PLATE DEVICE FOR A FUEL STACK AND FUEL CELL DEVICE COMPRISING THE SAME

Abstract

The present invention relates to a plate device (10) for an electrochemical fuel cell stack having stacked cells and a corresponding fuel cell device. The plate device is provided per each cell (20) for distributing and collecting a fluid across planar dimensions of a cell (20). A transition section (11) of the plate device (10) forms a flat shaped flow cross-section for a fluid to be transferred in a planar direction of the plate device (10) in fluid communication between a port (30, 31, 32, 33) and the cell (20), wherein a plurality of flow features (14) is disposed within the transition section (11) and the transition section (11) is enclosed by a boundary (17). According to the invention, the plate device (10) has at least one support feature (15, 16) that is integrally formed with the boundary (17) and with at least one of outermost arranged flow features (14) out of the plurality of flow features (14) for strutting the flat flow cross-section in a thickness direction of the plate device (10).

Claims

1. A plate device (10) for an electrochemical fuel cell (20) stack having stacked cells (20); wherein the plate device (10) being provided per each cell (20) for distributing and collecting a fluid across planar dimensions of a cell (20); wherein the plate device (10) comprises: a central cell section (12) encompassing a plurality of channels across planar dimensions of a cell (20); an outer port section (13) enclosing a cross-section opening of a fluid port (30, 31, 32, 33) passing through the plate device (10) in a thickness direction; and a transition section (11) forming a flat shaped flow cross-section for distributing or collecting a fluid to be transferred in a planar direction of the plate device (10) in fluid communication between the fluid port (30, 31, 32, 33) and the cell (20), wherein a plurality of flow features (14) is disposed within the transition section (11) and the transition section (11) is enclosed by a boundary (17), wherein the plate device (10) having at least one support feature (15, 16) being integrally formed with the boundary (17) and with at least one of outermost arranged flow features (14) out of the plurality of flow features (14) for strutting the flat flow cross-section in a thickness direction of the plate device (10).

2. The plate device (10) according to claim 1, wherein one kind of the support features (15) and the boundary (17) integrally form together a zig-zag contour extending into the transition section (11).

3. The plate device (10) according to claim 2, wherein a transition section (11) for an oxidant gas based operating fluid, or for a fuel gas based operating fluid has the kind of the support features (15) integrally forming with the boundary (17) a zig-zag contour.

4. The plate device (10) according to claim 1, wherein vias (18) are arranged between a fluid port (30, 31, 32, 33) and the transition section (11) for providing a fluid communication in between; and wherein another kind of the support features (16) and parts of the boundary (17) positioned between the vias (18) integrally form together protrusions of channeling walls extending into the transition section (11).

5. The plate device (10) according to claim 4, wherein a transition section (11) for a coolant fluid has the kind of the support features (16) integrally forming with the boundary (17) protrusions of channeling walls.

6. The plate device (10) according to claim 1, wherein at least a part of the plurality of flow features (14) is arranged in an array of equidistantly positioned rows of flow features (14) having the form of circular or prismatic pillars for diffusing a fluid flow.

7. The plate device (10) according to claim 6, wherein at least another part of the plurality of flow features (14) includes flow features (14) having an elongated cross-section for guiding a fluid flow.

8. The plate device (10) according to claim 1, having three fluid ports (31, 32, 33) for three operating fluids including an oxidant gas-based fluid, a fuel gas-based fluid and a coolant fluid; wherein the flow plate comprises a transition section (11) for at least one of the operating fluids, or the flow plate comprises one transition section (11) for each operating fluid.

9. The plate device (10) according to claim 1, having three fluid ports (31, 32, 33) for three operating fluids including an oxidant gas-based fluid, a fuel gas-based fluid and a coolant fluid; wherein the flow plate comprises on one side a transition section (11) for one of the operating fluids and on the other side a transition section (11) for another one of the operating fluids.

10. An electrochemical fuel cell device having a stack arrangement of stacked cells (20), and accommodating fluid ports (30, 31, 32, 33) for operating fluids passing through a stacking direction of the stack arrangement; wherein the fuel cell device comprises between each of the stacked cells (20) at least one plate device (10) according to claim 1 for distributing and collecting an operating fluid between the cells (20) and the fluid ports (30, 31, 32, 33).

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0028] Further objectives, advantages, features and applications of the present invention arise from the following description of the exemplary embodiments with reference to the drawings. In the drawing:

[0029] FIG. 1 shows a schematic representation of an overall configuration and sectioning of a plate device; and

[0030] FIG. 2 shows, in accordance with a certain stack structure of a fuel cell device, fractions of a cross-section of individual transition sections for different operating fluids on a plate device according to embodiments of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

[0031] FIG. 1 shows a plate device 10 in the perspective of a cross-section of a stack arrangement in a fuel cell device. In this plane view, the plate device 10 exhibits certain sections marked by dashed lines. A centrally arranged cell section 12 is congruent to a cell 20 not illustrated to be stacked on the plate device 10. The cell section 12 comprises channels (not illustrated) in contact with the cell 20 running parallel and straight between opposite sides of the cell 20. The cell 20 comprises a membrane-electrode assembly (MEA) including all electrochemically active elements of the cells 20 as well as gas diffusion layer on an upper and lower side for distributing fluids to the membrane. The fuel cell device comprises fluid ports 30 passing through the fuel cell stack in a stacking direction, as depicted by respective fluid port cross-sections arranged in two outer arranged port section 13 of the plate device 10 on opposite sides of the cell 20.

[0032] Between the cell section 12 and each of the two the port sections 13, the plate device 10 comprises transition sections 11. The transition sections 11 serve for distributing a fluid supplied by the fluid port 30 depicted on the left-hand side across the depicted width dimension of the cell 20 and for collecting the fluid across the width of the cell 20 for returning the fluid in the fluid port 30 depicted on the right-hand side. On one side, the transition sections 11 are in fluid communication with one of the fluid ports 30 by means of vias (not illustrated in FIG. 1), i.e. small bores or channels branching of fluid from and into the fluid ports 30 at a predefined stacking level and height of the respective plate device 10. On the other side, the transition sections 11 are in in fluid communication with gas diffusion layers of the cell 20 via an open interface area having a flat shaped flow cross-section across the width dimension of the cell 20.

[0033] The advantages of the disclosed invention apply to cells 20 having a type of membrane-electrode assembly of only one gas diffusion layer extending into the transition sections 11 of the plate device 10, as well as to a type of membrane-electrode assembly having two gas diffusion layers, each on one of opposite sides of the plate device 10 extending into the transition sections 11 of same.

[0034] FIG. 2 shows fractions of a specific configuration of different profiles of a plate device 10 for reactants according to embodiments of the invention. The fractions of the plate devices 10 depicted enclose delivering fluid ports, one fluid port 31 for an oxidant, one fluid port for a fuel 32, and one fluid port 33 for a coolant. In line with this, the profile of the plate device 10 on the left-hand side is designed to transfer a fuel gas, i.e. hydrogen, or an reacted exhaust gas thereof. The profile of the plate device 10 on the right-hand side is designed to transfer a coolant circulating around the cell.

[0035] When each fluid exits the supplying fluid port 31, 32, 33, it is contained in roughly a third of the width of the plate device 10, since there are three fluid port cross-sections. The fluid shall spread out to the full width of the plate device 10 as it enters the active area of the cell 20 via channels in the cell section 12 of the plate device 10. This spreading out of flow is promoted by flow features 14 in the transition sections 11 which is delimited by a boundary 17 in the form of a delimiting inner wall.

[0036] All transition sections 11 in the depicted embodiments exhibit a diffusive array of equidistantly arranged flow features 14 having a pillar shape through-out the entire area of transition section 11. Also for supporting a directivity and a broadening or narrowing of a fluid flow, the plate devices 10 might comprise other flow features 14 having an inclined, elongated cross-section for guiding or diverting a fluid flow.

[0037] The transition sections 11 for the fuel supplied via fluid port 32 depicted on the left-hand side, and likewise for a non-depicted transition section 11 for an oxidant supplied via fluid port 31 comprise a kind of the support features 15 that integrally forms together with the boundary 17 of the transition section 11 a zig-zag contour of a delimiting wall in the plate profile. The zig-zag contour also integrally encloses some of the pillar-like flow features 14 in a first row of the array of flow features 14 closest to the boundary 17. Plate material filling a space in imaginary triangles between such enclosed pillar-like flow features 14 and an original line of the boundary 17 as it was meant to be without said support features 15, supports the plate structure by additionally strutting the cavity of the transition section 11 and by reinforcing said enclosed flow features 14 against biased loads or distortion. As a result, the support features 15 strengthen the plate profile in the boundary 17 region of the cavity of the transition section 11.

[0038] As a side effect, due to the characteristic zig, zag shape and predetermined alignment of the direction of the exposed surfaces of the support features 15, a positive flow influence is effected by diverting a peripheral fluid flow from the boundary 17 into a direction of the cell 20.

[0039] On the right-hand side of FIG. 2, the transition section 11 for the coolant comprises another kind of support features 16 formed as a protrusion of walls extending from the boundary 17 into the space of the transition section 11 while separating a channeling of vias 18 connecting the fluid port 33 to the transition section 11. This kind of support features 16 are integrally formed together with the boundary 17 and some of the pillar-like flow features 14 of the array of flow features 14 being closest between said vias 18. Also with this kind of support features 16, plate material filling a space in an imaginary longitudinal area between said pillar-like flow features 14 and an original line of the boundary 17 as it was meant to be without said support features 16, supports the plate structure by additionally strutting the cavity of the transition section 11 and by reinforcing said enclosed flow features 14 against biased loads or distortion. Hence, these support features 16 likewise strengthen the plate profile in the boundary 17 region of the cavity of the transition section 11.

[0040] By choosing an appropriate alignment in parallel with the vias or with respect to an arrangement of other flow features 14 having an elongated cross-section, this kind of support features 16 contributes to guide and divert an initial fluid flow in a desired directivity for achieving an even flow distribution through-out a width of the cell 20.

REFERENCES

[0041] 10 plate device [0042] 11 transition section [0043] 12 cell section [0044] 13 port section [0045] 14 flow features [0046] 15 support features (zig-zag form) [0047] 16 support features (wall-protrusion form) [0048] 17 boundary [0049] 18 vias [0050] 20 cell [0051] 30 fluid port [0052] 31 oxidant port [0053] 32 fuel port [0054] 33 coolant port