Electrochemical cells and methods for their manufacture

Abstract

Examples of electrochemical cells are disclosed. The electrochemical cell can comprise a container, an inner half-cell within the container, an outer half-cell within the container, and a product transport tube for transporting hydrogen from the electrochemical cell. The inner half-cell can define a substantially gas-tight internal volume. An inner portion of the product transport tube can be within the internal volume. The inner portion of the product transport tube can be hydrogen permeable. A method of fabricating an electrochemical cell is also disclosed.

Description

[0001] Electrochemical cells and methods for their manufacture

[0002] FIELD

[0003] This invention relates to electrochemical cells, such as electrolysers and fuel cells.

[0004] BACKGROUND

[0005] Electrochemical cells are used for a variety of different purposes, such as the electrolysis of hydrogen or the generation of electricity. Multiple cells may be used in a single plant or facility. It can be difficult to maintain the electrochemical cells. In some instances, their configuration may prevent the maintenance of an individual cell without also affecting other cells.

[0006] SUMMARY

[0007] According to one example here is provided an electrochemical cell comprising a container, an inner half-cell within the container, an outer half-cell within the container, and a product transport tube for transporting hydrogen from the electrochemical cell; wherein: the inner half-cell defines a substantially gas-tight internal volume, an inner portion of the product transport tube is within the internal volume, and the inner portion of the product transport tube is hydrogen permeable.

[0008] Further examples may be implemented according to any of dependent claims 2 to 30.

[0009] In a further example there is provided a method of fabricating an electrochemical cell, the method comprising: providing a first ion exchange membrane and second ion exchange membrane, forming a first anode electrode layer and first cathode electrode layer on reverse surfaces of the first ion exchange membrane, forming a second anode electrode layer and second cathode electrode layer on reverse surfaces of the second ion exchange membrane, layering at least one inner porous transport layer and product transport tube between the first ion exchange membrane and second ion exchange membrane, joining the first ion exchange membrane and second ion exchange membrane to form an inner half-cell and gastight inner volume, layering the half-cell between at least two outer porous transport layers to form a layered half-cell, and placing the layered half-cell into a container.

[0010] Further examples may be implemented according to any of dependent claims 32 to 37.

[0011] It is acknowledged that the terms "comprise", "comprises" and "comprising" may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, these terms are intended to have an inclusive meaning - i.e., they will be taken to mean an inclusion of the listed components which the use directly references, and possibly also of other non-specified components or elements.

[0012] Reference to any document in this specification does not constitute an admission that it is prior art, validly combinable with other documents or that it forms part of the common general knowledge.

[0013] BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings which are incorporated in and constitute part of the specification, illustrate examples of the invention and, together with the general description of the invention given above, and the detailed description of embodiments given below, serve to explain the principles of the invention, in which:

[0015] Figure 1 depicts an example of an electrochemical cell.

[0016] Figure 2 depicts a further example of an electrochemical cell. Figure 3 depicts a perspective view of an example of an electrochemical cell.

[0017] Figure 4 depicts an example of a method of fabricating an electrochemical cell.

[0018] DETAILED DESCRIPTION

[0019] Electrochemical cells can be used for the generation of hydrogen via electrolysis or the generation of electricity via reverse electrolysis, amongst multiple other uses. An electrochemical cell can include an ion exchange membrane within a container that also houses a working fluid. In any example described herein, the working fluid may be a liquid.

[0020] Figure 1 depicts an example of an electrochemical cell 100. In this example, the electrochemical cell 100 comprises a container 190 (which in this example is a cylinder), an inner half-cell 120 within the container, and an outer half-cell 140 within the container 190. The inner half-cell 120 defines a substantially gas-tight internal volume 129. The example electrochemical cell 100 is configured so that in use, a working fluid (e.g. a feedstock) flows longitudinally through the container 190 and outer half-cell 140, but is excluded by the internal volume 129 defined by the inner half-cell 120. Gases which are generated in the inner half-cell 120 can collect in the substantially gas-tight internal volume 129 and can be captured for use as described herein. For example, the electrochemical cell 100 can be configured as an electrolyser for hydrogen production, such that water is fed through container 190 and outer half-cell 140, with hydrogen generated within inner cell 120 and collected from the internal volume 129. However, other configurations for the electrochemical cell 100 (e.g. as a fuel cell for energy production) are also possible.

[0021] Figure 2 depicts a structure of an example electrochemical cell 100 in further detail. In this example, electrochemical cell 100 comprises a product transport tube 180 which, in this example, is used for transporting hydrogen from the electrochemical cell 100. An inner portion of the product transport tube 180 resides within the gas-tight internal volume 129 defined by the inner half-cell 120. This inner portion is permeable to hydrogen or otherwise allows hydrogen to enter the product tube from the inner half-cell. For example, the inner portion can be porous so as to allow the ingress of hydrogen. In this way, hydrogen gas generated within the internal volume 129 defined by the inner half-cell 120 can be extracted for use. An external portion of the product transport tube can also protrude from outside of the inner half-cell 120 (as shown in Figure 3). The product transport tube 180 can be formed, for example, at least partially from metal, and the inner portion of the product transport tube 180 can be porous or can define holes or apertures to allow for hydrogen to flow from the inner half-cell 120 through the product transport tube 180. The product transport tube 180 can also be permeable to other gases when the electrochemical cell 100 is configured to generate gases other than hydrogen within internal volume 129.

[0022] The inner half-cell 120 can comprise at least one ion exchange membrane 122 that at least partially defines the internal volume 129. For example, in the case that the electrochemical cell 100 is an electrolyser for hydrogen production, the inner halfcell 120 can comprise a proton exchange membrane such as a perfluorosulfonic acid polymer (e.g. Nation). Other ion exchange membranes 122 such as anion exchange membranes (such as a methylated polybenzimidazole based membrane) can be used in other examples and applications of the electrochemical cell 100.

[0023] The ion exchange membrane 122 can be a catalyst-coated membrane (CCM) or can otherwise be adjacent to a catalyst. For example, the inner half-cell 120 can further comprise at least one cathode electrode layer 124 that is adjacent an inner surface of the at least one ion exchange membrane 122 such that the at least one cathode electrode layer 124 is within the internal volume 129. For example, the cathode electrode layer 124 can be deposited onto the ion exchange membrane 122, which can be a catalyst-coated membrane. The catalyst can at least partially comprise Pt, Ir, Ru, other platinum group metals, or Ni. The choice of the ion exchange membrane 122 / catalyst-coated membrane and the choice of catalyst can depend on the electrochemical applications of the electrochemical cell 100.

[0024] In cases where the electrochemical cell 100 is an electrolyser for hydrogen production, having the cathode electrode layer 124 adjacent to the ion exchange membrane 122 and within the internal volume 129 means that hydrogen can be generated within the internal volume 129. The hydrogen can then be collected via the inner portion of the inner product tube 180 residing within the internal volume 129, as this inner portion is hydrogen permeable or otherwise allows hydrogen to enter the product transport tube 180. A substantial bulk of the hydrogen generated at the cathode electrode layer 124 cannot otherwise escape from the inner volume 129 via other routes as the inner volume 129 defined by the inner half-cell 120 is substantially gas-tight.

[0025] Similarly, the outer half-cell 140 can comprise at least one anode electrode layer 144, with the at least one anode electrode layer 144 being adjacent to an outer surface of the ion exchange membrane 122 such that the at least one anode electrode layer 142 is outside of the internal volume 129 defined by the inner halfcell 120. For example, the anode electrode layer 144 can be deposited onto the ion exchange membrane 122, which can be a catalyst-coated membrane. The catalyst can at least partially comprise Pt, Ir, Ru, other platinum group metals, or Ni. This will also depend on the electrochemical reactions that take place at the cathode electrode layer 142.

[0026] In other examples of the electrochemical cell 100, the configuration of the cathode layer 124 and anode electrode layer 144 may be switched such that the cathode electrode layer 124 is within outer half-cell 140, and anode electrode layer 144 is within inner half-cell 120. The exact configuration of the cathode electrode layer 124 and anode electrode layer 144 can depend on the application of the electrochemical cell 100.

[0027] The electrochemical cell 100 can further comprise one or more porous transport layers (PTLs). In some examples, the inner half-cell 120 comprises at least one inner PTL 126 within the internal volume 129, as shown in Figure 2. The at least one inner PTL 126 can be adjacent to the at least one cathode electrode layer 124 and can be adjacent to the inner potion of the product transport tube 180. In the case that the electrochemical cell 100 is configured as an electrolyser for hydrogen production, the at least one inner PTL 126 can be used to transport hydrogen from the cathode electrode layer 124 within the inner volume 129 to the product transport tube 180.

[0028] In some examples, the cathode electrode layer 124 can be deposited onto the inner PTL 126. For example, the cathode electrode layer 124 can be deposited onto a portion of the PTL 126 that is closest to the inner surface of the ion exchange membrane 122. In other examples, the cathode electrode layer 124 can be deposited on both the inner surface of the ion exchange membrane 122 and the inner PTL 126.

[0029] Furthermore, the inner PTL 126 can be electrically conductive and can be in electrical contact with the cathode electrode layer 124. In examples where the product transport tube 180 is also electrically conductive, the inner PTL 126 can be electrically conductive and in electrical conduct with the product transport tube 180. Examples of electrically conductive inner PTLs 126 can include carbon cloth , titanium cloth, nickel felt, nickel foam, carbon felt, carbon paper, Toray paper, stainless steel meshes, or stainless steel felt. Using a conductive inner PTL 126 in electrical contact with the product transport tube 180 can create a conductive path from an external portion of the product transport tube 180 to the inner portion of the product tube within the internal volume 129 of the inner half-cell 120, to the inner PTL 126 via the inner portion of the product tube 180, and to the cathode electrode layer 124 via the inner PTL 126. In this way, a voltage can be applied to the cathode electrode layer 124 via an external portion of the product transport tube 180, simplifying the use of the electrochemical cell 100. Of course, other electrical connections are possible in other examples, and the electrochemical cell 100 may include an alternative conductive pathway to the cathode electrode layer 124 within the inner half-cell 120.

[0030] Similarly, the outer half-cell 140 can further comprise at least one outer PTL 146 outside the internal volume 129. The at least one outer PTL 146 can be adjacent to the at least one anode electrode layer 144. For example, the anode electrode layer 144 can be deposited onto a portion of the outer PTL 146 that is closest to an outer surface of the ion exchange membrane 122. In other examples, the anode electrode layer 146 can be deposited on both the outer surface of the ion exchange membrane 122 and the outer PTL 146.

[0031] The outer PTL 146 can also be electrically conductive and can be in electrical contact with the anode electrode layer 144. The outer PTL 146 can also be adjacent to an inner surface of the container 190. The inner surface of the container 190 can be electrically conductive and can be in electrical contact with the outer PTL 146. Using a conductive outer PTL 146 in electrical contact with an inner surface of the container 190 can create a conductive path from an external portion of the container 190 through to the inner surface of the container 190, to the outer PTL 146 via the inner surface of the container 190, and to the anode electrode layer 144 via the outer PTL 146. In this way, a voltage can be applied to the anode electrode layer 144 via the container itself 190 (or a portion of the container 190 that is in electrical contact with the inner surface of the container 190), simplifying the use of the electrochemical cell 100. Other electrical connections to the anode electrode layer 144 are also possible. The outer PTL 146 is not in electrical contact with the inner PTL 126 as they are separated by the ion exchange membrane 122. The outer PTL 146 is typically porous in at least a radial direction with respect to Figure 2 (in other words, porous through the thickness of the outer PTL 146) such that gases generated in electrochemical reactions can migrate to or from the anode electrode layer 144, or between the inner surface of the container 190 and the anode electrode layer 144. However, in some examples, the container 190 can be configured for feedstock (e.g. working fluids such as water) to run longitudinally through the container. In other words, when the electrochemical cell 100 is in use, a working fluid (e.g. water) runs through the longitudinal axis of the container 190 (i.e. "into" or "out of" the page with respect to Figure 2). In these examples, the outer PTL 146 can also be porous in at least a longitudinal direction with respect to the container 190 (i.e. "into" or "out of" the page with respect to Figure 2). If the outer PTL 146 is not sufficiently porous in this direction, then the working fluid used in the electrochemical cell 100 may not be able to adequately flow through the longitudinal axis of the container 190. Example materials for the outer PTL 146 can include carbon cloth or titanium cloth that has been woven such that the PTL 146 is porous both radially and longitudinally. Other examples of suitable materials for the outer PTL can include nickel felt, nickel foam, carbon felt, carbon paper, Toray paper, stainless steel meshes and stainless steel felt. These PTL materials can further be coated with metals to further enhance the cells electrochemical performance and durability.

[0032] The product transport tube 180 can be made of a section of porous tube of sintered metals (e.g. stainless steel, titanium, Hastelloy, inconel, monel, nickel), porous graphite tube, or metal meshes (e.g. stainless steel, titanium, Hastelloy, inconel, monel, nickel). The precise composition of the PTLs 126 and 146 and the product transport tube 180 can be selected according to the chemical environment of the cell. For example, for a proton exchange membrane water electrolyser the inner PTL 126 can be chosen from acidic anodic condition resistant titanium, and the outer PTL 146 and product transport tube 180 can be chosen from titanium, stainless steel or carbon. The inner half-cell 120 may be rolled, folded and / or provided with undulations when located in the container 190. This may allow a relatively large area of contact between the inner half-cell 120 and the working fluid in a compact container 190. The rolls, folds or undulations may be formed substantially transverse to the direction that fluid flows through the container 190. In other words, the inner half-cell may be substantially straight along the direction of flow (e.g. into or out of the page in Figure 2) so that it does not overly impede flow of fluid through the container 190, with the rolls, folds or undulations being across this direction (e.g. in the plane of the page in Figure 2). In the example electrochemical cell 100 depicted in Figures 1 and 2, the inner half-cell 120 and outer half-cell 140 are in the form of a spiral, and the container 190 is substantially cylindrical. In other examples, the container 190 may not be configured as a cylinder. Furthermore, the inner half-cell 120 and outer half-cell 140 may not be configured as a spiral. For example, the container 190 can have a substantially rectangular cross-section, and the inner half-cell 120 and outer half-cell 140 can be configured as a sheet within the container 190. The inner half-cell may be folded in a "zig zag" or pleated pattern or provided with a series of undulations. In some examples, a container 190 can contain a plurality of inner half-cells 120 and outer half-cells 140. For example, the inner half-cells 120 and outer half-cells 140 can be configured as modular sheets that slot or otherwise fit in to the container 190.

[0033] Figure 3 depicts a perspective view of an electrochemical cell 100 configured as an electrolyser for the production of hydrogen. The container 190 is substantially cylindrical and the inner half-cell 120 and outer half-cell 140 (not depicted) are configured in the shape of a spiral within the container 190. A cathode electrode layer 124 is within the inner volume 129 defined by the inner half-cell 120, while a anode electrode layer 144 is adjacent an outer surface of the ion exchange membrane 122 such that it is outside the inner volume 129. The electrolyser 100 further comprises an inner PTL 126 and an outer PTL 146 as described above that allow for the transport of gases and also respectively establish electrical connections between the cathode electrode layer 124 and product transport tube 180, and the anode electrode layer 144 and an outer surface of the container 190. In use, feedstock flows through entrance 192 longitudinally through the container 190 and through the outer PTL 146. A voltage is applied between the container 190 and an external portion of the product transport tube 180, and therefore appears between the cathode electrode layer 124 and anode electrode layer 144 of the electrolyser 100. Gaseous oxygen is generated at the anode electrode layer 144 of the outer surface of the ion exchange membrane 122 via electrolysis, and this gaseous oxygen can emerge as waste at a feedstock outlet 194 or can be harvested. Hydrogen is generated at the cathode electrode layer 124 within the inner volume 129 defined by the inner half-cell 120. This hydrogen does not inadvertently escape from the inner volume 129 as the inner volume 129 is substantially gas tight, but instead flows through the product transport tube 180 due to the porosity or hydrogen permeability of the inner portion of the product transport tube 180. Similarly, water / feedstock and gaseous oxygen generated at the anode electrode layer 144 can not enter the inner volume defined 129 by the inner half-cell 120, as the inner volume 129 is gas tight. This ensures that the hydrogen captured from the inner volume 129 via the product transport tube 180 is not contaminated.

[0034] Figure 4 depicts an example of a method of fabricating an electrochemical cell. In this example, a first ion exchange membrane and second ion exchange membrane are provided at 210. An anode electrode layer is formed on a first surface of the first ion exchange membrane at and a cathode electrode layer is formed on the reverse surface of the first ion exchange membrane at 230. Similarly, an anode electrode layer is formed on a first surface of the second ion exchange membrane at and a cathode electrode layer is formed on the reverse surface of the second ion exchange membrane at 240. The ion exchange membranes are then layered together with at least one interleaved PTL and a product transport tube at 240. A product transport tube is placed on the cathode electrode layer of the first ion exchange membrane. At least a portion of the product transport tube that overlies the boundary of the first ion exchange membrane is porous or permeable to hydrogen. In some examples, a second portion of the product transport tube can extend beyond an edge of the first ion exchange membrane. At least one PTL is then laid over the product transport tube. This at least one PTL will form the inner PTL of the electrochemical cell. The second ion exchange membrane is laid over the top of the first ion exchange membrane, the product transport tube, and the PTL, with the cathode electrode layer of the second ion exchange membrane facing the cathode electrode layer of the first ion exchange membrane.

[0035] The first and second ion exchange membranes are then joined to form an inner half-cell and a gas-tight inner volume defined by the ion exchange membranes at 250. For example, the first and second ion exchange membranes can be heat sealed; for instance, the ion exchange membranes may be Nation and may be crimped to form seams. In other examples, the two ion exchange membranes can be sealed using an adhesive. If an adhesive is used, then the adhesive can contain an ionomer. The two ion exchange membranes are thereby joined to define an inner volume. The inner volume is substantially gas tight and houses at least the hydrogen permeable / porous portion of the product transport tube, the inner PTL, and the cathode electrode layers of the ion exchange membranes. The reverse surfaces of the ion exchange membranes with the anode electrode layers now form the outer surface of the inner half-cell.

[0036] The inner half-cell is then layered between two PTLs at 260. These PTLs will form the outer PTLs and can be chosen accordingly. For example, the outer PTLs can be porous in a longitudinal direction if feedstock will flow longitudinally through the electrochemical cell in use. The ensemble is then rolled into a spiral at 270 and is placed into a cylindrical container to complete the electrochemical cell. Voltages can be applied to the cathode electrode layer and anode electrode layer via the product transport tube and container if the inner and outer PTLs are electrically conductive and in electrical contact with product transport tube and container.

[0037] It should be understood that the method depicted in Figure 4 is just one example and can be altered depending on the requirements of the electrochemical cell. For example, instead of using a first ion exchange membrane and second ion exchange membrane that are joined to form a half-cell, a single ion exchange membrane can be used. Anode and cathode electrode layers can be deposited on the reverse sides of the ion exchange membrane, and the ion exchange membrane can then be folded over itself and sealed or joined to define the inner volume at 250. Similarly, the anode and cathode electrode layers do not necessarily need to be deposited on the ion exchange membrane(s). For example, the anode and cathode electrode layers can be applied to the faces of the PTLs that are adjacent to the ion exchange membrane(s).

[0038] Furthermore, the exact number and nature of the PTLs can differ in other examples. For instance, more than one PTL can be included at 240, such that the inner volume that is defined by the inner half-cell once the ion exchange membranes are joined at 250 houses more than one inner PTL. In another example, the inner PTL can be integrated with the product transport tube. Similarly, in some examples, only one outer PTL may be used, meaning the inner half-cell is simply laid over a single PTL at 260 rather than being sandwiched between two PTLs. If a single outer PTL is used and an electrical connection through the container itself to the anode electrode layer is desired, the inner halfcell should be placed over the single outer PTL at 260 such that when the ensemble is rolled into a spiral, the outer PTL is situated between the outer surface of the ion exchange membrane and the inner surface of the container. A plurality of electrochemical cells that are disclosed herein can be used in a single system. For example, a system can comprise a plurality of electrochemical cells as substantially described herein. At least a portion of the electrochemical cells can be configured as electrolysers for hydrogen production. The plurality of electrochemical cells can be configured in parallel, as the electrochemical cells disclosed herein are compatible with a monopolar configuration. The plurality of electrochemical cells can also be configured in series if desired.

[0039] In summary, the methods of fabricating the electrochemical cells disclosed herein can reduce the complexity of manufacturing electrochemical cells. The electrochemical cells can eliminate the need for bipolar plates by virtue of their electrical connections. In the case that the electrochemical cell is configured for use as an electrolyser for hydrogen production, the use of an inner half-cell that defines a gas-tight inner volume can increase hydrogen capture in the electrolyser and can reduce hydrogen leakage. It can be safer and easier to pressurise the electrochemical cell with a working fluid given the shape of the container of the electrolyser. Furthermore, each electrochemical cell can be self-contained, allowing for simple maintenance of a given cell independently of the other cells within the system.

[0040] While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the Applicant's general inventive concept.

Claims

CLAIMS:

1. An electrochemical cel I, the electrochemical cell comprising: a container, an inner half-cell within the container, an outer half-cell within the container, and a product transport tube for transporting hydrogen from the electrochemical cell; wherein: the inner half-cell defines a substantially gas-tight internal volume, an inner portion of the product transport tube is within the internal volume, and the inner portion of the product transport tube is hydrogen permeable.

2. The electrochemical cell of claim 1, wherein the inner half-cell comprises at least one ion exchange membrane that at least partially defines the internal volume.

3. The electrochemical cell of claim 2, wherein the inner half-cell further comprises at least one cathode electrode layer adjacent an inner surface of the at least one ion exchange membrane such that the at least one cathode electrode layer is within the internal volume.

4. The electrochemical cell of claim 3, wherein the cathode electrode layer is deposited onto the ion exchange membrane.

5. The electrochemical cell of claim 3 or claim 4, wherein the cathode electrode layer at least partially comprises Pt, Ir, Ru, a platinum group metal, or Ni.

6. The electrochemical cell of any one of claims 2 to 5, wherein the inner halfcell further comprises at least one inner porous transport layer within the internal volume, wherein the at least one porous transport layer: is adjacent to the at least one cathode electrode layer, and is adjacent to the inner portion of the product transport tube.

7. The electrochemical cell of claim 6, wherein the cathode electrode layer is deposited onto the inner porous transport layer.

8. The electrochemical cell of claim 7, wherein the inner porous transport layer comprises carbon cloth or titanium cloth.

9. The electrochemical cell of any one of claims 6 to 8, wherein the product transport tube is electrically conductive and is in electrical contact with the at least one inner porous transport layer.

10. The electrochemical cell of any one of claims 2 to 9, wherein the outer halfcell comprises at least one anode electrode layer, the at least one anode electrode layer being adjacent to an outer surface of the at least one ion exchange membrane such that the at least one anode electrode layer is outside the internal volume.

11. The electrochemical cell of claim 10, wherein the anode layer is deposited onto the ion exchange membrane.

12. The electrochemical cell of claim 10 or claim 11, wherein the anode electrode layer at least partially comprises Pt, Ir, Ru, a platinum group metal, or Ni.

13. The electrochemical cell of any one of claims 10 to 12, wherein the at outer half-cell further comprises at least one outer porous transport layer outsideof the internal volume, wherein the at least one outer transport layer is adjacent to the at least one anode electrode layer.

14. The electrochemical cell of claim 13, wherein the at least one outer transport layer is adjacent to an inner surface of the container.

15. The electrochemical cell of claim 14, wherein at least the inner surface of the container is electrically conductive and is in electrical contact with the at least one outer transport layer.

16. The electrochemical cell of any one of claims 2 to 15, wherein the ion exchange membrane is a proton exchange membrane.

17. The electrochemical cell of claim 16, wherein the proton exchange membrane is a perfluorosulfonic acid polymer.

18. The electrochemical cell of any one of claims 2 to 15, wherein the ion exchange membrane is an anion exchange membrane.

19. The electrochemical cell of claim 18, wherein the ion exchange membrane is an methylated polybenzimidazole based polymer.

20. The electrochemical cell of any one of claims 2 to 19, wherein the at least one ion exchange membrane is joined to at least partially define the inner volume.

21. The electrochemical cell of claim 20, wherein the ion exchange membrane is heat sealed.

22. The electrochemical cell of claim 21, wherein the ion exchange membrane is crimped.

23. The electrochemical cell of claim 20, wherein the ion exchange membrane is sealed using an adhesive.

24. The electrochemical cell of claim 23, wherein the adhesive comprises an ionomer.

25. The electrochemical cell of any one of claims 1 to 24, wherein the inner portion of the product transport tube is porous.

26. The electrochemical cell of any one of claims 1 to 25, wherein the product transport tube is electrically conductive.

27. The electrochemical cell of any one of claims 1 to 26, wherein the container is substantially cylindrical.

28. The electrochemical cell of any one of claims 1 to 27, wherein the container is configured for feedstock to run longitudinally through the container.

29. The electrochemical cell of any one of claims 1 to 28, wherein the inner halfcell and outer half-cell are in the form of a spiral.

30. The electrochemical cell of any one of claims 1 to 29, wherein the electrochemical cell is configured as an electrolyser for hydrogen production.

31. A method of fabricating an electrochemical cell, the method comprising: providing a first ion exchange membrane and second ion exchange membrane, forming a first anode electrode layer and first cathode electrode layer on reverse surfaces of the first ion exchange membrane, forming a second anode electrode layer and second cathode electrode layer on reverse surfaces of the second ion exchange membrane, layering at least one inner porous transport layer and product transport tube between the first ion exchange membrane and second ion exchange membrane,joining the first ion exchange membrane and second ion exchange membrane to form an inner half-cell and gas-tight inner volume, layering the half-cell between at least two outer porous transport layers to form a layered half-cell, and placing the layered half-cell into a container.

32. The method of claim 31 further comprising, before placing the layered halfcell into the container, rolling the layered half-cell into a spiral.

33. The method of claim 32 wherein the container is cylindrical.

34. The method of claim 31 further comprising, before placing the layered half- cell into the container, forming one or more folds or undulations in the layered half-cell.

35. The method of any one of claims 31-34 wherein the container is configured to support a flow of fluid in a first direction therethrough.

36. The method of claim 35 when dependent on any one of claims 32-34 wherein the layered half-cell is rolled, folded or undulated in a second direction that is substantially transverse to the first direction.

37. The method of any one of claims 31 to 36 further comprising placing one or more further layered half-cells into the container.

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