Flow plates for electrochemical cells and electrochemical cells and electrochemical stacks including such flow plates

Abstract

The following disclosure relates to an improved flow plate for an electrochemical cell. The flow plate includes a flow field and a seal groove defined along a path of a first surface of the flow plate surrounding the flow field of the electrochemical cell. The seal groove is configured to receive an O-ring. The O-ring positioned within the seal groove is configured to be compressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the seal groove. The path of the seal groove includes a plurality of retention sections configured to retain the O-ring within the seal groove such that the O-ring does not fall out of the seal groove under a force of gravity.

Description

FLOW PLATES FOR ELECTROCHEMICAL CELLS AND ELECTROCHEMICAL CELLS AND ELECTROCHEMICAL STACKS INCLUDING SUCH FLOW PLATES

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 635,022, filed April 17, 2024, which is hereby incorporated by reference in its entirety.FIELD

[0002] The following disclosure relates to electrochemical or electrolysis cells and components thereof. More specifically, the following disclosure relates to improved flow plates for electrochemical cells, as well as electrochemical cells and electrochemical stacks including such flow plates.BACKGROUND

[0003] Hydrogen has been considered as an ideal energy carrier to store renewable energy. Proton exchange membrane water electrolysis (PEMWE) as a means for hydrogen production offers high product purity, fast load response times, small footprints, high efficiencies, and low maintenance efforts. It is regarded as a promising technology, especially when coupled with renewable energy sources.

[0004] An electrolysis cell or system uses electrical energy to drive a chemical reaction. For example, water is split to form hydrogen and oxygen. The products may be used as energy sources for later use. In recent years, improvements in operational efficiency have made electrolyzer systems competitive market solutions for energy storage, generation, and / or transport. For example, the cost of generation may be below $10 per kilogram of hydrogen in some cases. Increases in efficiency and / or improvements in operation will continue to drive the installation of electrolyzer systems.

[0005] During the assembly of the electrochemical cell, each layer must be effectively sealed to the adjacent layer. An elastomeric composition such as an O-ring may be used to provide a tight and dependable seal between electrochemical cells.

[0006] The O-ring may be placed within a groove of a flow plate during cell assembly, where the O-ring is configured to compresses against the mating surfaces, forming a tight seal. This may prevent leakage of the fluids within the electrochemical cell, maintain the structural integrity of the cell, and help to optimize cell performance. Proper selection of O- ring material, size, and groove design may help provide compatibility with the cellcomponents and operation of the cell. However, challenges arise in securing the O-ring in place during the assembly process while still forming a tight seal. Therefore, there remains a desire for an improved flow plate design, e.g., for securing an O-ring within a groove of the flow plate of an electrochemical cell.SUMMARY

[0007] In one embodiment, a flow plate for an electrochemical cell is provided. The flow plate includes a flow field positioned on a first surface of the flow plate, the flow field having a plurality of flow field channels configured to transfer fluid to an adjacent layer of the electrochemical cell and / or receive fluid from the adjacent layer of the electrochemical cell. The flow plate also includes a seal groove defined along a path of the first surface of the flow plate surrounding the flow field of the electrochemical cell. The seal groove is configured to receive an O-ring. The O-ring positioned within the seal groove is configured to be compressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the seal groove. The path of the seal groove includes a plurality of retention sections configured to retain the O-ring within the seal groove such that the O-ring does not fall out of the seal groove under a force of gravity.

[0008] In another embodiment, an electrochemical cell is provided. The electrochemical cell includes a flow plate, a membrane, and an adjacent layer positioned between the flow plate and the membrane. The flow plate includes a flow field positioned on a first surface of the flow plate, the flow field having a plurality of flow field channels configured to transfer fluid to the adjacent layer and / or receive fluid from the adjacent layer of the electrochemical cell. The flow plate also includes a seal groove defined along a path of the first surface of the flow plate surrounding the flow field of the electrochemical cell. The seal groove is configured to receive an O-ring. The O-ring positioned within the seal groove is configured to be compressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the seal groove. The path of the seal groove includes a plurality of retention sections configured to retain the O-ring within the seal groove such that the O- ring does not fall out of the seal groove under a force of gravity.

[0009] In another embodiment, an electrochemical stack is provided. The electrochemical stack includes a plurality of electrochemical cells, wherein each electrochemical cell of the plurality of electrochemical cells includes a flow plate as described herein.

[0010] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Exemplary embodiments are described herein with reference to the following drawings.

[0012] Figure 1A depicts an example of an electrochemical cell.

[0013] Figure IB depicts an example of a system including an electrochemical stack having a plurality of electrochemical cells of Figure 1A.

[0014] Figure 2 depicts another example of an electrochemical cell.

[0015] Figure 3 depicts, in an exploded view, an example of an electrochemical stack having a plurality of electrochemical cells.

[0016] Figure 4 depicts a flow plate for an electrochemical cell.

[0017] Figure 5A depicts a cross-sectional view of a seal groove defined in a flow plate of an electrochemical cell.

[0018] Figure 5B depicts a cross-sectional view of a seal groove defined in a flow plate of an electrochemical cell with an O-ring positioned in the seal groove.

[0019] Figure 6 depicts a cross-sectional view of a seal groove defined in a flow plate of an electrochemical cell with an O-ring positioned in the seal groove at a retention section.

[0020] Figure 7 depicts a path of a seal groove deviating from its trajectory at a retention section.DETAILED DESCRIPTION

[0021] The following disclosure provides an improved flow plate for an electrochemical cell, as well as electrochemical cells and stacks including such an improved flow plateconfiguration. As disclosed herein, the flow plate includes a seal groove configured to advantageously secure and retain an O-ring within the seal groove such that the O-ring does not fall out of the seal groove under a force of gravity.

[0022] Further, in certain examples, the improved flow plate may advantageously include a seal groove on both sides of the flow plate. Each seal groove may be defined along a path of a respective surface of the flow plate that surround respective flow fields of adjacent electrochemical cells.

[0023] As provided herein, such an improved flow plate with the seal groove configuration(s) advantageously allows for reliable sealing throughout the assembly process and operation of the electrochemical cells and stack.Electrochemical Cells and Stacks

[0024] Figure 1A depicts an example of an electrochemical cell for the production of hydrogen gas and oxygen gas through the splitting of water. The electrochemical cell includes a cathode, an anode, and a membrane positioned between the cathode and anode. Within the water-splitting electrolysis reaction, one interface runs an oxygen evolution reaction (OER) while the other interface runs a hydrogen evolution reaction (HER). For example, the anode reaction is H2O->2H++ / 2O2+2e and the cathode reaction is 2H++2e->H2. The water electrolysis reaction has recently assumed great importance and renewed attention as a potential foundation for a decarbonized "hydrogen economy."

[0025] Figu re IB depicts an example of an electrochemical system including an electrolyzer or electrochemical stack having a plurality of electrochemical cells of Figure 1A. In certain examples, the electrolyzer or electrochemical stack may contain 50-1000 cells, 50- 100 cells, 500-700 cells, or more than 1000 cells. Any number of cells may make up a stack. The electrochemical cells within the electrochemical stack may be configured to operate with 200 mV or less of pure resistive loss when operating at a high current density (e.g., at least 3 Amps / cm2, at least 4 Amps / cm2, at least 5 Amps / cm2, at least 6 Amps / cm2, at least 7 Amps / cm2, at least 8 Amps / cm2, at least 9 Amps / cm2, at least 10 Amps / cm2, at least 11Amps / cm2, at least 12 Amps / cm2, at least 13 Amps / cm2, at least 14 Amps / cm2, at least 15Amps / cm2, at least 16 Amps / cm2, at least 17 Amps / cm2, at least 18 Amps / cm2, at least 19Amps / cm2, at least 20 Amps / cm2, at least 25 Amps / cm2, at least 30 Amps / cm2, in a range of1-30 Amps / cm2, in a range of 3-20 Amps / cm2, in a range of 3-15 Amps / cm2, in a range of 3- 10 Amps / cm2, or in a range of 10-20 Amps / cm2).

[0026] As illustrated in the system of Figure IB, water (H2O) may be supplied to the anodic inlet of an electrolyzer or electrochemical stack 12. In some embodiments, only the anodic inlet of the electrochemical stack 12 may receive water. In these embodiments, the cathode side of the electrochemical stack 12 may not receive water (e.g., a dry cathode side may be used). In another embodiment, a cathode inlet may also receive water, wherein the water may be supplied to the cathode inlet to cool the electrochemical stack 12 during electrolysis.

[0027] The water supplied to the anodic inlet flows to an anodic inlet manifold that distributes the water to the anode side of the plurality of cells contained with the electrochemical stack 12. In embodiments where water is supplied to the cathode inlet, water supplied to the cathode inlet flows to a cathodic inlet manifold that distributes the water to the cathode side of the plurality of cells in the electrochemical stack 12. In certain examples, the amount of water (e.g., deionized (DI) water) transferred to or circulated through each cell of the electrochemical stack 12 may be in a range of 0.25-1 mL / Amp / cell / min, in a range of 0.25-5 mL / Amp / cell / min, or in a range of 0.5-1 mL / Amp / cell / min.

[0028] During electrolysis, oxygen (O2) is produced at the anode side of the electrolytic cells and hydrogen (H2) is produced at the cathode side of the electrolytic cells. Specifically, a water splitting electrolysis reaction is configured to take place within each individual cell in the cell stack 12. Each cell includes one interface (the anode side of the cell) configured to run an oxygen evolution reaction (OER) and another interface (the cathode side of the cell) configured to run a hydrogen evolution reaction (HER), such as depicted in Figure 1A.

[0029] During electrolysis, some of the water supplied to the anode side of an electrolytic cell may not be converted into oxygen. Accordingly, a two-phase flow of oxygen and unreacted water is outlet from each of the anode sides of the cells into an anodic outlet manifold 13. The two-phase flow of oxygen and unreacted water flows from out of the cell stack 12 through the anodic outlet manifold 13.

[0030] Additionally, in some embodiments, water may be supplied to the cathode side of the cell stack as a coolant. Accordingly, a two-phase flow of hydrogen and water is outlet from each of the cathode sides of the cells to a cathodic outlet manifold 14. The two-phase flow of hydrogen and water flows out of the cell stack 12 through the cathodic outlet manifold 14.

[0031] Figure 2 depicts an additional example of an electrochemical or electrolytic cell. Specifically, Figure 2 depicts a portion of an electrochemical cell 200 having a cathode flow field 202, an anode flow field 204, and a membrane 206 positioned between the cathode flow field 202 and the anode flow field 204.

[0032] In certain examples, the membrane 206 may be a catalyst coated membrane (CCM) having a cathode catalyst layer 205 and / or an anode catalyst layer 207 positioned on respective surfaces of the membrane 206. As used throughout this disclosure, the term "membrane" may refer to a catalyst coated membrane (CCM) having such catalyst layers. The overall thickness (i.e., for all layers of the membrane combined including the catalyst coatings, if present) may be less than 1000 microns, less than 500 microns, less than 100 microns, less than 50 microns, less than 10 microns, less than 5 microns, less than 2 microns, less than 1 micron, in a range of 1-1000 microns, in a range of 2-500 microns, in a range of 5-100 microns, or in a range of 10-50 microns.

[0033] In certain examples, additional layers may be present within the electrochemical cell 200. For example, one or more additional layers 208 may be positioned between the cathode flow field 202 and membrane 206. In certain examples, this may include a gas diffusion layer (GDL) 208 may be positioned between the cathode flow field 202 and membrane 206. This may be advantageous in providing a hydrogen diffusion barrier adjacent to the cathode on one side of the multi-layered membrane to mitigate hydrogen crossover to the anode side. In other words, the GDL is responsible for the transport of gaseous hydrogen to the cathode side flow field. For a wet cathode PEM operation, liquid water transport across the GDL is needed for heat removal in addition to heat removal from the anode side.

[0034] In certain examples, the GDL is made from a carbon paper or woven carbon fabrics. The GDL is configured to allow the flow of hydrogen gas to pass through it. Thethickness of the GDL may be within a range of 100-1000 microns, for example. As used herein, a "thickness" by which is film is characterized refers to the distance, or median measured distance, between the top and bottom faces of a film in a direction perpendicular to the plane of the film layer. As used herein, the top and bottom faces of a film refer to the sides of the film extending in a parallel direction of the plane of the film having the largest surface area.

[0035] S imilarly, one or more additional layers 210 may be present in the electrochemical cell between the membrane 206 and the anode 204. In certain examples, this may include a porous transport layer (PTL) positioned between the membrane 206 (e.g., the anode catalyst layer 207 of the catalyst coated membrane 206) and the anode flow field 204.

[0036] In certain examples, the PTL is made from a titanium (Ti) mesh / felt. As used herein, a Ti mesh / felt may refer to a structure created from microporous Ti fibers. The Ti felt structure may be sintered together by fusing some of the fibers together. Ti felt may be made by a special laying process and a special ultra-high temperature vacuum sintering process. The Ti felt may have an excellent three-dimensional network, porous structure, high porosity, large surface area, uniform pore size distribution, special pressure, and corrosion resistance, and may be rolled and processed.

[0037] Similar to the GDL, the PTL is configured to allow the transportation of the reactant water to the anode catalyst layers, remove produced oxygen gas, and provide good electrical conductivity for effective electron conduction. In other words, liquid water flowing in the anode flow field is configured to permeate through the PTL to reach the CCM.Further, gaseous byproduct oxygen is configured to be removed from the PTL to the flow fields. In such an arrangement, liquid water functions as both reactant and coolant on the anode side of the cell.

[0038] The thickness of the PTL may be within a range of 100-1000 microns, for example. The thickness may affect the mass transport within the cell as well as the durability / deformability and electrical / thermal conductivity of the PTL. In other words, a thinner PTLs compared to thicker PTLs (e.g., 1 mm) may provide better mass transport. However, when the PTL is too thin (e.g., less than 100 microns), the PTL may suffer frompoor two-phase flow effects as well. PTLs are less prone to deformation compared to GDLs. Thickness of PTLs may also affect lateral electron conduction resistance along the lands in between channels.

[0039] In some examples, an anode catalyst coating layer may be positioned between the anode 204 and the PTL.

[0040] The cathode flow field 202 and anode flow field 204 of the cell may individually include a flow field plate composed of metal, carbon, or a composite material having a set of channels machined, stamped, or etched into the plate to allow fluids to flow inward toward the membrane or out of the cell.

[0041] Figure 3 depicts, in an exploded view, an example of a segment of an electrochemical stack 300. The stack 300 includes two electrochemical cells stacked on top of one another (e.g., connecting, abutting, or the like): a first electrochemical cell 320, and a second electrochemical cell 340.

[0042] In certain examples, the stack 300 is not limited to two electrochemical cells. Instead, the stack may include any plurality of electrochemical cells. For example, a stack may include at least 2 cells, at least 3 cells, at least 4 cells, at least 5 cells, at least 10 cells, 50-1000 cells, 50-100 cells, 500-700 cells, or more than 1000 cells stacked on top of one another in the electrochemical system to provide an electrochemical stack.

[0043] Similar to the example discussed above in Figure 2, each electrochemical cell (i.e., electrochemical cells 320 and 340) of the stack 300 includes a cathode flow field 202, an anode flow field 204, and a membrane 206 positioned between the cathode flow field 202 and the anode flow field 204.

[0044] In certain examples, each cell may include additional layers such as a gas diffusion layer (GDL) and a porous transport layer (PTL), such as those layers described with reference to the electrochemical cell in Figure 2. For instance, the GDL may be positioned between the cathode flow field 202 and the membrane 206. On the opposite side of the cell, the PTL 210 may be present in each electrochemical cell between the membrane 206 and the anode 204. Additionally, in certain examples, the membrane 206 may be a catalyst coated membrane (CCM) having a cathode catalyst layer 205 and / or an anode catalyst layer207 positioned on respective surfaces of the membrane 206. However, in terms of simplicity, these additional layers are not illustrated in Figure 3.

[0045] In certain examples, as depicted in Figure 3, the cathode flow field 202 of the first electrochemical cell 320 and anode flow field 204 of the second electrochemical cell 340 may share a flow plate 400 (described in greater detail below). The flow plate 400 may be composed of metal, carbon, or a composite material having a set of channels machined, stamped, or etched into the plate to allow fluids to flow inward toward the membrane of the cell and / or outward from the membrane of the cell.

[0046] In this example, the flow plate 400 may be positioned between adjacent electrochemical cells. The flow plate 400 may contain a respective flow field corresponding to the electrochemical cell the flow field is abutting. For instance, the flow plate 400 may be positioned between the two electrochemical cells 320 and 340. The flow plate 400 may include the anode flow field 202 abutting the adjacent layer 208 of the electrochemical cell 320. Additionally, the flow plate 400 may include the cathode flow field 204 abutting the adjacent layer 210 of the second electrochemical cell 340.

[0047] To ensure a secure seal between the adjacent electrochemical cells 320 and 340, the flow plate 400 (i.e., including the anode flow field 202 and cathode flow field 204) incorporates a seal groove on each side of the flow plate 400. Each seal groove accommodates a corresponding O-ring 450, which serves as a sealing mechanism. Embodiments of the flow plate 400 are described below with reference to Figures 4-7.Flow Plates for Electrochemical Cells and Stacks

[0048] Figure 4 depicts a first side or surface of a flow plate 400 for an electrochemical cell. The flow plate 400 includes a flow field 402 having a plurality of flow field channels (not depicted) configured to transfer fluid to an adjacent layer and or receive fluid from the adjacent layer of the electrochemical cell. The flow field may be a cathode flow field 202 or an anode flow field 204 as described above.

[0049] The flow plate 400 may also include a seal groove 404 defined along a path 406 of a surface of the flow plate 400 surrounding the flow field 402 of the electrochemical cell.

[0050] The seal groove 404 is configured to receive an O-ring 450, which is depicted in Figure 5B. The O-ring 450 positioned within the seal groove 404 is configured to becompressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the seal groove 404. The path 406 of the groove 404 includes a plurality of retention sections 420 advantageously configured to retain the O-ring 450 within the seal groove 404 such that the O-ring 450 does not fall out of the seal groove 404 under a force of gravity.

[0051] In certain examples, as mentioned above with reference to Figure 3, both sides of the flow plate 400 may include a respective flow field and a respective seal groove, such as to provide a tight seal on both sides of the flow plate when the flow plate is assembled. The retention sections within the seal grooves on both sides of the plate are advantageous in retaining their respective O-rings during the assembly / manufacturing process. For example, after inserting an O-ring into one seal groove, the plate may be subsequently flipped over to access and install the second O-ring on the second, opposite surface. The retention sections advantageously are able to retain the first O-ring from falling out via the force of gravity while the second O-ring is installed.

[0052] For instance, a first side of the flow plate 400 may include a flow field 402 (i.e., either the cathode flow field 202 or the anode flow field 204 as described above) and a seal groove 404 defined along a path 406 of the first surface of the flow plate 400 surrounding the flow field 402 of the electrochemical cell. A respective O-ring 450 may be positioned within the seal groove 404 on the first surface and be configured to be compressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the seal groove 404.

[0053] Additionally, a second side of the flow plate 400 may also include a flow field 402 (i.e., either the cathode flow field 202 or the anode flow field 204 as described above) and a seal groove 404 defined along a path 406 of the second surface of the flow plate 400 surrounding the flow field 402 of a second, adjacent electrochemical cell. A respective Ciring 450 may be positioned within the seal groove on the second surface and be configured to be compressed against an opposing surface of the second electrochemical cell to form a seal such that the fluid within the second electrochemical cell does not escape the second electrochemical cell via the seal groove 404.

[0054] Referring back to Figure 4 and referencing to one side of the flow plate 400 for simplicity, the flow plate 400 may further include one or more side seal grooves 408.However, the flow plate 400 may include any number of side seal grooves 408 on the side of the flow field 400 and is not limited to two side seal grooves 408 depicted within Figure 4. The side seal grooves 408 are disposed between the circumference of the seal groove 404 and on either side of the flow plate 402 and the flow field 402. As such, the side seal grooves 408 do not surround the flow field 402.

[0055] Each side seal groove 408 is configured to receive a side seal O-ring 452. Each side seal O-ring 452 positioned within the side seal groove 408 is configured to be compressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the side seal groove.

[0056] As mentioned above, the flow plate 400 includes a seal groove 404 configured to receive an O-ring. The shape of the seal groove 404 may be any configurable shape for receiving such an O-ring.

[0057] In certain examples, the seal groove 404 may have a dovetail shape or configuration. Figures 5A and 5B depict the seal groove 404 having such a dovetail configuration. Specifically, Figure 5A depicts a cross-sectional view of the seal groove 404 in a dovetail configuration. Figure 5B depicts a cross-sectional view illustrating the seal groove in a dovetail configuration with an O-ring positioned in the seal groove 404.

[0058] Referring to Figures 5A and 5B, the dovetail seal groove 404 includes a first side wall 410, a second side wall 412, and a bottom wall 414. The bottom wall 414 of the dovetail seal groove 404 is positioned a certain distance (X) from the surface of the flow plate 400. The distance (X) refers to the depth of the dovetail seal groove 404 defined in the surface of the flow plate 400.

[0059] For example, the depth of the dovetail seal groove 404 at a distance (X) may be less than a diameter (D) of the O-ring 450 such that the O-ring 450 protrudes out of the seal groove 404 when positioned within the seal groove, as depicted in Figure 5B. In other words, the depth of the dovetail seal groove 404 at a distance (X) is configured to be shallower than the diameter (D) of the O-ring 450, ensuring that the O-ring 450 protrudesout of the seal groove 404. This configuration of the dovetail seal groove 404 advantageously serves to enhance the sealing effectiveness by allowing the O-ring 450 to exert pressure against the mating surface when the O-ring 450 is compressed by an adjacent surface, thereby providing a secure and dependable seal.

[0060] The bottom wall 414 of the dovetail seal groove 404 also extends a certain nominal or bottom width (N) as measured between the first side wall 410 to the second side wall 412. The bottom width (N) may refer to the width of the seal groove 404 at a depth (X) from the surface of the flow plate 400.

[0061] Furthermore, the first side wall 410 extends between the bottom wall 414 and the surface of the flow plate 400. Additionally, the second side wall 412 extends between the bottom wall 414 and the surface of the flow plate 400. The first side wall 410 and the second side wall 412 are separated from each other at the surface of the flow plate 400 by an opening width (O). In the dovetail configuration depicted in Figures 5A and 5B, the seal groove 404 has a greater bottom width (N) than the opening width (O).

[0062] In certain examples, the opening width (O) is equal to or greater than the diameter of the O-ring 450. For instance, referring to Figure 5B, a cross-sectional view illustrates the positioning of the O-ring 450 within the seal groove 404. As shown, the diameter (D) of the O-ring 450 is smaller than the opening width (O) of the seal groove 404. Thus, the O-ring 450 may fit into the seal groove 404 without compressing the O-ring during the installation process. This design ensures a proper fit and seal within the seal groove 404, facilitating effective functionality.

[0063] When the O-ring positioned within the seal groove is compressed by an opposing surface, the O-ring 450 is compressed into the seal groove 404. The diameter of the O-ring 450 may be compressed (i.e., a compression ratio) by 5-50% as measured in a direction between an opposing surface of the electrochemical cell and the bottom of the seal groove.

[0064] In certain examples the O-ring may have a compression ratio of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, or at least 50%.

[0065] The compression ensures optimal sealing performance, accommodating variations in surface contact while maintaining the integrity of the seal under varying conditions.

[0066] Furthermore, maintaining the compression of the O-ring within a range of 5-50% of its diameter provides that it does not overfill the seal groove 404. For example, in high- pressure environments exceeding ambient levels, such as those encountered in electrochemical systems, the compression prevents the O-ring from exceeding its designed limits, thus preserving its sealing effectiveness. By providing the O-ring remains within optimal compression parameters, the seal groove and installed O-ring maintain their integrity, preventing leaks and providing reliable performance even under demanding conditions.

[0067] Referring back to Figure 4, as mentioned above, the path 406 of the seal groove 404 includes a plurality of retention sections 420 configured to retain the O-ring 450 within the seal groove 404 such that the O-ring 450 does not fall out of the seal groove 404 under a force of gravity.

[0068] As depicted in Figure 4, the seal groove 404 includes 12 retention sections 420. However, the seal groove 404 may include any number of retention sections 420. In certain examples, the plurality of retention sections includes at least 2 retention sections, at least 4 retention sections, at least 6 retention sections, at least 8 retention sections, at least 10 retention sections, at least 15 retention sections, or at least 20 retention sections.

[0069] In certain examples, each retention section 420 of the seal groove may have a narrower opening width (O) compared to the opening width (O) of the seal groove elsewhere along the seal groove 404 (i.e., not at a retention section of the seal groove 404). This configuration ensures that the O-ring 450 remains firmly seated within the retention sections 420, minimizing the risk of displacement, and providing consistent sealing performance throughout the seal groove 404.

[0070] Specifically, within the retention section, the narrowed opening width of the groove may create a design in which the O-ring is overfilled within the retention sections while not being overfilled within the remainder of the seal groove. In other words, the fillvolume of the O-ring within may be variable through the path of the seal groove, particularly between the retention sections and non-retention sections of the seal groove.

[0071] In certain commercial applications, the O-ring may be configured to fill between 50-85% of the volume of the seal groove. In contrast to such commercial configurations, the present disclosure advantageously allows for the fill volume to be at least 85%, at least 90%, at least 95%, at least 100%, or at least 110% of the fill volume in certain sections (i.e., the retention sections) of the seal groove path. Specifically, in certain examples, the O-ring may be configured to overfill the retention sections (i.e., have a fill volume of at least 100% in those sections).

[0072] In certain examples, the fill volume may be variable along the seal path such that the overall / total fill volume is less than 90%, less than 85%, or less than 80% (i.e., the combination of overfilled retention sections is balanced with the 'underfilled' remaining sections of the seal groove path).

[0073] Figure 6 depicts the dovetail configuration at a retention section 420. As depicted, the opening width (O) of the seal groove 404 is narrower compared to the opening width (O) of the seal groove not at a retention section 420 (as depicted in Figure 5B). This configuration effectively pinches the O-ring 450 positioned within the seal groove 404 at each retention section, providing secure retention and preventing the O-ring 450 from dislodging during assembly or operation. Thus, this configuration ensures reliable sealing performance by maintaining the O-ring securely in place, enhancing the overall integrity of the seal groove 404 and O-ring 450.

[0074] In certain examples, the opening width (O) of the seal groove 404 at the retention sections 420 may be equal to or less than the diameter of the O-ring 450. For example, when the diameter of the O-ring is 3 millimeters (mm), then the opening width (O) of the seal groove 404 at the retention sections 420 may be equal to or less than 3 mm.

[0075] In other examples, the opening width (O) of the seal groove 404 at the retention sections 420 may be greater than the diameter of the O-ring 450. For example, when the diameter of the O-ring is 3 millimeters (mm), then the opening width (O) of the seal groove 404 at the retention sections 420 may be greater than 3 mm.

[0076] Additionally, or alternatively to the narrowed opening width within a retention section, each retention section 420 of the plurality of retention sections 420 may include a protrusion where the path 406 of the seal groove 404 deviates from its trajectory 416. This additionally or alternatively assists in retaining the O-ring 450 within the seal groove 404.

[0077] Figure 7 depicts the path 406 of the seal groove 404 deviating from its trajectory 416. The deviation in the path 406 from the trajectory 416 is referred to as a protrusion 422, which advantageously pinches the O-ring 450 such as to retain the O-ring 450 in the seal groove 404. The protrusion 422 may extend from a first endpoint 424 to a second endpoint 426 along the trajectory 416 of the original path 406 of the seal groove 404, wherein the distance from the first endpoint to the second endpoint is defined as the protrusion length. The protrusion length (P) between the first endpoint 424 and the second endpoint 426 may be at least 200% of the diameter of the O-ring 450, at least 300% of the diameter of the O- ring 450, at least 400% of the diameter of the O-ring 450, or at least 500% of the diameter of the O-ring 450.

[0078] The protrusion length (P) may dictate the severity of a bend of the O-ring when the O-ring is positioned in the seal groove 404. In other words, the curvature or radius of the bend is influenced by the protrusion length (P).

[0079] For example, a longer protrusion length (P) may result in a gradual bend of the O- ring 450 when the O-ring 450 is positioned in the seal groove 404. Alternatively, a shorter protrusion length (P) may result in a sharper or more severe bend of the O-ring 450 when the O-ring 450 is positioned in the seal groove 404.

[0080] The protrusion 422 may also deviate a certain deviation distance (DD) from the trajectory 416 of the original path 406 of the seal groove 404, wherein the deviation distance is measured from a center of the trajectory of the path of the seal groove to a center of the path of the seal groove at a deviation endpoint. As depicted in Figure 7, the deviation distance (DD) extends from a center endpoint 428 along the trajectory path 416 of the seal groove to a deviation endpoint 430. The center endpoint 428 is disposed between the first endpoint 424 and the second endpoint 426 along the trajectory 416 of the path 406.

[0081] In certain examples, the deviation distance (DD) from the trajectory 416 of the path 406 at the center endpoint 428 to the deviation endpoint 430 may be at least 10% of the diameter of the O-ring 450, at least 25% of the diameter of the O-ring 450, at least 33% of the diameter of the O-ring 450, at least 50% of the diameter of the O-ring 450, at least 66% of the diameter of the O-ring 450, at least 75% of the diameter of the O-ring 450, at least 100% of the diameter of the O-ring 450, at least 200% of the diameter of the O-ring 450, at least 300% of the diameter of the O-ring 450, at least 400% of the diameter of the O- ring 450, or at least 500% of the diameter of the O-ring 450.

[0082] In certain examples, the protrusion may be defined by a deviation trajectory between the center of the trajectory of the path of the seal groove at the first endpoint and the center of the path of the seal groove at the deviation endpoint. A trajectory angle may be defined as an angle between the trajectory of the path of the seal groove and the deviation trajectory. In certain examples, the trajectory angle is in a range of 10-80 degrees, in a range of 20-70 degrees, in a range of 30-60 degrees, or in a range of 40-50 degrees.

[0083] In certain examples, as noted above, the path 406 of the seal groove 404 may include a plurality of retention sections 420 positioned throughout the path of the seal groove to effectively and advantageously secure and retain the O-ring 450 within the seal groove 404 so that the O-ring 450 does not fall out due to gravity during the assembly process of the electrochemical cell and / or electrochemical stack.

[0084] Further, the path 406 of the seal groove 404 may be formed via machining, stamping, or etching the path. In certain examples, the formation of the path may include the use of one or more dovetail bits configured to carve or machine out a dovetail path from the composition of the flow plate. In certain specific examples, the tool or dovetail bit may be configured to be undersized such that no drop-hole allowance is required to initially fit the bit into the channel of the path. In other words, the width of the dovetail bit may be equal to or less than the opening width of the seal groove within the non-retention section of the path of the seal groove.

[0085] One or more embodiments of the disclosure may be referred to herein, individually and / or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention orinventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, are apparent to those of skill in the art upon reviewing the description.

[0086] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. As used herein, "for example," "for instance," "such as," or "including" are meant to introduce examples that further clarify more general subject matter. Unless otherwise expressly indicated, such examples are provided only as an aid for understanding embodiments illustrated in the present disclosure and are not meant to be limiting in any fashion. Nor do these phrases indicate any kind of preference for the disclosed embodiment.

[0087] The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter.

[0088] It is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is understood that the following claims including all equivalents are intended to define the scope of the disclosure. The claims should not be read as limited to the described order or elements unless stated to that effect. Therefore, all embodiments that come within the scope and spirit of the following claims and equivalents thereto are claimed as the disclosure.

Claims

CLAIMS1. A flow plate for an electrochemical cell, the flow plate comprising: a flow field positioned on a first surface of the flow plate, the flow field having a plurality of flow field channels configured to transfer fluid to an adjacent layer of the electrochemical cell and / or receive fluid from the adjacent layer of the electrochemical cell; and a seal groove defined along a path of the first surface of the flow plate surrounding the flow field of the electrochemical cell, wherein the seal groove is configured to receive an O-ring, wherein the O-ring positioned within the seal groove is configured to be compressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the seal groove, and wherein the path of the seal groove comprises a plurality of retention sections configured to retain the O-ring within the seal groove such that the O-ring does not fall out of the seal groove under a force of gravity.

2. The flow plate of claim 1, wherein the seal groove comprises a dovetail configuration, wherein the dovetail configuration comprises a first side wall, a second side wall, and a bottom wall, wherein the bottom wall is positioned at a depth from the first surface of the flow plate, wherein the bottom wall extends between the first side wall and the second side wall of the seal groove, wherein the bottom wall has a bottom width as measured between the first side wall and the second side wall, wherein the first side wall extends between the bottom wall and the first surface of the flow plate,wherein the second side wall extends between the bottom wall and the first surface of the flow plate, wherein the first side wall and the second side wall are separated from each other at the first surface by an opening width, and wherein the bottom width of the seal groove is greater than the opening width of the seal groove.

3. The flow plate of claim 1, wherein an opening width of the seal groove at the first surface of the flow plate is equal to or greater than a diameter of the O-ring.

4. The flow plate of claim 1, wherein a depth of the seal groove as measured from the first surface of the flow plate is less than a diameter of the O-ring such that the O-ring is configured to protrude out of the seal groove when positioned within the seal groove.

5. The flow plate of claim 1, wherein the O-ring positioned within the seal groove is configured to be compressed by 8-50% of a diameter of the O-ring by the opposing surface of the electrochemical cell.

6. The flow plate of claim 1, wherein an opening width of the seal groove at the first surface of the flow plate at a retention section of the plurality of retention sections is less than an opening width of the seal groove at the first surface of the flow plate not at the retention section of the plurality of retention sections.

7. The flow plate of claim 1, wherein each retention section of the plurality of retention sections comprises a protrusion extending in a perpendicular direction from a trajectory of the path of the seal groove, wherein the protrusion extends from a first endpoint to a second endpoint along the trajectory of the path of the seal groove, wherein a distance from the first endpoint to the second endpoint is defined as a protrusion length,wherein the protrusion deviates a deviation distance from the trajectory to a deviation endpoint, and wherein the deviation distance is measured from a center of the trajectory of the path of the seal groove to a center of the path of the seal groove at the deviation endpoint.

8. The flow plate of claim 7, wherein a deviation trajectory is defined between the center of the trajectory of the path of the seal groove at the first endpoint and the center of the path of the seal groove at the deviation endpoint, wherein a trajectory angle is defined as an angle between the trajectory of the path of the seal groove and the deviation trajectory, and wherein the trajectory angle is in a range of 10-80 degrees.

9. The flow plate of claim 7, wherein the protrusion length is at least 200% of a diameter of the O-ring.

10. The flow plate of claim 7, wherein the deviation distance is at least 10% of a diameter of the O-ring.

11. The flow plate of claim 1, wherein the plurality of retention sections comprises at least 4 retention sections.

12. The flow plate of claim 1, further comprising: a side seal groove is disposed along a side seal path on the first surface of the flow plate, wherein the side seal groove is positioned between a circumference of the seal groove and the flow field, wherein the side seal groove is configured to receive a side seal O-ring, and wherein the side seal O-ring within the side seal groove is configured to be compressed against the opposing surface of the electrochemical cell to form a seal such thatthe fluid within the electrochemical cell does not escape the electrochemical cell via the side seal groove, and wherein the path of the side seal groove comprises a plurality of side seal retention sections configured to retain the side seal O-ring within the side seal groove such that the side seal O-ring does not fall out of the side seal groove under the force of gravity.

13. The flow plate of claim 1, further comprising: an additional flow field disposed on a second surface of the flow plate opposite from the first surface of the flow plate, the additional flow field having a plurality of additional flow field channels configured to transfer fluid to an adjacent layer of an additional electrochemical cell and / or receive fluid from the adjacent layer of the additional electrochemical cell abutting the electrochemical cell; and an additional seal groove defined along a path of the second surface of the flow plate surrounding the additional flow field of the additional electrochemical cell, wherein the additional seal groove is configured to receive an additional O-ring, wherein the additional O-ring positioned within the additional seal groove is configured to be compressed against an opposing surface of the additional electrochemical cell to form an additional seal such that the fluid within the additional electrochemical cell does not escape via the additional seal groove, and wherein the path of the additional seal groove comprises a plurality of additional retention sections configured to retain the additional O-ring within the additional seal groove such that the additional O-ring does not fall out of the additional seal groove under the force of gravity.

14. The flow plate of claim 1, wherein the O-ring, when compressed against the opposing surface of the electrochemical cell, is configured to fill at least 100% of a volume of the seal groove within each retention section of the plurality of retention sections.

15. The flow plate of claim 14, wherein the O-ring, when compressed against the opposing surface of the electrochemical cell, is configured to fill less than 90% of an overall volume of the seal groove.

16. An electrochemical cell comprising: a flow plate; a membrane; and an adjacent layer positioned between the flow plate and the membrane, wherein the flow plate comprises: a flow field positioned on a first surface of the flow plate, the flow field having a plurality of flow field channels configured to transfer fluid to the adjacent layer of the electrochemical cell and / or receive fluid from the adjacent layer of the electrochemical cell; and a seal groove defined along a path of the first surface of the flow plate surrounding the flow field of the electrochemical cell, wherein the seal groove is configured to receive an O-ring, wherein the O-ring positioned within the seal groove is configured to be compressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the seal groove, and wherein the path of the seal groove comprises a plurality of retention sections configured to retain the O-ring within the seal groove such that the O-ring does not fall out of the seal groove under a force of gravity.

17. The electrochemical cell of claim 16, wherein the seal groove comprises a dovetail configuration, wherein the dovetail configuration comprises a first side wall, a second side wall, and a bottom wall, wherein the bottom wall is positioned at a depth from the first surface of the flowwherein the bottom wall extends between the first side wall and the second side wall of the seal groove, wherein the bottom wall has a bottom width as measured between the first side wall and the second side wall, wherein the first side wall extends between the bottom wall and the first surface of the flow plate, wherein the second side wall extends between the bottom wall and the first surface of the flow plate, wherein the first side wall and the second side wall are separated from each other at the first surface by an opening width, and wherein the bottom width of the seal groove is greater than the opening width of the seal groove.

18. The electrochemical cell of claim 16, wherein an opening width of the seal groove at the first surface of the flow plate is equal to or greater than a diameter of the O- ring.

19. The electrochemical cell of claim 16, wherein a depth of the seal groove as measured from the first surface of the flow plate is less than a diameter of the O-ring such that the O-ring is configured to protrude out of the seal groove when positioned within the seal groove.

20. The electrochemical cell of claim 16, wherein the O-ring positioned within the seal groove is configured to be compressed by 8-50% of a diameter of the O-ring by the opposing surface of the electrochemical cell.

21. The electrochemical cell of claim 16, wherein an opening width of the seal groove at the first surface of the flow plate at a retention section of the plurality of retention sections is less than an opening width of the seal groove at the first surface of the flow plate not at the retention section of the plurality of retention sections.

22. The electrochemical cell of claim 16, wherein each retention section of the plurality of retention sections comprises a protrusion extending in a perpendicular direction from a trajectory of the path of the seal groove, wherein the protrusion extends from a first endpoint to a second endpoint along the trajectory of the path of the seal groove, wherein a distance from the first endpoint to the second endpoint is defined as a protrusion length, wherein the protrusion deviates a deviation distance from the trajectory to a deviation endpoint, and wherein the deviation distance is measured from a center of the trajectory of the path of the seal groove to a center of the path of the seal groove at the deviation endpoint.

23. The electrochemical cell of claim 22, wherein a deviation trajectory is defined between the center of the trajectory of the path of the seal groove at the first endpoint and the center of the path of the seal groove at the deviation endpoint, wherein a trajectory angle is defined as an angle between the trajectory of the path of the seal groove and the deviation trajectory, and wherein the trajectory angle is in a range of 10-80 degrees, in a range of 20-70 degrees, in a range of 30-60 degrees, or in a range of 40-50 degrees.

24. The electrochemical cell of claim 22, wherein the protrusion length is at least 200% of a diameter of the O-ring.

25. The electrochemical cell of claim 22, wherein the deviation distance is at least 200% of a diameter of the O-ring.

26. The electrochemical cell of claim 16, wherein the plurality of retention sections comprises at least 4 retention sections.

27. The electrochemical cell of claim 16, further comprising: a side seal groove is disposed along a side seal path on the first surface of the flow plate, wherein the side seal groove is positioned between a circumference of the seal groove and the flow field, wherein the side seal groove is configured to receive a side seal O-ring, and wherein the side seal O-ring within the side seal groove is configured to be compressed against the opposing surface of the electrochemical cell to form a seal such that the fluid within the electrochemical cell does not escape the electrochemical cell via the side seal groove, and wherein the path of the side seal groove comprises a plurality of side seal retention sections configured to retain the side seal O-ring within the side seal groove such that the side seal O-ring does not fall out of the side seal groove under the force of gravity.

28. The electrochemical cell of claim 16, further comprising: a second flow plate; and an additional layer positioned between the second flow plate and the membrane, wherein the second flow plate comprises: a second flow field positioned on a surface of the second flow plate, the second flow field having a plurality of second flow field channels configured to transfer fluid to the additional layer of the electrochemical cell and / or receive fluid from the additional layer of the electrochemical cell; and a second seal groove defined along a path of the surface of the second flow plate surrounding the second flow field of the electrochemical cell, wherein the second seal groove is configured to receive a second O- ring, wherein the second O-ring positioned within the seal groove is configured to be compressed against an opposing surface of the electrochemical cell to form a seal such that the fluid within theelectrochemical cell does not escape the electrochemical cell via the second seal groove, and wherein the path of the second seal groove comprises a plurality of second retention sections configured to retain the second O-ring within the second seal groove such that the second O-ring does not fall out of the second seal groove under the force of gravity.

29. The electrochemical cell of claim 16, wherein the flow plate further comprises: an additional flow field disposed on a second surface of the flow plate opposite from the first surface of the flow plate, the additional flow field having a plurality of additional flow field channels configured to transfer fluid to an adjacent layer of an additional electrochemical cell and / or receive fluid from the adjacent layer of the additional electrochemical cell abutting the electrochemical cell; and an additional seal groove defined along a path of the second surface of the flow plate surrounding the additional flow field of the additional electrochemical cell, wherein the additional seal groove is configured to receive an additional O-ring, wherein the additional O-ring positioned within the additional seal groove is configured to be compressed against an opposing surface of the additional electrochemical cell to form an additional seal such that the fluid within the additional electrochemical cell does not escape via the additional seal groove, and wherein the path of the additional seal groove comprises a plurality of additional retention sections configured to retain the additional O-ring within the additional seal groove such that the additional O-ring does not fall out of the additional seal groove under the force of gravity.

30. The electrochemical cell of claim 16, wherein the O-ring, when compressed against the opposing surface of the electrochemical cell, is configured to fill at least 100% of a volume of the seal groove within each retention section of the plurality of retention sections.

31. The electrochemical cell of claim 30, wherein the O-ring, when compressed against the opposing surface of the electrochemical cell, is configured to fill less than 90% of an overall volume of the seal groove.

32. An electrochemical stack comprising: a plurality of electrochemical cells, wherein each electrochemical cell of the plurality of electrochemical cells comprises a flow plate as claimed in any of claims 16-31.

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