Optimized arrangement of fluidic channels of interconnectors for electrochemical device

Abstract

High-temperature electrolyzer comprising four corrugated interconnectors arranged to improve electrolyzer operation. Figure for the abstract: Fig. 6

Description

Title of the invention: Optimized arrangement of fluidic channels of interconnectors for an electrochemical device technical field

[0001] The present invention relates to the field of electrochemical devices and finds applications in particular in the sectors of renewable energy production, especially dihydrogen.

[0002] The invention is of particular, but not limiting, interest in solid oxide electrochemical devices, especially high-temperature electrolyzers. Prior art

[0003] Electrochemical devices known in the prior art generally include stacks of electrochemical cells which are connected together by interconnecting elements, also called "interconnectors".

[0004] In a high-temperature electrolyzer, the interconnectors have the function, in particular, of conveying in gaseous form fluids which are produced by the device.

[0005] There is a need to optimize the operation of such electrochemical devices, particularly in terms of electrochemical efficiency and / or mechanical resistance.

[0006] There is also a need to simplify the manufacture of such electrochemical devices. Description of the invention

[0007] The invention relates to an assembly for an electrochemical device, in particular for a high-temperature electrolyzer or high-temperature fuel cell, the assembly comprising an electrochemical cell, a first interconnector, and a second interconnector. The first and second interconnectors each comprise a surface forming an alternation of concave and convex portions. The first interconnector forms first channels, each delimited by one of the concave portions of the surface of the first interconnector, and arranged opposite one side of the electrochemical cell. The second interconnector forms second channels, each delimited by one of the concave portions of the surface of the second interconnector, and arranged opposite one side of the electrochemical cell.

[0008] According to a first embodiment, the first channels and / or the second channels each define a straight flow path.

[0009] According to a second embodiment, the first channels and / or the second channels each define a non-rectilinear flow path.

[0010] Within the framework of the invention, a non-rectilinear flow path can typically, but not exclusively, be a zig-zag or serpentine path.

[0011] For example, the flow path can be a curvilinear path.

[0012] A non-rectilinear flow path makes it possible to increase the length of the corresponding channel and to optimize the electrochemical efficiency and the mechanical resistance of the assembly.

[0013] Of course, the aforementioned variants can be combined, the whole being able in particular to include one or more first and / or second straight channels and one or more first and / or second non-straight channels.

[0014] In one embodiment, the first interconnector and the second interconnector are arranged relative to each other such that the convex parts of said surface of the first interconnector are respectively aligned with the convex parts of said surface of the second interconnector.

[0015] In other words, the first interconnector and the second interconnector of the assembly can be arranged head-to-tail.

[0016] Such an arrangement makes it possible to eliminate or reduce shear stresses on the cell of the assembly and, more generally, to improve the mechanical strength of the assembly.

[0017] Such an arrangement of interconnectors can be implemented with straight or non-straight channels, in particular within the framework of the first variant or the second variant described above.

[0018] In an alternative embodiment, the first interconnector and the second interconnector are arranged relative to each other such that the convex parts of said surface of the first interconnector are respectively aligned with the concave parts of said surface of the second interconnector.

[0019] This embodiment can, but not limited to, be implemented within the framework of the second variant mentioned above, in which one or more of said first channels and / or one or more of said second channels each define a non-rectilinear flow path, in particular a zig-zag or serpentine path.

[0020] In these different embodiments and variants, the first channels may be parallel to each other.

[0021] Similarly, the second channels can be parallel to each other.

[0022] In one embodiment, one or more of said first channels are parallel to one or more of said second channels.

[0023] In an embodiment in which the first and second channels each define a non-rectilinear flow path, in particular a zig zag or serpentine, one or more of said first channels are offset from one or more of said second channels along said flow path, so that first portions of the convex parts of said surface of the first interconnector are respectively aligned with portions of the convex parts of said surface of the second interconnector and that second portions of the convex parts of said surface of the first interconnector are respectively aligned with portions of the concave parts of said surface of the second interconnector.

[0024] Such an asymmetrical arrangement makes it possible to optimize the electrochemical efficiency and the mechanical resistance of the assembly.

[0025] Of course, the characteristics described above are not limiting.

[0026] In particular, said surface of the first interconnector may be a first surface of this first interconnector, said surface of the second interconnector may be a second surface of this second interconnector and said electrochemical cell may be a first electrochemical cell.

[0027] In one embodiment, the first interconnector includes a second surface forming second channels and intended to be arranged opposite a second electrochemical cell of the assembly.

[0028] Alternatively or complementarily, the second interconnector may include a first surface forming first channels and intended to be arranged opposite a third electrochemical cell of the assembly.

[0029] The invention also relates to an electrochemical device comprising one or more assemblies such as the assembly defined above.

[0030] In one embodiment, the device is a high-temperature electrolyzer.

[0031] In another embodiment, the device is a high-temperature fuel cell.

[0032] The invention also relates to a method for manufacturing an assembly as defined above.

[0033] The process preferably includes a step of shaping the first interconnector and / or the second interconnector so as to form said concave and convex parts.

[0034] By way of non-limitation, the shaping step can be carried out by hydroforming and / or stamping.

[0035] The invention generally makes it possible to optimize the operation of an electrochemical device while simplifying its manufacture.

[0036] Other advantages and features of the invention will become apparent from the following detailed, non-limiting description. Brief description of the figures

[0037] The following detailed description refers to the attached drawings on which: - [Fig.1] is a schematic view of an electrochemical device comprising stacks of electrochemical cells and interconnectors; - [Fig.2] is a schematic view of part of a stack of an electrochemical device, showing an electrochemical cell sandwiched between two interconnectors, the cell comprising two electrodes and an electrolyte arranged between the electrodes; - [Fig.3] is a schematic view of an interconnector according to the invention, comprising a corrugated part forming straight fluidic channels; - [Fig.4] is a partial schematic cross-sectional view of the corrugated part of the interconnector of [Fig.3]; - [Fig.5] is a schematic cross-sectional view of part of a stack of an electrochemical device according to the invention; - [Fig.6] is a schematic cross-sectional view of part of the stack of [Fig.5] forming an assembly which includes an electrochemical cell and two interconnectors similar to that of [Fig.3]; - [Fig.7] is a schematic view of an interconnector according to the invention, the interconnector forming curvilinear fluidic channels; - [Fig.8] is a schematic cross-sectional view of part of an assembly which includes an electrochemical cell and two interconnectors similar to that of [Fig.7]; - [Fig.9] is a schematic view of two series of fluidic channels formed by two interconnectors of an assembly according to the invention, the channels of the first series being offset from the channels of the second series along the direction of flow; - [Fig. 10] is a schematic view of part of the assembly forming the channels of [Fig. 9], following a cross-section made at a first coordinate of the flow direction; - [Fig.1 1] is a schematic view of part of the assembly forming the channels of [Fig.9], following a section made at a second coordinate of the flow direction.

[0038] Common references are used on the different figures to designate identical or analogous elements. Detailed description of implementation methods

[0039] Figures 1 to 11 include a reference frame defining orthogonal directions D1, D2 and D3.

[0040] An electrochemical device 1 according to the invention is represented in a simplified manner in [Fig.1].

[0041] In this non-limiting example, device 1 is a solid oxide electrolyzer configured to produce dihydrogen by gas phase electrolysis, i.e. a high temperature electrolyzer.

[0042] As an indication, electrolysis can be carried out at a temperature between 700°C and 850°C.

[0043] In the simplified example of [Fig.1], the device 1 comprises two stacks 2, each of which includes electrochemical cells, in this case electrolysis cells, between which interconnectors are interposed.

[0044] In each of the stacks 2, the electrochemical cells and the interconnectors are stacked alternately along the direction D3 which is vertical here.

[0045] [Fig.2] schematically shows part of a stack 2 including an electrochemical cell 3 and two interconnectors 4 which are stacked along the direction D3. The cells and interconnectors of the stacks 2 of the device 1 of [Fig.1] can be configured as described below with reference to [Fig.2].

[0046] In a manner known per se, the cell 3 comprises two electrodes 6 and 7, forming respectively an anode and a cathode, as well as an electrolyte 8 disposed between the electrodes 6 and 7. The cell 3 is configured to dissociate water molecules into dihydrogen and dioxygen by redox reaction. To this end, water vapor 10 is introduced at the cathode 7, which carries out the electrochemical reduction reaction resulting in the production of dihydrogen 11 in gaseous form and superoxide ions 12. A potential difference is imposed between the anode 6 and the cathode 7, creating an electric field that causes the superoxide ions 12 to migrate from the cathode 7 to the anode 6 through the electrolyte 8. At the anode 6, the superoxide ions 12 are oxidized, resulting in the production of dioxygen 13 in gaseous form.

[0047] The interconnector 4 located on the anode 6, i.e., the one situated towards the bottom of [Fig. 2], comprises channels (not shown in [Fig. 2]), called "first channels," which open opposite the anode 6 so as to evacuate the flow of dioxygen 13 thus produced. The interconnector 4 located on the cathode 7, i.e., the one situated towards the top of [Fig. 2], comprises channels (not shown in [Fig. 2]), called "second channels," which open opposite the cathode 7 so as to evacuate the flow of dihydrogen 11 thus produced. In this example, these different channels extend along the DI direction.

[0048] Of course, the interconnector 4 located on the cathode 7 of cell 3 in [Fig. 2] can also include first channels (not shown in [Fig. 2]) which open opposite the anode of another electrochemical cell (not shown to [Fig.2]) of stack 2, in order to evacuate a flow of dioxygen produced by this other cell. Similarly, the interconnector 4 located on the anode 6 of cell 3 of [Fig.2] can also include second channels (not shown in [Fig.2]) which open opposite the cathode of another electrochemical cell (not shown in [Fig.2]) of stack 2, in order to evacuate a flow of dihydrogen produced by this other cell.

[0049] The invention relates more specifically to interconnectors 4 for such a stacking 2.

[0050] A first embodiment of the invention is shown in figures 3 to 6.

[0051] Figures 3 and 4 show an interconnector 4 in the form of a plate or sheet having a first surface 21, which in this example is intended to come into contact with an anode of an electrochemical cell, and a second surface 22, opposite to the surface 21 according to D3, this second surface 22 being in this example intended to come into contact with a cathode of another electrochemical cell.

[0052] In this non-limiting example, the interconnector plate 4 is made of chrome or a chrome alloy.

[0053] The plate forming the interconnector 4 of figures 3 and 4 has been shaped to present a corrugated part 25, that is to say a part comprising an alternation, in this case along the direction D2, of concave and convex parts.

[0054] More specifically, the surfaces 21 and 22 of the interconnector 4 each have an alternation of concave parts 21A / 22A and convex parts 21B / 22B, so that the concave parts 21A of the surface 21 correspond to the convex parts 22B of the surface 22 and, conversely, that the convex parts 21B of the first surface 21 correspond to the concave parts 22A of the second surface 22 (see [Fig.4]).

[0055] In this example, the concave parts 21A / 22A of the first, respectively of the second, surface define hollows along D3 with respect to a part of this first, respectively second, surface which extends around the corrugated part 25 of the interconnector 4.

[0056] With reference to [Fig. 4], the convex portions 21B / 22B of the interconnector 4 respectively form surface elements 21S / 22S, also called "bearing surfaces". Without limitation, the bearing surfaces 21S and 22S are in this example planar and extend parallel to the directions DI and D2.

[0057] Fig. 5 shows part of a stack 2 according to the invention.

[0058] In this non-limiting example, stacking 2 of [Fig. 5] comprises cells electrochemical 3 as described above, interconnectors 4 similar to that in figures 3 and 4, and end plates 40 and 42.

[0059] The configuration of [Fig.5] is an assembled configuration which allows the commissioning of the device 1 formed by such a stack 2.

[0060] In the configuration of [Fig.5], the stack 2 is subjected to a clamping force on its various components which is exerted globally along the direction D3 and which can be exerted on the stack 2 by conventional clamping means (not shown).

[0061] With reference to Figures 4 and 5 and the preceding description, when the components of the stack 2 are assembled according to the configuration illustrated in [Fig. 5], the bearing surfaces 21S of each of the interconnectors 4 bear either on the anode of one of the cells 3 or on the end plate 40, depending on the position of the interconnector in the stack 2 (see [Fig. 5]). Similarly, depending on the position of the interconnector in the stack 2, the bearing surfaces 22S of each of the interconnectors 4 bear either on the cathode of one of the cells 3 or on the end plate 42, in this example via conventional contact grids (not shown).

[0062] In this configuration, the stack 2 forms fluidic channels 60 and 62 which extend along the DI direction, each defining a flow path which, in this non-limiting example, is rectilinear.

[0063] In this example, each of the channels 62 is delimited by one of the respective concave parts 21A of the surface 21 of the interconnectors 4, while each of the channels 60 is delimited by one of the respective concave parts 22A of the surface 22 of the interconnectors 4 (see figures 4 and 5).

[0064] In the example of [Fig. 5], channels 60 and 62 are arranged in a double row. On the one hand, each of the interconnectors 4 forms an alternating arrangement of channels 60 and 62 spaced apart along the direction D2, the interconnectors thus forming first rows of channels, also called "rows," which are spaced apart along the direction D3. On the other hand, the interconnectors 4 form second rows of channels, also called "columns," which are spaced apart along the direction D2, each of the second rows comprising an alternating arrangement of channels 60 and 62 spaced apart along the direction D3.

[0065] In this example and with reference to the preceding description, the channels 62 here correspond to said first channels intended to carry dioxygen, while the channels 60 correspond to said second channels intended to carry dihydrogen.

[0066] The stacking 2 of [Fig.5] thus comprises a stacking according to D3 of several sets El such as that illustrated in isolation in [Fig.6], each of these sets El comprising two interconnectors 4 and a cell 3.

[0067] With reference to Figures 4 and 6, for each of the assemblies El, the interconnectors 4 are arranged head-to-tail on either side of the cell 3, so that the bearing surfaces 22S of the interconnector 4 located towards the top of [Fig. 6] are respectively aligned with the bearing surfaces 21S of the interconnector 4 located towards the bottom of [Fig.6].

[0068] In other words, in each of the sets El, the interconnectors 4 of this set El are offset from each other along the direction D2, so that the channels 60 formed by one of these interconnectors 4 are respectively aligned with the channels 62 formed by the other of these interconnectors 4.

[0069] Such an arrangement makes it possible to define effort paths Fl which extend globally parallel to the direction D3 (see [Fig.6]).

[0070] With reference to [Fig.5], the four sets El indicated on this figure are further arranged in relation to each other in an analogous manner in order to create between them paths of effort that are globally parallel to D3.

[0071] According to the view of [Fig.5], the various interconnectors 4 of the stack 2 thus have a honeycomb structure.

[0072] Of course, the distribution of mechanical loads in the stack 2 and / or the circulation of gas flows in the channels 60 and / or 62 can be adjusted as needed, for example by playing on the dimension of the bearing surfaces 21S and / or 22S of the interconnectors 4.

[0073] Figures 7 and 8 illustrate a second embodiment of the invention.

[0074] This second embodiment is described solely in terms of its differences from the first embodiment, the preceding description applying by analogy.

[0075] The interconnector 4 of [Fig.7] differs mainly from that of figures 3 and 4 in that the concave parts of its corrugated part 25 form fluidic channels each defining a flow trajectory not rectilinear but curvilinear, that is to say a trajectory formed by curved, serpentine lines.

[0076] The surface of the interconnector 4 visible on [Fig.7] being the surface 21, the channels represented on this figure correspond to the channels 62.

[0077] In this example, the surface of the interconnector 4 which is opposite the surface 21 and which is not visible in [Fig.7] - corresponding to the surface 22 in the preceding description - also forms curvilinear channels which correspond to the channels 60 in the preceding description.

[0078] By way of non-limitation, the trajectory of channels 60 and 62 has a sinusoidal type shape in this second embodiment.

[0079] In this non-limiting example, the channels of interconnector 4 are parallel.

[0080] The El assembly illustrated in [Fig.8] differs mainly from that of [Fig.6], firstly, in that the interconnectors 4 of this set El form curvilinear channels as described above and, secondly, in that the interconnectors 4 of this set El are not offset from each other along the direction D2.

[0081] Thus, the convex parts 22B of the surface 22 of the interconnector 4 located towards the top of [Fig.8] are respectively aligned with the concave parts 21A of the surface 21 of the interconnector 4 located towards the bottom of [Fig.8], while the concave parts 22A of the surface 22 of the interconnector 4 located towards the top of [Fig.8] are respectively aligned with the convex parts 21B of the surface 21 of the interconnector 4 located towards the bottom of [Fig.8] (see by analogy [Fig.4] for the identification of the surfaces and the concave and convex parts of the interconnectors).

[0082] In other words, in the example of [Fig.8], the channels 60 formed by one of the interconnectors 4 of the assembly El are respectively aligned with the channels 60 formed by the other interconnector 4 of this assembly El, the channels 62 formed by one of the interconnectors 4 of the assembly El are respectively aligned with the channels 62 formed by the other interconnector 4 of this assembly El, and the bearing surfaces 22S of the interconnector 4 located towards the top of [Fig.8] are offset along D2 with respect to the bearing surfaces 21S of the interconnector 4 located towards the bottom of this figure (see by analogy [Fig.4] for the identification of the bearing surfaces).

[0083] In an unrepresented variant of this second embodiment, the interconnectors 4 of the assembly El are offset from each other along the direction D2, according to a configuration analogous to that of [Fig.6] in order to create force paths that are globally parallel to D3.

[0084] Figures 9 to 11 illustrate a third embodiment of the invention.

[0085] This third embodiment is described solely in terms of its differences from the second embodiment, the preceding description applying by analogy.

[0086] Figures 9 to 11 show an assembly El comprising an interconnector forming channels 60 - represented in solid line in [Fig.9] - and an interconnector forming channels 62 - represented in dashed line in [Fig.9].

[0087] The channels of each of these interconnectors are similar to the channels of the interconnector in [Fig.7], in that they define curvilinear flow paths.

[0088] The assembly El of figures 9 to 11 differs mainly from the assembly El of the second embodiment in that the channels 62 formed by one of the interconnectors of this assembly El are offset with respect to the channels 60 formed by the other interconnector of this assembly El, along the direction Dl, i.e. along the flow path, as illustrated in [Fig.9].

[0089] Such an offset makes it possible to obtain a progressive modification along the direction Dl of the relative alignment of channels 60 and 62, resulting in a positioning relative of channels 60 and 62 such as that illustrated in [Fig. 10] at certain coordinates along the direction Dl, a relative positioning of channels 60 and 62 such as that illustrated in [Fig. 11] at other coordinates along the direction Dl, as well as relative positionings of intermediate channels 60 and 62 (not shown) for other coordinates along the direction Dl.

[0090] Thus, with reference to [Fig. 10], certain portions of the convex parts 22B of the surface 22 of the interconnector 4 located towards the top of this figure, called "first portions", are respectively aligned with portions of the convex parts 21B of said surface 21 of the interconnector 4 located towards the bottom of this figure (see by analogy [Fig. 4] for the identification of the surfaces and convex parts of the interconnectors).

[0091] With reference to [Fig. 11], other portions of the convex parts 22B of the surface 22 of the interconnector 4 located towards the top of this figure, called "second portions", are respectively aligned with portions of the concave parts 21A of the surface 21 of the interconnector 4 located towards the bottom of this figure (see by analogy [Fig. 4] for the identification of the surfaces and the concave and convex parts of the interconnectors).

[0092] By way of non-limitation, an interconnector according to the invention, in particular according to any one of the embodiments described above, can be manufactured by shaping a metal plate, for example by hydroforming and / or stamping, so as to form the corresponding concave and convex parts.

[0093] Alternatively, the concave and convex parts of an interconnector according to the invention can be formed according to any other technique.

[0094] Numerous variations can be made to the preceding description, particularly concerning the geometry and / or material of the various components described above. For example, the invention can be implemented with a nickel interconnector 4. Alternatively, the interconnector 4 can be made of ferritic stainless steel or another ferritic alloy and include a coating comprising nickel or a nickel alloy.

[0095] In an unrepresented variant of any of the embodiments described above, one or more of the channels 60 and / or 62 may comprise a foam or other gas-permeable filling material.

[0096] For another example, when an interconnector according to the invention comprises one or more non-straight channels, the geometry of these channels may be different from those illustrated in Figures 7 to 11. For example, an interconnector may comprise one or more channels whose flow path forms a serpentine which is not formed by a succession of curved lines but by a succession of straight lines (not shown).

[0097] More generally, the invention can be implemented to form an electrochemical device different from that described above, for example a high-temperature fuel cell.

Claims

Demands

1. Assembly (El) for an electrochemical device (1), in particular for a high-temperature electrolyzer or high-temperature fuel cell, the assembly (El) comprising an electrochemical cell (3), a first interconnector (4) and a second interconnector (4), the first interconnector and the second interconnector each comprising a surface (21, 22) forming an alternation of concave parts (21A, 22A) and convex parts (21B, 22B), the first interconnector (4) forming first channels (62) which are each delimited by one of the respective concave parts (21A) of said surface (21) of the first interconnector (4) and which are arranged opposite a first side of the electrochemical cell (3),the second interconnector (4) forming second channels (60) which are each delimited by one of the respective concave parts (22A) of the surface (22) of the second interconnector (4) and which are arranged opposite a second side of the electrochemical cell (3).

2. Assembly (El) according to claim 1, wherein the first channels (62) and / or the second channels (60) each define a straight flow path.

3. Assembly (El) according to claim 1, wherein the first channels (62) and / or the second channels (60) each define a zig-zag or serpentine flow path, for example a curvilinear path.

4. Assembly (El) according to any one of claims 1 to 3, wherein the first interconnector and the second interconnector are arranged relative to each other such that the convex parts (21B) of said surface (21) of the first interconnector are respectively aligned with the convex parts (22B) of said surface (22) of the second interconnector.

5. Assembly (El) according to any one of claims 1 to 3, wherein the first interconnector and the second interconnector are arranged relative to each other such that the convex parts (21B) of said surface (21) of the first interconnector are respectively aligned with the concave parts (22A) of said surface (22) of the second interconnector.

6. Assembly (El) according to any one of claims 1 to 5, wherein one or more of said first channels (62) are parallel to one or more of said second channels (60).

7. Assembly (El) according to any one of claims 1 to 6 incorporating the features of claim 3, wherein one or more of said first channels (62) are offset relative to one or more of said second channels (60) along said flow path, such that first portions of the convex parts (21B) of said surface (21) of the first interconnector are respectively aligned with portions of the convex parts (22B) of said surface (22) of the second interconnector and second portions of the convex parts (21B) of said surface (21) of the first interconnector are respectively aligned with portions of the concave parts (22A) of said surface (22) of the second interconnector.

8. Assembly (E1) according to any one of claims 1 to 7, wherein: - said surface (21) of the first interconnector is a first surface of this first interconnector, - said surface (22) of the second interconnector is a second surface of this second interconnector, - said electrochemical cell (3) is a first electrochemical cell, and wherein: - the first interconnector comprises a second surface forming second channels and intended to be disposed opposite a second electrochemical cell of the assembly, and / or - the second interconnector comprises a first surface forming first channels and intended to be disposed opposite a third electrochemical cell of the assembly.

9. Electrochemical device (1), for example high-temperature electrolyzer or high-temperature fuel cell, comprising one or more assemblies (El) according to any one of claims 1 to 8. 14

10. Method of manufacturing an assembly (El) according to any one of claims 1 to 8, comprising a step of shaping the first interconnector and / or the second interconnector, for example by hydroforming and / or stamping, so as to form said concave and convex parts.

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