Integrated assembly for electrochemical devices

Abstract

The electrochemical device comprises a membrane electrode assembly, a gas diffusion layer disposed on one side of the membrane electrode assembly, and a porous transport layer disposed on the opposite side of the membrane electrode assembly. A thermoplastic film is impregnated within the outer peripheral edges of the gas diffusion layer and the porous transport layer to form an electrochemical assembly having sealed outer edges. A method for forming the electrochemical device is also disclosed.

Description

Technology Field

[0001] This application claims priority to U.S. Patent Application No. 18 / 789,953 of July 31, 2024, which is a part continuation of U.S. Application No. 18 / 415,937 of January 18, 2024, the whole of which is incorporated by reference herein.

[0002] The present disclosure relates to an electrochemical apparatus having an integrated layer arrangement and a method for manufacturing. Background Technology

[0003] Electrolyzers are known electrochemical devices that can be configured to convert electricity and water into hydrogen and oxygen. Electrolyzers comprising proton exchange membrane water electrolyzer (PEMWE) cell assemblies face various challenges. Various layers require precise thicknesses to balance compressive forces in the active region compared to sealed edge regions. While some configurations employ cell frames equipped with compressible gaskets, high axial loads and high internal pressures require the frames to be fabricated from relatively expensive materials. Furthermore, the frame requires inlet regions, such as flow channels, to deliver reactants to the active region, and dimensional tolerances for these regions and frame thicknesses must be strictly controlled to maintain proper flow balance. In addition, the gap between the frame and the porous transport layer (PTL) on the anode side must be managed so that the membrane electrode assembly (MEA) is not pushed into this gap due to high cathodic pressure from the opposite side, as this can have an adverse effect on membrane life and performance. means of solving the problem

[0004] In one exemplary embodiment, the electrochemical device comprises: a membrane electrode assembly comprising a proton exchange membrane having a cathodic catalyst between the proton exchange membrane and a gas diffusion layer and an anode catalyst between the proton exchange membrane and a porous transport layer, wherein the cathodic catalyst and the anode catalyst substantially extend to the outermost peripheral edge of the proton exchange membrane; and a thermoplastic film impregnated within the outer peripheral edge of the gas diffusion layer and the porous transport layer to form an electrochemical assembly having a sealed outer edge.

[0005] In additional non-limiting embodiments of any electrochemical device, the proton exchange membrane has a first surface and a second surface opposite to the first surface, the cathode catalyst comprises a first coating having a first coverage on the first surface, and the anode catalyst comprises a second coating having a second coverage on the second surface.

[0006] In additional non-limiting embodiments of any electrochemical device, the outermost peripheral edge extends around the outermost peripheral of the proton exchange membrane, and the first coverage and the second coverage extend to the outermost peripheral on the first surface and the second surface, respectively.

[0007] In additional non-limiting embodiments of any electrochemical device, the first coating covers the entire first surface up to the outermost peripheral edge, and the second coating covers the entire second surface up to the outermost peripheral edge.

[0008] In additional non-limiting embodiments of any electrochemical device, the first coating covers the first surface but leaves a portion of the first surface adjacent to the outermost periphery of the proton exchange membrane uncovered, and the second coating covers the second surface but leaves a portion of the second surface adjacent to the outermost periphery of the proton exchange membrane uncovered.

[0009] In additional non-limiting embodiments of any electrochemical device, the density of at least one of the first coating and the second coating varies across each of the first surface and the second surface.

[0010] In additional non-limiting embodiments of any electrochemical device, the density of at least one of the first coating and the second coating is greater near the central region of the proton exchange membrane than at the outermost periphery of the proton exchange membrane.

[0011] In an additional non-limiting embodiment of any electrochemical device, the density of the first coating varies over the first surface, and the density of the second coating varies over the second surface.

[0012] In additional non-limiting embodiments of any electrochemical device, the density of the first coating is greater in the central region of the proton exchange membrane than in the outermost periphery of the proton exchange membrane, and the density of the second coating is greater in the central region of the proton exchange membrane than in the outermost periphery of the proton exchange membrane.

[0013] In additional non-limiting embodiments of any electrochemical device, the sealed outer edge extends around the entire periphery of the electrochemical assembly.

[0014] In an additional, non-limiting embodiment of any electrochemical device, the electrochemical assembly comprises at least one reinforcing member impregnated with a thermoplastic film.

[0015] In an additional, non-limiting embodiment of any electrochemical device, the thermoplastic film comprises a plurality of support ribs forming a plurality of flow channels.

[0016] In additional non-limiting embodiments of any electrochemical device, the outermost peripheral edge of the proton exchange membrane is encapsulated by a thermoplastic film.

[0017] In an additional, non-limiting embodiment of any electrochemical device, the electrochemical device is a proton exchange membrane water electrolyzer.

[0018] In one exemplary embodiment, a method for forming at least part of an electrochemical device comprises the steps of: providing a membrane electrode assembly comprising a proton exchange membrane having a cathodic catalyst between the proton exchange membrane and a gas diffusion layer and an anode catalyst between the proton exchange membrane and a porous transport layer; substantially extending the cathodic catalyst and the anode catalyst to the outermost peripheral edge of the proton exchange membrane; and impregnating a thermoplastic film onto the outer peripheral edge of the gas diffusion layer and the porous transport layer to form an electrochemical assembly having a sealed outer edge.

[0019] In an additional, non-limiting embodiment of any method, the proton exchange membrane has a first surface and a second surface facing the first surface, and the method comprises the steps of: applying a first coating for a cathode catalyst having a first coverage on the first surface; and applying a second coating for an anode catalyst having a second coverage on the second surface.

[0020] In an additional, non-limiting embodiment of any method, the outermost peripheral edge extends around the outermost peripheral portion of the proton exchange membrane, and the first coverage and the second coverage extend to the outermost peripheral portion on the respective first surface and the second surface, and the method comprises the steps of: covering the entire first surface with a first coating up to the outermost peripheral edge; and covering the entire second surface with a second coating up to the outermost peripheral edge.

[0021] In an additional non-limiting embodiment of any method, the method comprises the step of varying the density of at least one of the first coating and at least one of the second coating across each of the first surface and the second surface such that the density of at least one of the first coating and the second coating is greater near the central region of the proton exchange membrane than at the outermost peripheral region of the proton exchange membrane.

[0022] In an additional, non-limiting embodiment of any method, the method comprises the steps of: providing a membrane electrode assembly as a pre-fabricated roll of material to be completely coated with a first coating and a second coating; cutting a portion of the pre-fabricated roll of material to a desired length; and trimming the portion to a desired size for the membrane electrode assembly.

[0023] In an additional non-limiting embodiment of any method, the method comprises the step of providing a membrane electrode assembly in which the first coverage in the outer peripheral region of the first surface is smaller than the coverage in the central region of the first surface; and the step of providing a membrane electrode assembly in which the second coverage in the outer peripheral region of the second surface is smaller than the coverage in the central region of the second surface.

[0024] In one exemplary embodiment, the electrochemical device comprises: a membrane electrode assembly; a gas diffusion layer disposed on one side of the membrane electrode assembly; a porous transport layer disposed on the opposite side of the membrane electrode assembly; and a thermoplastic film forming an electrochemical assembly having an outer edge that is impregnated within the outer peripheral edge of the gas diffusion layer and the porous transport layer and sealed therein.

[0025] In additional non-limiting embodiments of any electrochemical device, the sealed outer edge extends around the entire periphery of the electrochemical assembly.

[0026] In an additional, non-limiting embodiment of any electrochemical device, the electrochemical assembly comprises at least one reinforcing member impregnated with a thermoplastic film.

[0027] In additional non-limiting embodiments of any electrochemical device, at least one reinforcement is provided at the outer peripheral edge of a porous transport layer, and / or at least one reinforcement is provided at the outer peripheral edge of a gas diffusion layer.

[0028] In additional non-limiting embodiments of any electrochemical device, at least one reinforcing member comprises a fibrous material.

[0029] In an additional, non-limiting embodiment of any electrochemical device, the thermoplastic film comprises a plurality of support ribs forming a plurality of flow channels.

[0030] In additional non-limiting embodiments of any electrochemical device, the membrane electrode assembly comprises a proton exchange membrane having a cathodic catalyst between the proton exchange membrane and a gas diffusion layer and an anode catalyst between the proton exchange membrane and a porous transport layer.

[0031] In additional non-limiting embodiments of any electrochemical device, the outer peripheral edge of the proton exchange membrane is encapsulated by a thermoplastic film.

[0032] In additional non-limiting embodiments of any electrochemical device, a first film layer is disposed between a gas diffusion layer and a membrane electrode assembly, and a second film layer is disposed between a porous transport layer and a membrane electrode assembly.

[0033] In additional non-limiting embodiments of any electrochemical device, the active region of the gas diffusion layer is thicker than the thickness of the sealed outer edge portion corresponding to the gas diffusion layer.

[0034] In an additional, non-limiting embodiment of any electrochemical device, a plate is attached to the side of the porous transport layer facing the membrane electrode assembly, and thus the plate is formed as part of an electrochemical assembly having a sealed outer edge.

[0035] In an additional, non-limiting embodiment of any electrochemical device, the electrochemical device is a proton exchange membrane water electrolyzer.

[0036] In one exemplary embodiment, a method for forming at least a part of an electrochemical device comprises the steps of: positioning a gas diffusion layer on one side of a membrane electrode assembly; positioning a porous transport layer on the opposite side of the membrane electrode assembly; and impregnating a thermoplastic film on the outer peripheral edge of the gas diffusion layer and the porous transport layer to form an electrochemical assembly having a sealed outer edge.

[0037] In an additional, non-limiting embodiment of any method, the method comprises the step of providing at least one reinforcement to an electrochemical assembly, wherein the at least one reinforcement is provided at the outer peripheral edge of a porous transport layer, and / or at least one reinforcement is provided at the outer peripheral edge of a gas diffusion layer.

[0038] In an additional non-limiting embodiment of any method, the membrane electrode assembly comprises a proton exchange membrane having a cathodic catalyst between the proton exchange membrane and a gas diffusion layer and an anode catalyst between the proton exchange membrane and a porous transport layer, and the method comprises the step of encapsulating the outer peripheral edge of the proton exchange membrane with a thermoplastic film.

[0039] In an additional non-limiting embodiment of any method, the method comprises the steps of: placing a first thermoplastic film layer between a gas diffusion layer and a membrane electrode assembly; placing a second thermoplastic film layer between a porous transport layer and a membrane electrode assembly; and heating and compressing the outer peripheral edges of the gas diffusion layer, the membrane electrode assembly, the porous transport layer, and the first and second thermoplastic film layers to form an electrochemical assembly.

[0040] In an additional, non-limiting embodiment of any method, the method comprises the steps of: placing a first release film layer between a first platen and a gas diffusion layer prior to the heating and compression steps; placing a second release film layer between a second platen and a porous transport layer; and separating the assembly from the first platen and the second platen when the heating and compression are completed.

[0041] In an additional, non-limiting embodiment of any method, the method comprises the step of placing an electrochemical assembly on one or more dipole plates or separator plates.

[0042] In an additional, non-limiting embodiment of any method, the method comprises the step of forming a flow port through the outer peripheral edge of an electrochemical assembly dimensioned to communicate a fluid to a corresponding port within one or more bipolar plates or separators.

[0043] In an additional, non-limiting embodiment of any method, the method comprises the step of forming a thermoplastic film having a plurality of supporting ribs that form a plurality of flow channels.

[0044] The present disclosure may include any one or more of the above and / or below individual features alone or in any combination thereof.

[0045] The various features and advantages of at least one disclosed exemplary embodiment will become apparent to those skilled in the art through the following detailed description. The drawings accompanying the detailed description may be briefly described as follows. Brief explanation of the drawing

[0046] Figure 1 is a schematic diagram of a selected part of an electrochemical device. FIG. 2 is a schematic diagram of an integrated cell assembly according to one embodiment. FIG. 3 is a schematic diagram of a bonding process / layup for an integrated cell assembly according to one embodiment. Figure 4 illustrates the integrated cell assembly of Figure 3 having a bipolar separator. FIG. 5 is a schematic diagram of a bonding process / layup for an integrated cell assembly according to another embodiment. FIG. 6 is a schematic diagram of a bonding process / layup for an integrated cell assembly according to another embodiment. FIG. 7 is a schematic diagram of a bonding process / layup for an integrated cell assembly according to another embodiment. FIGS. 8 to 13 illustrate various steps for forming an electrochemical assembly according to one embodiment. FIG. 14 is a schematic diagram of another embodiment of an integrated cell assembly. FIG. 15 is a schematic diagram of another embodiment of an integrated cell assembly. Similar reference numbers and names in various drawings represent similar elements. Specific details for implementing the invention

[0047] The present disclosure relates to a component that may be suitable for an electrochemical device such as a PEMWE.

[0048] FIG. 1 is a schematic diagram of an electrochemical device (e.g., an assembly) (20) according to one embodiment. The electrochemical device (20) may be an electrolytic cell assembly such as a PEMWE. It should be noted that the operation of an electrolytic cell assembly is known, and that a PEMWE is merely one example of an electrolytic cell and other forms may be used. The teachings disclosed herein may also be used in other electrochemical devices such as fuel cells. The electrochemical device (20) may include any of the features disclosed herein. In the embodiment of FIG. 1, the PEM (22) is located between the anode catalyst layer (24) and the cathode catalyst layer (26). The anode portion (28) has an anode flow field component (30) and an anode transport layer (32). The cathode portion (34) has a cathode flow field component (36) and a cathode transport layer (38). FIG. 1 illustrates that O2 is generated and removed at the anode (28) and H2 is generated and removed at the cathode (34). The power source (40) can be operated to supply current to promote an electrolytic reaction to produce hydrogen and oxygen, for example.

[0049] FIG. 2 discloses an integrated cell assembly (50) according to one embodiment. The integrated cell assembly (50) may be integrated into an electrochemical device comprising any of the electrochemical devices disclosed herein. The integrated cell assembly (50) may have a "unified cathode layer" (UCL) (52) disposed on one side of a bipolar separator (54), and an anode assembly (56) disposed on the opposite side of the bipolar separator (54). A membrane electrode assembly (MEA) (58) is disposed on the side of the UCL (52) opposite the bipolar separator (54). A potting (60) for guiding fluid flow may be formed through various layers (indicated by a dotted line).

[0050] In the embodiment of FIG. 3, the gas diffusion layer (GDL) (62), MEA (58), and porous transport layer (PTL) (64) can be combined into a single laminated structure as shown in FIG. 4. A thermoplastic bonding film (66) may be used to secure the multiple layers together and form an edge seal, thereby eliminating the need for a separate cell frame and active area. In the embodiment, the porous substrate may be impregnated or coated with an uncured material that can be cured in situ. In the embodiment, the MEA edge (68) may be encapsulated by an edge seal formed as shown in FIG. 4.

[0051] In an embodiment, on the negative side of the integrated cell assembly (10), a thermoplastic material may be impregnated into the GDL (62) to form the UCL (52). In an embodiment, the GDL (62) may be a porous conductive substrate that forms a flow field. In an embodiment, a thermoplastic film (66) may be impregnated along the periphery of the GDL (62) into a reinforcing layer, such as a mesh, for example. In another embodiment, the thermoplastic film (66) may be heat-pressed onto the substrate. The potting (60) may be cut through the film and the substrate or formed in other ways. Additionally, the inner edge of the film may be provided with supporting ribs, such as fingers, that form a channel leading to an adjacent port of the UCL (52). In an embodiment, this is required only when there is no channel on the negative side of the bipolar plate, because if gas can flow through the bipolar plate channel under the UCL seal, fingers will not be required. This will be discussed in more detail below.

[0052] Likewise, on the anode side of the integrated cell assembly (10), a thermoplastic material may be impregnated into the PTL (64) to form a "unified anode layer" (UAL). In an embodiment, a thermoplastic film (66) may be impregnated into a reinforcing layer along the periphery of the porous conductive substrate of the PTL (64).

[0053] FIG. 3 illustrates an example of a bonding process / layup method in which a GDL (62), an MEA (58), and a PTL (64) are combined into a single laminated structure. The MEA (58) comprises a PEM (70) having a cathode catalyst (72) on one side and an anode catalyst (74) on the opposite side. The GDL (62) is positioned on one side of the MEA (58), and the PTL (64) is positioned on the opposite side of the MEA (58). A thermoplastic film (66) is impregnated within the outer peripheral edges of the GDL (62) and the PTL (64) to form an electrochemical assembly (76) having a sealed outer edge (90) as shown in FIG. 4. In the example, the sealed outer edge (90) extends around the entire periphery of the electrochemical assembly (76).

[0054] Various materials can be used to form the film layer. In the examples, the film layer comprises a material that cures in situ, such as a specific plastic (e.g., DuPont PVF "Tedlar", or a cross-linked polymer), a UV / thermal / reactive curing resin, etc. A porous substrate is impregnated or coated with an uncured material and then cured in situ.

[0055] In an embodiment, the electrochemical assembly (76) comprises at least one reinforcement (78) impregnated with a thermoplastic film (66). In the example illustrated in FIGS. 3 and 4, the reinforcement (78) is part of the PTL (64). The reinforcement (78) may be positioned on the anode side. In an embodiment, the reinforcement may be provided around the entire outer peripheral edge of the PTL (64). In an embodiment, the reinforcement (78) comprises a woven fibrous material, for example, glass or carbon fiber fabric, or other similar forms of reinforcement material. In another embodiment, the reinforcement (78) comprises a fibrous material such as spun fibers, scattered fibers, etc.

[0056] In an embodiment, a first layer (80) of the bonding film (66) is placed between the GDL (62) and the MEA (58), and a second layer (82) of the bonding film (66) is placed between the PTL (64) and the MEA (58). In an embodiment, to form an electrochemical assembly (76), various layers are placed between a first platen, e.g., an upper platen (84), and a second platen, e.g., a lower platen (86). These platens (84, 86) are pressed together to form a sealed outer edge (90) of the electrochemical assembly (76). When the platens (84, 86) are pressed together, heating and curing steps may occur in a known manner to form a sealed outer edge (90). In the example, a release film layer (88) is placed between each platen (84, 86) and each of the GDL (62) and PTL (64) so ​​that the sealed electrochemical assembly (76) can be easily peeled off from the platens (84, 86).

[0057] As illustrated in FIG. 4, the outer edges of the GDL (62), PTL (64), and reinforcement (78) are all impregnated with a thermoplastic material to form an integrated assembly (76). The outer edge (68) of the MEA (58) can be completely encapsulated as illustrated. The thicknesses of the PTL (64) and the reinforcement region (78) are precisely matched to each other as a result of a compression process, as illustrated by 92. Additionally, as illustrated by 98, there is no gap between the reinforcement (78) and the PTL (64). Since the assembly (76) has a sealed outer peripheral edge (90), an open active center region (94) of the GDL (62) is provided, as illustrated by 94. In an embodiment, the thickness of the active center region (94) of the GDL (62) may be thicker than the sealed outer edge portion of the GDL (62).

[0058] Next, an electrochemical assembly (76) may be placed on one side of the bipolar separator (54). Another electrochemical assembly (76) may be placed on the opposite side of the bipolar separator (54). Subsequently, another bipolar separator (54) may be stacked on the electrochemical assembly (76), and the stacking of the plate (54) and the assembly (76) may continue until a desired number of assemblies (76) are provided. Potting (60) through the plate (54) and the assembly (76) may be used to guide fluid flow. Potting (96) may be provided on the bipolar separator (54). To prevent or reduce the possibility of leakage from the potting (60, 96), a seal (100) may be installed on the bipolar separator (54).

[0059] Except for the fact that the assembly of FIG. 5 does not have a reinforcing member (78), FIG. 5 illustrates an embodiment similar to FIG. 4. The reinforcing mesh material may be omitted. The outer peripheral edge of the PTL (64) may be edge-sealed directly during the compression process.

[0060] Except that a reinforcement (78) is provided on the outer peripheral edge of the GDL (62) in the assembly of FIG. 6, FIG. 6 illustrates an embodiment similar to FIG. 4. The reinforcement (78) may also be placed on the negative side.

[0061] In any of the configurations disclosed herein, the electrode coatings for the cathode catalyst (72) and the anode catalyst (74) may extend further outward toward the peripheral edge of the sealed edge region (e.g., compare FIG. 5 with FIG. 14 to 15). Referring to FIG. 5 and FIG. 14 to 15, the PEM (70) has an outermost edge (118). The PEM (70) also has a total length (L1) extending from one edge to the opposite edge, as shown in FIG. 5. The electrode coatings for the cathode catalyst (72) and the anode catalyst (74) each have an outermost edge (120, 122). The electrode coating for the cathode catalyst (72) has a total length (L2) extending from one edge to the opposite edge. The electrode coating for the anode catalyst (74) has a total length (L3) extending from one edge to the opposite edge. The first layer (80) of the bonding film (66) has an innermost edge (124) and an outermost edge (126). The second layer (82) of the bonding film (66) has an innermost edge (128) and an outermost edge (130). In an embodiment, the innermost edge (128) of the second layer (82) of the bonding film (66) is radially outside the innermost edge (124) of the first layer (80) of the bonding film with respect to the central axis (A) of the laminated assembly. In another embodiment, the innermost edge (128) may be radially inside the innermost edge (124), or both edges (124, 128) may be in a common radial position.

[0062] FIG. 5 illustrates an embodiment in which the respective outermost edges (120, 122) of the electrode coatings for the cathode catalyst (72) and the anode catalyst (74) overlap in an area adjacent to the innermost edge (128) of the second layer (82) of the bonding film (66). In this embodiment, the contact area between the electrode coating for the cathode catalyst (72) and the first layer (80) of the bonding film (66) is larger than the contact area between the electrode coating for the anode catalyst (74) and the second layer (82) of the bonding film (66). Additionally, in this embodiment, the respective outermost edges (120, 122) of the electrode coatings for the cathode catalyst (72) and the anode catalyst (74) stop immediately in front of the outermost edge (118) of the PEM (70). In the example, each outermost edge (120, 122) of the electrode coating on the cathode catalyst (72) may stop at each distance (D1, D2) from the outermost edge (118) of the PEM (70) which is 15% or less of the total length (L1) of the PEM (70) from one edge to the opposite edge.

[0063] FIG. 14 illustrates an embodiment in which the respective outermost edges (120, 122) of the electrode coatings for the cathode catalyst (72) and the anode catalyst (74) overlap in an area closer to the outermost edges (126, 130) of the first layer (80) and the second layer (82) of the bonding film (66) compared to the configuration of FIG. 5. Additionally, in the embodiment, the respective outermost edges (120, 122) of the electrode coatings for the cathode catalyst (72) may stop at respective distances (D1, D2) from the outermost edge (118) of the PEM (70) that are less than 10% of the total length of the PEM (70). In this embodiment, the coverage distance to the outermost edge (118) is greater than that of the configuration of FIG. 5.

[0064] In another embodiment, each outermost edge (120, 122) of the electrode coating on the cathode catalyst (72) may be stopped at each distance (D1, D2) from the outermost edge (118) of the PEM (70) which is 5% or less of the total length of the PEM (70) and 3% or more of the total length of the PEM (70).

[0065] In another embodiment, each outermost edge (120, 122) of the electrode coating on the cathode catalyst (72) may be stopped at each distance (D1, D2) from the outermost edge (118) of the PEM (70) which is less than 3% of the total length of the PEM (70).

[0066] FIG. 15 illustrates an embodiment in which the respective outermost edges (120, 122) of the electrode coatings for the cathode catalyst (72) and the anode catalyst (74) may extend substantially or completely to the outermost edge (118) of the PEM (70). In the embodiment, the respective outermost edges (120, 122) of the electrode coatings for the cathode catalyst (72) may cover the entire upper and lower surfaces of the PEM (70), for example, 100% of the total length is covered. For the purposes of this disclosure, the term “substantially” means within ±5% of the stated value or relationship unless otherwise indicated.

[0067] In each embodiment, the outermost edge (126, 130) of the bonding film (66) is radially outside the outermost edge (118) of the PEM (70) and the outermost edge (120, 122) of the coating.

[0068] Various techniques may be used to form catalysts (72, 74) on the PEM (70) to achieve the disclosed coverage distance. In the embodiments, various methods exist for applying the electrodes, such as spraying, screen printing, decal transfer, or other application methods. In the embodiments, the coating of catalysts (72, 74) is applied to the respective upper and lower surfaces of the PEM (70), and the coverage for the coating may extend substantially or completely to the outermost edge (118) of the PEM (70). The density of the coverage may vary near the outermost edge region of the PEM (70). In the embodiments, the density of the coverage may decrease toward the outermost edge (118), for example, while the active portion of the PEM (70) includes a completely covered area, the area near the outer periphery edge may include an overspray or over-coverage area. This promotes the encapsulation of the outer edge of the MEA (58) to provide a completely sealed assembly.

[0069] FIG. 7 illustrates an embodiment similar to the embodiment of FIG. 4, except that in the assembly of FIG. 7, a bipolar separator plate (54) or a separator plate having potting on only one side is attached to the PTL (64) side facing the MEA (58) and is formed as part of an assembly (76) having a sealed outer edge (90). The plate (54) may or may not be pre-sintered in the PTL (64).

[0070] FIGS. 8 through 13 illustrate various steps for forming an electrochemical assembly (76) having a sealed outer edge (90) according to one embodiment. FIG. 8 illustrates an example of a bonding film layer (66) formed as a "frame." The bonding film layer (66) may be composed of, for example, PEEK, PPS, HDPE, PVDF, PTFE, or other similar materials. The film layer (66) has an outer peripheral edge (102) having an open central region (104). In an embodiment, one or more edges of the film layer (66) defining the open central region (104) may have a plurality of supporting ribs (106) forming a plurality of flow channels (108).

[0071] FIG. 9 illustrates a film layer (66) applied over a flow substrate (110), for example, a GDL and / or PTL porous substrate material. FIG. 10 illustrates a film layer (66) heat-pressed within the substrate (110). In an embodiment, the flow field may be composed of a porous conductive substrate material such as metal or carbon.

[0072] FIG. 11 illustrates an example of a potting (60) that can be cut through layers (66, 110) or formed in other ways to create a support area and a flow area if necessary.

[0073] FIG. 12 illustrates an (e.g., final) integral assembly of a UCL (52) having a support region or rib (106), a flow region or channel (108), and a potting (60). Thus, rather than having separate frame and flow field assemblies, the seal / frame and flow region are integrated into a single integral assembly. The integral assembly can be formed such that there is no gap between the seal and the active region, a very thin "frame" can be provided, and the seal region can be mechanically reinforced by a substrate, which can enable the use of less expensive plastics / materials.

[0074] FIG. 13 illustrates the UCL (52) being loaded axially onto a separator plate (54). The MEA (58) may be placed on top of the UCL (52).

[0075] In an embodiment, a method for forming at least a part of an electrochemical device may include the steps of: positioning a GDL (62) on one side of an MEA (58); positioning a PTL (64) on the opposite side of an MEA (58); and / or impregnating a thermoplastic film (66) on the outer peripheral edge of the GDL (62) and the PTL (64) to form an electrochemical assembly (76) having a sealed outer edge (90).

[0076] The above method may further include any additional steps, either alone or in any combination.

[0077] In an embodiment, the method may include the step of providing at least one reinforcement (78) to the electrochemical assembly. At least one reinforcement (78) may be provided on the outer peripheral edge of the PTL (64) and / or at least one reinforcement may be provided on the outer peripheral edge of the GDL (62).

[0078] In an example, the MEA (58) comprises a PEM (70) having a cathode catalyst (72) between the PEM (70) and the GDL (62) and an anode catalyst between the PEM (70) and the PTL (64). The method may include the step of encapsulating the outer peripheral edge of the PEM (70) with a thermoplastic film.

[0079] In an embodiment, the method may include the steps of: placing a first thermoplastic film layer (66) between the GDL (62) and the MEA (58); placing a second thermoplastic film layer (66) between the PTL (64) and the MEA (58); and / or heating and compressing the outer peripheral edges of the GDL (62), MEA (58), PTL (64), and the first and second thermoplastic film layers (66) to form an electrochemical assembly (76).

[0080] In an embodiment, the method may include the steps of: placing a first peel film layer (88) between a first platen (84) and a GDL (62) prior to the heating and compression step; placing a second peel film layer (88) between a second platen (86) and a PTL (64); and peeling the electrochemical assembly (76) from the first platen (84) and the second platen (86) when the heating and compression are completed.

[0081] In an example, the method may include the step of placing an electrochemical assembly (76) on one or more bipolar plates or separator plates (54).

[0082] In an embodiment, the method may include the step of forming a flow port (60) through the outer peripheral edge of the electrochemical assembly (76). The flow port (60) may be dimensioned to communicate a fluid to a corresponding port (96) within one or more bipolar plates or separators (54).

[0083] In an embodiment, the method may include the step of forming a thermoplastic film (66) having a plurality of support ribs (106). The support ribs (106) may form a plurality of flow channels (108).

[0084] In an example, the method may include the step of applying a first coating for a cathode catalyst having a first coating coverage on a first surface, and the step of applying a second coating for an anode catalyst having a second coating coverage on a second surface.

[0085] In an embodiment, the proton exchange membrane has an outermost edge extending around the outermost periphery of the proton exchange membrane, and the method may include the step of covering the entire first surface with a first coating up to the outermost edge, and the step of covering the entire second surface with a second coating up to the outermost edge.

[0086] In an embodiment, the method may include the step of varying the density of at least one of the first coating and the second coating across each of the first surface and the second surface such that the density of at least one of the first coating and the second coating is greater near the center of the proton exchange membrane than at the outermost periphery of the proton exchange membrane.

[0087] In an embodiment, the method may include the steps of: providing a membrane electrode assembly as a pre-fabricated roll of material that is completely coated with a first coating and a second coating; cutting a portion of the pre-fabricated roll of material to a desired length; and trimming the portion to a desired size for the membrane electrode assembly.

[0088] In an embodiment, the method may include the step of providing a membrane electrode assembly in which the first coverage in the outer peripheral region of the first surface is smaller than the coverage in the central region of the first surface; and the step of providing a membrane electrode assembly in which the second coverage in the outer peripheral region of the second surface is smaller than the coverage in the central region of the second surface.

[0089] The present disclosure provides a GDL (62), MEA (58), and PTL (64) combined into a single laminated structure that eliminates the need for separate parts for the cell frame and active region components. Additionally, while low-cost materials such as LDPE may be employed as edge seals, the cathode GDL itself may be reinforced with materials such as carbon fibers, or possibly with plastic or glass fiber mesh. The cost of these materials may be significantly lower than that of bulk equivalents (carbon fiber composites or glass-filled PEEK / PPS / PSU frames). Furthermore, the lamination process can be well controlled so that no gaps exist at the PTL / edge seal boundary, which can completely protect the MEA (58) from cross-pressure related problems. Additionally, as the bonding film layer is melted and extruded, the dimensional tolerance of the seal material for the active region sheet thickness is relaxed and can be "shaped" during the process.

[0090] In certain situations or conditions where the outlet flow area for hydrogen and water may be restricted or blocked due to impregnation of the entire seal area (e.g., when the cathode channel is omitted primarily in the bipolar plate), or when the film between the flow area and the port is completely omitted, the substrate may not be able to provide adequate mechanical support to the opposing anode assembly and the seal. In this case, the impregnated film may be provided with "fingers" that create a "rib and channel" structure over the outlet. A specific geometry is configured so that the ribs / channels provide adequate mechanical support to the opposing seal and a sufficient open flow area for H2 and water exists.

[0091] The disclosed technology can be used to form a component having a cross-flow structure that can be integrated into an electrochemical device. The component may be a conductive bipolar plate that can be stamped or otherwise formed in a manner that facilitates cross-flow on both sides of the plate. The plate may be formed in a manner that reduces manufacturing complexity and manufacturing costs.

[0092] The foregoing description is illustrative rather than limiting. Changes and modifications to the disclosed examples that do not depart from the essence of the invention will be apparent to a person skilled in the art.

Claims

Claim 1 An electrochemical device comprising: a membrane electrode assembly; a gas diffusion layer disposed on one side of the membrane electrode assembly; a porous transport layer disposed on the opposite side of the membrane electrode assembly; and a thermoplastic film forming an electrochemical assembly having an outer edge that is impregnated within the outer peripheral edge of the gas diffusion layer and the porous transport layer and sealed therein. Claim 2 In claim 1, the sealed outer edge extends around the entire periphery of the electrochemical assembly: and / or the active region of the gas diffusion layer is thicker than the thickness of the sealed outer edge portion corresponding to the gas diffusion layer, in an electrochemical device. Claim 3 An electrochemical device according to claim 1 or 2, wherein the electrochemical assembly comprises at least one reinforcing member impregnated with a thermoplastic film, and at least one reinforcing member is provided on the outer peripheral edge of a porous transport layer, and / or at least one reinforcing member is provided on the outer peripheral edge of a gas diffusion layer. Claim 4 An electrochemical device according to any one of claims 1 to 3, wherein the thermoplastic film comprises a plurality of supporting ribs forming a plurality of flow channels. Claim 5 An electrochemical device according to any one of claims 1 to 4, wherein the membrane electrode assembly comprises a proton exchange membrane having a cathodic catalyst between the proton exchange membrane and a gas diffusion layer and an anode catalyst between the proton exchange membrane and a porous transport layer, wherein, in some cases, the outer peripheral edge of the proton exchange membrane is encapsulated by a thermoplastic film. Claim 6 In any one of paragraphs 1 to 5, the electrochemical device is an electrochemical device that is a proton exchange membrane water electrolytic cell. Claim 7 A method for forming at least a part of an electrochemical device, comprising the steps of: positioning a gas diffusion layer on one side of a membrane electrode assembly; positioning a porous transport layer on the opposite side of the membrane electrode assembly; and impregnating a thermoplastic film on the outer peripheral edge of the gas diffusion layer and the porous transport layer to form an electrochemical assembly having a sealed outer edge. Claim 8 A method according to claim 7, comprising the step of providing at least one reinforcement to an electrochemical assembly, wherein at least one reinforcement is provided to the outer peripheral edge of a porous transport layer, and / or at least one reinforcement is provided to the outer peripheral edge of a gas diffusion layer. Claim 9 The method of claim 7 or 8, wherein the membrane electrode assembly comprises a proton exchange membrane having a cathodic catalyst between the proton exchange membrane and a gas diffusion layer and an anode catalyst between the proton exchange membrane and a porous transport layer, and the method comprises the step of encapsulating the outer peripheral edge of the proton exchange membrane with a thermoplastic film. Claim 10 A method according to claim 9, comprising the steps of: placing a first thermoplastic film layer between a gas diffusion layer and a membrane electrode assembly; placing a second thermoplastic film layer between a porous transport layer and a membrane electrode assembly; and heating and compressing the outer peripheral edges of the gas diffusion layer, the membrane electrode assembly, the porous transport layer, and the first and second thermoplastic film layers to form an electrochemical assembly. Claim 11 A method according to any one of claims 7 to 10, comprising the steps of: placing an electrochemical assembly on one or more bipolar plates or separators; and forming a flow port through the outer peripheral edge of the electrochemical assembly, which is dimensioned to communicate a fluid to a corresponding port within one or more bipolar plates or separators. Claim 12 An electrochemical device comprising: a membrane electrode assembly comprising a proton exchange membrane having a cathodic catalyst between the proton exchange membrane and a gas diffusion layer and an anode catalyst between the proton exchange membrane and a porous transport layer, wherein the cathodic catalyst and the anode catalyst substantially extend to the outermost peripheral edge of the proton exchange membrane; and a thermoplastic film forming an electrochemical assembly having an outer edge that is impregnated within the outer peripheral edge of the gas diffusion layer and the porous transport layer and sealed therein. Claim 13 An electrochemical apparatus according to claim 12, wherein the proton exchange membrane has a first surface and a second surface opposite to the first surface, the cathode catalyst comprises a first coating having a first coverage on the first surface and the anode catalyst comprises a second coating having a second coverage on the second surface; the outermost peripheral edge extends around the outermost peripheral of the proton exchange membrane, and the first coverage and the second coverage extend to the outermost peripheral on each of the first surface and the second surface; the first coating covers the entire first surface up to the outermost peripheral edge, and the second coating covers the entire second surface up to the outermost peripheral edge; or the first coating covers the first surface but leaves a portion of the first surface adjacent to the outermost peripheral of the proton exchange membrane uncovered, and the second coating covers the second surface but leaves a portion of the second surface adjacent to the outermost peripheral of the proton exchange membrane uncovered. Claim 14 An electrochemical device according to claim 13, wherein the density of at least one of the first coating and the second coating varies across each of the first surface and the second surface; or wherein the density of the first coating varies across the first surface and the density of the second coating varies across the second surface. Claim 15 In any one of paragraphs 12 to 14, the electrochemical device is an electrochemical device that is a proton exchange membrane water electrolytic cell. Claim 16 A method for forming at least a part of an electrochemical device, comprising the steps of: providing a membrane electrode assembly comprising a proton exchange membrane having a cathodic catalyst between the proton exchange membrane and a gas diffusion layer and an anode catalyst between the proton exchange membrane and a porous transport layer; substantially extending the cathodic catalyst and the anode catalyst to the outermost peripheral edge of the proton exchange membrane; and impregnating the outer peripheral edge of the gas diffusion layer and the porous transport layer with a thermoplastic film to form an electrochemical assembly having a sealed outer edge. Claim 17 A method according to claim 16, wherein the proton exchange membrane has a first surface and a second surface facing the first surface, and comprises the steps of: applying a first coating for a cathode catalyst having a first coverage on the first surface; and applying a second coating for an anode catalyst having a second coverage on the second surface. Claim 18 A method according to claim 17, wherein the outermost peripheral edge extends around the outermost peripheral portion of a proton exchange membrane, and the first coverage and the second coverage extend to the outermost peripheral portion on each of the first surface and the second surface, and the method comprises the steps of: covering the entire first surface with a first coating up to the outermost peripheral edge; and covering the entire second surface with a second coating up to the outermost peripheral edge. Claim 19 A method according to claim 17, comprising the steps of: providing a membrane electrode assembly as a pre-fabricated roll of material to be completely coated with a first coating and a second coating; cutting a portion of the pre-fabricated roll of material to a desired length; and trimming said portion to a desired size for the membrane electrode assembly. Claim 20 A method according to claim 19, comprising the steps of: providing a membrane electrode assembly in which the first coverage in the outer peripheral region of the first surface is smaller than the coverage in the central region of the first surface; and providing a membrane electrode assembly in which the second coverage in the outer peripheral region of the second surface is smaller than the coverage in the central region of the second surface.

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