A bipolar plate for a fuel cell and a fuel cell stack

Abstract

The bipolar plate (100) comprises a first plate (102) with a first bead seal (108), a second plate (104) with a second bead seal (106). The first plate (102) and the second plate (104) are disposed and joined opposite to each other in a manner that the first bead seal (108) and the second bead seal (106) forms a channel (114) therebetween, characterized in that, a stiffener (110) is positioned inside and along the channel (114). The stiffener (110) supports the bead seal (108, 106) against deformation of the sealing surface.

Description

1. Title of the invention:A BIPOLAR PLATE FOR A FUEL CELL AND A FUEL CELL STACK2. Applicants: a. Name: Bosch Global Software Technologies Private Limited Nationality: INDIAAddress: 123, Industrial Layout, Hosur Road, Koramangala, Bangalore - 560095, Karnataka, India b. Name: Robert Bosch GmbHNationality: GERMANYAddress: Postfach 30 0220, 0-70442, Stuttgart, GermanyComplete Specification:The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.Field of the invention:

[0001] The present invention relates to a bipolar plate for a fuel cell and a fuel cell stack.Background of the invention:

[0002] According to a prior art US2009197147, a metal bead seal for fuel cell plate is disclosed. A bead seal structure is disclosed for sealing between plates of a fuel cell system, wherein the bead seal structure militates against a leakage of fluids from the fuel cell system and a cost thereof is minimized.Brief description of the accompanying drawings:

[0003] An embodiment of the disclosure is described with reference to the following accompanying drawings,

[0004] Fig. 1 illustrates a peripheral cross-sectional view of a bead seal of a bipolar plate of a fuel cell, according to an embodiment of the present invention.Detailed description of the embodiments:

[0005] Fig. 1 illustrates a peripheral cross-sectional view of a bead seal of a bipolar plate of a fuel cell, according to an embodiment of the present invention. The bipolar plate 100 comprises a first plate 102 with a first bead seal 108, a second plate 104 with a second bead seal 106. The first plate 102 and the second plate 104 are disposed and joined opposite to each other in a manner that the first bead seal 108 and the second bead seal 106 forms a channel 114 therebetween, characterized in that, a stiffener 110 is positioned inside and along the channel 114.

[0006] According to an embodiment of the present invention, the stiffener 110 comprises a flat surface at two ends and curved portion between the two ends which functions as spring. The stiffener 110 internally makes surface contacts with both of the first bead seal 108 and the second bead seal 106. The stiffener 110 is internally welded 112 with both of the first bead seal 108 and the second bead seal 106. An example of the welding is laser welding. The surface contact instead of linecontact provides technical advancement in terms of robust support and load bearing capability to the bipolar plates 100. The geometry / shape of the stiffener 110 is variable and depends on the loading of bipolar plates 100. Thus, shapes which behavior similar to spring is usable.

[0007] According to an embodiment of the present invention, the stiffener 110 is positioned in any one manner selected from a group comprising of continuously along entire length of said channel 114, and in segments along entire length of the channel 114. In simple words, the stiffener 110 is either laid out for the entire length of the channel 114 or is provided in segments.

[0008] According to an embodiment of the present invention, a fuel cell stack (not shown) is disclosed. The fuel cell stack comprises a plurality of bipolar plates 100 stacked on top or beside each other in a housing, a Membrane Electrode Assembly (MEA) (not shown), positioned next to each of the plurality of bipolar plates 100. Each of the bipolar plates 100 comprises the channel 114 formed between the first bead seal 108 and the second bead seal 106. The plurality of bipolar plates 100 are arranged in a staking direction over the bead seals 108, 106, characterized in that, the stiffener 110 positioned inside and along the channel 114.

[0009] The stiffener 110 comprises flat surface at two ends and curved portion between the two ends which functions as the spring. The stiffener 110 makes surface contacts with both of the first bead seal 108 and the second bead seal 106 of the bipolar plate 100. The stiffener 110 is internally welded with both of the first bead seal 108 and the second bead seal 106 with respective flat surface at the two ends.

[0010] According to an embodiment of the present invention, the stiffener 110 is positioned in any one manner selected from the group comprising continuously along entire length of the channel 114, and in segments along entire length of the channel 114.

[0011] According to the present invention, an improvement on the profile of the bead seal 108, 106 in bipolar plates 100 is provided. The stiffener 110 is welded with bead seal 108, 106 using laser welding. The intermittent welding is enough for holding the stiffener 110. The stiffener 110 acts like a spring while tightening the fuel cell stack. The stiffener 110 is compressed while tightening of the fuel cell stack. The stiffener 110 supports the bead seal 108, 106 against deformation of the sealing surface. Thus, in comparison to existing solution, the bipolar plate 100 is robustly supported by the stiffener 110 which will prevent from deformation and thereby reducing any dangerous scenarios or leakages.

[0012] It should be understood that the embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.

Claims

We claim:

1. A bipolar plate (100) for a fuel cell, said bipolar plate (100) comprises: a first plate (102) with a first bead seal (108); a second plate (104) with a second bead seal (106), said first plate (102) and said second plate (104) are disposed and joined opposite to each other in a manner that said first bead seal (108) and said second bead seal (106) forms a channel (114) therebetween, characterized in that, a stiffener (110) is positioned inside and along said channel (114).

2. The bipolar plate (100) as claimed in claim 1, wherein said stiffener (110) comprises flat surface at two ends and curved portion between said two ends.

3. The bipolar plate (100) as claimed in claim 2, wherein said stiffener (110) makes surface contacts with both of said first bead seal (108) and said second bead seal (106).

4. The bipolar plate (100) as claimed in claim 1, wherein said stiffener (110) is internally welded with both of said first bead seal (108) and said second bead seal (106).

5. The bipolar plate (100) as claimed in claim 1, wherein said stiffener (110) is positioned in any one manner selected from a group comprising of continuously along entire length of said channel (114), and in segments along entire length of said channel (114).

6. A fuel cell stack, comprises: a plurality of bipolar plates (100) stacked in a housing; a Membrane Electrode Assembly (MEA) positioned next to each of said plurality of bipolar plates (100), each of said bipolar plates (100)comprises a channel (114) formed between a first bead seal (108) and a second bead seal (106), characterized in that, a stiffener (110) positioned inside and along said channel (114).

7. The fuel cell stack as claimed in claim 6, wherein said stiffener (110) comprises flat surface at two ends and curved portion between said two ends.

8. The fuel cell stack as claimed in claim 7, wherein said stiffener (110) makes surface contacts with both of said first bead seal (108) and said second bead seal (106) of said bipolar plate (100).

9. The fuel cell stack as claimed in claim 6, wherein said stiffener (110) is internally welded with both of said first bead seal (108) and said second bead seal (106).

10. The fuel cell stack as claimed in claim 6, wherein said stiffener (110) is positioned in any one manner selected from a group comprising of continuously along entire length of said channel (114), and in segments along entire length of said channel (114).

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