BIPOLAR PLATE WITH SEALING ARRANGEMENT, FUEL CELL WITH BIPOLAR PLATE, AND METHOD FOR SEALINGLY COVERING

Abstract

The invention relates to a bipolar plate (30) for a fuel cell (10). The bipolar plate (30) has a first bipolar plate half (32) and a second bipolar plate half (34), and the bipolar plate (30) has at least one fluid channel (36) for carrying at least one fluid (F). The first bipolar plate half (32) has at least one bonded connection (40) to the second bipolar plate half (34), and the bipolar plate (30) comprises at least one sealing arrangement (50) which sealingly covers the at least one bonded connection (40). The invention also relates to a fuel cell and a method for sealingly covering a bonded connection of the first bipolar plate half (32) to the second bipolar plate half (34) of the bipolar plate (30).

Claims

1. A bipolar plate (30) for a fuel cell (10), wherein the bipolar plate (30) comprises a first bipolar plate half (32), a second bipolar plate half (34), at least one fluid channel (36) for conveying at least one fluid (F), wherein the first bipolar plate half (32) has at least one materially bonded connection (40) to the second bipolar plate half (34), and wherein the bipolar plate (30) comprises at least one sealing device (50) that covers the at least one materially bonded connection (40) in a leaktight fashion.

2. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) comprises at least two sealing halves (52).

3. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) is additively applied onto the bipolar plate (30).

4. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) covers the at least one materially bonded connection (40) in a leaktight fashion on two sides of the bipolar plate (30).

5. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) has a height (H1) and the first bipolar plate half (32) and the second bipolar plate half (34) respectively have a height (H2), the height (H1) of the at least one sealing device (50) corresponding to the height (H2) of the first bipolar plate half (32) and/or of the second bipolar plate half (34).

6. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) is arranged in the at least one fluid channel (36) and/or a sealing groove.

7. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) has a width (B1) and the at least one materially bonded connection (40) has a width (B2), the width (B1) of the sealing device (50) corresponding to at least 500% of the width (B2) of the materially bonded connection (40).

8. A fuel cell (10) having at least one membrane-electrode unit (12), at least one gas diffusion layer (14) and at least one bipolar plate (30) as claimed in claim 1, characterized in that the sealing device (50) of the bipolar plate (30) is arranged between the at least one membrane-electrode unit (12), the gas diffusion layer (14) and/or an edge reinforcement and the at least one bipolar plate (30).

9. The fuel cell (10) as claimed in claim 8, characterized in that the sealing device (50) is connected in a fluid-tight fashion to the at least one membrane-electrode unit (12) and/or to the at least one bipolar plate (30).

10. A method (200) for the leaktight covering of a materially bonded connection of the first bipolar plate half (32) to the second bipolar plate half (34) of the bipolar plate (30) of the fuel cell (10) as claimed in claim 8, the method having the following steps: arrangement (202) of the first bipolar plate half (32) on the second bipolar plate half (34), materially bonded connection (204) of the first bipolar plate half (32) to the second bipolar plate half (34),and leaktight covering (206) of the materially bonded connection (40) with at least one sealing device (50).

11. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) comprises at least two sealing halves (52), one of the at least two sealing halves (52) respectively being arranged on one of at least two sides of the bipolar plate (30).

12. The bipolar plate (30) as claimed in claim 3, characterized in that the at least one sealing device (50) is adhesively bonded to the bipolar plate (30).

13. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) is adhesively bonded to the bipolar plate (30).

14. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) covers the at least one materially bonded connection (40) in a leaktight fashion on opposite sides of the bipolar plate (30).

15. The bipolar plate (30) as claimed in claim 1, characterized in that the at least one sealing device (50) is arranged in the at least one fluid channel (36) and/or a sealing groove in and/or on the first bipolar plate half (32) and/or the second bipolar plate half (34).

16. A method (200) for the leaktight covering of a materially bonded connection of the first bipolar plate half (32) to the second bipolar plate half (34) of the bipolar plate (30) of the fuel cell (10) as claimed in claim 9, the method having the following steps: arrangement (202) of the first bipolar plate half (32) on the second bipolar plate half (34), materially bonded connection (204) of the first bipolar plate half (32) to the second bipolar plate half (34), and leaktight covering (206) of the materially bonded connection (40) with at least one sealing device (50).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] A bipolar plate according to the invention, a fuel cell and a method will be explained in more detail below with the aid of the drawings in which, respectively schematically:

[0019] FIG. 1 shows a side view of a fuel cell having a plurality of bipolar plates and a multiplicity of sealing devices at the materially bonded connections of the bipolar plate halves,

[0020] FIG. 2 shows a side view of a further fuel cell having a plurality of bipolar plates and a multiplicity of sealing devices at the materially bonded connections of the bipolar plate halves, and

[0021] FIG. 3 shows a flowchart of a method according to the invention.

DETAILED DESCRIPTION

[0022] Elements with the same function and functionality are respectively provided with the same references in FIGS. 1 to 3.

[0023] FIG. 1 shows a side view of a fuel cell 10 having a plurality of bipolar plates 30 and a multiplicity of sealing devices 50 at the materially bonded connections 40 of the bipolar plate halves 32, 34. The fuel cell 10 is constructed in a stacked fashion with alternating bipolar plates 30 and membrane-electrode units 12. The membrane-electrode unit 12 may comprise the gas diffusion layers 14 and/or the gas diffusion layers 14 may directly adjoin the membrane-electrode unit 12. The bipolar plates 30 are formed from a first bipolar plate half 32 and a second bipolar plate half 34. The bipolar plate halves 32, 34 are arranged in contact with one another on a front side and are connected to one another by means of materially bonded connections 40. At the connection locations, in particular on the connection locations on the rear side of the bipolar plate halves 32, 34, the coating of the bipolar plate halves 32, 34 is damaged by the thermal input of the materially bonded connection 40 and the material of the bipolar plate halves 32, 34 is therefore at risk of corrosion. Configured in this way, the bipolar plate 30 forms fluid channel structures for example for three fluids F1, F2, F3 of a fuel cell 10. For example, a channel structure for a cooling liquid F3 to flow through is formed between two materially bonded connections 40. Adjacent respectively above and below at the materially bonded connections 40, channel structures are formed for hydrogen F1 and oxygen F2. The channel structures for hydrogen F1 and oxygen F2 are configured so as to transmit fluid to the membrane-electrode units 12 and/or gas diffusion layers 14. In order to protect the materially bonded connections 40 against environmental influences in the fuel cell 10, and in particular against corrosion, at least one sealing device 50 is respectively arranged on and/or at the materially bonded connections 40. In FIG. 1, a sealing half 52 of a sealing device 50 is respectively arranged above and below at the materially bonded connections 40. In the left channel structure, the sealing device 50 is configured with a height H1 which is substantially less than the height H2 of the channel structure and of the first bipolar plate half 32 or of the second bipolar plate half 34. The sealing devices 50 according to the invention are therefore arranged sealing and covering, particularly on the rear sides of the bipolar plate halves 32, 34, at the materially bonded connection 40 for corrosion protection of said locations of the materially bonded connections 40, and they therefore advantageously allow corrosion protection of the bipolar plate halves 32, 34 and/or of the materially bonded connection 40. At the same time, however, flow around the sealing devices 50 still remains possible because of the small height H1 of the sealing devices 50. In the central region of the fuel cell 10 shown in FIG. 1, the sealing device 50 is configured with a height H1 which corresponds or substantially corresponds to the height H2 of the channel structure and of the first bipolar plate half 32 and/or of the second bipolar plate half 34. The sealing devices 50 may be adhesively bonded, clamped and/or otherwise fastened to the respective bipolar plates 30 and/or the fuel cell 10. As described above, damage in the coating of the bipolar plate halves 32, 34 makes it possible for the coating to be undermined at the fault. In this case, there is a risk that even sizeable coating regions adjacent to the weld seam 40 and/or the weld point 40 may break away. Not only the relatively small area of a weld seam 40 and/or a weld point 40, but also the adjacent zone, are therefore in danger of corrosion. Through leaktight covering of the materially bonded connection 40 by the at least one sealing device 50 according to the invention, over a width B1 of 110, 125, 150, 200, 250 or 300% of the width B2 of the materially bonded connection 40, this is prevented or at least advantageously influenced. A bipolar plate 30 according to the invention configured in this way and the fuel cell 10 according to the invention are particularly advantageous since the at least one materially bonded connection 40 is covered in a leaktight fashion by the at least one sealing device 50 and protection of the connection locations, particularly the rear sides of the connection locations, of the bipolar plate halves 32, 34 against corrosion influences and/or environmental influences is therefore made possible with economical and simple means.

[0024] FIG. 2 shows a side view of a further fuel cell 10 having a plurality of bipolar plates 30 and a multiplicity of sealing devices 50 at the materially bonded connections 40 of the bipolar plate halves 32, 34. Further to the comments relating to the fuel cell 10 in FIG. 1, the fuel cell 10 in FIG. 2 shows that the sealing devices 50 shown on the left cover the respective materially bonded connections 40 in a leaktight fashion on two sides, in particular on opposite sides, of the bipolar plate 30. The left sealing devices 50 engage laterally around the bipolar plates 30 in an edge region of the bipolar plates 30. Merely one materially bonded sealing device 50 therefore makes it possible to cover the materially bonded connection 40 in a leaktight fashion on two sides, in particular on opposite sides, of the bipolar plate 30. A sealing device 50 configured in this way is formed, for example, as a U-profiled section and is arranged fitted laterally on the bipolar plate 30. Besides the leaktight covering of the materially bonded connection 40 of the first bipolar plate half 32 to the second bipolar plate half 34, this preferred embodiment of the sealing device 50 allows for example clamping of the sealing device 50 on the bipolar plate 30 and/or furthermore lateral dampening, sealing and/or alignment of the bipolar plate 30.

[0025] FIG. 3 shows a flowchart of a method 200 according to the invention for the leaktight covering of a materially bonded connection 40 of the first bipolar plate half 32 to the second bipolar plate half 34 of the bipolar plate 30 according to the first aspect for the fuel cell 10 according to the second aspect. In a first method step 202, the first bipolar plate half is arranged on the second bipolar plate half. In a second method step 204, the first bipolar plate half is connected in a materially bonded fashion to the second bipolar plate half and the materially bonded connection 40 is therefore produced. In a third method step 206, the materially bonded connection 40 is covered in a leaktight fashion with at least one sealing device 50.