阅读说明：本技术 燃料电池装置 (Fuel cell device ) 是由 M·格雷策尔 N·克卢伊 于 2019-03-04 设计创作，主要内容包括：本发明涉及一种燃料电池装置(1),所述燃料电池装置带有燃料电池堆叠(12),燃料电池堆叠由多个沿堆叠方向相叠地堆叠的单元电池(11)形成,单元电池分别具有一个或多个介质通道(8)和膜电极组件(2),所述膜电极组件包括阴极、阳极和布置在阴极与阳极之间的膜,并且所述燃料电池装置带有基本上平行于堆叠方向伸延的介质引导部(22),介质引导部如此与燃料电池堆叠(12)可连接或相连接,以便将介质基本上横向于堆叠方向引导到燃料电池堆叠(12)的单元电池(11)的介质通道(8)中或从燃料电池堆叠的单元电池的介质通道中引导出,并且介质引导部包括至少间接地相互连接的引导边腿(24a,24b),所述引导边腿与燃料电池堆叠(12)可连接或相连接。介质引导部(22)的引导边腿(24a,24b)嵌入到燃料电池堆叠(12)的基本上平行于堆叠方向伸延的边腿接纳部(26)中。(The invention relates to a fuel cell arrangement (1) having a fuel cell stack (12) which is formed from a plurality of unit cells (11) which are stacked one on top of the other in a stacking direction and each have one or more media channels (8) and a membrane electrode assembly (2) which comprises a cathode, an anode and a membrane arranged between the cathode and the anode, and having a media guide (22) which extends substantially parallel to the stacking direction and is connectable or connected to the fuel cell stack (12) in such a way that media are guided into or out of the media channels (8) of the unit cells (11) of the fuel cell stack (12) substantially transversely to the stacking direction, and which comprises at least indirectly connected guide legs (24a,24b) the guide leg is connectable to the fuel cell stack (12). The guide legs (24a,24b) of the media guide (22) engage in leg receptacles (26) of the fuel cell stack (12) which extend substantially parallel to the stacking direction.)

1. A fuel cell arrangement (1) having a fuel cell stack (12) formed by a plurality of unit cells (11) stacked one on top of the other in a stacking direction, each having one or more media channels (8) and a membrane electrode assembly (2) comprising a cathode, an anode and a membrane arranged between the cathode and the anode, and having a media guide (22) extending substantially parallel to the stacking direction, which is connectable or connected to the fuel cell stack (12) in such a way that media are guided substantially transversely to the stacking direction into or out of the media channels (8) of the unit cells (11) of the fuel cell stack (12), and comprising at least indirectly interconnected guide legs (24a,24b) which can be connected or connected to the fuel cell stack (12), characterized in that the guide legs (24a,24b) of the medium guide (22) engage in leg receptacles (26) of the fuel cell stack (12) which extend substantially parallel to the stacking direction.

2. A fuel cell device (1) according to claim 1, characterized in that the leg receiving portion (26) of the fuel cell stack (12) is formed as a groove extending substantially parallel to the stacking direction.

3. The fuel cell device (1) as claimed in claim 1 or 2, characterized in that the medium guide (22) is formed so as to be elastically yielding in such a way that the guide leg (24a,24b) is held in the leg receptacle (26) under prestress.

4. A fuel cell device (1) according to any one of claims 1 to 3, characterised in that the leg receiving portion (26) has a cut-out (27) which is configured such that a guide element (28) configured or arranged in one and/or the other guide leg (24a,24b) can be received in the cut-out.

5. A fuel cell device (1) according to claim 4, characterized in that the guide element (28) is receivable in the cut-out (27) with a form fit.

6. A fuel cell device (1) according to claim 4 or 5, characterized in that the guide element (28) is formed from another material than the guide leg (24a,24 b).

7. A fuel cell device (1) according to claim 6, characterized in that the guiding element (28) is formed by a sealing material.

8. The fuel cell device (1) according to any one of claims 1 to 7, wherein the guide leg (24a,24b) is indirectly connected to each other via a guide tab (23).

9. The fuel cell device (1) according to any one of claims 1 to 7, wherein the leading edge legs (24a,24b) are directly connected to each other.

10. The fuel cell device (1) according to any one of claims 1 to 9, characterized in that a plurality of medium guides are provided in the medium guides (22), which are formed as a first medium introduction portion (22a) for introducing a first reaction medium and as a first medium lead-out portion (22b) for leading out an at least partially consumed first reaction medium, and which are formed as a second medium introduction portion (22c) for introducing a second reaction medium and as a second medium lead-out portion (22d) for leading out an at least partially consumed second reaction medium.

Technical Field

The present invention relates to a fuel cell device with a fuel cell stack formed by a plurality of unit cells stacked one on top of 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 includes a cathode, an anode, and a membrane disposed between the cathode and the anode. The media guide extends substantially parallel to the stacking direction and is connectable or connected to the fuel cell stack in such a way that the media are guided into or out of the media channels of the unit cells of the fuel cell stack substantially transversely to the stacking direction. The media guide comprises here at least indirectly interconnected guide legs which can be connected or connected to the fuel cell stack.

Background

Known fuel cell devices have channels configured within the fuel cell stack in the stacking direction. To ensure that the reaction media do not mix, costly sealing arrangements are required. Furthermore, it should be ensured that the medium does not reach the environment to the outside during operation of the fuel cell stack. DE 102005038931 a1 shows a fuel cell stack having a plurality of U-shaped media inlets which are mounted laterally on the fuel cell stack.

A fuel cell arrangement according to the preamble of claim 1 is known from the applicant's unpublished application. The guide leg is connected to the fuel cell stack material in a form-fitting manner, so that in other words the media guide is bonded to the fuel cell stack.

Disclosure of Invention

It is therefore an object of the present invention to provide a fuel cell device which allows a simplified introduction of media into the fuel cell stack and provides an alternative and reliable coupling between the media guide and the fuel cell stack.

This object is achieved by a fuel cell arrangement with the features of claim 1. Advantageous embodiments with suitable embodiments of the invention are specified in the dependent claims.

In particular, the guide leg of the media guide engages in a leg receptacle of the fuel cell stack, which leg receptacle extends substantially parallel to the stacking direction.

In this way, the guide leg of the media guide can be positioned laterally at the fuel cell stack with a predetermined stop at the fuel cell stack. This reduces the effort required to fit the media guide at the correct location. In addition, the assembly time for assembling the media guide is minimized due to the leg receiving portion configured at the fuel cell stack.

This arrangement is furthermore advantageous because a different material can be selected for the media guidance than for the cell or for the bipolar plate of the cell. Furthermore, the number of sealing marks which have to be produced for sealing the medium guide can be reduced. Thereby, manufacturing complexity is also reduced.

It has proven to be expedient for the leg receiving sections of the fuel cell stack to be formed as grooves which run substantially parallel to the stacking direction. Such a groove can be produced very simply in terms of production technology.

It is also advantageous if the media guide is formed so as to be elastically yielding that the guide leg is held in the leg receptacle under prestress. The media guide can be secured in a self-locking manner during assembly on the fuel cell stack by means of such a prestress, wherein a material-fit connection of the guide leg to the fuel cell stack, in particular to the leg receptacle of the fuel cell stack, can preferably additionally be formed in order to establish a secure connection.

Preferably, the restoring force is directed outward, since the pressure generated by the medium likewise causes an outward directed force on the guide leg. Due to the addition of the force of the flowing medium and the restoring force provided by the elasticity, a still stronger and thus also more reliable connection of the medium guide at the fuel cell stack is achieved.

The additional fixing of the guide leg in the leg receptacle can be achieved in that the leg receptacle has a cut-out (or undercut, i.e. Hinterschneidung) which extends (preferably substantially parallel to the stacking direction) and is designed such that a guide element which is formed or arranged in one and/or the other guide leg can be received in the cut-out.

In order to additionally reinforce the fastening of the guide leg, it has proven to be advantageous if the guide element can be received in the cutout in a form-fitting manner.

In this connection, it may also be expedient for the guide element to be formed from another material than the guide leg. For example, the guide element can be formed from a material with adhesive properties, so that, if appropriate in addition to a form fit, an adhesive bonding of the guide element in the cutout is additionally achieved and a material-fit connection is thereby additionally formed.

The connection of the media guide to the fuel cell stack faces challenges in maintaining the tightness due to the pressure prevailing in the media guide or in the fuel cell stack caused by the media guided in the media guide or in the fuel cell stack. In order to meet this requirement, it has therefore proven to be expedient for the guide element to be formed from a sealing material.

In one embodiment of the media guide, the guide legs are connected to one another indirectly via guide tabs. It is thus possible to describe a U-shape, in which the open end of the "U" is directed towards the fuel cell stack and the medium is thus guided from the outside close to the fuel cell stack. I.e. the medium flows substantially parallel to the stacking direction in the medium guide. The media arrive in the fuel cell stack in a lateral or sideways direction (xy-direction) with respect to the stacking direction (z-direction).

Alternatively, the guide leg can also be connected directly to one another, so that a C-shaped profile of the media guide is realized in cross section, with the end of the "C" opening toward the fuel cell stack. Here, too, the medium flows substantially parallel to the stacking direction in the medium guide and reaches the fuel cell stack in a transverse or lateral direction with respect to the stacking direction.

Furthermore, the fuel cell device to be produced in a simple manner is characterized in that a plurality of medium guides are provided. The plurality of medium guiding parts are preferably a first medium introducing part for introducing the first reaction medium and a first medium withdrawing part for withdrawing the at least partially consumed first reaction medium. Furthermore, the plurality of medium guiding sections are a second medium introducing section for introducing the second reaction medium and a second medium withdrawing section for withdrawing the at least partially consumed second reaction medium. In this way, two reaction media are guided laterally along the fuel cell stack (i.e. outside the stack) in the media guide, wherein the two reaction media can enter or exit the unit cells of the fuel cell stack perpendicularly to the stacking direction and thus transversely.

In order to additionally guide the coolant along the fuel cell stack outside the stack and to guide the coolant laterally into the unit cells or between two unit cells into the fuel cell stack, it has proven to be expedient if the medium guide is additionally a coolant inlet and a coolant outlet.

Drawings

Further advantages, features and details of the invention emerge from the claims, the following description of a preferred embodiment and the accompanying drawings. Wherein:

figure 1a shows a fuel cell device in a perspective view,

figure 1b shows a further fuel cell device in a perspective view,

figure 2 shows a (first) bipolar plate of a unit cell in a top view,

figure 3 shows section III-III of figure 2,

fig. 4 shows the (first) bipolar plate of fig. 2 in a top view, with a composite layer applied,

figure 5 shows the section V-V of figure 4 (uncompressed state),

fig. 6 shows the (first) bipolar plate of fig. 4, with a fuel cell assembly laid over the bipolar plate,

figure 7 shows section VII-VII of figure 6 (uncompressed state),

fig. 8 shows the arrangement of fig. 6, with the connection layer applied,

figure 9 shows section IX-IX of figure 8 (uncompressed state),

figure 10 shows a unit cell with a (second) bipolar plate of a fuel cell stack in top view,

fig. 11 shows the (second) bipolar plate in bottom view, i.e. in a view towards the face of the second bipolar plate facing the membrane electrode assembly,

figure 12 shows in perspective view a fuel cell stack formed by a plurality of unit cells according to figure 10,

figure 13 shows a cross-sectional view XIII-XIII through the plurality of unit cells stacked one on top of the other (pressed state) of figure 10,

figure 14 shows a cross-sectional view XIV-XIV of figure 10 through a plurality of stacked unit cells (in a pressed state),

fig. 15 shows a cross section of fig. 1a, which extends perpendicularly to the stacking direction, through a fuel cell stack, where a medium guide is mounted,

figure 16 shows a cross-section of figure 1b extending perpendicular to the stacking direction through a fuel cell device,

figure 17 shows a perspective detail view of the fuel cell device according to figure 1b,

FIG. 18 shows a detail of the leg receiving portion and the end of the guide leg, an

Fig. 19 shows a further detail of the leg receptacle, in which the guide leg engages.

Detailed Description

It is pointed out in advance that the dimensions, the dimensional relationships and the proportions of the illustrations shown are not defined and can vary. In particular, the individual layers are shown in the sectional views in such a way that it is possible to understand the mutual position and the sequence in which the individual layers are stacked on top of one another.

Fig. 1a and 1b each show a fuel cell arrangement 1 with a fuel cell stack 12. The fuel cell stack 12 is formed of a plurality of unit cells 11 stacked one on another in the stacking direction (z direction). The unit cells 11 have one or more media channels 8 (fig. 2) and membrane electrode assemblies 2 (fig. 6), respectively. Each of the membrane electrode assemblies 2 in the unit cell 11 includes a cathode, an anode, and an ion-conductive membrane disposed between the cathode and the anode.

The fuel cell device 1 furthermore has a media guide 22 which extends parallel to the stacking direction and is connected to the fuel cell stack 12 in such a way that the media is guided into the media channels 8 of the individual cells 11 of the fuel cell stack 12 or out of the media channels of the individual cells of the fuel cell stack substantially transversely to the stacking direction. The present fuel cell device 1 comprises for this purpose a plurality of medium guides 22, which are a first medium introduction part 22a for introducing a first reaction medium (for example hydrogen) to the anode and a first medium discharge part 22b for discharging the first reaction medium not consumed in the unit cell 11. Further, the medium guide part 22 is divided into a second medium introduction part 22c for introducing a second reaction medium (e.g., oxygen or air) to the cathode and a second medium lead-out part 22d for leading out the second reaction medium that is not consumed in the unit cell 11. Finally, the medium guide is further divided into a coolant inlet 22e for introducing a coolant (e.g. liquid water) and a coolant outlet 22f for discharging the (partially) heated coolant.

The production or construction of the individual cells 11 of the illustrated fuel cell stack 12 is explained below by way of example with the aid of fig. 2 to 11.

In fig. 2 one of the unit cells 11 is shown with bipolar plates 7. The first bipolar plate 7a has an inner, active region 3 shown by dashed lines and an outer, edge region 5 shown by dashed lines. In the edge region 5, a plurality of media channels 8 are formed, which can be divided into a first media inlet channel 8a, which is shown on the left side of the drawing, and a first media outlet channel 8b, which is shown on the right side of the drawing. In each case, a pair of leg receptacles 26, which are discussed in more detail below, is formed around the medium channel 8. The other leg receptacle 26 is formed at the long edge 17a of the bipolar plate 7.

In the present case, five of the first medium inlet channels 8a and five of the first medium outlet channels 8b are formed in the first bipolar plate 7 a. Other numbers are possible. The first medium inlet channel 8a and the first medium outlet channel 8b are in flow communication with each other via a first flow field 13 a. The flow field 13a is located in the active region 3 and is capable of supplying the adjacent mea 2 with the reaction medium. In the example according to fig. 2, the flow field 13a has a plurality of guide sections or walls 14 for distributing the reaction medium uniformly over the surface of the membrane electrode assembly 2. However, other types of flow fields 13a can also be used, for example flow fields in which the flow of the reaction medium is guided in a corrugated manner over the region of the active surface. Furthermore, the spacing of the walls 14, wall portions or tabs may also be varied. The depth of the channels formed by adjacent walls 14 may also be implemented to be different depths and may vary.

As is evident from fig. 3, section III-III of fig. 2, a flow field 13c is also formed on the side of the first bipolar plate 7a facing away from the mea 2, which flow field is used for flowing through another medium, for example a coolant.

As shown in fig. 4, a composite layer 15, in particular a bonding layer, is applied to the first bipolar plate 7a in the edge region 5. The composite layer 15 is formed in multiple parts or has recesses 16 in the region of the media ducts 8a, 8 b. The recess 16 ensures that the medium inlet channel 8a and the medium outlet channel 8b are not sealed and allow subsequent through-conduction of the medium.

The composite layer 15 installed in the edge region 5 extends along the long edge 17a of the first bipolar plate 7a, so that a flush finish with the edge region 5 is produced, which is predetermined by the dimensions of the bipolar plate 7. The region for the leg receiving portion 26 also remains free at the composite layer 15. The composite layer 15 seals the active surface or the active region 3 from the environment, wherein the material of the composite layer 15 is selected such that the sealing function is ensured. In the section V-V in fig. 5, 4, the flush termination of the composite layer 15 or joining material with the bipolar plate 7 along the long edge 17a of the bipolar plate can be seen. The section of the composite layer 15 at the short edge 17b also preferably ends flush with the bipolar plate 7. The selected illustration of the composite layer 15 is exemplary. The composite layer may be designed to be much thinner than the first bipolar plate 7 a.

The fuel cell assembly with the membrane electrode assembly 2 in fig. 6 is applied or laid onto the first bipolar plate 7a covered with the composite layer 15 according to fig. 4. Basically, the active region 3, which is again depicted in the figure by an internal dashed line, is preset by the dimensions of the membrane electrode assembly 2. The active region 3 extends not only in the plane (xy-plane) but also in the stacking direction (z-direction) pointing outwards or inwards from the plane of the drawing.

The active region 3 is a region in which electrochemical reactions occur in the fuel cell formed by the membrane electrode assembly 2. In an electrochemical reaction, fuel (e.g., hydrogen) is directed to an 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 flow of electrons from the fuel cell passes through an electrical consumer, preferably to an electric motor for driving the motor vehicle or to a battery. The electrons are then directed to the cathode. At the cathode, the oxidizing medium (e.g., oxygen or air containing oxygen) is reduced by absorbing electrons to anions that react directly with protons to water.

In order to ensure that the fuel reaches the anode directly or the oxidizing medium reaches the cathode directly, a sealing structure 4 is associated laterally with the membrane electrode assembly 2 (fig. 6, 8). The combination of the membrane electrode assembly 2 and the sealing structure 4 here forms a common fuel cell assembly. The sealing structure 4 here comprises components which extend into the edge region 5 or even project beyond the edge region 5. These components are therefore arranged outside the active region 3. In other words, the edge region 5 defines the active region 3 in a radial or transverse direction or on a circumferential side.

As can be seen in fig. 6 and 8, the sealing arrangement 4 comprises a sealing tongue 6 which extends into the edge region 5 or beyond the edge region and serves to cover axially gas-tightly the media channels 8 which are formed in the adjacent bipolar plate 7 and are 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 at the long edge 9b of the membrane electrode assembly 2. The sealing tongues 6 currently all have a rectangular shape. However, polygonal shapes of the sealing tongues are possible, rounded sealing tongues 6 also being considered.

The sealing structure 4 and in particular the sealing tongue 6 are formed dimensionally stable with respect to pressure and/or tensile loads acting axially on the sealing structure and the sealing tongue. It can furthermore be seen that the sealing tongue 6 extends 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 to completely cover the edge region or to project laterally beyond said edge region.

It can furthermore be seen that the sealing structure 4 has a sealing edge 10 which seals the membrane-electrode assembly 2 transversely. The seal line formed by the sealing edge 10 seals the membrane electrode assembly 2 against the media exiting laterally.

The sealing tongue 6 on the left side of the fuel cell assembly covers the left media channel 8 of the first bipolar plate 7a in an axially gas-tight manner. The right sealing tongue 6 of the fuel cell assembly covers the right media channel 8 of the first bipolar plate 7a in an axially gas-tight manner. In other words, the left sealing tongue 6 is formed as a first inlet sealing tongue 6a for axially gas-tightly covering the left first medium inlet channel 8 a. Correspondingly, the right sealing tongue 6 is shaped as a first outlet sealing tongue 6b for covering the right first medium outlet channel 8b in an axially gas-tight manner. The sealing tongues 6 arranged at the long edges 17a of the bipolar plates 7a rest on the composite layer 15. The sealing tongues can be divided into a second entry sealing tongue 6c and a second exit sealing tongue 6 d.

A plastic or plastic mixture can be used as the material of the composite layer 15, which preferably has a lower thermal stability than the plastic or plastic mixture of the sealing structure 4 or sealing tongue 6. As a result, the sealing tongue 6 can sink into the composite layer 15 during the (hot) pressing process and preferably merge with it, wherein the sealing tongue 6 ensures its dimensional stability. In other words, the melting point of the material of the sealing structure 4 is higher than the melting point of the material of the composite layer 15.

In the central region, i.e. at the location of the active region 3, the sealing structure 4 of the fuel cell assembly is adapted in its outer contour to an inner contour predetermined by the composite layer 15. In this case, the sealing tongue-free section of the sealing structure 4 forms a contact point, a contact line 18 or a contact surface with the composite layer 15, so that the sealing function is additionally ensured.

The section VII-VII of fig. 7, 6 shows a section of a part of the unit cell 11 without pressing. It can be seen that the first sealing tongues 6a, 6b project beyond the composite layer 15 and together with the composite layer form a projection (ueberstan) 19. In this case, the required sealing in the lateral direction is ensured. The figures chosen here are not to be understood as being true to scale. The thickness of the individual layers can vary, in particular after a joining process or a bonding process (hot-pressing process), after which the individual layers can appear to function as a single, common layer or as a single, common layer. The region of the recess 16 between the entry sealing tongue 6a and the channel 8 is then also minimized in such a way that the entry sealing tongue 6a axially covers the channel 8. The media can be introduced into the membrane electrode assembly 2 transversely and in the stacking direction below the first inlet sealing tongue 8 a. The (partially) consumed medium can then leave the unit cells 11 of the fuel cell stack 12 laterally and in the stacking direction below the first exit sealing tongues 8 b.

In fig. 8, a connecting layer 20 is applied on the first entry sealing tongue 6a and on the first exit sealing tongue 6b, which connecting layer is to be understood as a further joining layer. The composite layer 15 and the connection layer 20 ensure reliable connection of the first bipolar plate 7a to the second bipolar plate 7b in the stacking direction. The composite layer 15 and the connecting layer 20 are configured in an overlapping region 21 in such a way that the two layers have a contact surface in the stacking direction. Thereby, the sealing function is ensured. The overlap 21 can be seen in more detail in the section IX-IX of fig. 9, 8. Here, the uncompressed state is also shown, which is not to scale, but which is intended to indicate the stack arrangement of the individual layers.

The second bipolar plate 7b can now be applied to the composite layer 15 and the connection layer 20 connected thereto for completing the unit cell 11. This can be gathered from fig. 10. The first bipolar plate 7a and the second bipolar plate 7b can be joined to each other by a joining layer in such a way that a unit cell provided with at most small protrusions is formed by the first bipolar plate 7a, the fuel cell assembly, and the second bipolar plate 7 b. Preferably, however, the respective layers of the unit cells 11 are connected in the stacking direction without edges or dislocation.

Like the first bipolar plate 7a, the second bipolar plate 7b shown in fig. 10 and 11 also has a flow field 13c for conducting a cooling medium on its side facing away from the mea 2. The flow field 13c is located substantially in the active region 3. The flow fields are in flow communication with the coolant inlet channels 8e and with the coolant outlet channels 8 f. Furthermore, the second bipolar plate 7b also comprises a recessed region which forms the leg receptacle 26.

The second bipolar plate 7b has one or more second medium inlet channels 8c and one or more second medium outlet channels 8d on its side facing the membrane electrode assembly 2 (fig. 11). Furthermore, the second bipolar plate comprises a second flow field 13b in flow communication with the second medium inlet channel 8c and the second medium outlet channel 8d, via which one of the reaction media can be introduced to the membrane electrode assembly 2.

A fuel cell stack 12 formed of a plurality of unit cells 11 is shown in fig. 12. The fuel cell stack 12 has the advantage that the bipolar plate 7 can be designed with smaller dimensions than known bipolar plates, so that the production costs of the fuel cell stack 12 are reduced. The bipolar plate 7 is in principle rectangular in shape, wherein the invention is not dependent on the rectangular shape of the bipolar plate 7, but can be used without restriction with any shape, for example with round or curved lines. In this connection, it is essential in any case that a plurality of leg receptacles 26, which are formed parallel to the stacking direction and at which the medium guides 22 can be fastened, are present at the fuel cell stack 12.

Fig. 13 shows an exemplary cross-sectional view along section XIII-XIII of fig. 10 through the fuel cell stack 12. It can be seen that the composite layer 15 touches or contacts both the first bipolar plate 7a and the second bipolar plate 7b after the joining process or hot pressing process, wherein the bipolar plates 7 are connected or joined to one another via the composite layer 15. It can furthermore be seen that the second medium inlet channel 8c is covered axially gas-tightly by a second inlet sealing tongue 6c which extends into the edge region 5 or beyond the edge region. Correspondingly, a second outlet sealing tongue 6d is provided at the opposite side of the second bipolar plate 7b, which second outlet sealing tongue extends into the edge region 5 or beyond the edge region, in order to cover the second medium outlet channel 8c in an axially gas-tight manner. In fig. 13, it can also be seen that the second reaction medium is conducted laterally and in the stacking direction to the mea 2 over the sealing structure 4. Correspondingly, above the sealing structure 4 in the stacking direction, the (partially) consumed second reaction medium is also withdrawn laterally again from the unit cell 11 or from the fuel cell stack 12.

The second bipolar plate 7b of the first unit cell 11 forms together with the first bipolar plate 7a of the further unit cell 11 a complete channel cross section for the passage of the cooling medium. In other words, the second bipolar plate of the first unit cell and the first bipolar plate of the other unit cell then also form the coolant inlet channel 8e and the coolant outlet channel 8 f. The second bipolar plate 7b of the first battery cell 11 and the first bipolar plate 7a of the further battery cell 11 can here likewise be bonded to one another using a bonding agent or bonding medium. Alternatively, an additive-made one-piece design of the adjacent bipolar plates 7 is possible.

Fig. 14 shows an exemplary cross-sectional view along the section XIV-XIV of fig. 10 through the fuel cell stack 12. It can be seen that the second bipolar plate 7a is applied to the tie layer 20 and the composite layer 15 in the stacking direction. It can furthermore be seen that the first reaction medium is conducted in the stacking direction to the membrane electrode assembly 2 below the sealing structure 4. The first medium inlet channel 8a is covered axially in a gas-tight manner by the first inlet sealing tongue 6 a. The introduction of the first reaction medium is effected laterally or in the transverse direction with respect to the stacking direction. Correspondingly, the (partially) consumed first reaction medium is also withdrawn laterally or laterally again from the unit cells 11 or from the fuel cell stack 12 below the sealing structure 4 in the stacking direction.

Fig. 15 shows a sectional view through the fuel cell device 1 according to fig. 1b, which essentially corresponds to a plan view of the cell 11 according to fig. 10. It can be seen, however, that the media guide 22 now engages with its guide legs 24a,24b in the leg receptacle 26.

The media guide 22 shown here has a guide web 23 which connects two guide leg legs 24a,24b at the ends to one another. Each of the guide leg portions 24a,24b is received in one of the leg receiving portions 26 of the fuel cell stack 12 that extend parallel to the stacking direction. The open side of the medium guide 22 is directed toward the fuel cell stack 12 so that the medium flowing through the medium guide can reach laterally into the unit cell 12. The media guide 22 is formed substantially rectangular in cross section, but other configurations are possible. Preferably, the medium channel 22 is formed from a (in particular form-stable) plastic.

Fig. 16 shows a further embodiment of the media guide 22, wherein a cross section through the fuel cell stack 12 of fig. 1b can be seen here. In this case, the media guide 22 is formed in a semicircular or C-shaped manner, so that the guide legs 24a,24b are directly connected to one another without the guide webs 23 being present.

As can be seen from the detail view according to fig. 17, the media guide 22 is formed so as to be elastically yielding. The guide legs 24a,24b are thereby held in the leg receptacles 26 of the fuel cell stack 12 under a prestress, in particular directed outward. That is, the reset force (indicated by force arrow 29) is effective and the media guide 22 is locked in the leg receiver 26 by this reset force. Furthermore, the guide legs 24a,24b are additionally locked by the pressure of the medium flowing in the medium guide 22. The media also causes an outwardly directed force which, in addition to the restoring force, causes a still stronger connection between the media guide 22 and the fuel cell stack 12.

Alternatively or additionally, the leg receptacle 26 can also be formed according to the detail shown in fig. 18. The leg receiver 26 has a cutout 27 into which a guide element 28 formed or arranged on the guide legs 24a,24b can be received. Inside the leg receptacle 26, opposite the cut-out 27, an obliquely running insertion surface 30 is formed, which facilitates the insertion of the guide legs 24a,24b into the leg receptacle 26. The insertion surface 30 is arranged at an angle both with respect to the long edge 17a of the bipolar plate 7 and with respect to the short edge 17b of the bipolar plate. The insertion surface 30 merges into a (transverse) contact surface 31 oriented parallel to the plate edge, which presets and/or defines the penetration depth of the guide leg 24a,24b into the leg receptacle 26. Starting from the contact surface 31, the leg receptacle 26 then merges into a groove-shaped contact surface 32, which preferably forms the cutout 27.

In the example according to fig. 17, the guide element 28 is formed in one piece with the guide leg 24a,24b, whereas in the example according to fig. 19, the guide element 28 is formed from a different material than the guide leg 24a,24 b. The further material may be, for example, an (additional) sealing material in order to additionally ensure the tightness of the fuel cell stack 12.

The current design of the fuel cell device 1 allows the media guide 22 to be arranged at the fuel cell stack 12 with positional accuracy. The fastening of the guide legs 24a,24b in the leg receptacles 26 of the fuel cell stack 12 by means of a non-positive and/or material-positive connection takes up large forces which are directed away from the fuel cell stack 12 and which are exerted by the pressure of the medium flowing in the medium guide 22. The media guide 22 is characterized by its superior self-locking function.

Based on the current design, the outwardly directed force additionally locks the media guide 22 at the fuel cell stack 12. This also means that the greater the pressure generated by the media in the media guide 22, the more firmly the connection between the guide legs 24a,24b in the leg receiving portion 26 of the fuel cell stack 12 is made.

List of reference numerals:

1 fuel cell device

2 Membrane Electrode Assembly (MEA)

3 active region

4 sealing structure

5 edge area

6 sealing tongue

6a first entry sealing tongue

6b first leaving sealing tongue

6c second entry sealing tongue

6d second exit sealing tongue

7 Bipolar plate

7a first bipolar plate

7b second bipolar plate

8 medium channel

8a first Medium intake channel

8b first Medium exit channel

8c second Medium intake channel

8d second Medium exit channel

8e Coolant inlet passage

8f Coolant exit passage

Short edge of 9a membrane electrode assembly

Long edge of 9b membrane electrode assembly

10 sealing ring

11 unit cell

12 fuel cell stack

13 first flow field

13b second flow field

13c flow field (Cooling medium)

14 wall

15 composite layer

16 concave part

Long edge of 17a bipolar plate

Short edge of 17b bipolar plate

18 contact wire

19 projection

20 connecting layer

21 overlap part

22 media guide

22a first medium introducing part

22b first medium lead-out part

22c second medium introducing part

22d second medium lead-out part

22e Coolant introduction part

22f coolant lead-out part

23 guide tab

24a guide side leg (left side)

24b guide side leg (Right side)

26 side leg receiving part

27 cut-out portion

28 guide element

29 force arrow

30 introduction face

31 (lateral) contact surface

32 (grooved) contact surface