Electrochemical system and plate assembly for an electrochemical system

Abstract

A plate assembly (1) for an electrochemical system (10), in particular an electrolysis cell system, comprises a plurality of plates (2, 3, 4, 5, 6) having mutually aligned openings (9) into which a multi-part connecting clip (8) holding the plates (2, 3, 4, 5, 6) together is inserted.

Description

[0001] Electrochemical system and plate arrangement for an electrochemical system

[0002] The invention relates to an electrochemical system, for example in the form of an electrolysis cell system, and a plate arrangement for such a system.

[0003] DE 10 2017 108 413 A1 discloses a polymer electrolyte membrane electrolysis device comprising a cell stack with a plurality of functional cell stack elements. According to the teaching of DE 10 2017 108 413 A1, the various cell stack elements are essentially loosely placed on top of one another and then pressed together. The completed cell stack is held together by tie rods, which in this case are referred to as struts. Forces between the end plates of the cell stack are transmitted via the struts and arrangements of disc springs. Overall, the electrolysis device according to DE 10 2017 108 413 A1 is characterized by simple maintenance and repair options.

[0004] Another electrolyzer for hydrogen production is described in DE 10 2022 110 122 A1. In this case as well, an electrolysis stack, including two end plates, is held together by tie rods. The bipolar plates of the electrolysis stack are each composed of two half-sheets, between which channels for a coolant are formed. The coolant circuit of the electrolyzer according to DE 10 2022 110 122 A1 is separate from the process water, which is used for electrolysis, i.e., the production of hydrogen from water.

[0005] DE 10 2022 110 126 A1 relates to an electrochemical cell and a method for manufacturing a component of an electrochemical cell. The component of the electrochemical cell, in particular an electrolysis cell, comprises an open-porous sintered body which, among other things, defines a channel with a defined geometry for guiding a fluid. The guidance of fluids is also addressed in DE 10 2023 109 185 A1, which relates to a cell stack of an electrochemical system, in particular an electrolysis cell system. According to DE 10 2023 109 185 A1, several groups of protrusions are formed by bipolar plates of the cell stack, which function as support structures and simultaneously as flow-guiding structures.

[0006] A plate arrangement for an electrochemical cell, in particular a fuel cell, disclosed in DE 10 2022 112 175 B3, comprises a grid designed as expanded metal, intended for sandwich-like arrangement between a first plate and a second plate parallel to it. The grid comprises a plurality of nodes and webs which absorb forces within a cell stack, conduct electrical currents and simultaneously influence the flow of media flowing between plates of the cell stack.

[0007] DE 40 28 212 A1 discloses, without reference to electrochemical systems, a nut-plate connection. In this connection, a nut is inserted into an opening in a plate, acting as a blind fastener. By axially shortening the nut on the blind side, it is partially expanded radially and thus clamped to the plate. AIMgSiPb-6012 and AICuMgPb are mentioned as possible materials for the nut that can be fastened to the plate.

[0008] The invention is based on the objective of further developing plate arrangements for electrochemical systems, in particular electrochemical cell stacks, compared to the prior art, especially from an assembly technology perspective.

[0009] This problem is solved according to the invention by a plate arrangement with the features of claim 1. According to claim 6, the plate arrangement can be part of an electrochemical system. The plate arrangement according to the application comprises several plates which have aligned openings into which a multi-part connecting clip holding the plates together is inserted.

[0010] In this context, the term "plates" does not exclusively refer to solid or semi-rigid plate-shaped elements. Rather, individual plates, which are held together by the connecting clip, can also be flexible elements, i.e., films, as long as they are not yet integrated into the plate stack. Porous transport layers, which have a function within an electrochemical cell to be manufactured, can also be considered part of the plate arrangement according to the application.

[0011] The connecting clip, which holds the plates of the arrangement according to the application together, is constructed in two parts in numerous embodiments. Particularly in cases where higher forces need to be absorbed and / or particularly high geometric precision is required, a three-part construction of the connecting clip is also conceivable. In such a case, two sleeve-shaped parts of the clip can exist, which are first fitted together. Subsequently, a third, pin- or needle-shaped part can be inserted into the already joined sleeve-shaped parts to improve their cohesion, in particular to secure an already established snap connection between the two sleeve-shaped parts against unintentional loosening.

[0012] In the case of a two-part connecting clip, it consists of an inner and an outer part. These two clip parts, like those of a three- or more-part connecting clip, hold together, for example, five to ten flat components, which are generally referred to as plates. The connecting clip provides pre-tensioning with a force of, for example, 50 N to 150 N per clip. During assembly of the plate arrangement, the clip parts—that is, the inner and outer parts—snap together, for example, by the locking protrusions of the outer part engaging in the locking recesses of the inner part. To promote elastic deformation of a clip part, it can, for example, have several sleeve segments separated from each other by slots.

[0013] The individual components of the connecting clip are primarily made of plastic. Both plastic injection molding and additive manufacturing processes, i.e., 3D printing, are suitable for producing the plastic clip parts. In both cases, the plastic clip parts can be fiber-reinforced, for example, with glass fiber or carbon fiber-reinforced plastic components. The fibers can be in the form of short fiber segments, which are distributed within the plastic in a geometrically undefined or only partially defined manner, or as longer fibers, so-called continuous fibers.

[0014] The electrochemical system according to claim 6 comprises at least one single plate arrangement according to claim 1. In particular, such a stacked electrochemical system comprises a plurality of such plate arrangements.

[0015] The electrochemical system is, for example, a fuel cell system, in particular a polymer electrolyte fuel cell stack, an electrolysis cell system, in particular a polymer electrolyte electrolyzer for water electrolysis, or a redox flow cell system, i.e. a flow battery.

[0016] If the connecting clip, particularly in a two-part design, is hollow, the openings in the plate assembly, which are only partially closed by each connecting clip, can be used, for example, to convey media or to accommodate mechanically active components such as tie rods. This assumes that the openings of several stacked plate assemblies are aligned. In the case of media conveyance through the openings, this means that media, namely cooling or operating fluids, are guided in the stacking direction of the cell stack. The connecting clips can, in principle, be distributed across the plate assembly in any desired pattern.In particular, a pattern can be formed in which individual connecting clips are placed approximately uniformly around the perimeter of the plate arrangement, the plate arrangement having, for example, a square, rectangular, trapezoidal, hexagonal, or octagonal footprint. The connecting clips are located, in particular, in the area of ​​media feedthroughs, whereby the corresponding media do not necessarily have to be routed through the clips.

[0017] Holding the individual plates of the plate assembly together with the connecting clips is particularly important during the assembly of the individual electrochemical cells as well as the entire cell stack. During assembly, the position of the flat and other cell components can change in various ways. For example, parts are rotated, shifted, or turned. Stresses from vibrations can also occur. This applies both to arrangements of flat components that still need to be inserted into a frame and to groups of components that already enclose a frame.

[0018] In all these cases, the connecting clips make a significant contribution to the reliable handling of the panel assembly. This also applies to tests, such as electrical and leak tests, which must be carried out during production.

[0019] After completion of the electrochemical system, for example, an electrolysis cell system, the connecting clips, which are electrically insulating components, are integrated into the stack of electrochemical cells in a space-saving manner and, as already mentioned, can also perform additional functions as components of mechanical or fluid power systems. If the connecting clips compress seals that are either integrated into the plate assembly or subjected to force by it, the compression effect can be dimensioned such that a deformation reserve is maintained in the seals. The entirety of the connecting clips installed in the cell stack can be designed to absorb compressive forces in the stacking direction and / or shear forces.The possibility of disassembling the connecting clips and subsequently dismantling the entire plate assembly exists in numerous applications.

[0020] An embodiment of the invention is explained in more detail below with reference to a drawing. The drawing shows:

[0021] Fig. 1 shows an electrochemical system, namely an electrolysis cell system comprising several identical plate arrangements, in a sectional perspective view.

[0022] Fig. 2 shows a single plate arrangement of the electrochemical system according to Fig. 1 including a connecting clip,

[0023] Fig. 3 shows the arrangement according to Fig. 2 in perspective view,

[0024] Fig. 4 shows a top view of a plate of the electrochemical system according to Fig. 1.

[0025] Fig. 5 shows the connecting clip and, in part, several plates of the arrangement according to Fig. 2.

[0026] A plurality of identical plate arrangements 1 are used in an electrochemical system 10, namely an electrolysis cell system for the production of hydrogen. The plate arrangement 1 comprises a first plate 2 and a second plate 3 as outer plates. Between the two outer plates 2, 3 are two inner plates 4, 5. An intermediate element inserted between the inner plates 4, 5 is designated 6. The intermediate element 6 and the plates 2, 3, 4, 5 are held together by a connecting clip 8, the design of which will be described in more detail later. Another plate 7 adjoins the first plate 2 but is located outside the plate assembly 2, 3, 4, 5, 6, which is held together by the connecting clip 8.

[0027] As shown in Fig. 4, the plate arrangement 1 has a square base shape with rounded corners in the exemplary embodiment. The electrochemical system 10 is stacked. Means for supplying and removing operating and cooling media located outside the stack are not shown. Each connecting clip 8 forms a circular opening 9. The openings 9 can be used, for example, for the passage of tie rods and, as shown in Fig. 4, are distributed approximately uniformly around the circumference of the plate arrangement 1. Furthermore, coolant inlets 21, coolant outlets 22, anode-side inlets 23, anode-side outlets 24, and cathode-side outlets 25 are visible in Fig. 4.

[0028] Each connecting clip 8 consists of an inner clip part 11 and an outer clip part 12. In the exemplary embodiment, a flange 13 of the outer clip part 12 rests on the first plate 2. In the arrangement according to Fig. 1, the first plate 2 is located at the bottom of the plate arrangement 1, while in the arrangements according to Figures 2, 3, and 5, it is located on the upper side of the plate arrangement 1. The different orientations of the plate arrangement 1 according to Figures 1 to 5 do not indicate the actual spatial arrangement of the components of the electrochemical system 10. In particular, it is possible to orient the plate-shaped elements 2, 3, 4, 5, 6 vertically.

[0029] The previously mentioned flange 13 of the clip outer part 12 connects to a sleeve-shaped section 14 of the clip outer part 12. In the exemplary embodiment, the outer circumferential surface of the sleeve-shaped section 14 is completely cylindrical. In contrast, several locking projections 15 are formed on the inner circumferential surface of the sleeve-shaped section 14, which interact with the clip inner part 11. Specifically, the locking projections 15 each engage in a locking recess 17, which is formed in a sleeve segment 16 of the clip inner part 11. The clip inner part 11 has several sleeve segments 16, between each of which a slot 18 is formed.

[0030] A flange of the inner clip part 11, connected to all sleeve segments 16, is designated 19. In addition to the slots 18, recesses 20 adjoining the flange 19 represent targeted weakening of the sleeve segment 16. The assembly of the clip parts 11, 12, as well as the separation of the inner clip part 11 from the outer clip part 12, is possible without damage.

[0031] The loose width of the connecting clip 8, measured between the top of the first plate 2 and the bottom of the second plate 3, is specified as D8. D2 indicates the overall height of the plate assembly 1, including the connecting clip 8, measured in the same direction. As can be clearly seen in Fig. 1, the connecting clips 8 can be integrated into the electrochemical system 10 without requiring significant space. The mechanical function of the connecting clips 8 is particularly useful during the assembly of the plate assembly 1 and the entire electrochemical system 10. Both clip parts 11 and 12 are made of plastic, so that the connecting clip 8 does not create an electrically conductive connection between the plates 2 and 3.

[0032] List of reference signs

[0033] 1. Plate arrangement

[0034] 2 first record

[0035] 3 second record

[0036] 4 internal plates

[0037] 5 internal plate

[0038] 6 Intermediate element

[0039] 7 more records

[0040] 8 connecting clips

[0041] 9 Opening

[0042] 10 electrochemical system

[0043] 11 Clip inner part

[0044] 12 Clip outer part

[0045] 13 Flange of the clip outer part

[0046] 14. Sleeve-shaped section of the clip outer part

[0047] 15 Rastvorsprung

[0048] 16 Sleeve segment of the clip inner part

[0049] 17 Rest recess

[0050] 18 Slot between two sleeve segments

[0051] 19 Flange of the clip inner part

[0052] 20 Recess, adjoining flange 19

[0053] 21 Coolant inlet

[0054] 22 Coolant outlet

[0055] 23 Inlet, anode side

[0056] 24 Outlet, anode side

[0057] 25 Outlet, cathode side

[0058] D2 Total height

[0059] D8 width

Claims

Patent claims 1. Plate arrangement (1 ) for an electrochemical system (10), comprising several plates (2, 3, 4, 5, 6) which have aligned openings (9) into which a multi-part connecting clip (8) holding the plates (2, 3, 4, 5, 6) together is inserted.

2. Plate arrangement (1 ) according to claim 1 , characterized in that the connecting clip (8) is formed by two clip parts (11 , 12), namely a clip inner part (11 ) and a clip outer part (12).

3. Plate arrangement (1 ) according to claim 2, characterized in that at least one of the clip parts (11 , 12) has several sleeve segments (16) separated from each other by slots (18).

4. Plate arrangement (1 ) according to claim 2 or 3, characterized in that locking projections (15) are located on the outer part (12) of the clip which engage in locking recesses (17) of the inner part (11 ).

5. Plate arrangement (1 ) according to one of claims 1 to 4, characterized in that the connecting clip (8) is made of plastic.

6. Electrochemical system (10) comprising a plate arrangement (1) according to claim 1.

7. Electrochemical system (10) according to claim 6, characterized in that it is designed as a fuel cell system.

8. Electrochemical system (10) according to claim 6, characterized in that it is designed as an electrolysis cell system.

9. Electrochemical system (10) according to claim 6, characterized in that it is designed as a redox flow cell system.

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