Description:Complete 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] This invention is related to a fuel cell housing with a drainage unit.

Background of the invention

[0002] The fuel cell stack consists of multiple cells stacked together to form power generation system , this fuel cell stack is housed/enclosed within a housing to protect the cell stack from external damage due to accident and also to prevent direct exposure of leaked gases into atmosphere. The fuel cell stack are fed with reactant gases for power generation and coolant to maintain the stack at optimum temperature to attain maximum possible efficiency. Due to the power generation cycles the stack gets heated up and also gets cooled down when the power generation is stopped. Also, there are chances or possibilities for the reactant gases/coolant vapor to escape out of the cell body into the surrounding region due to defective sealing , pressurized supply , and other reasons . It is then important to dilute the escaped gas with excess of air to prevent the chance of fire or also prevent direct contact of high concentration hydrogen onto atmosphere. This dilution is done within the stack casing by purging the casing with excess amount of air so that the hydrogen gets diluted and the safe H2 level is maintained .

[0003] A US patent 6808834 discloses a fuel cell stack comprising: a plurality of fuel cells electrically connected in series and having equivalent active section areas and circumferences.Each fuel cell comprising a laminate of layers, an electrolyte membrane and catalyst, electrode and gas diffusion layers the functions of which may be combined in any combination in multifunction layers; end and separator plates delimiting each cell; and cooling layers the cooling function of which also may be combined with other layers in respective multifunction layers, the cooling layers each projecting beyond the circumferential outer periphery of the laminate of the other layers thereby comprising an inner active section area and a peripheral cooling fin area, wherein the ratio (14:15) of circumference and active area of the stack, defined by the geometrical shape of the active area, being greater than the corresponding ratio of a square active area, wherein the material of the cooling layers is a foil made of expanded graphite, which foil has a larger specific heat conductivity parallel to the plane of each fuel cell than orthogonal to that plane.

Brief description of the accompanying drawings
[0004] Figure 1 illustrates a fuel cell housing with a drainage unit, in accordance with an embodiment of the invention; and

Detailed description of the embodiments
[0005] Figure 1 illustrates a fuel cell housing with a drainage unit, in accordance with an embodiment of the invention. The fuel cell housing 10 comprises multiple fuel cells 12 stacked horizontally and the housing 10 having a box frame structure covering the fuel cell 12 stack in horizontal boundaries. The housing 10 further comprises a top portion 14 , a bottom portion 16 and the side walls 18. The inner surface 20 of top portion 14 of the housing 10 is made tilted/curved vertically towards the side walls 18 from a center point 22 of the top portion 14, such that, condensed water formed in the fuel cell housing 10 is directed away from the top portion 14 to the side walls 18.

[0006] Further the construction of the fuel cell housing and the components of the fuel cell housing is explained in detail. The top portion 14 and the bottom portion 16 of the housing 10 comprises a set of plates fastened onto the top and bottom portions (14 & 16) of horizontal boundaries to form an enclosure. According to one embodiment of the invention , the top portion 14 is made as an external component to the housing 10 attached onto the side walls 18 of the housing 10. The housing 10 comprises at least one guide fin 24 formed on an inner surface 26 of each the side walls 18 of the housing 10 for directing the condensed water from the top portion 14. The at least one guide fin 24 collects the condensed water from the top portion 14 and guides the collected condensed water towards the bottom portion 16 of the housing 10.

[0007] According to one embodiment of the invention, the number of guide fins 24 are made according to the size of the fuel cell housing 10. For forming the guide fins 24 on the inner surface 26 of the side walls 18, the thickness of the side walls 18 of the housing 10 is increased to a predefined value, such that, the water is guided towards the bottom portion 16 of the housing 10. According to one embodiment of the invention , the guide fins 24 are made according to the inclination of the top portion 14 towards the side walls 18, such that, the condensed water is properly collected and guided towards the bottom portion 16 of the housing 10. According to one embodiment of the invention, the inner surface 26 of the side walls 18 are provided with guiding surface / wall with channels (recess portion) to drain the water into bottom portion 16 of the housing 10.

[0008] The fuel cell housing 10 comprises at least one drain port 28 made on the bottom portion 16 of the housing 10, such that, the condensed water from the at least guide fin 24 is made to flow out of the housing 10. According to one embodiment of the invention, the fuel cell housing 10 has two drain ports 28 made on either ends of the bottom portion 18 of the housing 10. The location of the drain port 28 will be in line with the at least one guide fin 24 , such that a smooth flow of condensed water is achieved.

[0009] The fuel cell housing 10 comprises a drain valve 30 positioned in proximity to the at least one drain port 28, for collecting the drained water coming from the at least one drain port 28. According to one embodiment of the invention, the drain valve 30 is made as an integral part of the housing 10 such that, the condensed water flows from the top portion 14 to the drain valve 30 via the at least one guide fin 24 and the at least one drain port 28. According to one embodiment of the invention, the drain valve 30 is made as an external component of the housing 10. The drain ports 28 and the drain valve 30 makes the drainage unit 11 of the fuel cell housing 10.

[0010] An inner surface 26 of each of the side wall 18 is coated with an anti-corrosive material for smooth flow of the condensed water from the top portion 14 to the bottom portion 16 of the housing 10. According to one embodiment of the invention, the anti-corrosive material is a hydrophobic material. However, it is to be understood that the material as disclosed above is not limited to hydrophobic material , but can be of any other material that is used to carry the condensed water easily from one place to another , which is known to a person skilled in the art.

[0011] A method of fuel cell housing 10 is explained in detail. In the process of dilution , due to the reaction of Hydrogen and the oxidant, the water vapor is created, and this created water vapor gets condensed on the surface (i.e.., on the inner surface 20 of the top portion 14) of the fuel cell housing 10. Due to the lack of flowing out of the housing 10 and the stacked fuel cells 12, the water gets condenses on the surface of the housing 10. If this condensed water is not removed or drained at a regular time interval, it will be escaped from the fuel cell housing 10, causing damage to the fuel cell housing 10.

[0012] The fuel cells 12 stacked in the horizontal direction (as mentioned in this invention) , the top portion 14 of the housing 10 has a relatively larger surface area compared to the side walls 18 of the housing 10 and , if the water gets condensed on the inner surface 20 of top portion 14, then there are chances of water dripping onto the cell(s) surfaces 12 are high. This water if dripped onto the surface of cells 12, it may cause multiple problem such as short circuit, blockage of cell 12, if the dripped water gets freeze .This problem is even more significant in Horizontal stack(cells stacked in horizontal direction) than in vertical stack (cells stacked in vertical direction).

[0013] The new fuel cell housing 10 design disclosed in the invention provides the solution to the above-mentioned problem. The inner surface 20 of the top portion 14 is designed as a curved surface such that the condensed water is directed away from top portion 14 towards side wall 18. The curved/titled/inclined inner surface 20 directs the water dew drops towards side walls 18 of the housing 10 and prevents dripping of water onto cells/stack 12, This curved inner surface 20 is tilted/curved vertically towards the side walls 18 from the center point 20 of the top portion 14 .
[0014] The guide fins 24 present on the inner surface 26 of the side walls 18 provides surface for the condensation of the vapor and collects the water droplets and guides the water droplets onto bottom portion 16 of the housing 10.

[0015] The inner surface 26 of the side walls 18 being coating with the anti-corrosive material (which is hydrophobic material) helps in carrying the condensed water towards the bottom portion 16 of the housing 10 with much ease. This coating further reduces the possibilities of the formation of ice on casing surface. With the bottom portion 16 comprising the drain ports 28 and the drain valve 30 for draining the collected water, removing the water from that is drained (via the drain port 28) with the help of drain valve 30 is achieved without much hassle. This process of draining the water in the water collection portion (drain valve 30) prevents the possibility of freeze and blockage in the housing 10.

[0016] It should be understood that 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 fuel cell housing (10) with a drainage unit (11), said fuel cell housing (10) comprising :
- multiple fuel cells (12) stacked horizontally;
- said housing (10) having a box frame structure covering said fuel cell (12) stack in horizontal boundaries;
- a top portion (14) , a bottom portion (16) and side walls (18) forms said housing (10);
characterized in that :
- an inner surface(20) of top portion (14) of said housing (10) is made tilted/curved vertically towards said side walls (18) from a center point (22) of said top portion (14), such that, condensed water formed in said fuel cell housing (10) is directed away from said top portion(14) to said side walls (18).

2. The fuel cell housing (10) as claimed in claim 1, comprises at least one guide fin (24) is formed on an inner surface (26) of each said side walls (18) of said housing (10) for directing said condensed water from said top portion (14).

3. The fuel cell housing (10) as claimed in claim 2, wherein said at least one guide fin (24) adapted to collect said condensed water from said top portion (14) and guides said collected condensed water towards said bottom portion (16) of said housing (10).

4. The fuel cell housing (10) as claimed in claim 1, wherein said housing (10) comprises at least one drain port (28) made on said bottom portion (16) of said housing (10), such that, said condensed water from said at least guide fin (24) is made to flow out of said housing (10).

5. The fuel cell housing (10) as claimed in claim 4, wherein a drain valve (30) positioned in proximity to said at least one drain port (28) , for collecting said drained water coming from said at least one drain port (28) .

6. The fuel cell housing (10) as claimed in claim 1, wherein an inner surface (26) of each of said side wall (18) is coated with an anti-corrosive material for smooth flow of said condensed water from said top portion (14) to said bottom portion (16) of said housing (10).

7. The fuel cell housing (10) as claimed in claim 6, wherein said anti-corrosive material is a hydrophobic material.

8. The fuel cell housing (10) as claimed in claim 1, wherein said top portion (14) is made as an external component of said housing (10), attached onto said side walls (18).

9. The fuel cell housing (10) as claimed in claim 1, wherein said drain valve (30) is made integrated in said housing (10) for collecting said condensed water flowing from said top portion (14) to said drain valve (30) via said at least one guide fin (24) and said at least one drain port (28).

10. The fuel cell housing (10) as claimed in claim 1, wherein said at least one drain port (28) and said drain valve (30) together forms said drainage unit (11).