] It can be seen that the sealing structure 4 comprises a sealing tongue 6 extending into or over the edge region 5 for the axial, gas-tight covering of a media channel 8 formed in an adjacent bipolar plate 7 and located in the edge region 5. The fuel cell assembly shown here has a total of four sealing tongues 6. Two of the sealing tongues 6 are arranged opposite one another on the shorter edge 9a of the membrane electrode assembly 2. The other two sealing tongues 6 are arranged opposite one another and offset from one another on the long edge 9b of the membrane electrode assembly 2. In the present case, the sealing tongues 6 all have a rectangular shape. Polygonal shapes of the sealing tongues are possible, however, and rounded sealing tongues 6 are also conceivable.

[0031] The sealing structure 4 and in particular the sealing tongues 6 are dimensionally stable with respect to the axially acting compressive and / or tensile stress. Furthermore, it can be seen that the sealing tongues 6 extend beyond the edge region 5. However, it is also possible for one or more of the sealing tongues 6 to extend only into the edge region 5, but not completely cover it or protrude laterally beyond it.

[0032] Furthermore, it can be seen that the sealing structure 4 has a sealing edge 10 that laterally seals the membrane electrode assembly 2. The sealing line formed by the sealing edge 10 seals the membrane electrode assembly 2 against the lateral escape of media.

[0033] The sealing tongue 6 of the fuel cell assembly on the left side axially covers the left media channels 8 of the first bipolar plate 7a in a gas-tight manner. The right sealing tongue 6 of the fuel cell assembly axially covers the right media channels 8 of the first bipolar plate 7a in a gas-tight manner. In other words, the left sealing tongue 6 is formed as a first inlet sealing tongue 6a for axially gas-tight covering of the first media inlet channel 8a on the left. Accordingly, the right sealing tongue 6 is formed as a first outlet sealing tongue 6b for axially gas-tight covering of the first media outlet channel 8b on the right. The sealing tongues 6 provided on the long edge 17a of the bipolar plate 7a rest on the composite layer 15. They can be subdivided into a second inlet sealing tongue 6c and a second outlet sealing tongue 6d.

[0034] The material of the composite layer 15 can be a plastic or a plastic mixture, which preferably has lower thermal stability than the plastic or plastic mixture of the sealing structure 4 or the sealing tongues 6. Thus, during a (hot) pressing process, the sealing tongues 6 can sink into the composite layer 15 and preferably fuse with it, while the sealing tongues 6 retain their dimensional stability. In other words, the melting point of the material of the sealing structure 4 is above the melting point of the material of the composite layer 15.

[0035] In the central region, i.e., where the active region 3 is located, the outer contour of the sealing structure 4 of the fuel cell assembly is adapted to the inner contour defined by the composite layer 15. The sections of the sealing structure 4 without sealing tongues form contact points, contact lines 18, or contact surfaces with the composite layer 15, thus additionally ensuring a sealing function.

[0036] Fig. 7, section VII-VII from Fig. 6 shows an unpressed sectional view of the partial unit cell 11. It can be seen that the first sealing tongues 6a, 6b project beyond the composite layer 15 and form projections 19 with it. This ensures the necessary sealing in the lateral direction. Here, too, the selected representation is not to scale. The thicknesses of the individual layers can vary, particularly after a bonding or joining process (hot pressing process), after which they can appear or act like a single common layer. The area of ​​the recess 16 lying between the inlet sealing tongue 6a and the channels 8 is then minimized such that the inlet sealing tongues 6a axially cover the channels 8. A medium can be supplied to the membrane electrode assembly 2 laterally and in the stacking direction below the first inlet sealing tongue 8a.(Partially) used medium can then leave the unit cell 11 of the fuel cell stack 12 laterally and in the stacking direction below the first outlet sealing tongue 8b.

[0037] In Fig. 8, a connecting layer 20 is applied to the first inlet sealing tongue 6a and to the first outlet sealing tongue 6b, which is to be understood as a further joining layer. The composite layer 15 and the connecting layer 20 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 21 with the connecting layer 20 such that the two layers have a contact surface in the stacking direction. This ensures a sealing function. The overlaps 21 are Fig. 9, section IX-IX from Fig. 8, for more details. Here, too, an unpressed state is shown, which is not to scale but is intended to illustrate the stacked arrangement of the individual layers.

[0038] A second bipolar plate 7b can now be applied to the composite layer 15 and the connecting layer 20 connected to it to complete the unit cell 11. This is Fig. 10. The first bipolar plate 7a and the second bipolar plate 7b can be joined together by the joining layers, such that a unit cell comprising the first bipolar plate 7a, the fuel cell assembly, and the second bipolar plate 7b is formed, with at most minimal overhangs. Preferably, however, the individual layers of the unit cell 11 are connected without edges or offsets in the stacking direction, so that a joining line 25, which will be discussed further below, can be easily applied or applied.

[0039] Like the first bipolar plate 7a, the one in Fig. 10 and Fig. The second bipolar plate 7b shown in Figure 11 has a flow field 13c for conducting a cooling medium on its side facing away from the membrane electrode assembly 2. This flow field 13c is located essentially in the active region 3. It is fluidly connected to coolant inlet channels 8e and coolant outlet channels 8f.

[0040] On its side facing the membrane electrode arrangement 2, the second bipolar plate 7b has one or more second media inlet channels 8c and one or more second media outlet channels 8d ( Fig. 11). It also comprises a second flow field 13b fluidly connected to the second media inlet channel 8c and the second media outlet channel 8d, via which one of the reaction media can be supplied to the membrane electrode assembly 2.

[0041] In Fig. 12 shows a fuel cell stack 12 formed from a plurality of unit cells 11. This fuel cell stack 12 has the advantage that the bipolar plates 7 can be designed with smaller dimensions compared to known bipolar plates, thus reducing the manufacturing costs of the fuel cell stack 12. In the present case, the bipolar plates 7 are rectangular in shape, whereby the present invention is not dependent on a specific shape of the bipolar plates 7, but can also be applied without restriction to any shape, for example, with round or curved lines.

[0042] Fig. 13 shows an exemplary sectional view along section XIII-XIII of Fig. 10 through a fuel cell stack 12. It can be seen that the composite layer 15, after the joining or hot-pressing process, touches or contacts both the first bipolar plate 7a and the second bipolar plate 7b, wherein the bipolar plates 7 are connected or joined to one another via the composite layer 15. It can also be seen that the second media inlet channels 8c are axially covered in a gas-tight manner by the second inlet sealing tongues 6c extending into or over the edge region 5. The situation is corresponding on the opposite side of the second bipolar plate 7b, where second outlet sealing tongues 6d extending into or over the edge region 5 are provided for axially gas-tight covering of the second media outlet channels 8d. Fig. 12 also shows that a second reaction medium is guided laterally and in the stacking direction above the sealing structure 4 to the membrane electrode assembly 2. Accordingly, the (partially) consumed second reaction medium is also laterally guided out of the unit cells 11 or out of the fuel cell stack 12 in the stacking direction above the sealing structure 4.

[0043] The second bipolar plate 7b of a first unit cell 11 then forms, together with a first bipolar plate 7a of a further unit cell 11, 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. The second bipolar plate 7b of the first unit cell 11 and the first bipolar plate 7a of the further unit cell 11 can also be joined together with a joining agent or joining medium. Alternatively, a generatively manufactured one-piece design of the adjacent bipolar plates 7 is possible.

[0044] Fig. 14 shows an exemplary sectional view along section XIV-XIV of Fig. 10 through a fuel cell stack 12. It can be seen that, in the stacking direction, the second bipolar plate 7a is applied to the connecting layer 20 and the composite layer 15. It can also be seen that a first reaction medium is guided to the membrane electrode assembly 2 below the sealing structure 4 in the stacking direction. The first media inlet channels 8a are covered in an axially gas-tight manner by the first inlet sealing tongues 6a. The first reaction medium is supplied laterally or in a lateral direction with respect to the stacking direction. Accordingly, the (partially) used first reaction medium is also guided out of the unit cell 11 or the fuel cell stack 12 laterally or to the side in the stacking direction below the sealing structure 4.

[0045] In Fig. 15 shows a sectional view through the fuel cell device 1, which essentially corresponds to the plan view of the unit cells 11 according to Fig. 10. It can be seen that, however, joining lines 25 are now applied to the fuel cell stack 12 or to its unit cells 11, which essentially run in the stacking direction. The joining lines 25 extend along the entire or whole fuel cell stack 12. The joining lines 25 are arranged on the left and right sides, i.e. on both sides of the media channels 8, so that they seal the media channels 8 against the environment. The same material can be used for the joining lines 25 as for the composite layer 15 or the connecting layer 20, so that the joining lines 25 can also be referred to as a joining layer. The use of a different material for the joining lines 25 is possible. The media guides 22 can now be applied to these joining lines 25, whereby they are connected to the fuel cell stack 12.

[0046] This is in Fig.16 can be seen in more detail. The media guides 22 shown here have a guide web 23 and two guide legs 24a, 24b connected to the latter at their ends. Each of the guide legs 24a, 24b is connected to the fuel cell stack 12 by means of one of the joining lines 25; preferably glued. The open side of the media guides 22 faces the fuel cell stack 12, so that a medium flowing through them can enter the unit cells 12 from the side. The media guides are essentially rectangular in cross-section, but another shape is possible. Preferably, the media channels 22 are formed from a particularly dimensionally stable plastic. When using electrically insulating joining lines 25, one or more of the media channels 22 could even be formed from a metal.

[0047] The present design of the fuel cell device 1 allows the edge region 5 to be as narrow as possible in order to save on expensive material for the bipolar plates 7. The external media guides 22 can also be made of a different material than the bipolar plates 7, thus making them more cost-effective. A circumferential seal around the media guides 22 can be omitted. However, the selected configuration still ensures a secure seal for each unit cell 11 and allows for a maximization of the active area 3 compared to known unit cells 11. LIST OF REFERENCE SYMBOLS 1 fuel cell device 2 membrane electrode assembly (MEA) 3 active area 4 Sealing structure 5 Marginal area 6 Sealing tongue 6a first inlet seal tongue 6b first outlet sealing tongue 6c second inlet seal tongue 6d second outlet sealing tongue 7 Bipolar plate 7a first bipolar plate 7b second bipolar plate 8 Media channel 8a first media entry channel 8b first media outlet channel 8c second media entry channel 8d second media outlet channel 8e Coolant inlet channel 8f coolant outlet channel 9a short edge of the membrane electrode assembly 9b long edge of the membrane electrode assembly 10 Sealing ring 11 Unit cell 12 fuel cell stacks 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 18 contact lines 19 Overhang 20 connection layer 21 overlaps 22 Media guide 22a first media feed 22b first media discharge 22c second media feed 22d second media discharge 22e Coolant supply 22f coolant discharge 23 Guide bridge 24a Guide leg (left) 24b Guide leg (right) 25 joining line

Claims

[1] 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 having one or more media channels (8) and a membrane electrode arrangement (2) arranged between two bipolar plates (7), which comprises a cathode, an anode and a membrane arranged between the cathode and the anode, and with a plurality of media guides (22) running substantially parallel to the stacking direction, the media guide (22) is joined to the bipolar plates (7) of the fuel cell stack (12) in such a way as to guide media substantially laterally to the stacking direction into or out of the media channels (8) of the unit cells (11) of the fuel cell stack (12), wherein the media guides (22) comprise a coolant supply (22e) joined to a first long edge (17a) of the bipolar plates (7) and a second media discharge (22c) joined to the first long edge (17a) of the bipolar plates (7) for discharging an at least partially used second reaction medium, and wherein the media guides (22) comprise a coolant outlet (22f) joined to a second long edge (17a) of the bipolar plates (7) and a second media supply (22c) joined to the second long edge (17a) of the bipolar plates (7) for supplying the second reaction medium, characterized by , that the media guides (22) have a first media feed (22a) joined to a first short edge (17b) of the bipolar plates (7) for feeding a first reaction medium and comprise a media discharge (22) joined to a second short edge (17b) of the bipolar plates (7) for discharging the at least partially consumed first reaction medium. [2] Fuel cell device (1) according to claim 1, characterized by that the media guides (22) comprise a guide web (23) and guide legs (24a, 24b) connected thereto, and that the guide legs (24a, 24b) are or can be connected to the fuel cell stack (12). [3] Fuel cell device (1) according to claim 1 or 2, characterized by that the media guides (22) are connected to the fuel cell stack (12) by means of joining lines (25) which run essentially in the stacking direction and are arranged on both sides of the media channels (8). [4] Fuel cell device (1) according to one of claims 1 to 3, characterized bythat the unit cells (11) have an active region (3) and an edge region (5) located outside the active region (3), in which the one or more media channels (8) are formed for guiding the at least one medium into or out of the active region (3). [5] Fuel cell device (1) according to one of claims 1 to 4, characterized by that the unit cells (11) comprise a first bipolar plate (7a) with a first media inlet channel (8a) and a first media outlet channel (8b), as well as a first flow field (13a) connecting the first media inlet channel (8a) to the first media outlet channel (8b). [6] Fuel cell device (1) according to claim 5, characterized bythat the unit cells (11) comprise a second bipolar plate (7b) with a second media inlet channel (8c) and a second media outlet channel (8d), as well as a second flow field (13b) connecting the second media inlet channel (8c) to the second media outlet channel (8d). [7] Fuel cell device (1) according to one of claims 1 to 6, characterized by that a sealing structure (4) is laterally assigned to the membrane electrode arrangement (2) for the axial gas-tight covering of the one or more media channels (8). [8] Fuel cell device (1) according to claim 7, characterized by that the sealing structure (4) has a sealing edge (10) which laterally seals the membrane electrode arrangement (2).

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