Electrolyser Cell

Abstract

The electrolyzer cell comprises a first half cell comprising a housing at least partially enclosing a cell interior, a first electrode coated with a first catalytic coating, the first electrode being coupled to the housing within the cell interior without welding, a second electrode being coupled to the housing within the cell interior without welding, and a separator positioned between the first and second electrodes, where a voltage is applied between the first and second electrodes.

Description

[Background technology]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Application No. 63 / 305,473, filed February 1, 2022, and entitled “DETACHABLE ELECTRODES FOR AN ELECTROLYZER CELL,” the disclosure of which is incorporated herein by reference in its entirety.

[0002] The production of hydrogen can play a key role because hydrogen gas is required for many chemical processes. As of 2019, approximately 70 million tons of hydrogen are produced annually worldwide for a variety of uses, such as in oil refining, in the production of ammonia (through the Haber process), in the production of methanol (through the reduction of carbon monoxide), or as a fuel in transportation.

[0003] Historically, the majority of hydrogen (about 95%) has been produced from fossil fuels (e.g., by steam reforming of natural gas, partial oxidation of methane, or coal gasification). Other methods of hydrogen production include biomass gasification, low or no CO2 emission methane pyrolysis, and water electrolysis. Electrolysis uses electricity to split water molecules into hydrogen gas and oxygen gas. To date, electrolysis systems and methods have generally been more expensive than fossil fuel-based production methods. However, fossil fuel-based methods can be more environmentally damaging and generally result in increased CO2 emissions. Thus, there is a need for cost-competitive and environmentally friendly hydrogen gas production electrolysis systems and methods. Summary of the Invention [Means for solving the problem]

[0004] The present disclosure describes an electrolyzer cell comprising a housing at least partially enclosing a cell interior, a first electrode coated with a first catalytic coating, the first electrode being coupled to the housing within the cell interior without welding, a second electrode being coupled to the housing within the cell interior without welding, and a separator positioned between the first and second electrodes, where a voltage is applied between the first and second electrodes.

[0005] The present disclosure also describes a method including providing a first electrode and a second electrode coated with a first catalytic coating; coupling the first electrode to an electrolyzer cell housing without welding such that the first electrode is within the cell interior of the housing; coupling the second electrode to the housing without welding within the cell interior; positioning a separator between the first and second electrodes; pumping electrolyte into the cell interior; and applying a voltage between the first and second electrodes to generate hydrogen gas at the first or second electrode.

[0006] The present disclosure also describes a method of maintaining an electrolyzer cell, the method including removing an electrolyzer cell from an electrolyzer system, the electrolyzer cell comprising a housing at least partially enclosing a cell interior, a first electrode coated with a first catalytic coating, the first electrode being coupled to the housing inside the cell without welding, a second electrode being coupled to the housing inside the cell without welding, and a separator positioned between the first and second electrodes; removing the first electrode from the electrolyzer cell; replacing the removed first electrode with a replacement electrode coated with a replacement catalytic coating; and coupling the replacement electrode to the housing inside the cell without welding. [Brief description of the drawings]

[0007] The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0008] [Figure 1] FIG. 1 is a schematic diagram of an exemplary electrolyzer cell for the electrolysis of water to produce hydrogen gas.

[0009] [Diagram 2] FIG. 2 is a cross-sectional view of an exemplary electrolyzer cell including an anode pan assembly and a cathode pan assembly separated by a separator.

[0010] [Diagram 3] FIG. 3 is an enlarged cross-sectional view of an exemplary anode assembly and cathode assembly of the exemplary electrolyzer cell of FIG.

[0011] [Figure 4] FIG. 4 is an enlarged cross-sectional view of another exemplary anode assembly and cathode assembly of the exemplary electrolyzer cell of FIG.

[0012] [Diagram 5] 5A-5C show enlarged cross-sectional views of a rim insert for engaging an exemplary electrode assembly for use in an electrolytic cell.

[0013] [Figure 6] FIG. 6 is an enlarged cross-sectional view of another exemplary electrode assembly engaged by a rim insert. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Detailed Description The following detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of example, specific embodiments in which the present invention may be practiced. These embodiments, also referred to herein as "examples", are described in sufficient detail to enable those skilled in the art to practice the present invention. The exemplary embodiments may be combined, other embodiments may be utilized, or structural and logical changes may be made without departing from the scope of the present invention. While the disclosed subject matter will be described in conjunction with the enumerated claims, it is understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

[0015] References herein to "one embodiment," "an embodiment," "an example embodiment," and the like indicate that the embodiment being described may include a particular feature, structure, or characteristic, but that not all embodiments necessarily include that particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with one embodiment, it is provided that this is within the knowledge of one of ordinary skill in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described.

[0016] Values ​​expressed in range format should be interpreted in a flexible manner to include not only the values ​​explicitly recited as limits of that range, but also all individual values ​​or subranges contained within that range, as if each value and subrange were explicitly recited. For example, a recited range of values ​​"about 0.1 to about 5" should be interpreted to include not only the explicitly recited values ​​of about 0.1 and about 5, but also all individual concentrations within the recited range of values ​​(e.g., 1, 1.23, 2, 2.85, 3, 3.529, and 4) and subranges falling within the recited range (e.g., about 0.1% to 0.5%, about 1.21% to 2.36%, about 3.3% to 4.9%, or about 1.2% to 4.7%), to name just a few. The description "about X to Y" has the same meaning as "about X to about Y" unless otherwise indicated. Similarly, the statement "about X, Y, or about Z" has the same meaning as "about X, about Y, or about Z," unless otherwise indicated.

[0017] As used herein, the terms "a," "an," or "the" are used to include "one or more than one" unless the context clearly dictates otherwise. The term "or" is used to refer to a non-exclusive "or" unless otherwise indicated. Unless otherwise indicated, the phrase "at least one of," when referring to a listed group, is used to mean any combination of one or two or more of the group members. For example, the statement "at least one of A, B, and C" can have the same meaning as "A; B; C; A and B; A and C; B and C; or A, B, and C," or the statement "at least one of D, E, F, and G" can have the same meaning as "D; E; F; G; D and E; D and F; D and G; E and F; E and G; F and G; D, E, and F; D, E, and G; D, F, and G; E, F, and G; or D, E, F, and G." Commas can be used to the left or right of the decimal symbol as a separator or digit grouping symbol, e.g., "0.000,1" is equivalent to "0.0001."

[0018] In the methods described herein, steps can be performed in any order without departing from the principles of the invention, except when a time or sequence of operations is explicitly recited. Furthermore, the steps defined can be performed in parallel unless express language recites them to be performed separately. For example, the recited act of doing X and the recited act of doing Y can be performed simultaneously in a single operation, and the resulting process would fall within the literal scope of the process. Recitation in a claim to the effect that a first step is performed, and then several other steps are subsequently performed, shall be taken to mean that the first step is performed before any of the other steps, but that the other steps may be performed in any suitable sequence, unless the sequence is further recited within the other steps. For example, a claim element reciting "step A, step B, step C, step D, and step E" shall be interpreted to mean that step A is performed first and step E is performed last, and that steps B, C, and D may be performed in any sequence between steps A and E (including one or more steps being performed in parallel with step A or step E) and the sequence still falls within the literal scope of the claimed process. A given step or subset of the steps may also be repeated.

[0019] Moreover, recited steps can be performed in parallel unless express claim language recites them as being performed separately. For example, a claimed step of doing X and a claimed step of doing Y can be performed simultaneously in a single operation, and the resulting process would fall within the literal scope of the claimed process.

[0020] The term "about" as used herein can allow for a degree of variation within a value or range, e.g., within 10%, within 5%, within 1%, within 0.5%, within 0.1%, within 0.05%, within 0.01%, within 0.005%, or within 0.001% of a stated value, or within a stated limit of a range, inclusive of the exact value or range stated.

[0021] The term "substantially" as used herein refers to a "majority of" or "mostly," such as at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or greater, or 100%.

[0022] In addition, phraseology or terminology employed herein and not otherwise defined should be understood to be for purposes of description only and not for purposes of limitation. Furthermore, all publications, patents, and patent documents referred to herein are incorporated herein by reference in their entirety as if individually incorporated by reference. In the event of inconsistent usage between this document and those documents so incorporated by reference, the usage in the incorporated references should be considered to support that of this document, and in the event of irreconcilable inconsistencies, the usage in this document shall prevail.

[0023] Hydrogen gas (H2) can be formed electrochemically by a water splitting reaction in which water is split into oxygen gas (O2) and H2 gas at the anode and cathode of an electrochemical cell, respectively. Examples of such electrochemical processes include, but are not limited to, proton electrolyte membrane (PEM) electrolysis and alkaline water electrolysis (AWE). In such electrochemical reactions, the operating energy required to drive the water splitting electrolysis reaction is high due to additional energy costs as a result of various energy inefficiencies. For example, to reduce unwanted migration of ionic species between the electrodes, the cathode and anode may be separated by a separator, such as a membrane, which can reduce the migration of ionic species. Although the separator can improve the overall efficiency of the cell, this may come at the cost of additional resistive losses within the cell, which in turn increases the operating voltage. Other inefficiencies in water electrolysis may include solution resistive losses, electrical conduction inefficiencies, and / or electrode overpotentials, among others.

[0024] 1 is a schematic diagram of a typical water electrolyzer cell 100 that uses electrical power to convert water (H2O) into hydrogen gas (H2) and oxygen gas (O2). In one embodiment, the electrolyzer cell 100 comprises a housing, e.g., an overall chassis structure that defines and at least partially encloses an interior of the cell 100. The housing can divide the cell 100 into two half cells, a first half cell 111 and a second half cell 121. In one embodiment, the first and second half cells 111, 121 are separated by a separator 131, such as a membrane 131. In one embodiment, the separator 131 comprises a porous membrane (e.g., a microporous or nanoporous membrane), an ion exchange membrane, or an ion solvation membrane. In embodiments where separator 131 includes an ion exchange membrane, the membrane can be of different types, such as an anion exchange membrane (AEM), a cation exchange membrane (CEM), a proton exchange membrane (PEM), or a bipolar ion exchange membrane (BEM).

[0025] In embodiments where the separator 131 is a cation exchange membrane, the cation exchange membrane can be a conventional membrane, such as those available from Asahi Kasei Corp. (Tokyo, Japan), or from Membrane International Inc. (Glen Rock, NJ, USA), or from Chemours Company (Wilmington, DE, USA). Examples of cation exchange membranes include, but are not limited to, membranes sold by Chemours Company under the trade name N2030WX, and membranes sold by Asahi Kasei Corp. under the trade names F8020 / F8080 or F6801. Examples of materials that can be used to form the cation exchange membrane include, but are not limited to, perfluoropolymers containing anionic groups, such as sulfonic acid groups and / or carboxylic acid groups. However, it should be understood that in some embodiments, cation exchange membranes that are more restrictive and therefore restrict migration of one species of cation while allowing migration of another species of cation, depending on the need to restrict or allow migration of a particular cation or anionic species between electrolytes, can be used. Similarly, in some embodiments, depending on the need to restrict or allow migration of a particular anion species between electrolytes, anion exchange membranes may be used that are more restrictive, thus allowing migration of one species of anion while restricting migration of another species of anion. Such restrictive cation and anion exchange membranes are commercially available and can be selected by one of skill in the art.

[0026] In some examples, separator 131 can be selected such that it can function in acidic and / or alkaline electrolyte solutions, as appropriate. Other properties for separator 131 that may be desirable include, but are not limited to, high ionic selectivity, low ionic resistance, high burst strength, and high stability in electrolyte solutions within a temperature range of room temperature up to 150° C. or higher.

[0027] In one embodiment, the separator 131 is stable within a temperature range of about 0°C to about 150°C, for example, about 0°C to about 100°C, about 0°C to about 90°C, etc., for example, about 0°C to about 80°C, about 0°C to about 70°C, etc., for example, about 0°C to about 60°C, about 0°C to about 50°C, etc., for example, about 0°C to about 40°C, or about 0°C to about 30°C, etc.

[0028] To achieve a desired product or products in the electrolyte solution, it may be useful to use ion-specific ion exchange membranes that allow migration of one type of ion (e.g., cations for CEMs and anions for AEMs) but not another, or one type of ion and another.

[0029] In one embodiment, the first half cell 111 includes a first electrode 112, which may be disposed proximate to a separator 131, and the second half cell 121 includes a second electrode 122, which may be disposed proximate to the separator 131, for example, on the opposite side of the separator 131 from the first electrode 112. In one embodiment, the first electrode 112 is an anode for the electrolyzer cell 100 and the second electrode 122 is a cathode for the electrolyzer cell 100, and thus, in the remainder of this disclosure, the first half cell 111 may also be referred to as the anode half cell 111, the first electrode 112 may also be referred to as the anode 112, the second half cell 121 may also be referred to as the cathode half cell 121, and the second electrode 122 may also be referred to as the cathode 122. Each of the electrodes 112, 122 can be coated with one or more electrocatalysts to accelerate the reaction towards hydrogen gas (H2 gas) and / or oxygen gas (O2 gas). Examples of electrocatalysts include, but are not limited to, highly dispersed metals or alloys of platinum group metals such as platinum, palladium, ruthenium, rhodium, iridium, or combinations thereof such as platinum-rhodium, platinum-ruthenium, nickel mesh coated with ruthenium oxide (RuO2), or high surface area nickel.

[0030] The ohmic resistance of the separator 131 can affect the voltage drop across the anode 112 and the cathode 122. For example, as the ohmic resistance of the separator 131 increases, the voltage across the anode 112 and the cathode 122 can increase, and vice versa. In some embodiments, the separator 131 has a relatively low ohmic resistance and a relatively high ionic mobility. In some embodiments, the separator 131 has a relatively high hydration characteristic that increases with temperature, thus decreasing the ohmic resistance. By selecting a separator 131 with a lower ohmic resistance, as known in the art, the voltage drop across the anode 112 and the cathode 122 at a specified temperature can be reduced.

[0031] In one embodiment, the anode 112 is electrically connected to an external positive conductor 116 (also referred to as the "anode conductor 116") and the cathode 122 is electrically connected to an external negative conductor 126 (also referred to as the "cathode conductor 126"). When the separator 131 is wetted and in electrolytic contact with the electrodes 112 and 122 and an appropriate voltage is applied across the conductors 116 and 126, O2 gas is liberated at the anode 112 and H2 gas is liberated at the cathode 122. In one configuration, an electrolyte, for example, consisting of a solution of KOH in water, is pumped into the half cells 111, 121. For example, the electrolyte can flow into the anode half cell 111 through a first electrolyte inlet 114 and into the cathode half cell 121 through a second electrolyte inlet 124. In an embodiment, the flow of electrolyte through the anode half cell 111 traps the produced O2 gas as bubbles 113 that exit the anode half cell 111 through a first outlet 115. Similarly, the flow of electrolyte through the cathode half cell 121 can trap the produced H2 gas as bubbles 123 that can exit the cathode half cell 121 through a second outlet 125. Gas can be separated from the electrolyte downstream of the electrolyzer cell 100 using one or more suitable separators. In an embodiment, the produced H2 gas is dried and collected in a high pressure canister or pumped into further process elements. The O2 gas can simply be allowed to vent to the atmosphere or can be stored for other uses. In an embodiment, the electrolyte is recycled back into the half cells 111, 121 as needed.

[0032] In one embodiment, a typical voltage across the electrolyzer cell 100 (e.g., the voltage difference between the anode conductor 116 and the cathode conductor 126) is between about 1.5 volts (V) and about 3.0 V. In one embodiment, the operating current density for the electrolyzer cell 100 is about 0.1 A / cm 2 ~About 3A / cm 2Each cell 100 has a size large enough to produce very large quantities of H2 gas when operated at these current densities. In one embodiment, the active area of ​​each cell 100 (e.g., width x height for a rectangular cell) is about 0.25 square meters (m 2 ) ~ approx. 15m 2 , about 1m 2 ~about 5m 2 etc., for example, about 2m 2 ~about 4m 2 , about 2.25m 2 ~about 3m 2 etc., approximately 2.5m 2 ~ approx. 2.9m 2 In one embodiment, the total volume (e.g., width x height x depth) of each cell is approximately 0.1 cubic meters (m 3 ) ~ approx. 2m 3 , about 0.15m 3 ~about 1.5m 3 etc., for example, about 0.2 m 3 ~ approx. 1m 3 , approx. .25m 3 ~about 0.5m 3 etc., for example, about 0.275 m 3 ~about 0.3m 3 In one embodiment, the total volume of the entire electrolyzer system (e.g., the combined volume of all cells in all stacks in a plant) is about 1 m 3 ~about 25,000m 3 , about 5m 3 ~about 2,500m 3 etc., for example, about 10m 3 ~ approx. 100m 3 , about 25m 3 ~about 75m 3 For example, about 30 m 3 ~About 50m 3 It is.

[0033] Removable Electrode Assembly As discussed above, the efficiency of an electrolyzer cell may depend on the resistive losses between the anode and the cathode. One parameter that may affect the ohmic resistance between the electrodes is the distance between the anode and the cathode, with a larger gap between the electrodes resulting in a larger resistance compared to a correspondingly smaller gap. Thus, in certain embodiments, an electrolyzer cell may be configured such that the space or gap between the anode and the cathode is as small as possible. In one exemplary configuration, one or both of the anode and the cathode are positioned such that the electrodes are in contact with the separator, also referred to as a "zero gap" configuration. In an embodiment of the zero gap configuration, one face or surface of the anode is in contact with a first surface of the separator, and one face or surface of the cathode is in contact with an opposing second surface of the separator.

[0034] Zero gap technology has been used in the chlor-alkali industry for some time. Most or all chlor-alkali zero gap configurations include a cathode current collector (such as a sheet of drawn nickel) welded to a support (such as a support rib) which is in turn welded to the cathode half cell. The anode, typically fabricated from titanium, contains a sheet of drawn titanium welded to a support which is in turn welded to the anode half cell. The drawn titanium sheet anode is typically coated with a platinum group metal-containing catalyst. Typically, the titanium structure on the anode side supports a separator (e.g., a membrane). In one embodiment, a resilient element is positioned adjacent to the drawn nickel sheet on the cathode side, and a coated fine woven mesh is then folded over the resilient member, thereby affixing it under the drawn nickel sheet. This cathode assembly can then be positioned over the anode assembly, which includes a supported separator (e.g., a membrane, supported by the drawn titanium sheet of the anode). This entire structure can be compressed, thereby loading the woven mesh on the cathode side against both the elastic element and the membrane, the membrane onto the stretched titanium sheet on the anode side, and the elastic element onto the stretched nickel sheet on the cathode side, resulting in a zero gap structure. The coated stretched titanium sheet forms the anode electrode, the coated fine nickel mesh forms the cathode electrode, and the stretched nickel sheet acts as the cathode current collector.

[0035] The zero gap architecture minimizes or eliminates the relatively resistive fluid gap between the electrodes and the separator, which in turn reduces the distance between the electrodes in the electrolyzer cell, thereby minimizing the prevailing high cell voltage source. However, the zero gap architecture will be most beneficial if the contact resistance across the two electrode contacts is low. For example, the zero gap architecture can be made possible by the low electrical contact resistance inherent in nickel-nickel contacts and the low contact resistance between a surface coated with a platinum group metal catalyst and another nickel surface.

[0036] Typically, both electrodes are coated with one or more catalytic coating compositions. The catalytic coating materials have a finite useful life, which is typically inversely proportional to the current density at which the electrolyzer cell is operated. The voltage required to be applied across the cell for the same hydrogen gas production will increase as the catalytic coating material or materials degrade over time. At some point, it becomes economically advantageous to replace one or both of the electrodes to restore full catalytic activity in the cell.

[0037] In previous cells, one or both electrodes are bonded to the support structure using a weld to ensure an electrical connection between the electrode and the support structure. However, such a welded connection between the electrode and the rest of the cell structure can make the process of replacing the electrode more time consuming and labor intensive. Servicing the cell can require disassembly of the entire cell, breaking the weld, replacing the electrode, and rewelding before the cell can be re-operated.

[0038] 2 shows an example of an electrolyzer cell pan structure 200 that can provide a zero gap architecture, for example, where one or both electrodes are pressed against a separator without the electrodes being welded to any other structure of the electrolyzer cell 200. The electrolyzer cell 200 includes a housing that at least partially surrounds the cell interior and electrodes 202, 204 that are coupled to the housing within the cell interior, where each electrode 202, 204 can be part of a corresponding half cell. For example, the first electrode 202 is included as part of the first half cell and the second electrode 204 is included as part of the second half cell. In a non-limiting example, the first electrode 202 is the anode of the electrolyzer cell 200 and the second electrode 204 is the cathode of the electrolyzer cell 200, and thus the electrodes 202, 204 will also be referred to as the anode 202 and the cathode 204, and the corresponding half cells will also be referred to as the anode half cell and the cathode half cell. However, there are instances where the anode 202 and the cathode 204 are more generally referred to as "electrodes 202, 204" or "electrodes 202, 204."

[0039] The separator 210 can be installed between the anode half cell and the cathode half cell, for example, by being positioned between the anode 202 and the cathode 204. As discussed above, the separator 210 can be configured to reduce migration of certain species between the electrodes 202, 204 while allowing one or more other species to pass from the anode half cell to the cathode half cell and / or from the cathode half cell to the anode half cell. In certain examples, the separator 210 comprises a diaphragm, a membrane electrode assembly (MEA), or a membrane such as an ion exchange membrane (IEM) (e.g., an anion exchange membrane (AEM), a cation exchange membrane (CEM), or a proton exchange membrane (PEM)), a bipolar ion exchange membrane (BEM), an ion solvating membrane (ISM), or a microporous or nanoporous membrane. In some examples, separator 210 can comprise more than one type of separator, e.g., more than one type of membrane (as is the case for a bipolar ion exchange membrane), and / or can be part of a composite structure (such as a membrane electrode assembly (MEA)), which can also include one or more separator components (e.g., to separate the anion exchange membrane (AEM) from the cation exchange membrane (CEM)), or one or more support structures to provide mechanical integrity to the one or more separators. In addition to these components, individual gaskets or gasket tapes may be provided between and along the periphery of the components to seal the compartments from fluid leakage.

[0040] As discussed above, in one embodiment, the electrodes 202, 204 are each mounted in a "zero gap" configuration with respect to the separator 210. While the term "zero gap" would typically imply that one or both electrodes 202, 204 are in actual physical contact with the separator 210, in this disclosure the term "zero gap" is expanded to mean that all the structure between the two current collectors 226, 230 (described below) is in mechanical contact with no space for liquid electrolyte to collect. In other words, there may be one or more spacer materials interposed between one or both of the current collectors 226, 230 and the separator 210, but the overall structure would still be considered a "zero gap architecture" as that term is used herein, as long as there is no liquid electrolyte gap between the two current collectors 226, 230.

[0041] The enclosure of the cell 200 can include pan assemblies for one or both of the half cells. In some embodiments, each pan assembly includes a pan with an interior for receiving electrolyte. For example, the anode half cell can include an anode pan assembly 212 including an anode-side pan 214 for receiving anolyte, and the cathode half cell can include a corresponding cathode pan assembly 216 including a cathode-side pan 218 for receiving catholyte. The pan assemblies 212, 216 can be configured such that electrolyte flowing through the pans 214, 218 will contact its corresponding electrode 202, 204, such that, for example, H2 gas can be generated from the cathode 204, and in some embodiments, O2 gas can be generated from the anode 202. Each pan assembly 212, 216 may also include an inlet for receiving electrolyte into the interior of the pan 214, 218 and one or more outlets (not shown) so that the electrolyte and generated gases may exit the pan 214, 218.

[0042] In one embodiment, each electrode 202, 204 is electrically connected to its corresponding pan 214, 218 such that electrical current can flow from the pan 214, 218 to the electrode 202, 204 (as is the case for current flowing from the anode side pan 214 to the anode 202) or from the electrode 202, 204 to the pan 214, 218 (as is the case for current flowing from the cathode 204 to the cathode side pan 218). Each half cell can include one or more additional structures to provide electrical connections between the electrodes 202, 204 and the pans 214, 218. For example, one or both of the electrodes 202, 204 can be part of a corresponding electrode assembly that includes the electrodes 202, 204 and one or more additional structures that enhance the operation of the electrolyzer cell 200. For example, the first electrode 202 (e.g., anode 202) can be part of a first electrode assembly 222 (which will also be referred to herein as an "anode assembly 222"), and the second electrode 204 (e.g., cathode 204) can be part of a second electrode assembly 224 (which will also be referred to herein as a "cathode assembly 224").

[0043] In some embodiments, one or both of the electrode assemblies 222, 224 includes its corresponding electrode 202, 204, a current collector, and an optional resilient element (also sometimes referred to as a "mattress"). In some embodiments, the anode assembly 222 includes the anode 202, an anode current collector 226, and an optional anode-side resilient element 228. Similarly, in some embodiments, the cathode assembly 224 includes the cathode 204, a cathode current collector 230, and an optional cathode-side resilient element 232.

[0044] Each electrode assembly 212, 214 is coupled to its respective pan 214, 218, i.e., such that electrical connections exist between the anode 202 and the anode side pan 214 and between the cathode 204 and the cathode side pan 218. In one embodiment, one or both of the electrodes 202, 204 comprises a fine mesh structure, such as a fine woven mesh. A fine mesh, such as a woven mesh, is advantageous because it provides a large relative surface area, a relatively large open area for electrolyte and gas flow to and from the electrodes, e.g., about 1 m 2 ~about 4m 2 At least 1m of 2 It has been found that these make excellent electrodes for electrolyzer cells because they are readily available in sizes large enough for large commercial electrolyzer cells, with active areas of 100 nm to 150 nm.

[0045] In some embodiments, a fluid pressure differential can be applied across the separator 210 (e.g., pressure on the cathode side of the separator 210 is greater than on the anode side, or vice versa). The pressure differential can act on the resilient elements 228, 232 to load the electrodes 202, 204 and create effective electrical contact across the active areas of the electrodes 202, 204, particularly for fine mesh electrodes, without requiring welding to bond the electrodes 202, 204 to other structures within the electrolyzer cell 200.

[0046] In some embodiments, the woven mesh of one or both of the electrodes 202, 204 comprises a network of sets of intersecting wires that may be perpendicular or angled relative to one another, alternately crossing and bending over one another. For example, any particular wire may alternate between passing under an adjacent intersecting wire and then over the next intersecting wire. In some embodiments, one or both of the electrodes 202, 204 may comprise a woven wire mesh electrode formed from wires having a wire diameter of about 0.18 mm diameter with an opening in the mesh of about 0.44 mm and an open area of ​​about 50% to about 60%, such as about 50% to about 55%. In some embodiments, one or both of the electrodes 202, 204 are formed from a stretched mesh, where one or both of the electrodes 202, 204 are fabricated from a sheet of material that is about 0.13 mm thick with a diamond-shaped long side (LWD) of about 2 mm and a diamond-shaped short side (SWD) of about 1 mm.

[0047] In some embodiments, one or both of the anode 202 and the cathode 204 are made primarily or entirely from nickel. Fabricating both the anode 202 and the cathode 204 from nickel allows for the use of non-welded electrodes, for example, fabricated from a fine woven mesh, for both electrodes 202, 204, since nickel has a very low contact resistance. In some embodiments, one or both of the anode 202 and the cathode 204 are coated with one or more catalytic materials, for example, in the form of one or more catalytic coating layers on the electrodes 202, 204. In some embodiments, the one or more catalytic materials can be electrically conductive.

[0048] The current collectors 226, 230 of each electrode assembly 222, 224 act to distribute electrical current flowing into or out of its respective electrode 202, 204. In one embodiment, the current collectors 226, 230 of each electrode assembly 222, 224 comprise a rigid structure, such as a rigid metal plate or mesh, that is electrically connected, either directly or indirectly, to its corresponding electrode 202, 204. In one embodiment, each current collector 226, 230 can comprise an expanded metal sheet, such as an expanded nickel sheet.

[0049] In some embodiments, each elastic element 228, 232 comprises a compressible, expandable structure that provides a controlled load when compressed. For example, the elastic elements 228, 232 can be compressed between the separator 210 and the current collectors 226, 230, and the resulting load that occurs as the elastic elements 228, 232 attempt to expand back to their fully extended positions acts to load the electrodes 202, 204 against the separator 210 and provide a zero gap configuration between the electrodes 202, 204 and the separator 210. In some embodiments, the elastic elements 228, 232 are also electrically conductive (e.g., the elastic elements 228, 232 are made of or coated with a conductive material such as nickel) so that electricity will be conducted from the current collectors 226, 230 to the electrodes 202, 204 or vice versa. In one embodiment, one or more elastic elements 228, 232 each comprise one or more conductive filaments woven together into the elastic layer that can expand and collapse to apply a controlled load when the elastic layer is compressed. In some embodiments, one or both of the elastic elements 228, 232 can be a corrugated mesh having a preload of about 2 pounds per square inch when compressed by about 3 mm. In one embodiment, the uncompressed thickness of one or both of the elastic elements 228, 232 can be about 5 mm to about 7 mm. One or both of the elastic elements 228, 232 can have a corrugation pitch of about 10 mm. In one embodiment, one or both of the elastic elements 228, 232 are formed from a wire having a wire diameter of about 0.15 mm.

[0050] 2, both the anode assembly 222 and the cathode assembly 224 include elastic elements 228, 232, such that, for example, the anode-side elastic element 228 provides a loading force to compress the anode 202 against one side of the separator 210 and the cathode-side elastic element 232 provides a loading force to compress the cathode 204 against the opposing side of the separator 210. In other embodiments, discussed below, elastic elements are present only on one side of the separator 210 (e.g., only the anode assembly 222 includes the elastic element 228 and the cathode assembly 224 omits the elastic element 232, or vice versa, such that only the cathode assembly 224 includes the elastic element 232 and the anode assembly 222 omits the elastic element 228). In such a configuration, the resilient elements on only one side of the separator 210 can create a sufficient compressive load such that both electrodes 202 , 204 are compressed against the opposing side of the separator 210 .

[0051] In certain embodiments, the current collectors 226, 230 can be coupled to their respective pans 214, 218, e.g., such that the current collectors 226, 230 are electrically connected to the pans 214, 218 that provide a portion of the electrical path between the electrodes 202, 204 and the pans 214, 218. To accommodate this electrical connection between the current collectors 226, 230 and their corresponding pans 214, 218, in certain embodiments, each pan assembly 212, 216 includes one or more ribs extending between the electrode assembly 222, 224 and the rear wall of the pan. For example, the anode pan assembly 212 can include one or more ribs 234 extending between the rear wall 236 of the anode side pan 214 and the anode assembly 222, while the cathode pan assembly 216 can include one or more ribs 238 extending between the rear wall 240 of the cathode side pan 218 and the cathode assembly 224. One or more ribs 234 may be welded to a rear wall 236 of the anode side pan 214 , while one or more ribs 238 may be welded to a rear wall 24 of the cathode side pan 218 .

[0052] The one or more ribs 234, 238 of each pan assembly 212, 216 can be electrically coupled to its corresponding electrode assembly 222, 224 by one or more welds, such as one or more welds 242 that electrically couple the anode assembly 222 to the one or more ribs 234 of the anode pan assembly 212 and one or more welds 244 that electrically couple the cathode assembly 224 to the one or more ribs 238 of the cathode pan assembly 216. As shown in FIG. 2, in one embodiment, the one or more welds 242 can electrically couple the one or more ribs 234 to the anode current collector 226 and the one or more welds 244 can electrically couple the one or more ribs 238 to the cathode current collector 230.

[0053] In some embodiments, the electrodes 202, 204 can be electrically connected to one or more ribs 234, 238 and one or more welds 242, 244. In embodiments where the electrode assemblies 222, 224 include current collectors 226, 230 that are welded to the one or more ribs 234, 238, the electrodes 202, 204 of the electrode assemblies 222, 224 can then be electrically coupled to the current collectors 226, 230 via physical contact between the electrodes 202, 204 and the current collectors 226, 230, e.g., the flexible electrodes 202, 204 are wrapped around the back side of the current collectors 226, 230 such that there is physical contact between the mesh electrodes 202, 204 and the current collectors 226, 230 and / or through elastic elements 228, 232, which may also be made from a conductive material such as metal. In one embodiment, the mesh electrodes 202, 204, current collectors 226, 230, and resilient elements 228, 232 of each electrode assembly 222, 224 can each be made from nickel. When the load pressure across the interface is high enough (e.g., the load pressure provided by one or both of the resilient elements 228, 232 and the pressure differential across the cell), the contact resistance of the contact point between the nickel surface and another conductive material is so low that when the nickel electrodes 202, 204 contact the nickel resilient elements 228, 232 or the nickel current collectors 226, 230, electricity will easily flow through the contact point between the two nickel structures. As explained in more detail below, this can allow the electrodes 202, 204 to be bonded to the electrode assemblies 222, 224 without requiring welding between the electrodes 202, 204 and another structure, while still providing low resistance between the electrodes 202, 204 and the remainder of the electrolyzer cell 200.

[0054] The electrodes 202, 204 can be electrically coupled to an electrical current supply via one or more ribs 234, 238 and one or more welds 242, 244. During operation of the electrolyzer cell 200, current flows from a conductor (similar to the anode conductor 116 in the electrolyzer cell 100 of FIG. 1) contacting the anode side pan 214, the current can then flow to one or more ribs 234 of the anode pan assembly 212 (e.g., through a weld between the rib 234 and the back wall 236), then through one or more welds 242, to the anode current collector 226, and then into the anode 202 (e.g., through a contact between the anode current collector 226 and the anode 202 or through the conductive anode side resilient element 228). The current can then pass between the anode 202 and the cathode 204 through the separator 210. Current can then flow from the cathode 204 to the cathode current collector 230 (e.g., via contact between the cathode 204 and the cathode current collector 230 or via the conductive cathode-side resilient element 232), then from the cathode current collector 230 to the one or more ribs 238 via one or more welds 244. Current can then flow from the one or more ribs 238 to the cathode side pan 218 (such as via welds between the one or more ribs 238 and the rear wall 240 of the cathode side pan 218), and finally out of the electrolyzer cell 200 via a conductor (similar to the cathode conductor 126 in the electrolyzer cell 100 of FIG. 1 ) that contacts the cathode side pan 218.

[0055] The geometry and spacing of one or more ribs 234, 238 can dictate the current flow through the pan assemblies 212, 216. The geometry of the ribs 234, 238 can include, without limitation, the number of ribs 234, 238, the height of the ribs 234, 238 (e.g., the distance between the back walls 236, 240 and the electrode assemblies 222, 224 to which the ribs 234, 238 are connected), the physical design of the ribs 234, 238, the pitch between adjacent ribs 234, 238, and / or the thickness of the ribs 234, 238. As current flows through the ribs 234, 238 and the welds 242, 244, the geometry, spacing or density, and / or cross-sectional area of ​​the welds 242, 244 can also affect the current flow through the pan assemblies 212, 216. For example, as increasingly higher currents flow through the cell, the density and cross-sectional area of ​​the welds 242, 244 can affect localized Joule heating and the formation of localized hot spots, which can cause damage to the separator 210. In certain embodiments, the geometry, spacing, and cross-sectional area of ​​the ribs 234, 238 and / or welds 242, 244 can facilitate efficient operation of the electrolyzer cell 200 at high current densities.

[0056] Further details regarding the geometry and other configurations of the one or more ribs 234, 238 and the one or more welds 242, 244 for coupling the one or more ribs 234, 238 to the electrode assemblies 222, 224 (e.g., current collectors 226, 230) are described in U.S. Pat. No. 11,390,956, issued July 19, 2022, and entitled "ANODE AND / OR CATHODE PAN ASSEMBLIES IN AN ELECTROCHEMICAL CELL, AND METHODS OF USE AND MANUFACTURE THEREOF," the disclosure of which is incorporated by reference in its entirety into this specification.

[0057] In certain embodiments, one or both of the pan assemblies 212, 216 also include a baffle plate that fits within its corresponding pan 214, 218, generally aligned with the orientation of the pans 214, 218 and electrode assemblies 222, 224 of that particular pan assembly 212, 216. For example, the anode pan assembly 212 can include an anode-side baffle plate 246 that is located within the interior of the anode-side pan 214, and the cathode pan assembly 216 can include a cathode-side baffle plate 248 that is located within the interior of the cathode-side pan 218. Each baffle plate 246, 248 is coupled to its corresponding set of one or more ribs 234, 238 to position the baffle plate 246, 248 within its corresponding pan 214, 218, e.g., at a defined position relative to its corresponding electrode assembly 222, 224 and / or its corresponding back wall 236, 240.

[0058] In one embodiment, one or both of the baffle plates 246, 248 comprise a solid plate configured to fit over or within one or more ribs 234, 238 of its corresponding pan assembly 212, 216. In other embodiments, one or both of the baffle plates 246, 248 may comprise a stretched metal plate or mesh. In one embodiment, one or both of the baffle plates 246, 248 are made from a conductive metal, such as, but not limited to, nickel, stainless steel, and the like. In another embodiment, one or both of the baffle plates 246, 248 are made from a polymeric material.

[0059] As will be appreciated by one of ordinary skill in the art, the contribution of internal power dissipation to the internal temperature distribution within the electrolyzer cell 200 can be reduced or minimized through operating conditions such as the temperature and flow rate of electrolyte flowing through the electrolyzer cell 200 (e.g., through the pan assemblies 212, 216). High electrolyte flow rate increases, and in some embodiments maximizes, convective heat transfer within the electrolyzer cell 200, thereby helping to reduce or minimize heat storage and corresponding attendant temperature rise within the cell 200 that may otherwise result from high current densities. The baffle plates 246, 248 can provide mixing of the electrolyte as it flows through the pan assemblies 212, 216 and enhance convective heat transfer within the electrolyte during electrolysis.

[0060] In some embodiments, the baffle plates 246, 248 are designed and positioned within their corresponding pans 214, 218 so that gas produced in the electrode assemblies 222, 224 can mix with the electrolyte on the side of the baffle plates 246, 248 closest to the electrode assemblies 222, 224, resulting in a relatively low density column and defining a riser section. The low density mixture can rise relatively quickly through the riser section. Once above the top of the baffle plates 246, 248, the gas breaks off and flows into an outlet (such as a manifold, not shown in FIG. 2). A small portion of the electrolyte can then follow the side of the baffle plates 246, 248 closer to the rear walls 236, 240 of the pans 214, 218 (i.e., the side opposite the electrode assemblies 222, 224) and fall back into the faller region, thereby creating a circulation loop.

[0061] Gas generated at the electrodes 202, 204 impinges on the electrolyte flow, lifting some of the electrolyte upward and disturbing some of the electrolyte to the side. Gas lift occurs along the area adjacent to the electrode assemblies 222, 224. The presence of the baffle plates 246, 248 creates strong circulation in the pan assemblies 212, 216. The electrolyte flow in the riser section on the side of the baffle plates 246, 248 closest to the electrode assemblies 222, 224 is strongly directed upward due to gas lift, and the flow in the faller section on the side of the baffle plates 246, 248 closest to the back walls 236, 240 is strongly directed downward. The relatively high velocities and shear rates in the riser section help sweep gas away from the electrode assemblies 222, 224 and provide efficient top-to-bottom mixing in the pans 214, 218, promoting increased convective cooling.

[0062] The baffle plates 246, 248 can be used to create a rapid flowing circulation loop so that the electrolyte remains substantially isothermal as it flows through the pan assemblies 212, 216. Due to the high degree of top-to-bottom mixing and circulation, rapid thermal equilibration of the electrolyte can be achieved as it flows into and through the pan assemblies 212, 216. Another advantage is that the relatively cool electrolyte can be introduced relatively quickly into the pan assemblies 212, 216 where it can equilibrate with the warm circulating electrolyte fluid. The circulation rate (i.e., wrap of the recirculation loop during the electrolyte's transit through the pan assemblies 214, 218) can be any value between 1 and 200. A high circulation rate can also help promote a greater shear rate adjacent to the separator 210, sweep gas away from the separator 210, and / or enhance or maximize heat transfer from the separator 210 to the electrodes 202, 204.

[0063] Further details regarding the baffle plates in the pan assemblies 212, 216 are described in U.S. Pat. No. 11,444,304, issued September 13, 2022, and entitled "ANODE AND / OR CATHODE PAN ASSEMBLIES IN AN ELECTROCHEMICAL CELL, AND METHODS TO USE AND MANUFACTURE THEREOF," the disclosure of which is incorporated by reference herein in its entirety.

[0064] The pan assemblies 212, 216 can be coupled together and enclose the interior of the electrolyzer cell 200. For example, a flange 250 of the anode side pan 214 can be coupled to a corresponding flange 252 of the cathode side pan 218 using one or more fasteners 254, etc. In the embodiment shown in Figure 2, the one or more fasteners 254 include one or more bolts and corresponding nuts that can be used to securely affix the flanges 250 and 252 together, enclose the interior of the pans 214, 218, and form the overall electrolyzer cell 200.

[0065] The electrodes 202, 204 of the electrolyzer cell 200 are coupled to other structures of its pan assemblies 212, 216 without the use of welding of the electrodes 202, 204. In other words, the anode 202 is not welded to any structure of the anode assembly 222 or the anode pan assembly 212, and the cathode 204 is not welded to any structure of the cathode assembly 224 or the cathode pan assembly 216. As discussed above, the catalytic coating, which may be present on the anode 202 or the cathode 204, or both, has a finite life during operation of the electrolyzer cell 200. Furthermore, the catalytic coating tends to lose activity over time such that eventually one or both of the electrodes 202, 204 will need to be replaced to refresh the catalytic coating. 2 above, each electrode 202, 204 is simply placed in intimate contact with its corresponding current collector 226, 230 and / or its corresponding resilient element 228, 232. In particular, in examples where the electrodes 202, 204 and one or both of the current collectors 226, 230 and resilient elements 228, 232 comprise nickel, the low contact resistance at the nickel / nickel interface makes the use of non-welded electrodes 202, 204 particularly viable. However, in other examples, one or both of the electrode assemblies 222, 224 can include one or more fastening structures.

[0066] 3 and 4 show examples where the electrode assemblies 222, 224 include a fastening structure that does not include welding the electrodes 202, 204 to another structure, i.e., without any welding on the electrodes 202, 204. For example, as shown in FIG. 3, the anode assembly 222 includes a fastening structure in the form of a clamp 256 that fits over the anode assembly 222 and clamps together the anode 202, the anode-side resilient element 228, and the anode current collector 226. Similarly, the cathode assembly 224 can include a corresponding fastening structure in the form of a clamp 258 that fits over the cathode assembly 224 and clamps together the cathode 204, the cathode-side resilient element 232, and the cathode current collector 230. In an example, each clamp 256, 258 can apply a clamping force to its corresponding electrode 202, 204 and / or its corresponding current collector 226, 230. For example, one or both of the clamps 256, 258 can be made from a resilient material and can be sized to be slightly less than the combined thickness of the electrodes 202, 204, the resilient elements 228, 232, and the current collectors 226, 230 such that when the clamps 256, 258 are fitted over the electrode assemblies 222, 224, the clamps 256, 258 will apply a clamping force against the electrodes 202, 204 and / or the current collectors 226, 230. In one embodiment, the clamps 256, 258 are relatively thin such that the clamps 256, 258 will not increase the separation between the current collectors 226, 230, e.g., so that the clamps 256, 258 do not contact or interfere with other structures of the cell 200.

[0067] 3 illustrates an embodiment in which both the anode assembly 222 and the cathode assembly 224 include corresponding elastic elements 228, 232 such that the anode-side elastic element 228 exerts a first controlled load on the anode 202 to compress the anode 202 against a first side of the separator 210 and provide a zero gap architecture on the anode side of the separator 210, and the cathode-side elastic element 232 exerts a second controlled load on the cathode 204 to compress the cathode 204 against an opposing second side of the separator 210 and provide a zero gap architecture on the cathode side of the separator 210. However, as discussed above, the electrolyzer cell is not limited to a configuration in which both electrode assemblies 222, 224 include elastic elements.

[0068] FIG. 4 shows an embodiment in which only one of the electrode assemblies includes a resilient element. In FIG. 4, structures that are the same or substantially the same as those in the embodiment of FIG. 3 are given the same reference numbers. The only difference between the exemplary electrolyzer cell of FIG. 3 and that of FIG. 4 is that the anode assembly 222′ in FIG. 4 includes only the anode 202 and the anode current collector 226, and does not include an anode-side resilient element. Instead, the resilient element 232, which is part of the cathode assembly 224, is configured to produce sufficient controlled load to both compress the cathode 204 onto the separator 210 and also to compress the separator 210 onto the anode 202, providing a zero gap architecture on both the anode and cathode sides of the separator 210. 4, the anode 202 contacts only the anode current collector 226, and the corresponding clamp 256' is smaller because it needs to fit only across the combined thickness of the anode 202 and anode current collector 226. The cathode assembly 224 in FIG. 4 is the same or substantially the same as that described above with respect to the embodiment of FIG.

[0069] Other bonding structures can also be used to ensure electrical contact between one or both of the electrodes 202, 204 and their corresponding current collectors 226, 230 and / or corresponding resilient elements 228, 232. FIGS. 5A-5C show a cross-sectional view of a portion of one of the electrode assemblies in an electrolyzer cell with an edge insert 260 that can be inserted into a seam 262 formed between the electrode assembly and the pan. The edge insert 260 can include one or more structures that provide a non-welded bond between the electrode and its corresponding current collector and / or its corresponding resilient element. FIGS. 5A-5C show an example in which the edge insert 260 is used to bond and secure the cathode 204 to the cathode current collector 230 and / or the cathode-side resilient element 232 to form the cathode assembly 224, where the edge insert 260 is used along the seam 262 between the cathode assembly 224 and the cathode-side pan 218. 5A-5C also do not depict the structure associated with the corresponding anode assembly 222 and anode half cell. However, one skilled in the art will understand that similar or the same edge insert 260 may be used to bond and / or secure the anode 202 to the anode current collector 226 and / or anode-side resilient element 228 along the seam between the anode assembly 222 and the anode-side pan 214.

[0070] 5A-5C, the edge insert 260 includes a top cover portion 264, a seam portion 266, and an optional flange portion 268. In one embodiment, the top cover portion 264 is sized and configured to fit over the cathode 204 on the same side of the cathode 204 on which the separator 210 will be positioned. The top cover portion 264 can also be configured such that if any of the wires forming the elastic element 232 protrude through the open space of the mesh cathode 204, they will not come into contact with the separator 210. As will be understood by one of ordinary skill in the art, it is common for the ends of the wires at the edge of the elastic element 232 to protrude therethrough and damage the separator 210, for example, by piercing or otherwise perforating through the separator 210. In this manner, the top cover portion 260 can protect the separator 210 from piercing by loose protruding wire ends of the elastic element 232.

[0071] In one embodiment, the seam portion 266 is sized and configured to fit within the seam 262 between the cathode assembly 224 and the cathode side pan 218. The seam 262 can be relatively narrow, for example, about 1 mm to about 5 mm, such as about 2 mm or less, such that the seam portion 266 should be narrower than the small gap. The relatively narrow seam portion 266 can allow a person assembling the electrolyzer cell to simply insert the seam portion 266 of the rim insert 260 into the gap formed in the seam 262 without having to use any tools or other specialized equipment to do so. This greatly simplifies the installation process for a person assembling the electrolyzer cell.

[0072] In some embodiments, the edge insert 260 can also include one or more structures to engage the electrode assembly 224. In the embodiment shown in FIGS. 5A-5C, the edge insert 260 includes a deformable protrusion 270 located on the seam portion 266. In the embodiment shown, the protrusion 270 is located at a distal end of the seam portion 266, but the protrusion 270 can be located at another location along the seam portion 266, for example, if the seam portion 266 is longer than the combined thickness of the cathode 204, the current collector 230, and the elastic element 232. As can be seen in FIG. 5A, the protrusion 270 can be configured to protrude from the seam portion 266 on the same side of the seam portion 266 that would be located proximate the cathode assembly 224. The protrusion 270 can be deformable between an extended position and a compressed position. When the seam portion 266 is inserted into the gap between the cathode assembly 224 and the pan 218 at the seam 262, the deformable protrusion 270 will be deformed (e.g., squeezed) by the cathode 204 toward the seam portion 266 such that the protrusion 270 moves from its extended position (as shown in FIG. 5A ) to its squeezed position (as shown in FIG. 5B ). The deformation of the protrusion 270 can allow the seam portion 266 and the protrusion 270 to fit within the gap between the cathode 204 and the wall of the pan 218. After the seam portion 266 is inserted deep enough into the seam 262, the protrusion 270 will no longer be engaged by the cathode 204 such that the protrusion 270 can recoil back toward its extended position away from the seam portion 266, as shown in FIG. 5C . When the protrusion 270 returns to its extended position, the protrusion 270 can engage a back side of the cathode 204, such as a portion of the cathode 204 that is folded over the back side of the cathode current collector 230. In one embodiment, the protrusion 270 can provide a clamping force similar to the clamping force discussed above with respect to the clamps 256, 258 in FIG.

[0073] In one embodiment, the rim insert 260 is a resilient rim insert that includes at least one structure that resiliently engages the electrode assembly 222, 224 to which the rim insert 260 is coupled. In one embodiment, the resilient structure that resiliently engages the electrode assembly 222, 224 is a protrusion 270, described above.

[0074] In one embodiment, the flange portion 268 of the rim insert 260 can be configured to fit over the flange 252 of the pan 218. The flange portion 268 can provide additional stability for the rim insert 260 after it is inserted into place and can provide further assurance that the rim insert 260 will be inserted to a desired depth appropriate to the cathode assembly 224 and pan 218 and that the rim insert 260 will be oriented as desired relative to the cathode assembly 224 and pan 218.

[0075] In one embodiment, the edge insert 260 can be sized to extend along a substantial length of the seam 262, for example, along all or substantially all of at least one edge of the electrode assemblies 222, 224. In another embodiment, the edge insert 260 can have a length along the edge of the electrode assemblies 222, 224 that is less than the length of the seam 262, but multiple edge inserts 260 can be used around the periphery of the electrode assemblies 222, 224 to secure the electrode assemblies 222, 224 together such that there will be sufficient electrical contact between each electrode 202, 204 and its corresponding current collector 226, 230 and / or its corresponding resilient element 228, 232.

[0076] In one embodiment, the rim insert 260 is made from a plastic or other polymeric material that is preferably chemically inert and resistant to the electrolyte that will flow through the corresponding pans 214, 218. In one embodiment, the plastic or polymeric material of the rim insert 260 comprises a moldable material, such as an injection moldable thermoplastic, including, but not limited to, polypropylene, polyethylene, acrylonitrile butadiene styrene (ABS), nylon, and polyethylene terephthalate (PET).

[0077] 5A-5C, the electrode 204 is bent around from the separator side of the electrode assembly 224 (i.e., the top side in FIGS. 5A-5C) to the back side of the electrode assembly 224 such that a portion of the electrode 204 contacts the current collector 230 and the edge insert 260 engages the electrode 204 on the back side of the electrode assembly 224 (e.g., the protrusion 270 engages the back side of the electrode 270). In another embodiment, shown in FIG. 6, the electrode assembly 224' is configured such that the electrode 204' is positioned only on the separator side of the electrode assembly 224' and the electrode 204' does not wrap around the electrode assembly 224' and does not contact the current collector 230. In such an embodiment, the loading force provided by the elastic element 232 is sufficient to hold the electrode 204' in place relative to the rest of the electrode assembly 224', and the rim insert 280 is not configured to actually secure the electrode 204' to the electrode assembly 224'. Rather, the rim insert 280 is configured simply to prevent wires or other structures at the edge of the electrode assembly 224' from protruding into and damaging the separator, as discussed above. Otherwise, the rim insert 280 can be substantially similar or the same as the rim insert 260 of FIGS. 5A-5C , which engages the electrode 204 on the back side of the electrode assembly 224. For example, the rim insert 280 can include a top cover portion 282, a seam portion 284, and an optional flange portion 286, which can serve similar or the same functions as the top cover portion 264, the seam portion 266, and the flange portion 268 of the rim insert 260.

[0078] In one embodiment, the edge insert 280 includes a deformable protrusion 288 located on the seam portion 284, e.g., at a distal end of the seam portion 284. The protrusion 288 can be similar to the protrusion 270, for example, by being configured to protrude from the seam portion 284 on a side of the seam portion 284 (e.g., on the side opposite the flange portion 286) that will be positioned proximate the electrode assembly 224'. The protrusion 288 can be deformable between an extended position and a compressed position such that when the seam portion 284 is inserted into the gap between the electrode assembly 224' and the pan 218, the deformable protrusion 288 will be deformed (e.g., compressed) toward the seam portion 284 such that the protrusion 288 moves from its extended position to its compressed position (similar to the movement of the protrusion shown between FIGS. 5A and 5B). After the seam portion 284 is inserted sufficiently deep into the seam, the protrusion 288 will no longer be engaged by the electrode assembly such that the protrusion 288 may rebound back toward its extended position and engage the back side of the current collector 230.

[0079] For example, the use of non-welded electrodes 202, 204 with bendable and formable electrodes 202, 204 bent around the remainder of the electrode assembly 222, 224 (as shown in the embodiment of FIG. 2), with fastening structures (such as clamps 256, 258 shown in FIGS. 3 and 4), with edge inserts 260, 280 of FIGS. 5A-5C or 6, or with some other bonding or fastening structure significantly simplifies electrode replacement procedures. Maintenance becomes as simple as removing the cell 200 from the electrolytic cell, removing one or both electrodes 202, 204 (e.g., by removing the non-welded fastening or fastening structure), optionally replacing one or both of the elastic elements 228, 232, positioning one or both new electrodes 202, 204, and (optionally) repositioning the non-welded fastening or fastening structure. No machining or welding of the electrodes 202, 204 is required, and the number of cell components requiring replacement is reduced, and in some embodiments, minimized. The reshuffling operation can be performed quickly in a factory or central facility without the need for advanced skills, specialized labor, or large and expensive equipment.

[0080] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. The inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof) or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0081] In the event of a conflicting usage between this document and any document so incorporated by reference, the usage in this document shall control.

[0082] The terms "a" or "an" are used herein, as is common in patent documents, to include "one or more than one," independent of any other instance or usage of "at least one" or "one or more." The term "or" is used herein to refer to a non-exclusive "or," such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. The terms "including" and "in which" are used herein as the plain English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, i.e., systems, devices, articles, compositions, formulations, or processes that include elements in addition to those listed after such terms in a claim, are still considered to be within the scope of that claim. Also, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels and are not intended to impose numerical requirements on their objects.

[0083] The method embodiments described herein can be implemented, at least in part, in a machine or computer. Some embodiments can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform the methods as described in the above embodiments. Such method implementations can include code, such as microcode, assembly language code, higher level language code, or the like. Such code can include computer-readable instructions for performing various methods. The code can form part of a computer program product. Furthermore, in some embodiments, the code can be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memory (RAM), read-only memory (ROM), and the like.

[0084] The above description is intended to be illustrative and not restrictive. For example, the above described embodiments (or one or more aspects thereof) may be used in combination with each other. Other embodiments may also be used by those skilled in the art upon review of the above description. The Abstract is provided to comply with 37 C.FR §1.72(b) to enable the reader to quickly ascertain the nature of the present technical disclosure. It should be considered with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above detailed description, various features may be grouped together to simplify the disclosure. This should not be construed as intending that an unclaimed disclosed feature is essential to any claim. Rather, the subject matter of the invention may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are herein incorporated into the detailed description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments may be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. 1. An electrolyser cell comprising: a housing at least partially enclosing an interior of the cell; a first electrode coated with a first catalytic coating, the first electrode being coupled to the housing within the cell without welding; a second electrode coupled to the housing within the cell without welding; a separator positioned between the first electrode and the second electrode, wherein a voltage is applied between the first electrode and the second electrode; and 1. An electrolyzer cell comprising:

2. 10. The electrolyzer cell of claim 1, further comprising a non-welded fastening structure for coupling the first electrode to the housing without welding.

3. The electrolyzer cell of claim 2 , wherein the non-welded fastening structure comprises a resilient edge insert.

4. The electrolyzer cell of any one of claims 1-3, wherein the first electrode comprises a first mesh sheet.

5. 5. The electrolyzer cell of claim 1, wherein the second electrode comprises a second mesh sheet.

6. Electrolyzer cell according to any one of claims 1 to 5, further comprising a resilient element configured to compress the first electrode against the separator.

7. 7. The electrolyser cell of any one of claims 1-6, wherein the second electrode is coated with a second catalytic coating.

8. 8. The electrolyzer cell of claim 1, further comprising a first electrode assembly including the first electrode and a first current collector.

9. 9. The electrolyzer cell of claim 8, wherein the first current collector is welded to the housing and the first electrode is coupled to the first current collector without welding.

10. 1. A method comprising: Providing a first electrode coated with a first catalytic coating and a second electrode; coupling, without welding, the first electrode to a housing of an electrolyzer cell such that the first electrode is within a cell interior of the housing; coupling the second electrode to the housing within the cell without welding; Positioning a separator between the first electrode and the second electrode; delivering an electrolyte into an interior of the cell; applying a voltage between the first electrode and the second electrode, and generating hydrogen gas at the first electrode or the second electrode; A method comprising:

11. The method of claim 10 , wherein coupling the first electrode to the housing comprises coupling the first electrode with a non-welded fastening structure.

12. The method of claim 10 or claim 11, wherein the first electrode comprises a first mesh sheet.

13. The method of any one of claims 10-12, wherein the second electrode comprises a second mesh sheet.

14. 14. The method of any one of claims 10-13, further comprising positioning a resilient element between the housing and the first electrode, the resilient element configured to compress the first electrode against the separator.

15. 1. A method of maintaining an electrolytic cell, the method comprising: removing an electrolyzer cell from an electrolyzer system, the electrolyzer cell comprising: a housing at least partially enclosing a cell interior; a first electrode coated with a first catalytic coating, the first electrode being coupled to the housing within the cell interior without welding; a second electrode being coupled to the housing within the cell interior without welding; and a separator positioned between the first electrode and the second electrode; removing the first electrode from the electrolytic cell; replacing the removed first electrode with a replacement electrode coated with a replacement catalytic coating; coupling the replacement electrode to the housing within the cell without welding; A method comprising:

16. The method of claim 15 , wherein coupling the replacement electrode to the first housing comprises fastening the replacement electrode to the housing with a non-welded fastening structure.

17. 17. The method of claim 15 or claim 16, wherein the first electrode comprises a first mesh sheet.

18. The method of any one of claims 15-17, wherein the second electrode comprises a second mesh sheet.

19. The method of any one of claims 15-18, wherein the second electrode is coated with a second catalytic coating.

20. 20. The method of claim 19, further comprising removing the second electrode from the electrolyzer cell, replacing the removed second electrode with a second replacement electrode that is coated with a second replacement catalytic coating, and coupling the second replacement electrode to the housing within the cell without welding.

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