COMPONENT FOR A REDOX FLOW CELL AND METHOD FOR PRODUCING A COMPONENT FOR A REDOX FLOW CELL

Abstract

The invention relates to a component for a redox flow cell, with an electrode frame (1, 11), an electrode (4, 14), a membrane (2) and a bipolar plate (3), wherein the electrode (4, 14) is arranged in the electrode frame (1, 11) and is enclosed circumferentially by the latter, and the electrode frame (1, 11) is arranged between membrane (2) and bipolar plate (3). It is essential that the electrode frame (1, 11) is connected to at least the membrane (2) in an integrally bonded manner by adhesive bonding. The invention furthermore relates to methods for producing a component for a redox flow cell.

Claims

1. A component for a redox flow cell, comprising an electrode frame (1, 11), an electrode (4, 14), a membrane (2) and a bipolar plate (3), the electrode (4, 14) is arranged in the electrode frame (1, 11) and is circumferentially enclosed by said electrode frame, and the electrode frame (1, 11) is arranged between membrane (2) and the bipolar plate (3), and the electrode frame (1, 11) is cohesively connected by a cohesive connection to at least the membrane (2) by adhesive bonding.

2. The component as claimed in claim 1, wherein the electrode frame (1) is additionally cohesively connected by the cohesive connection to the bipolar plate (3).

3. The component as claimed in claim 2, wherein the cohesive connection between at least one of the electrode frame (1, 11) or the bipolar plate (3) is formed by an adhesive film.

4. The component as claimed in claim 1, wherein a liquid-tight seal is formed between the electrode frame (1, 11) and the membrane (2), at least apart from one or more channels for at least one of supplying or discharging a liquid electrolyte to/from the electrode (4, 14), by the cohesive connection.

5. The component as claimed at least in claim 2, wherein a liquid-tight seal is formed between the electrode frame (1) and the bipolar plate (3), at least apart from one or more channels for at least one of supplying or discharging a liquid electrolyte to/from the electrode (4, 14), by the cohesive connection.

6. The component as claimed in claim 1, wherein the membrane (2) overlaps the electrode frame (1, 11) in an encircling manner or the membrane overlaps the frame in a direction of a length and in a direction of a width by less than 15%, with respect to the length and, respectively, the width of the frame.

7. A fully integrated individual cell comprising a component as claimed in claim 1 with the electrode frame (1) acting as a first electrode frame, the electrode (4) acting as a first electrode, the bipolar plate (3) acting as a first bipolar plate (3), the membrane (2), at least one second electrode frame (11) and one second electrode (14), the individual cell has a layer structure with indirectly or directly arranged elements having an order of the first bipolar plate, the first electrode frame (1) with the first electrode (4), the membrane (2), the second electrode frame (11) with the second electrode (14), and the cohesive connection is at least between the first bipolar plate and the first electrode frame (1), between the first electrode frame (1) and the membrane (2) and also between the membrane (2) and the second electrode frame (11).

8. The fully integrated individual cell as claimed in claim 7, wherein the electrode frame (1, 11) has channels for feeding and draining a liquid electrolyte to/from the electrode (4, 14).

9. A cell combination for a redox flow battery, comprising a plurality of fully integrated individual cells, which are arranged one above the other, as claimed in claim 8, the fully integrated individual cells are arranged one above the other and cohesively connected.

10. A method for producing a component for a redox flow cell, comprising arranging an electrode frame with an electrode (4, 14) between a membrane (2) and a bipolar plate (3), and cohesively connecting the electrode frame (1, 11) at least to the membrane (2) by adhesive bonding.

11. The method as claimed in claim 10, further comprising cohesively connecting electrode frame (1) to the bipolar plate (3).

12. The method as claimed in claim 10, further comprising forming a fully integrated individual cell by at least the bipolar plate (3) acting as a first bipolar plate being cohesively connected to the electrode frame (1) as first electrode frame, the first electrode frame being cohesively connected to the membrane (2) acting as a first membrane, and the membrane (2) being cohesively connected to a second electrode frame (11).

13. The method as claimed in claim 12, further comprising forming the integrated cell combination comprising the plurality of fully integrated individual cells by first forming the plurality of the fully integrated the individual cells and, in a subsequent method step, connecting a stack of individual cells to the bipolar plate (23) of an individual one of the cells adjacent in the combination by cohesive connection of the second electrode frame of an adjacent one of the individual cells, and, in a common method step, cohesively connecting the individual cells to one another.

14. The method as claimed in claim 12, further comprising forming the integrated cell combination by first forming the plurality of the fully integrated individual cells, said fully integrated individual cells being formed with a second bipolar plate, cohesively connecting said second bipolar plate, on that side which is averted from the membrane to the second electrode frame, and forming a plurality of intermediate elements which each comprise a first electrode frame with a first electrode, a membrane and a second electrode frame with a second electrode, and alternatively arranging one of the fully integrated individual cells and one of the intermediate elements in the integrated cell combination, with the first and last elements of the cell combination each being one of the fully integrated individual cells.

15. The method as claimed in claim 14, wherein at least the elements of the first electrode frame, the membrane and the second electrode frame of the intermediate element are cohesively connected to one another before the integrated cell combination is formed.

16. The component as claimed in claim 1, wherein the electrode frame is connected to the bipolar plate by adhesive bonding.

17. The component as claimed in claim 4, wherein the cohesive connection is an encircling liquid-tight cohesive connection that is formed between electrode frame (1, 11) and membrane (2).

18. The component as claimed in claim 5, wherein the cohesive connection is an encircling liquid-tight cohesive connection is formed between electrode frame (1) and bipolar plate (3).

19. The fully integrated individual cell of claim 7, further comprising a second bipolar plate, and a layer structure with indirectly or directly arranged elements having an order of the first bipolar plate, the first electrode frame (1) with the first electrode (4), the membrane (2), the second electrode frame (11) with the second electrode (14), the second bipolar plate, and the second bipolar plate is cohesively connected to the second electrode frame.

20. The fully integrated individual cell as claimed in claim 8, wherein the channels are formed as lines in the electrode frame (1, 11).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Further preferred features and embodiments are described below with reference to exemplary embodiments and the figures, in which:

[0051] FIG. 1 shows a first exemplary embodiment of two components for a redox flow cell with a common membrane, wherein the electrodes are not illustrated;

[0052] FIG. 2 shows the exemplary embodiment according to FIG. 1 with electrodes illustrated;

[0053] FIG. 3 shows a sectional illustration according to section line A in FIG. 1;

[0054] FIG. 4 shows a sectional illustration according to section line B in FIG. 1; and

[0055] FIG. 5 shows a sectional illustration according to section line C in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] All of the figures show schematic illustrations. In FIGS. 1 to 5, identical reference symbols denote identical or identically acting elements.

[0057] FIGS. 1 and 2 show exploded illustrations in a perspective view in order to be able to better illustrate the arrangement and configuration of the individual layers.

[0058] FIG. 1 shows an exploded illustration of an exemplary embodiment of a component according to the invention for a redox flow cell. This component comprises an electrode frame 1, a membrane 2 and a bipolar plate 3. The electrode frame has a cutout in order to accommodate an electrode. This is shown in FIG. 2 by the electrode 4 which is in the form of a felt electrode.

[0059] The electrode 4 is therefore circumferentially enclosed by the electrode frame 1. Furthermore, the electrode frame 1 is arranged between membrane 2 and bipolar plate 3.

[0060] The electrode frame 1 is connected to the bipolar plate 3 in an interlocking manner by an adhesive film 5. This also provides a liquid-tight connection between electrode frame 1 and bipolar plate 3, so that an electrolyte, which is supplied to the electrode 4 by lines (not illustrated) which are formed in the electrode frame 1 during use, therefore cannot escape between electrode frame 1 and bipolar plate 3. The adhesive film 5 therefore performs the function of the threaded rods, customary in the prior art, in respect of the arrangement of the bipolar plate 3 on the electrode frame 1 and furthermore the function of the O-ring seal, customary in the prior art, between electrode frame 1 and bipolar plate 3.

[0061] A fully integrated individual cell is furthermore formed with the component according to FIG. 1 by a second electrode frame 11 and a second electrode 14 additionally being provided:

[0062] The fully integrated individual cell therefore has the bipolar plate 3 as first bipolar plate, the electrode frame 1 as first electrode frame and the membrane 2 and additionally the second electrode frame 11 with second electrode 14 as illustrated in FIG. 2.

[0063] In addition to the cohesive connection already described above of the first electrode frame 1 to the bipolar plate 3 by the adhesive film 5 as first adhesive film, the second electrode frame 11 is furthermore cohesively connected to the membrane 2 by a second adhesive film 15.

[0064] The membrane 2 only slightly overlaps both the electrode frame 11 and the electrode frame 1, in particular by less than 10% both in the direction of the length (x-direction) with respect to the length of the frame and also in the direction of the width (y-direction) with respect to the width of the frame, as will be explained in greater detail below in relation to FIGS. 3 to 5.

[0065] In this way, the second adhesive film 15 fulfills the function both of cohesively connecting the first electrode frame 1 to the second electrode frame 11 and also of cohesively connecting the membrane 2 to the second electrode frame 11. Overall, the membrane 2 is also fixedly connected to the first electrode frame 1 in this way.

[0066] Furthermore, the second adhesive film 15 acts as a seal between first electrode frame 1, second electrode frame 11 and the membrane 2 mounted therebetween.

[0067] In one exemplary embodiment of a method according to the invention, a plurality of the above-described fully integrated individual cells are first formed (for example 10 pieces). The fully integrated individual cells are then arranged one above the other, in each case with the interposition of a further adhesive film:

[0068] FIGS. 1 and 2 each illustrate a further bipolar plate 23 which is associated with an adjacent, further fully integrated individual cell (not completely illustrated) or is applied as an end plate. A third adhesive film 25 for cohesively connecting the second electrode frame 11 to the further bipolar plate 23 of the further individual cell is arranged between the further bipolar plate 23 and the second electrode frame 11 of the upper fully integrated individual cell.

[0069] In this way, a stack of individual cells which are arranged one above the other can be formed in a cost-effective manner in order to form a redox flow battery. The mechanical stability is ensured here by the adhesive films (5, 15, 25). In addition, in a further preferred embodiment, bores can be provided, for example, in the corner regions of the bipolar plates and electrode frames, it being possible for threaded rods to be passed through said bores in order to additionally press the above-described elements against one another. Two bores 7a and 7b for receiving threaded rods of this kind are identified by way of example in FIG. 1.

[0070] In an alternative exemplary embodiment, the third adhesive film (25) is replaced by a flat seal (not illustrated) (the use of a seal which is in the form of an O-ring likewise lies within the scope of the invention), and the second electrode frame (11) has a corresponding guide receptacle for spatially fixing this O-ring seal. Therefore, in this case, only elements of the fully integrated individual cell are cohesively connected to one another by the first adhesive film (5) and the second adhesive film (15). The fully integrated individual cells in the stack structure are, however, pressed against one another by the abovementioned threaded rods, wherein the respectively interposed O-ring seals provide the corresponding sealing action in relation to the liquid electrolyte, used during use, between the second electrode frame (11) of one fully integrated individual cell and the bipolar plate (23) of the adjacent fully integrated individual cell.

[0071] As described above, FIG. 2 illustrates the exploded illustration according to FIG. 1 with first electrode (4), which is arranged in the first electrode frame (1), and second electrode (14), which is arranged in the second electrode frame (11).

[0072] FIG. 3 shows a section along section line (A) in FIG. 1. The section plane here is perpendicular to the first bipolar plate (3) and therefore also perpendicular to the elements, which lie parallel to the first bipolar plate (3), first adhesive film (5), first electrode frame (1), membrane (2), second adhesive film (15), second electrode frame (11), third adhesive film (15) and further bipolar plate (23).

[0073] FIGS. 3 to 5 likewise show the view of the individual elements in a manner spaced apart from one another according to an exploded illustration for the purpose of better clarity. The individual elements actually lie directly one on the other.

[0074] As shown in FIG. 3, the membrane 2 has a distance X on both sides in relation to the outer edges of the other elements. Therefore, in particular, the second adhesive film 15 and also the two electrode frames 1 and 11 overlap the membrane 2. As a result, the membrane 2 is therefore cohesively connected to the second electrode frame 11 by the second adhesive film 15 on one side. However, similarly, the second electrode frame 11 is cohesively connected to the first electrode frame 1 at least in edge regions by the second adhesive film 15.

[0075] FIG. 4 shows a section according to the section line B illustrated in FIG. 1, wherein the section plane is perpendicular to the bipolar plate 3 in this case too.

[0076] This sectional illustration shows that, in the regions in which the electrode frames 1 and 11 have a cutout for receiving the electrodes, the membrane also circumferentially overlaps the electrode frames by a distance Y.

[0077] Therefore, owing to the overlap by the length Y, the membrane 2 can be cohesively connected to the electrode frame 11 by the second adhesive film 15 in a simple manner.

[0078] Furthermore, the distance X between the outer edge of the membrane 2 and the outer edge, in particular of the electrode frames (1, 11), firstly allows the use only of an adhesive film for cohesively connecting the two electrode frames and the membrane to the second electrode frame 11, as described above. Furthermore, this results in a saving in material for the membrane 2 compared to the design of a membrane of full size, for example of the size of the bipolar plate (3).

[0079] Sinceas mentioned in the introductory partthe material costs of the membrane 2 make up a considerable proportion of the total costs of a redox flow cell, a significant cost saving can be achieved in this way.

[0080] FIG. 5 shows a sectional illustration according to section line C in FIG. 2. The sectional plane is perpendicular to the bipolar plate 3 in this case too. The sectional illustration according to FIG. 5 is therefore comparable to the sectional illustration according to FIG. 4, but with the electrodes (4, 14) which are arranged in the electrode frames (1, 11) being illustrated. This figure shows that the adhesive films (5, 15 and 25) do not overlap the electrodes 4 and 14. The adhesive films therefore have the same cutout which the electrode frames also have for receiving the electrodes. Therefore, adhesive bonding of the electrodes is avoided in this way.

[0081] As shown, in particular, in FIGS. 1 and 2, the adhesive films (5, 15 and 25) form encircling, uninterrupted seals between the respectively adjacent elements and therefore act like separate O-ring seals from the prior art already known.

[0082] In particular, the bores 7a and 7b for receiving threaded rods do not completely penetrate the edge regions of the adhesive films, and therefore an encircling sealing action is ensured.