ELECTRICALLY ISOLATED ELECTROCHEMICAL CELL AND METHOD OF MANUFACTURING THE SAME

Description

INCORPORATION BY REFERENCE OF RELATED PATENT APPLICATIONS

This application is based upon and claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63/645,472, filed May 10, 2024, the entire contents of all of which are incorporated herein by reference in their entirety.

FIELD OF INVENTION

The present disclosure relates to electrochemical cells and stacks, more particularly to components for electrochemical cells and stacks designed for electrical isolation, low leak rates, small cell pitch, and high-speed manufacturing.

BACKGROUND

Electrochemical cells are devices for inducing chemical reactions using electricity or generating electricity using chemical reactions. If electricity is the output, the cells may be considered fuel cells or expander cells, depending on the chemical product. If electricity is the input, the cells may be considered electrolyzer cells, compressor cells or purifier cells, depending on the chemical product. For example, an electrolyzer takes electrical energy and stores it in a fuel such as hydrogen by splitting water into its constituent elements. In contrast, a fuel cell may be thought of essentially as an electrolyzer running in reverse—hydrogen and oxygen are provided to the cell, which then combines these molecules to form water, releasing electrical energy in the process. Other chemical reactions may be promoted by use of an electrochemical cell or stack of cells such as the reduction of carbon dioxide into carbon monoxide, ethylene, or ethylene glycol, the reduction of nitrogen into ammonia or associated compounds, the formation of hydrogen peroxide from water and oxygen or the extraction of lithium from lithium brine solutions. The basic elements of these devices are two electrodes, an ion-conducting electrolyte, and an ion-permeable layer separating the two electrodes, although it is possible to operate an electrolyzer or fuel cell in a membrane-less configuration, as well. Electrochemical cells may also include a separator between the electrodes to prevent products from mixing inside of the cell. In the case of solid-electrolytic cells, the membrane and separator may be combined into a unitized, solid, ion-conducting layer. A complete electrochemical cell may also include flow fields for delivering reactants to the electrodes, seals for isolating reactants from each other and the environment, and one or more impermeable separator plates, also referred to as bipolar plates, for isolating one cell from adjacent cells in a stack and, in certain embodiments, for containing a separate cooling fluid for thermal management of the cell. Impermeability may be defined as a material having a permeability coefficient for a particular gas species of <1.0×10⁻¹¹ [mol gas/(m s Pa^0.5)].

A variety of electrolytes can be used in electrochemical cells, including proton exchange membranes, anion exchange membranes, solid-oxide ceramic membranes, and liquid alkaline solutions such as potassium hydroxide and sodium hydroxide. Different electrolytes demand different operating conditions, and each comes with its own benefits and limitations. Advantages of proton and anion exchange membrane electrolytes may include relatively low operating temperature and a cell that can be constructed using a unitized-layer electrolyte/membrane. Electrolyzers using such membranes have the distinct advantage over other electrolyzers of being able to operate using relatively pure, liquid water, rather than a caustic solution or water vapor as a feed stock, thereby greatly simplifying the balance of system in practice. Relatively pure water may be defined as water containing no more than 5% by weight of elements other than hydrogen and oxygen. Such electrolyzers may also be operated without liquid water on the cathode, allowing production of hydrogen in a gas phase having non-zero vapor-phase moisture content. A non-zero vapor-phase moisture content may be defined as gas containing more than one part per million water vapor, by volume.

The impact of carbon dioxide on global climate change is well-documented. As society's efforts to address global climate change accelerate, the need for deep decarbonization of most or all human energy use has become clear and urgent. The use of hydrogen as a carbon-free energy carrier is essential to reaching certain segments of human industry that are difficult or impossible to decarbonize directly with electricity. Examples of such segments include steel production, fertilizer manufacturing, construction, and heavy transport such as trucking, marine and air vehicles. In addition to these segments, the energy density and stable storage characteristics of hydrogen has made it the most viable candidate for seasonal-scale energy storage and establishment of grid resiliency using only renewable electricity, which will be required for complete conversion of energy use to carbon-free sources. These and other benefits have driven a high level of interest in “green hydrogen” production.

Hydrogen is given a “green” label if it is produced by electrolysis from renewable electricity (wind, solar, hydropower, etc.). Other “colors” of hydrogen are conventionally assigned to other energy sources. The scale required to meet the potential demand for green hydrogen in the future global energy system is daunting. Production capacities for electrolyzers will need to increase by many orders of magnitude and their costs reduced by a factor of ten or more over the next decade to meet such demand. Up to now, production of hydrogen electrolyzers has been a niche industry with small systems and limited deployments based on cells and stacks designed for research and development. Only minor considerations have been made for the speed of manufacturing necessary to produce and assemble cells and stacks at a rate commensurate with society's eventual need.

BRIEF SUMMARY

Recognizing the urgent need for innovative electrolyzer technology in fighting climate change, the present application is directed toward components for a scalable electrolysis cell and stack, and method of high-speed manufacturing those components. Embodiments of the present application are directed to the design and manufacturing of critical elements for these cells and stacks including bipolar plates, hydrogen and water seals, flow fields, membranes, reinforcing sub-gaskets, and efficient assembly of these components into a unitized cell. The present disclosure includes innovative designs for component geometry, innovative materials, and dimensions that overcome limitations of prior art electrochemical cells and stacks. These limitations include:

• • Challenges with electrical isolation from cell to cell within liquid containing plenums in an electrochemical stack.
  • Limitations on cell pitch/thickness due to shorting through the liquid containing plenums.
  • Challenges with complex supply chains and sourcing of raw materials or discrete components.
  • Limited manufacturing process speed.
  • Leakage of hydrogen and/or water and gas cross-over, including long-term reliability of seals in service.
  • High material scrap and low recyclability.
  • Difficulties in aligning cell component with precision and the robustness of component positioning cell during stacking.

The description below will focus on water electrolysis for hydrogen production for clarity, but may be applied to other electrochemical processes such as fuel cells, hydrogen compressors, hydrogen expanders, carbon dioxide electrolyzers, ammonia electrolyzers, and lithium brine electrolyzers, by one skilled in the art.

The basic process of water electrolysis involves providing water to a positively charged anode and conducting ions between the anode and a negatively charged cathode. Oxygen gas is produced at the anode while hydrogen gas is produced at the cathode. The particular ion conducted between the anode and the cathode depends on the electrolyte used. In an acidic cell, positively charged hydronium ions (H₃O⁺) are conducted from the anode to the cathode. In an alkaline cell, negatively charged hydroxide ions (OH⁻) are conducted from the cathode to the anode. In both systems, the overall reaction is the same: (2)H₂O(/)→(2)H₂(g)+O₂(g). Electricity must be provided to drive the reaction. The open-circuit, or thermo-neutral, voltage for the basic reaction of hydrogen to liquid water is 1.481 V, therefore a voltage higher than 1.481 V must be applied to a hydrogen electrolysis cell fed with liquid water to cause the reaction to progress (as discussed below, an overpotential is usually required for the reaction to proceed at acceptable rates). The size (i.e., active area) of the cell determines the rate of hydrogen/oxygen production from one cell at a given applied voltage. The total current required for a particular applied voltage may be proportional to the active area of the cell. In practical systems, multiple cells may be “stacked” on top of each other to increase production capacity. This stacking of cells results in the need to apply a higher voltage (integer multiple of the cell count) to drive the reaction. For example, a single cell of 1000 cm² active area may produce the same hydrogen flow as two stacked cells of 500 cm², but the 500 cm² stack will require an input of 2 times the voltage and ½ of the current. Flexibility in selecting required voltage and current may be a significant consideration in the design and cost of a total electrolysis system. For example, power supplies for higher current and lower voltage may be more expensive than those for higher voltage and lower current due to the size of the required electrical conductors and additional materials required for their construction. Therefore, an easily scalable cell active area is a significant advantage for cost and flexibility of deployment.

The elements of a hydrogen electrolyzer stack may include a stack of repeating components (configured as repeating “cells”) and a system of non-repeating components to hold the cells together in a stacked configuration. As the name implies, the repeating components are those whose quantity scales with stack height and may typically include the membrane/electrolyte, anode and cathode electrodes, anode and cathode electrode reinforcement layers, water and hydrogen flow fields, water and hydrogen seals, and a bipolar cell separator plate. The non-repeating components may typically include end units and a mechanical system for maintaining compression on the stack of repeating components (the “stack core”), along with power terminals, electrical isolators, fluid distribution and/or drain/purge manifolds. The stack compression system may include compliant elements such as tension members, springs, and adjustable members (rods, bolts, wedges, etc.) to generate and maintain compressive loading in the stack core. This compression of the stack core may be essential to ensure both electrical contact and fluid sealing between individual cells and with the end units. In a typical electrolyzer stack, the compliant elements may be located outside the stack core, as the core itself may be relatively “stiff” mechanically. In this case a relatively “soft”, or compliant, compression system, external to the stack core, may be required to ensure ongoing compressive load is maintained as the stack height changes with time or temperature or pressure. These external elements may be large and/or expensive and/or cumbersome for manufacturing. Alternately, repeating components with built-in compliance may enable a designer to minimize or eliminate the need for substantial external springs, rods, bolts, etc., leading to an advantage in cost, size, and speed of assembly for the stack. In this context, compliance may be defined as the inverse of an effective elastic spring constant along a z-axis, which is an axis aligned with the axis of stacking cells (i.e., change in “z” [mm] per unit of applied force [kgf]).

The present disclosure is directed toward novel designs and methods of manufacturing for electrochemical cell components which provide improved electrical isolation within the liquid-containing plenums of a stack of such cells. In a typical electrochemical stack, electrically conductive components such as the bipolar separator plate may come in contact with the liquid plenums. When voltage is applied to the stack, these charged plates may cause reactions directly in the liquid plenum, an undesired condition as such a reaction reduces the efficiency of the stack and, in the case of electrolysis, also generates reaction products where they are not wanted. For example, in a water electrolyzer, plenum electrolysis caused by live plates contacting the water plenums may result in hydrogen generation on the anode side, which may result in a safety hazard if the reaction rate is too high. The reaction rate in the plenums may be reduced by increasing the distance between the conductive components contacting the plenum. This is typically accomplished by making the cells thicker (i.e., a greater cell “pitch”), which is undesirable from cost and size perspective for an electrolyzer. The higher the conductivity of the liquid in the plenum, the larger the cell pitch must be to maintain an acceptable reaction rate. Alkaline water electrolyzers using Potassium Hydroxide at high concentrations (up to 7 molar) typically have cell pitches greater than 10 mm, even up to 20 mm. Mathematical modelling (see FIG. 22) shows that, with highly conductive electrolyte, a cell pitch of less than 5 mm may result in a parasitic current through the water plenums of greater than 10%. PEM fuel cells on the other hand may have cell pitches as low as 1.0-1.5 mm, but these fuel cell stacks require very low conductivity for the liquid filling the plenums (<10 μS/cm). This requirement for very low conductivity may increase the cost, complexity and maintenance requirements for such systems. The subject matter of the present application overcomes these limitations by providing components whose materials and geometry decouples the conduction path length from the cell pitch.

The present disclosure is also directed toward novel designs and methods of manufacturing electrochemical cell components which provide for hermetic sealing of critical fluid chambers within a cell. An electrolysis cell typically requires three seals: 1) cathode (e.g., hydrogen) to the environment; 2) anode (e.g., water+oxygen) to the environment; and 3) cross-leakage between cathode and anode within the cell. Typical prior art cells rely on compressible gaskets and seals to be engaged at all sealing interfaces through the compression of the stack. This sealing approach can drive the need for tight dimensional tolerances, which may significantly increase cost. This approach may also force design decisions that require large cell pitch to fit compressible seals into the cell. The subject matter of the present application overcomes these limitations by providing materials and geometry that allow hermetic seals to be created during manufacturing. A hermetic seal may be defined as a bond between two layers wherein the bond is gastight and of equal or greater mechanical strength than the materials being bonded. Gastight may be defined as a material or bond having a leakage coefficient for a particular gas species of <3.0×10⁻⁸ [mol gas/(m s Pa^0.5)]. One example of a hermetic seal is a hot-melt seal between two thermoplastic materials wherein the materials mix in a molten state at the bond line to form a single, mixed material after cooling and solidifying. The subject matter of the present application provides materials and geometry for cell components that allow such a hermetic seal to be created for all three seal regions defined above.

The present disclosure is also directed toward novel materials and methods of manufacturing electrochemical cell components which provide simultaneously for speed and ease of manufacturing, and adequate mechanical properties in the service environment of an operating electrochemical cell. During fabrication of cell components, it may be desirable to use hot-melt lamination processes. It may further be desired to have a relatively low melt temperature for these components to allow simpler machinery and faster line speeds. However, materials selected must also withstand the electrochemical cell and stack operating environment and mechanical properties in-situ must be adequate to resist creeping or deforming under mechanical stress at the operating temperature of the stack. It may be that materials with good hot melt properties for manufacturing processing have inadequate properties at operating conditions. The subject matter of the present application provides a material for cell components which contains a cross-linker that can increase the temperature resistance of the material only after it has been processed into cells. In this way the cross-linkable material may be processed into cells at relatively low temperatures and then converted into a material with higher temperature properties after the component or cell fabrication is finished. One such cross-linker may be a photo-initiated cross-linker that enables the cross-linking to be controlled as a desired point in the manufacturing process. Examples of materials containing photo-initiated cross-linkers include LOCTITE AA 3106 acrylated urethane, LOCTITE AA 3526 modified acrylic, and LOCTITE SI 5083 acetoxy silicone.

The present disclosure is also directed toward novel designs and methods of manufacturing electrochemical cell components which provide for precise location and assembly unitization to simplify and reduce variation during cell stacking operations. A typical electrochemical cell may contain 12 discrete layers or more. A typical electrochemical stack may contain as many as 400 individual cells, or more. Handling potentially more than 4,000 discrete components to handle and position during cell stack creates high risk for misalignment, which may result in a non-working stack. Discovering failures only after the stack is built may result in significant additional cost to diagnose and repair. Additionally, decompressing and then recompressing an electrochemical stack may result in a performance loss relative to the performance achievable with a single compression cycle. Preassembly of discrete components into unitized assemblies with precise component alignment is a typical method used to address these stacking problems. However, reliance on traditional compressible seals for the critical sealing interfaces limits the extent to which unitization can be taken, and multiple discrete sub-assemblies for each cell may still need to be aligned during cell stacking, each with the risk of failure. The subject matter of the present application provides materials, geometry, and methods of fabrication that enable unitization of complete cells with precise placement of all discrete components and the integration of testable, hermetic seals prior to cell stacking. These materials, geometries, and methods overcome prior art limitations and minimize the potential failures at the stack level.

For convenience we may define a cartesian coordinate system with perpendicular x-y-z axes where “x” is parallel to the general direction of water flow through the cell, “y” is perpendicular to x, but in the same plane defined by a single cell, and “z” is generally parallel to the direction of stacking of the cells. In this context the compression system generally works to apply compressive load along the z axis, holding the cells and their various repeating components in contact with each other. Compliance of the stack core may then be measured along a z-axis, so defined.

It is to be understood that both the foregoing general descriptions and the following detailed descriptions are exemplary and explanatory only and not restrictive of the disclosure, as claimed. Further objects, features, and advantages of the present application will become apparent from the detailed description of preferred embodiments which is set forth below, when considered together with the figures provided.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are incorporated into and constitute a part of this specification. The drawings illustrate certain embodiments only of the present disclosure and, together with the foregoing and following descriptions, explain the principles of the disclosure. Wherever possible the same identification numbers have been used to indicate common or like components across different figures.

FIG. 1A shows a cross-sectional view of a preferred embodiment of the layers of an electrolysis cell of the present disclosure illustrating key features provided to improve electrical isolation of the cell.

FIG. 1B shows a cross-sectional view of the layers of a typical prior art cell illustrating the correlation between cell isolation and cell pitch.

FIG. 2 shows an isometric view of a preferred embodiment of an electrolysis cell of the present disclosure illustrating the thickness, or pitch of the cell along a z-axis.

FIG. 3 shows a plan view of a preferred embodiment of an electrolysis cell of the present disclosure illustrating the conduction length along an x-axis which may be varied to increase cell isolation independent of cell pitch.

FIG. 4 shows a cross-sectional view of a preferred embodiment of the layers of an electrolysis cell of the present disclosure illustrating material and geometric features enabling the creation of hermetic seals at various interfacial layers between discrete components and sub-assemblies.

FIGS. 5 and 6 show isometric views of a preferred embodiment of an electrolysis cell of the present disclosure illustrating the materials and features enabling the creating of a fully unitized cell assembly with hermetic sealing at all within-cell interfaces.

FIG. 7 shows an isometric view of a preferred embodiment of an anode gasket assembly of the present disclosure illustrating materials and features enabling a unitized anode-gasket assembly.

FIG. 8 shows a plan view of a preferred embodiment of an anode gasket assembly of the present disclosure illustrating materials and features enabling a unitized anode-gasket assembly.

FIG. 9 shows an isometric view of a preferred embodiment of a half-cell assembly of the present disclosure illustrating materials and features enabling fabrication of a unitized half-cell assembly with hermetic sealing of the cathode chamber.

FIG. 10 shows a plan view of a preferred embodiment of a half-cell assembly of the present disclosure illustrating materials and features enabling fabrication of a unitized half-cell assembly with hermetic sealing of the cathode chamber.

FIG. 11 shows an isometric view of a preferred embodiment of a half-cell assembly of the present disclosure illustrating materials and features of a unitized half-cell assembly after final processing with hermetic sealing of the cathode chamber.

FIG. 12 shows a plan view of a preferred embodiment of a half-cell assembly of the present disclosure illustrating materials and features enabling a unitized half-cell assembly after final processing with hermetic sealing of the cathode chamber.

FIG. 13 shows an isometric view of a preferred embodiment of a membrane sub-gasket assembly of the present disclosure illustrating materials and features enabling fabrication of a unitized membrane sub-gasket assembly with hermetic sealing of the internal seal between anode and cathode.

FIG. 14 shows a plan view of a preferred embodiment of a membrane sub-gasket assembly of the present disclosure illustrating materials and features enabling fabrication of a unitized membrane sub-gasket assembly with hermetic sealing of the internal seal between anode and cathode.

FIG. 15 shows an isometric view of a preferred embodiment of a membrane sub-gasket assembly of the present disclosure illustrating materials and features of a unitized membrane sub-gasket assembly after final processing with hermetic sealing of the internal seal between anode and cathode.

FIG. 16 shows a plan view of a preferred embodiment of a membrane sub-gasket assembly of the present disclosure illustrating materials and features of a unitized membrane sub-gasket assembly after final processing with hermetic sealing of the internal seal between anode and cathode.

FIG. 17 shows an isometric view of a preferred embodiment of a bipolar plate assembly of the present disclosure illustrating materials and features enabling fabrication of a unitized bipolar plate assembly enabling a conductive, central area and a non-conductive edge area.

FIG. 18 shows a plan view of a preferred embodiment of a bipolar plate assembly of the present disclosure illustrating materials and features enabling fabrication of a unitized bipolar plate assembly enabling a conductive, central area and a non-conductive edge area.

FIG. 19 shows an isometric view of a preferred embodiment of a bipolar plate assembly of the present disclosure illustrating materials and features of a unitized bipolar plate assembly after final processing enabling a conductive, central area and a non-conductive edge area.

FIG. 20 shows a plan view of a preferred embodiment of a bipolar plate assembly of the present disclosure illustrating materials and features of a unitized bipolar plate assembly after final processing enabling a conductive, central area and a non-conductive edge area.

FIGS. 21A and 21B show isometric views of a preferred embodiment of an electrolysis stack of the present disclosure illustrating the alignment of individual cell water plenums within the stack to create conductive water columns spanning cells which may be subject to electrical potentials from the charged plates of each cell resulting in undesired reactions within the water column. FIG. 21B is a section view of FIG. 21A showing the subject water columns within the stack.

FIG. 22 shows electrical modeling results for a typical electrolyzer stack illustrating the fraction of applied current lost through the liquid columns as a function of conduction path length (d_cond) for full capacity and 20% capacity operating conditions.

FIG. 23 shows an exploded, top isometric view of a preferred embodiment of a portion of an electrolysis cell of the present disclosure illustrating features enabling electrical isolation within liquid-containing plenums of a repeating stack of cells.

FIG. 24 shows a plan view from the bottom of a preferred embodiment of the electrolysis cell depicted in FIG. 23.

FIG. 25 shows a cross-section of a preferred embodiment of the electrolysis cell depicted in FIGS. 23 and 24.

FIG. 26 shows an exploded, top isometric view of a preferred embodiment of a portion of an electrolysis cell of the present disclosure illustrating features enabling electrical isolation within liquid-containing plenums of a repeating stack of cells.

FIG. 27 shows a plan view from the bottom of a preferred embodiment of the electrolysis cell depicted in FIG. 26.

FIG. 28 shows a cross-section of a preferred embodiment of the electrolysis cell depicted in FIGS. 26 and 27.

DETAILED DESCRIPTION OF DRAWINGS

Definitions

The present invention may be understood more readily by reference to the following detailed description of the preferred embodiments of the invention and the Examples included herein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. As used herein, the following meanings apply unless otherwise indicated.

As used herein, the singular forms “a”, “an”, and “the” include plural references unless indicated otherwise. It is noted that in this disclosure, terms such as “comprises,” “comprised,” “comprising,” “contains,” “containing” and the like can have the meaning attributed to them in U.S. patent law; e.g., they can mean “includes,” “included,” “including” and the like. Terms such as “consisting essentially of’ and “consists essentially of’ have the meaning attributed to them in U.S. patent law, e.g., they allow for the inclusion of additional features or steps that do not detract from the novel or basic characteristics of the invention, i.e., they exclude additional unrecited features or steps that detract from the novel or basic characteristics of the invention. The terms “consists of’ and “consisting of’ have the meaning ascribed to them in U.S. patent law; namely, that these terms are closed ended. Accordingly, these terms refer to the inclusion of a particular features or step and the exclusion of all other features or steps.

The terms “about” or “approximate” and the like are synonymous and are used to indicate that the value modified by the term has an understood range associated with it, where the range can be ±20%, ±15%, ±10%, ±5%, or ±1%. The term “substantially” is used to indicate that a value is close to a targeted value, where close can mean, for example, the value is within 80% of the targeted value, within 85% of the targeted value, within 90% of the targeted value, within 95% of the targeted value, or within 99% of the targeted value.

The term “cell pitch” means the distance between repeating elements in adjacent cells within a stack, typically measured from the same location on one cell to the corresponding location on an adjacent cell.

The term “conduction path length” means the total distance that electrical current must travel through liquid (e.g. water) in a plenum between the conductive components of adjacent cells in a stack.

The term “edge extension” means the non-conductive region extending from the conductive area to the liquid plenum, designed to increase the electrical conduction path length between adjacent cells.

The term “unitized assembly” means a pre-assembled component comprising multiple discrete layers bonded together to form a single handling unit with precise alignment of all constituent components.

The term “liquid plenum” refers to a chamber or channel within a cell designed to contain and distribute liquid (typically water) throughout the cell and between cells in a stack.

The term “parasitic current” means undesired electrical current flowing through conductive liquid in the liquid plenums between adjacent cells in a stack, resulting in efficiency losses and potentially hazardous reactions.

The term “non-conductive” refers to a material having an electrical resistivity of at least 10⁶ ohm-meters (Ω·m) at standard temperature and pressure.

The “active area” of a cell means the area of an electrochemical cell where the desired electrochemical reaction occurs.

The term “hot-melt seal” means a hermetic seal formed by heating thermoplastic materials to their melting point, allowing them to flow together at the interface, and then cooling to form a single, homogeneous material without a distinct bond line.

The term “cross-linkable formulation” means a material composition that can undergo a chemical reaction to form cross-links between polymer chains, thereby increasing its mechanical strength, temperature resistance, and chemical stability after initial processing.

The term “photo-initiated cross-linking” means a cross-linking process activated by exposure to light of specific wavelengths (typically ultraviolet), allowing controlled timing of the cross-linking reaction during manufacturing.

The term “bonding promoter” means a chemical compound or treatment applied to a surface to enhance adhesion between dissimilar materials during a bonding process.

Detailed descriptions of several preferred embodiments will now be given in reference to the accompanying drawings. Although descriptions relate to water electrolysis, it is understood that the described features, components, and methods are applicable and adaptable, by those skilled in the art, to other electrochemical technologies including reduction of carbon dioxide into carbon monoxide, ethylene, or ethylene glycol, the reduction of nitrogen into ammonia or associated compounds, the formation of hydrogen peroxide from water and oxygen or the extraction of lithium from lithium brine solutions, hydrogen compressors, hydrogen purifiers, and fuel cells. FIG. 1A shows a cross section through the liquid-containing water plenums of a repeating stack of cells of a preferred embodiment of the present application (101a). A coordinate system is defined in 102a. 103a illustrates an electrically conductive, impermeable separator (bipolar) plate; 104a illustrates an electrically conductive, permeable, cathode chamber; 105a represents an ionically-conductive separator membrane; 106a illustrates an electrically conductive, permeable, anode chamber; 107a illustrates a non-conductive cell edge extension with a length along an x-axis of 112a (d_cond); 108a illustrates a non-conductive cathode chamber seal embedded within the permeable cathode chamber 104a and hermetically connected to edge extension 107a; 109a illustrates the liquid filling the water columns of the stack formed by the water plenums of each cell and the resulting connection between cells caused by this liquid column; 110a illustrates the thickness, or “pitch” of a single cell within the stack of repeating cells; 111a illustrates the resulting electrical path length between adjacent cells. Dimension 111a may be equal to or greater than twice the edge extension length (112a) and may not be a function of cell pitch (110a). Design choices for the edge extension length may allow a total conductive path length between adjacent cells to be 1 times the cell pitch, 1.5 times the cell pitch, 2 times the cell pitch, 3 times the cell pitch, 5 times the cell pitch, or 10 times the cell pitch.

FIG. 1B shows a cross section through the liquid-containing water plenums of a repeating stack of cells of a prior art electrolyzer (101b). A coordinate system is defined in 102b. 103b illustrates an electrically conductive, impermeable separator (bipolar) plate; 104b illustrates the cathode flow channels of 103b; 105b represents an ionically-conductive separator membrane; 106b illustrates the anode flow channels of 103b; 109b illustrates the liquid filling the water columns of the stack formed by the water plenums of each cell and the resulting connection between cells caused by this liquid column; 110b illustrates the thickness, or “pitch” of a single cell within the stack of repeating cells; 111b illustrates the resulting electrical path length between adjacent cells. Dimension 111b may be substantially equal to the cell pitch (110b) with limited ability to increase this path length without increasing the pitch of the cells, and thereby length of the stack.

FIG. 2 shows an isometric view of a preferred embodiment electrolysis cell (201). A coordinate system is defined in 202. 203 illustrates one of a multitude of liquid plenums defined along the non-conductive edges of the cell. 204 illustrates the conductive central area of the cell. 205 illustrates the non-conductive border area of the cell. As cells are repeatedly stacked, the liquid plenums 203 may align to create continuous liquid columns (2104, FIG. 21B) that may electrically and/or ionically connect the edges of each cell along a stacking direction (aligned with the z-axis).

FIG. 3 shows a plan view of a preferred embodiment electrolysis cell (301). A coordinate system is defined in 302. 303 illustrates one of a multitude of liquid plenums defined along the non-conductive edges of the cell. 304 illustrates the conductive central area of the cell. 305 illustrates the non-conductive border area of the cell. 112a illustrates the edge extension length defined in FIG. 1A which separates the liquid water column (2104, FIG. 21B) created by liquid plenums 303 from the conductive central area of the cell 304.

FIG. 4 shows a cross section of a cell of a preferred embodiment of the present application (401). A coordinate system is defined in 402. 403 illustrates a bipolar plate assembly (BPA) comprising a conductive, impermeable separator plate 411, a conductive, permeable cathode flow field 412, a non-conductive, edge extension 410, and a non-conductive, gas-tight cathode chamber seal 413 embedded within cathode flow field 412; 404 illustrates a membrane sub-gasket assembly (MSGA) comprising an ion conducting membrane 421, and one or more sub-gasket layers 420; 422 illustrates a cathode electrode positioned between BPA 403 and MSGA 404, and hermetically sealed adjacent to cathode chamber 412 by hermetic bond line 452. 405 illustrates an anode gasket assembly (AGA) comprising a conductive, permeable anode flow field 431, a conductive, permeable anode electrode 432, and a non-conductive, gas-tight anode chamber seal 430, wherein the anode chamber is hermetically seal at bond line 453. Upon stacking cells 401, only a single, cell-to-cell, non-hermetic seal must be engaged with compression of the cell stack as all seals within the unitized cell assembly 401 have been hermetically bonded. Hermetic bonding at 453 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, a light-activated adhesive method, or an epoxy adhesive method.

FIG. 5 shows an exploded, top isometric view of a preferred embodiment electrolysis cell (501). A coordinate system is defined in 502. 503 illustrates a half-cell assembly (HCA); 504 illustrates an anode gasket assembly (AGA); 505 illustrates the hermetically bonded area between assemblies 503 and 504, enabling a within-cell hermetic seal of an anode chamber illustrated by area 506. Hermetic bonding at 505 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, a light-activated adhesive method, or an epoxy adhesive method. Hermetic bonding at 505 may be accomplished with a piecewise or continuous roll lamination method. Material selected for the various layers of the cell may include a cross-linkable formulation to enable initial components and assemblies to be fabricated with relative low temperature processes, while allowing post-fabrication treatment to enhance the mechanical properties to match the environmental and operating service conditions of the cell (e.g. the materials discussed previously). Such material formulation may include a light-reactive cross-linker and activator, a heat-reactive cross-linker and activator, a humidity-reactive cross-linker and activator, or a time-sensitive cross-linker and activator. A light-reactive cross-linker such as ultraviolet activated cross-linking may be advantageous for efficient manufacturing as cross-linking can be controlled and only executed at the desired process step. Such a desired cross-linking step may be performed after cell assembly 501 is fully unitized and all hermetic seals have been formed or may be performed for each sub-assembly or sub-component during manufacturing prior to unitization.

FIG. 6 shows an exploded, bottom isometric view of the preferred embodiment electrolysis cell (601) of FIG. 5. A coordinate system is defined in 602. 603 illustrates a half-cell assembly (HCA); 604 illustrates an anode gasket assembly (AGA); 605 illustrates the hermetically bonded area between assemblies 603 and 604, enabling a within-cell hermetic seal of an anode chamber illustrated by area 606. Hermetic bonding at 605 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, a light-activated adhesive method, or an epoxy adhesive method. Hermetic bonding at 605 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 7 shows an exploded, top isometric view of a preferred embodiment anode gasket assembly (AGA) (701). A coordinate system is defined in 702. 703 illustrates a non-conductive, gas-tight anode chamber seal which defines a sealed anode chamber 706; 704 illustrates an anode electrode; 705 illustrates an electrically conductive, permeable anode flow field; 707 illustrates a multiplicity of tab features included in anode chamber seal 703 that provide unitization of all components into a single assembly. Lamination of layers 703, 704, and 705 may be arranged to allow tabs 707 to penetrate the porous layers 704 and 705, effectively bonding all layers together into a unified assembly. Bonding at 707 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, a light-activated adhesive method, or an epoxy adhesive method. Bonding at 707 may be accomplished with a piecewise or continuous roll lamination method. All layers 703, 704, and 705 in AGA 701 may be constructed from 2-dimensional patterns cut from sheets or rolls of material with substantially uniform thickness. This arrangement may provide significant manufacturing cost and speed advantages by enabling the use of high volume film extrusion or casting processes for raw materials and high-speed roll conversion processes for component, assembly, and cell fabrication. Material selected for chamber seal 703 may include a cross-linkable formulation to enable initial components to be fabricated with relative low temperature processes, while allowing post-fabrication treatment to enhance the mechanical properties to match the environmental and operating service conditions of the cell. Such material formulation may include a light-reactive cross-linker and activator, a heat-reactive cross-linker and activator, a humidity-reactive cross-linker and activator, or a time-sensitive cross-linker and activator. A light-reactive cross-linker such as ultraviolet activated cross-linking may be advantageous for efficient manufacturing as cross-linking can be controlled and only executed at the desired process step.

FIG. 8 shows a plan view of a preferred embodiment anode gasket assembly (AGA) (801). A coordinate system is defined in 802. 803 illustrates a non-conductive, gas-tight anode chamber seal which defines a sealed anode chamber 806; 804 illustrates an anode electrode; 805 (not shown) illustrates an electrically conductive, permeable anode flow field; 807 illustrates a multiplicity of tab features included in anode chamber seal 803 that provide unitization of all components into a single assembly. Lamination of layers 803, 804, and 805 may be arranged to allow tabs 807 to penetrate the porous layers 804 and 805, effectively bonding all layers together into a unified assembly. Bonding at 807 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, a light-activated adhesive method, or an epoxy adhesive method. Bonding at 807 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 9 shows an exploded, top isometric view of a preferred embodiment half-cell assembly (HCA) as manufactured (901). A coordinate system is defined in 902. 903 illustrates a bipolar plate assembly (BPA); 904 illustrates a cathode electrode; 905 illustrates a membrane sub-gasket assembly (MSGA). 907 illustrates the hermetically bonded area between 903 and 905 forming a gas-tight, hermetically sealed cathode chamber 906. Cathode electrode 904 may be captured during fabrication within the boundary defined by cathode chamber 906 between 903 and 904, becoming precisely fixed in position so as to not be allowed to shift position during subsequent handling or assembly steps. Bonding at 907 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, or an epoxy adhesive method. Bonding at 907 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 10 shows a plan view of a preferred embodiment half-cell assembly (HCA) as manufactured (1001). A coordinate system is defined in 1002. 1003 illustrates a bipolar plate assembly (BPA) (underneath); 1004 illustrates a cathode electrode (below MSGA); 1005 illustrates a membrane sub-gasket assembly (MSGA). 1007 illustrates the hermetically bonded area between 1003 and 1005 forming a gas-tight, hermetically sealed cathode chamber 1006. Cathode electrode 1004 may be captured during fabrication within the boundary defined by cathode chamber 1006 between 1003 and 1004, becoming precisely fixed in position so as to not be allowed to shift position during subsequent handling or assembly steps. Bonding at 1007 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, or an epoxy adhesive method. Bonding at 1007 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 11 shows an exploded, top isometric view of a preferred embodiment half-cell assembly (HCA) after final processing (1101). A coordinate system is defined in 1102. 1103 illustrates a bipolar plate assembly (BPA); 1104 illustrates a cathode electrode; 1105 illustrates a membrane sub-gasket assembly (MSGA). 1107 illustrates the hermetically bonded area between 1103 and 1105 forming a gas-tight, hermetically sealed cathode chamber 1106. Cathode electrode 1104 may be captured during fabrication within the boundary defined by cathode chamber 1106 between 1103 and 1104, becoming precisely fixed in position so as to not be allowed to shift position during subsequent handling or assembly steps. Bonding at 1107 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, or an epoxy adhesive method. Bonding at 1107 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 12 shows a plan view of a preferred embodiment half-cell assembly (HCA) after final processing (1201). A coordinate system is defined in 1202. 1203 illustrates a bipolar plate assembly (BPA) (underneath); 1204 illustrates a cathode electrode (below MSGA); 1205 illustrates a membrane sub-gasket assembly (MSGA). 1207 illustrates the hermetically bonded area between 1203 and 1205 forming a gas-tight, hermetically sealed cathode chamber 1206. Cathode electrode 1204 may be captured during fabrication within the boundary defined by cathode chamber 1206 between 1203 and 1204, becoming precisely fixed in position so as to not be allowed to shift position during subsequent handling or assembly steps. Bonding at 1207 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, or an epoxy adhesive method. Bonding at 1207 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 13 shows an exploded, top isometric view of a preferred embodiment membrane sub-gasket assembly (MSGA) as manufactured (1301). A coordinate system is defined in 1302. 1303 and 1305 illustrate non-conductive, gas-tight sub-gaskets; 1304 illustrates an ion-conducting membrane. All layers 1303, 1304, and 1305 in MSGA 1301 may be constructed from 2-dimensional patterns cut from sheets or rolls of material with substantially uniform thickness. This arrangement may provide significant manufacturing cost and speed advantages by enabling the use of high volume film extrusion or casting processes for raw materials and high-speed roll conversion processes for component, assembly, and cell fabrication. Material selected for sub-gaskets 1303 and 1305 may include a cross-linkable formulation to enable initial components to be fabricated with relative low temperature processes, while allowing post-fabrication treatment to enhance the mechanical properties to match the environmental and operating service conditions of the cell. Such material formulation may include a light-reactive cross-linker and activator, a heat-reactive cross-linker and activator, a humidity-reactive cross-linker and activator, or a time-sensitive cross-linker and activator. A light-reactive cross-linker such as ultraviolet activated cross-linking may be advantageous for efficient manufacturing as cross-linking can be controlled and only executed at the desired process step.

FIG. 14 shows a plan view of a preferred embodiment membrane sub-gasket assembly (MSGA) as manufactured (1401). A coordinate system is defined in 1402. 1403 and 1405 illustrate non-conductive, gas-tight sub-gaskets; 1404 illustrates an ion-conducting membrane; 1407 illustrates a hermetically bonded area between 1403, 1404, and 1405. Hermetically bonded area 1407 may ensure that gas or fluid cross-over between the cathode and anode chambers of the cell does not occur during operation of the electrolysis cell. Bonding at 1407 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, or an epoxy adhesive method. Bonding at 1407 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 15 shows an exploded, top isometric view of a preferred embodiment membrane sub-gasket assembly (MSGA) after final processing (1501). A coordinate system is defined in 1502. 1503 and 1505 illustrate non-conductive, gas-tight sub-gaskets; 1504 illustrates an ion-conducting membrane.

FIG. 16 shows a plan view of a preferred embodiment membrane sub-gasket assembly (MSGA) after final processing (1601). A coordinate system is defined in 1602. 1603 and 1605 illustrate non-conductive, gas-tight sub-gaskets; 1604 illustrates an ion-conducting membrane; 1607 illustrates a hermetically bonded area between 1603, 1604, and 1605. Hermetically bonded area 1607 may ensure that gas or fluid cross-over between the cathode and anode chambers of the cell does not occur during operation of the electrolysis cell. Bonding at 1607 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, or an epoxy adhesive method. Bonding at 1607 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 17 shows an exploded, top isometric view of a preferred embodiment bipolar plate assembly (BPA) as manufactured (1701). A coordinate system is defined in 1702. 1703 illustrates a conductive, non-permeable separator plate; 1704 illustrates a conductive, permeable cathode flow field; 1705 illustrates a non-conductive, gas-tight layer functioning as the cathode chamber seal and non-conductive edge area for the BPA. All layers 1703, 1704, and 1705 in BPA 1701 may be constructed from 2-dimensional patterns cut from sheets or rolls of material with substantially uniform thickness. This arrangement may provide significant manufacturing cost and speed advantages by enabling the use of high volume film extrusion or casting processes for raw materials and high-speed roll conversion processes for component, assembly, and cell fabrication. Material selected for chamber seal 1705 may include a cross-linkable formulation to enable initial components to be fabricated with relative low temperature processes, while allowing post-fabrication treatment to enhance the mechanical properties to match the environmental and operating service conditions of the cell. Such material formulation may include a light-reactive cross-linker and activator, a heat-reactive cross-linker and activator, a humidity-reactive cross-linker and activator, or a time-sensitive cross-linker and activator. A light-reactive cross-linker such as ultraviolet activated cross-linking may be advantageous for efficient manufacturing as cross-linking can be controlled and only executed at the desired process step. The surfaces of separator plate 1703 and/or cathode flow field 1704 may be treated to enhance adhesive bonding strength with cathode chamber seal 1705. Such enhancements may be accomplished by a chemical primer, a reactive chemical treatment such as phosphonic acid modification (e.g., 3-aminopropyl phosphonic acid), phenyl grafting, amine grafting, diazonium salt treatment, other acid or alkali treatment, physical roughening of the surface by surface finishes specified during raw material procurement, sanding, bead blasting, plasma or corona treatment, ozone treatment, surface oxidation, chemical etching, or laser etching, or other such bonding promotors available to industry. Bonding promoters may be included in the raw material formulation for 1705 such as maleated compounds including maleic anhydride, silanes, and phosphates.

FIG. 18 shows a plan view of a preferred embodiment bipolar plate assembly (BPA) as manufactured (1801). A coordinate system is defined in 1802. 1803 illustrates a conductive, non-permeable separator plate; 1804 illustrates a conductive, permeable cathode flow field (not shown); 1805 illustrates a non-conductive, gas-tight layer functioning as the cathode chamber seal 1807 and non-conductive edge area for the BPA. Cathode chamber seal area 1807 may act to bond 1803, 1804, and 1805 into a single, unitized component. Bonding at 1807 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, or an epoxy adhesive method. Bonding at 1807 may be accomplished with a piecewise or continuous roll lamination method.

FIG. 19 shows an exploded, top isometric view of a preferred embodiment bipolar plate assembly (BPA) after final processing (1901). A coordinate system is defined in 1902. 1903 illustrates a conductive, non-permeable separator plate; 1904 illustrates a conductive, permeable cathode flow field; 1905 illustrates a non-conductive, gas-tight layer functioning as the cathode chamber seal and non-conductive edge area for the BPA.

FIG. 20 shows a plan view of a preferred embodiment bipolar plate assembly (BPA) after final processing (2001). A coordinate system is defined in 2002. 2003 illustrates a conductive, non-permeable separator plate; 2004 illustrates a conductive, permeable cathode flow field (not shown); 2005 illustrates a non-conductive, gas-tight layer functioning as the cathode chamber seal 2007 and non-conductive edge area for the BPA. Cathode chamber seal area 2007 may act to bond 2003, 2004, and 2005 into a single, unitized component. Bonding at 2007 may be accomplished using a hot-melt method, an ultrasonic welding method, an inductively heated bonding method, a laser welding method, a pressure sensitive adhesive method, or an epoxy adhesive method. Bonding at 2007 may be accomplished with a piecewise or continuous roll lamination method.

FIGS. 21A and 21B show isometric views of a preferred embodiment electrolyzer stack incorporating the components and assemblies previously described (2101a, 2101b). A coordinate system is defined in 2102. 2101b is a section view of stack 2101a illustrating the liquid columns 2104 formed from alignment of cell liquid plenums (203) once stacked. 2105 illustrates a multiplicity of cells (201) stacked on top of each other wherein the thickness (or pitch) of each cell is represented by 205 (t_cell). The overall length of the cell stack is illustrated by 2106, which may be minimized for a stack of a given number of cells by minimizing cell pitch 205.

FIG. 22 shows electrical modeling results for a typical electrolyzer stack illustrating the fraction of applied current lost through the liquid columns (2203) as a function of conduction path length (2204, d_cond) for full capacity (2206) and 20% capacity (2207) operating conditions. Conduction path length (2204) for preferred embodiments of the present application represents 111a from FIG. 1A, while 2204 for prior art represents the cell pitch, or 111b from FIG. 1B. The results show that as d_cond becomes smaller, the fraction of current (and therefore stack capacity) that is lost through the liquid columns increases non-linearly (2206, 2207). The increase is more significant at lower capacity, which may impact the minimum safe turn-down for a stack with a given cell pitch. For prior art electrolyzers where 111b (d_cond) is proportional to cell pitch, designs may be limited to >10 mm to avoid significant current loss and the associated undesired reactions in the liquid columns. For preferred embodiments of the present application where cell pitch is decoupled from 111a (d_cond), cell pitch may be reduced to <5, <3, <2, or even <1 mm while maintaining 111a (d_cond) at >5, >10, or >15 mm by increasing dimension 112a shown in FIG. 2. Small cell pitch with low liquid column current loss may allow the manufacturing of stacks with greatly reduced size for a given power/capacity. This may be a significant advantage in terms of stack power density (kW/L), stack cost ($/kW), stack turndown capabilities (% full capacity), stack recyclability, and/or shipping logistics and installation costs.

FIG. 23 shows an exploded, top isometric view of a preferred embodiment of an electrolysis cell (2301). A coordinate system is defined in 2302. 2303 illustrates an electrically conductive bipolar plate (BP); 2304 illustrates an electrically conductive flow field (FF). 2305 illustrates an electrically non-conductive sub-gasket surrounding and electrically non-conductive ion exchange membrane (2306) forming an integrated assembly (2307). Each of the components (2303, 2304, 2305) have water plenum features (2313, 2314, 2315, respectively) that align when the components are laminated. In this embodiment, the electrically conductive components (2303, 2304) extend from under the membrane (2306) to the water plenums. In order to achieve electrical isolation within the liquid-containing water plenums of a repeating stack of such cells, plenums 2315 of the non-conducting sub-gasket are cut smaller than the plenums of both 2313, and 2314, as illustrated further in FIG. 24.

FIG. 24 shows a plan view from the bottom of a preferred embodiment electrolysis cell (2401). A coordinate system is defined in 2402. 2403 illustrates the electrically conductive bipolar plate (BP) described in FIG. 23 (2303). 2415 illustrates the water plenum features (2313, 2314, 2315) described in FIG. 23 as shown in laminated form from the bottom view of the cell. 2404 illustrates a detail view of one such water plenum highlighting the edge of the conductive bipolar plate (2405), the edge of the non-conductive sub-gasket (2406) and the non-conductive edge extension (2407) achieved to provide electrical isolation in this embodiment.

FIG. 25 shows a cross-section of a cell of a preferred embodiment of the present application (2501). A coordinate system is defined in 2502. 2503 illustrates an electrically conductive bipolar plate (BP). 2504 illustrates a first electrically conductive flow field (FF1). 2505 illustrates an electrically non-conductive sub-gasket (SG) with a thickness of 2514. 2506 illustrates a second electrically conductive flow field (FF2). The overall cell pitch of the present embodiment is illustrated by dimension 2513. The non-conductive edge extension described in FIG. 24 (2407) is illustrated in this cross-section view by dimensions 2512. The overall conduction length between electrically conductive components through the electrically conductive liquid filling the plenums (2515) is illustrated by dimensions 2511. As can be seen in this view, the non-conductive edge extension provided by the dimensional differences of the sub-gasket (2505) and the bipolar plate (2503), first flow field (2504), and second flow field (2506) may significantly increase the overall conduction length from adjacent electrically conductive components. Whereas said overall conduction length without such a non-conductive edge extension may be limited to the thickness 2514 of the non-conductive sub-gasket 2505, by incorporating a non-conductive edge extension, the total conduction length may increase to the sum of the thickness 2514 of the non-conductive sub-gasket 2505 and two times the non-conductive edge extension length 2512. This may result in a significant reduction in parasitic current loss between adjacent cells in a stack (e.g., as shown in FIG. 22).

FIG. 26 shows an exploded, top isometric view of a preferred embodiment electrolysis cell (2601). A coordinate system is defined in 2602. 2603 illustrates an electrically conductive bipolar plate and flow field assembly (BPA). 2605 illustrates an electrically non-conductive sub-gasket surrounding and electrically non-conductive ion exchange membrane (2606) forming an integrated assembly (2607). 2608 illustrates an electrically non-conductive water seal (WS). Each of the components (2603, 2605, 2608) have water plenum features (2613, 2615, 2618, respectively) that align when the components are laminated. In this embodiment, the electrically conductive components (2603) extend from under the membrane (2606) to the water plenums. In order to achieve electrical isolation within the liquid-containing water plenums of a repeating stack of such cells, plenums 2615 and 2618 of the non-conducting sub-gasket and water seal are cut smaller than the plenums of 2613, as illustrated further in FIG. 27.

FIG. 27 shows a plan view from the bottom of a preferred embodiment electrolysis cell (2701). A coordinate system is defined in 2702. 2703 illustrates the electrically conductive bipolar plate assembly (BPA) described in FIG. 26 (2603). 2714 illustrates the water plenum features (2613, 2615, 2618) described in FIG. 26 as shown in laminated form from the bottom view of the cell. 2704 illustrates a detail view of one such water plenum highlighting the edge of the conductive bipolar plate (2705), the edge of the non-conductive water seal (2706) and the non-conductive edge extension (2707) achieved between the bipolar plate assembly and the water seal (2608) to provide electrical isolation for 3 of the 4 edges of the water plenum in this embodiment. The fourth edge of the water plenum is isolated by flap 2715 with overlap length 2708 formed in the sub-gasket (2605) and wrapped around bipolar plate assembly 2703 to fully encapsulate the fourth conductive edge with non-conductive sub-gasket material.

FIG. 28 shows a cross-section of a cell of a preferred embodiment of the present application (2801). A coordinate system is defined in 2802. 2803 illustrates an electrically conductive bipolar plate (BP). 2804 illustrates a first electrically conductive flow field (FF1). 2805 illustrates an electrically non-conductive sub-gasket (SG) fully encapsulating bipolar plate (2803) and first flow field (2804) along a fourth edge of the water plenum (2714) and having a thickness of 2814. 2806 illustrates a second electrically conductive flow field (FF2). 2807 illustrates an electrically non-conductive water seal (WS) having a thickness of 2816. The overall cell pitch of the present embodiment is illustrated by dimension 2813. The non-conductive edge extension described in FIG. 27 (2707) is illustrated in this cross-section view by dimensions 2822 created by water seal 2807. Although only one edge may be shown in cross section view 2801, said dimension 2822 applies to three of the four edges for the water plenum 2714 as shown in FIG. 27. The overall conduction length between electrically conductive components through the electrically conductive liquid filling the plenums (2815) is illustrated by dimensions 2811 for the fourth edge of water plenum 2714 and by dimension 2821 for the first three edges of water plenum 2714. As can be seen in this view, the non-conductive edge extension provided by the dimensional differences of the sub-gasket (2805) and the bipolar plate (2803), first flow field (2804), and second flow field (2806) may significantly increase the overall conduction length from adjacent electrically conductive components along a fourth edge of water plenum 2714. Whereas the said overall conduction length without such a non-conductive edge extension may be limited to the thickness 2814 of the non-conductive sub-gasket 2805, by incorporating a non-conductive edge extension, the total conduction length may increase to the sum of the thickness 2814 of the non-conductive sub-gasket 2805 and two times the non-conductive edge extension length 2812. This may result in a significant reduction in parasitic current loss between adjacent cells in a stack. Likewise, as can be seen in this view, the non-conductive edge extension provided by the dimensional differences of the water seal (2807) and the bipolar plate (2803) and first flow field (2804) may significantly increase the overall conduction length from adjacent electrically conductive components along the first three edges of water plenum 2714. Whereas the said overall conduction length without such a non-conductive edge extension may be limited to the thickness 2816 of the non-conductive water seal 2807, by incorporating a non-conductive edge extension, the total conduction length may increase to the sum of the thickness 2816 of the non-conductive water seal 2807 and two times the non-conductive edge extension length 2822. This may result in a significant reduction in parasitic current loss between adjacent cells in a stack.

Exemplary Embodiments

Bipolar Plate Assembly

In some embodiments, the present application provides a bipolar plate assembly (BPA) for an electrochemical cell. In some embodiments, the BPA comprises three primary layers: a conductive impermeable sheet (BP) that serves as the bipolar separator plate, a conductive porous sheet (H2Shim) functioning as the cathode flow field, and a non-conductive, gas-tight, non-conductive thermoplastic sheet (H2Seal). In one aspect, the non-conductive thermoplastic sheet extends beyond the conductive sheets along the x-axis, creating electrically isolated water plenums when individual cells are stacked. This extension significantly increases the conduction path length through the liquid-containing plenums between adjacent cells, thereby reducing parasitic current and improving stack efficiency. In some embodiments, the conductive impermeable sheet (BP) is a metal foil, e.g. stainless steel, Ti, Ni, or Ni-plated steel. In some embodiments, the conductive porous sheet (H2Shim) is a metal mesh (woven mesh, expanded metal, knitted metal wire), e.g. stainless steel, Ti, Ni, or Ni-plated steel. In preferred embodiments, the BP and H2Shim are composed of the same material. In some embodiments, the thermoplastic sheet (H2Seal) comprises any thermoplastic, including polyolefin or rubber-based thermoplastics (e.g. SIS, SEBS, or SIPS). SIS is a styrene-isoprene-styrene a block copolymer that combines the properties of rubber (elasticity) with the processing advantages of thermoplastics. SEBS is a styrene-ethylene-butylene-styrene, another block copolymer. SIPS is a styrene-isoprene-propylene-styrene block copolymer.

In another aspect, the non-conductive thermoplastic layer serves multiple functions beyond electrical isolation, including: bonding the bipolar plate, conductive porous sheet, and thermoplastic sheet into a unitized assembly, which eliminates alignment errors during stack assembly. Additionally, the non-conductive thermoplastic sheet creates an embedded hydrogen seal by flowing into the conductive porous sheet during the lamination process, providing a gastight barrier without requiring separate compressible gaskets.

In another aspect, to enhance bonding between the dissimilar materials, the conductive impermeable sheet (bipolar plate) can undergo etching or chemical treatment prior to assembly. In another aspect, the thermoplastic material is specifically selected as a hot-melt composition with UV cross-linking capabilities. This allows initial processing at relatively low temperatures for manufacturing efficiency, while enabling post-assembly UV treatment to enhance the material's temperature resistance and mechanical properties for in-service conditions. In some embodiments, the thermoplastic material is selected to have a relatively low elastic modulus, preventing curling of the assembly due to thermal expansion differences between the layers after lamination. This ensures dimensional stability of the completed assembly, which is critical for proper stack function.

In one aspect, the manufacturing process employs high-speed roll lamination methods combined with precision laser or die cutting. Post-cutting of plenum and border geometry ensures dimensional accuracy, while an integrated thermoplastic elastomer (TPE) slug recycling system minimizes material waste. The UV cross-linking step may be deliberately performed after web lamination and slug recycling, allowing the entire manufacturing process to occur at lower temperatures while still achieving the necessary in-situ mechanical properties.

In yet another aspect, all components are constructed from two-dimensional patterns of sheet material with substantially uniform thickness, enabling raw materials to be sourced in roll or coil form. This approach significantly enhances manufacturing scalability and reduces costs compared to molded or machined components used in prior art electrochemical cells.

Membrane Sub-Gasket Assembly

In another embodiment, the present application provides a membrane sub-gasket assembly (MSGA) for an electrochemical cell. In one aspect, the MSGA comprises an ionically conductive membrane layer (M) and at least one reinforcement border layer, referred to as a sub-gasket (SG). The sub-gasket is formed from a hot-melt processable thermoplastic material that is cross-linkable by ultraviolet light. This material selection enables efficient manufacturing while ensuring robust in-service performance.

In another aspect, a hermetic bond is created between the membrane and sub-gasket in an overlap region. This hermetic bond serves two functions: it creates an internal seal between the hydrogen and oxygen chambers of the cell, preventing cross-contamination of reactants, and it provides mechanical reinforcement to the membrane in this critical seal region. The reinforcement is particularly important as the membrane alone may lack sufficient mechanical integrity to maintain a reliable seal under normal operating conditions.

In another aspect, a manufacturing process for a MSGA can leverage cross-linking capabilities of a thermoplastic material. In one aspect, the cross-linking reaction is deliberately delayed until after the MSGA has been integrated into a complete cell assembly, which permits initial processing at relatively low temperatures, facilitating faster production speeds and lower energy requirements, while the subsequent UV-initiated cross-linking enhances the assembly's high-temperature mechanical properties for in-service conditions. UV cross-linking step is specifically performed after web lamination and slug recycling processes are complete. This ensures that all manufacturing steps requiring material flow or deformation can occur at lower temperatures where the thermoplastic behaves optimally for processing. Once the final geometry is established, the cross-linking reaction transforms the material properties to meet the more demanding in-service requirements.

In yet another aspect, MSGA manufacturing includes thermal decomposition of the membrane border prior to bonding with the sub-gasket. This controlled decomposition modifies the membrane surface chemistry, significantly improving adhesion between the dissimilar materials and ensuring a robust, hermetic seal between the hydrogen and oxygen chambers of the cell.

Half Cell Assembly

In yet another embodiment, the present application provides a half-cell assembly (HCA) for an electrochemical cell. In one aspect, the HCA comprises three primary components: a bipolar plate assembly (BPA), a cathode electrode (CE), and a membrane sub-gasket assembly (MSGA). The materials of these components may be those set forth previously. These components are precisely aligned and joined to create a unitized sub-assembly that simplifies subsequent stack assembly operations.

In one aspect, the HCA includes hermetic sealing between the MSGA and BPA. The MSGA is hot-melt sealed to the BPA, completely encapsulating the cathode electrode within a gastight hydrogen region. This hermetic seal eliminates the need for compressible gaskets that would otherwise be required during stack assembly, thereby reducing cell pitch and improving stack power density. In one aspect, the hot-melt seal is formed specifically between the sub-gasket portion of the MSGA and the hydrogen seal (H2Seal) portion of the BPA. The thermoplastic materials for these components are selected to have compatible properties, including similar melting temperatures, viscosities, and chemical compatibility. This compatibility enables homogeneous mixing at the interface during hot-melt processing, effectively eliminating any distinct bond line between the layers after processing. The absence of a distinct bond line eliminates a potential failure point that could develop during thermal cycling or long-term operation. Instead, the processed assembly features a continuous material transition between components, with mechanical properties equivalent to or exceeding those of the base materials.

In another aspect, this HCA manufacturing approach ensures precise alignment of the cathode electrode within the assembly while simultaneously creating a hermetic hydrogen seal. The completed half-cell assembly constitutes a pre-tested, hermetically sealed component that significantly reduces the complexity and variability of subsequent stack assembly operations.

Anode Gasket Assembly

In another embodiment, the present application provides an anode-gasket assembly (AGA) for an electrochemical cell. In one aspect, the AGA comprises three primary components: a water seal (WS), an anode electrode (AE), and an anode flow field (AFF). The water seal may be constructed from a specialized thermoplastic material that enables hot bonding of all three components into a unitized assembly. In preferred embodiments, the water seal comprises a thermoplastic rubber-based pressure sensitive adhesive in filament form factor, e.g. 3M VHB EXTRUDABLE TAPE. In some embodiments the water seal is a thermoplastic material, e.g. an olefin or a rubber. In some embodiments, the anode electrode is carbon or metal felt or metal mesh (e.g. a woven mesh, expanded metal, knitted metal wire). In preferred embodiments, the anode electrode includes an electrocatalyst coating or treatment. In some embodiments, the anode flow field is a metal (e.g. stainless steel, Ti, Ni, or plated steel) or a metal mesh (e.g. a woven mesh, expanded metal, knitted metal wire). This unitization ensures precise alignment of components and significantly simplifies handling during manufacturing operations.

In one aspect, the thermoplastic material is specifically formulated as a hot-melt composition, allowing it to flow and create strong bonds during the lamination process. The thermoplastic material is preferably UV cross-linkable. Initially, the material remains thermally processable during manufacturing. After assembly, UV exposure triggers cross-linking reactions that significantly enhance the material's high-temperature mechanical properties in-situ, ensuring reliable performance under operating conditions. In another aspect, as with other embodiments, cross-linking is performed after completion of the lamination process and any associated slug recycling operations. This timing allows all manufacturing steps to occur at relatively low temperatures, which increases processing speed and reduces energy requirements, while still achieving the necessary in-situ mechanical properties required for service conditions. In another aspect, the thermoplastic material features a low elastic modulus, which prevents curling of the assembly due to differential thermal expansion between the components after lamination. This ensures dimensional stability of the completed assembly, maintaining precise alignment of components throughout the service life of the cell. The unitized nature of the resulting anode-gasket assembly significantly reduces the number of discrete components that must be handled during final cell assembly, minimizing the potential for misalignment errors and enabling higher manufacturing throughput of complete cells.

Integrated Cell Assembly

In another embodiment, the present application provides an integrated cell assembly that combines a half-cell assembly (HCA) and an anode-gasket assembly (AGA) into a fully unitized electrochemical cell. In one aspect, the integrated cell assembly is formed by hot bonding HCA and AGA components into a single, unitized assembly. This unitization ensures precise alignment of all internal components and significantly simplifies handling during manufacturing and stack assembly operations.

In one aspect, a hermetic seal is created between the HCA and AGA by hot bonding the HCA and AGA, specifically between the sub-gasket portion of the membrane sub-gasket assembly (MSGA) and the water seal (WS) portion of the AGA. The hot bond completely encapsulates the anode electrode and anode flow field within a gastight water region. This hermetic seal eliminates the need for compressible gaskets that would otherwise be required during stack assembly, thereby reducing cell pitch and improving stack power density.

The thermoplastic materials for these components are carefully selected to have compatible properties, including similar melting temperatures, viscosities, and chemical compatibility. This compatibility enables homogeneous mixing at the interface during hot-melt processing, effectively eliminating any distinct bond line between the layers after processing. As with prior embodiments, the absence of a distinct bond line is significant as it eliminates a potential failure point that could develop during thermal cycling or long-term operation. Instead, the processed assembly features a continuous material transition between components, with mechanical properties equivalent to or exceeding those of the base materials.

The result is a completely unitized cell assembly with hermetically sealed hydrogen and water chambers, and only a single cell-to-cell interface that must be engaged during stack compression. This significant reduction in stack assembly complexity improves reliability while enabling smaller cell pitch and higher manufacturing throughput.

Integrated Cell Assembly

In yet another embodiment, the present application provides an integrated cell assembly that enables electrical isolation of water plenums of adjacent cells in a stack assembly, thereby significantly reducing cell pitch while maintaining electrical efficiency in stacked configurations.

In one aspect, the integrated cell assembly features a conductive central area and a non-conductive edge area. Water plenums are arranged adjacent to non-conductive edge area rather than adjacent to conductive components. This arrangement electrically isolates the water plenums of adjacent cells when assembled in a stack configuration, creating a significantly longer conduction path through the liquid electrolyte between the conductive areas of adjacent cells. By extending this conduction path length, the embodiment minimizes the potential for unwanted electrolysis reactions to occur within the water plenums.

In a variation of this embodiment, the integrated cell assembly comprises an electrically conductive bipolar plate (BP), an electrically conductive flow field (FF), and an electrically non-conductive sub-gasket surrounding an electrically non-conductive ion exchange membrane, forming an integrated assembly. Each of these components includes water plenum features that align when the components are laminated. The water plenums of the non-conducting sub-gasket are specifically dimensioned to be smaller than the corresponding plenums of both the conductive bipolar plate and the conductive flow field. This creates a non-conductive edge extension at the periphery of each water plenum, which electrically isolates the water plenums of adjacent cells when assembled in a stack configuration.

In a further variation of this embodiment, the integrated cell assembly comprises an electrically conductive bipolar plate and flow field assembly (BPA), an electrically non-conductive sub-gasket surrounding an electrically non-conductive ion exchange membrane forming an integrated assembly, and an electrically non-conductive water seal (WS). Each of these components includes water plenum features that align when the components are laminated. The conductive components extend from under the membrane to the water plenums. To achieve electrical isolation within the liquid-containing water plenums, the plenum openings in both the non-conducting sub-gasket and water seal are specifically dimensioned to be smaller than the corresponding plenum opening in the conductive bipolar plate assembly. Furthermore, a flap in the sub-gasket may be wrapped around bipolar plate assembly to fully encapsulate one or more conductive edges with non-conductive sub-gasket material.

In both variations, a dimensional difference creates a non-conductive edge extension at the periphery of each water plenum, which electrically isolates the water plenums of adjacent cells when assembled in a stack configuration.

In another aspect, the foregoing configurations permit flexibility in controlling the conduction path length independent of cell pitch. The length between conductive areas can be engineered to be 1.0, 1.5, 2, 3, 5, or even 10 times the cell pitch, depending on application requirements and expected electrolyte conductivity. This flexibility represents a significant advancement over prior systems where conduction path length is directly constrained by cell pitch.

In another aspect, the foregoing constructions and geometries also enable exceptionally small cell pitch in stacks, even when using conductive electrolytes, without electrical shorting in the plenums. While prior systems required cell pitches of 10 mm or greater to avoid significant parasitic current through water plenums containing conductive electrolyte, the present embodiment allows cell pitches below 5 mm, below 3 mm, or even below 1 mm while maintaining acceptable electrical isolation.

In still another aspect, by decoupling the conduction path length from cell pitch, these embodiments achieve significant improvements in stack power density (kW/L), stack cost ($/kW), stack turndown capabilities, stack recyclability, and shipping/installation logistics through reduced stack size for a given power capacity.

Further Embodiments

• • A-1. An electrolysis cell comprising:
  • a membrane,
  • an anode,
  • a cathode,
  • an anode flow field,
  • a cathode flow field,
  • a bipolar plate assembly, and
  • a liquid plenum fluidically connected to an electrically conductive area of the electrolysis cell, wherein the electrolysis cell comprises a cell pitch.
  • A-2. The electrolysis cell of A-1, wherein a conductive path in the liquid plenum between the electrically conductive area of the electrolysis cell and an electrically conductive area of an adjacent electrolysis cell is at least 1.5 times the cell pitch, 2 times the cell pitch, 3 times the cell pitch, 5 times the cell pitch, or 10 times the cell pitch.
  • A-3. The electrolysis cell of A-1 to A-2, further comprising a nonconductive edge bounding at least a portion of the liquid plenum, wherein the nonconductive edge comprises an edge extension arranged between a conductive area of the electrolysis cell and the liquid plenum.
  • A-4. The electrolysis cell of A-3, wherein the length of the edge extension is at least 0.25 times the cell pitch, 0.5 times the cell pitch, 1 times the cell pitch, 2 times the cell pitch, or 5 times the cell pitch.
  • A-5. The electrolysis cell of A-1 to A-4, further comprising an electrically non-conductive sub-gasket surrounding the membrane, wherein each of the bipolar plate assembly, the anode or cathode flow field, and the sub-gasket comprise liquid plenum features that align when stacked, and wherein the liquid plenum features of the sub-gasket are dimensioned smaller than corresponding liquid plenum features of the bipolar plate assembly and anode or cathode flow field to create a non-conductive edge extension.
  • A-6. The electrolysis cell of A-5, wherein the non-conductive edge extension provides an electrical isolation path between electrically conductive components of adjacent cells in a stack that is greater than the thickness of the non-conductive sub-gasket.
  • A-7. The electrolysis cell of A-5 to A-6, wherein the electrical isolation path is equal to the sum of the thickness of the non-conductive sub-gasket plus two times the length of the non-conductive edge extension.
  • A-8. The electrolysis cell of A-1 to A-7, further comprising an electrically non-conductive sub-gasket surrounding the membrane, wherein each of the bipolar plate assembly, the anode or cathode flow field, and the sub-gasket comprise liquid plenum features that align when stacked; and
  • an electrically non-conductive water seal having water plenum features that align with the liquid plenum features of the bipolar plate assembly, anode or cathode flow field, and sub-gasket when stacked.
  • A-9. The electrolysis cell of A-5 to A-8, wherein the liquid plenum features of the water seal are dimensioned smaller than corresponding liquid plenum features of the bipolar plate assembly to provide electrical isolation for at least three edges of the liquid plenum.
  • A-10. The electrolysis cell of A-5 to A-9, wherein a fourth edge of the liquid plenum is electrically isolated by a flap formed in the sub-gasket that wraps around the bipolar plate assembly to encapsulate the fourth edge with non-conductive material.
  • A-11. The electrolysis cell of A-10, wherein the flap has an overlap length sufficient to extend the electrical isolation path along the fourth edge to at least 1.5 times the cell pitch.
  • B-1. A cell stack comprising a plurality of integrated electrolytic cells, each electrolytic cell comprising a conductive central area and a non-conductive edge area, wherein the non-conductive edge area comprises a plurality of water plenums in fluid communication with water plenums of adjacent cells in the cell stack, wherein the non-conductive edge area comprises an edge extension length arranged between the conductive area of each electrolysis cell and the water plenum.
  • B-2. The cell stack of B-1, wherein the edge extension is at least 0.25 times the cell pitch, 0.5 times the cell pitch, 1 times the cell pitch, 2 times the cell pitch, or 5 times the cell pitch.
  • B-3. The cell stack of B-1 to B-2, wherein a conductive path between the conductive central areas of adjacent cells in the cell stack along the edge extension length and via a plenum is at least 1.5 times the cell pitch, 2 times the cell pitch, 3 times the cell pitch, 5 times the cell pitch, or 10 times the cell pitch.
  • C-1. An electrolysis cell comprising:
  • a membrane,
  • an anode,
  • a cathode,
  • an anode flow field,
  • a cathode flow field,
  • a bipolar plate assembly, and
  • a nonconductive edge
  • wherein the electrolysis cell is hermetically sealed against the environment and against cross-leakage between the cathode and the anode without use of compressible seals or gaskets.
  • D-1. A bipolar plate assembly for an electrochemical cell comprising
  • a conductive impermeable sheet, a conductive porous sheet, and a non-conductive, gas-tight, thermoplastic sheet, wherein the non-conductive thermoplastic sheet and extends beyond the conductive sheets along an x-axis and comprises water plenums spaced from the conductive sheets by an edge extension length.
  • D-2. The bipolar plate assembly of D-1, wherein the nonconductive thermoplastic sheet is bonded to the conductive impermeable sheet and the conductive porous sheet to create a hermetic seal against the environment.
  • D-3. The bipolar plate assembly of D-1 to D-2, wherein the nonconductive thermoplastic sheet is flowed into the conductive porous sheet to create an embedded gas seal against the environment.
  • D-4. The bipolar plate assembly of D-1 to D-3, wherein the conductive impermeable sheet is etched or chemically treated to promote bonding.
  • D-5. The bipolar plate assembly of D-1 to D-4, wherein the nonconductive thermoplastic sheet is a hot melt.
  • D-6. The bipolar plate assembly of D-1 to D-5, wherein the nonconductive thermoplastic sheet is UV cross-linkable to enhance high temperature mechanical properties in-situ.
  • D-7. The bipolar plate assembly of D-1 to D-6, wherein the nonconductive thermoplastic sheet comprises a low elastic modulus material.
  • D-8. The bipolar plate assembly of D-1 to D-7, wherein the conductive impermeable sheet, conductive porous sheet, and a non-conductive thermoplastic sheet are joined, shaped, or finished with an approach selected from the group consisting of roll lamination, laser/die cutting, laser etching, integrated TPE slug recycling, and UV cross-linking, and combinations thereof.
  • D-9. The bipolar plate assembly of D-1 to D-8, wherein the conductive impermeable sheet and the conductive porous sheet are comprised sheet material having substantially uniform thickness capable of being sourced in roll or coil form.
  • E-1. A membrane sub-gasket assembly for an electrochemical cell comprising
  • an ionically conductive membrane layer, and
  • at least one reinforcement border layer,
  • wherein the border layer comprises a hot-melt thermoplastic material which is cross-linkable via exposure to UV light.
  • E-2. The membrane sub-gasket assembly of E-1, wherein the ionically conductive membrane layer and the at least one reinforcement border layer are hermetically bonded in an overlap region to provide an internal cell between hydrogen and oxygen and to provide mechanical reinforcement to the membrane in the internal seal region.
  • E-3. The membrane sub-gasket assembly of E-1 to E-2, wherein the at least one reinforcement border layer is cross-linked after integration into an electrolytic cell to enhance high temperature mechanical properties in-situ.
  • E-4. The membrane sub-gasket assembly of E-1 to E-3, wherein UV cross-linking occurs post web lamination and slug recycling to allow processing at low temperatures for manufacturing while achieving necessary in-situ mechanical properties.
  • E-5. The membrane sub-gasket assembly of E-1 to E-4, wherein the at least one reinforcement border layer is subjected to a thermal decomposition step to enhance bonding with an adjacent component or layer.
  • F-1. A half-cell assembly for an electrochemical cell comprising
  • a bipolar plate assembly according to any of D-1 to D-9,
  • a cathode electrode, and
  • a membrane sub-gasket assembly according to any of E-1 to E-5.
  • F-2. The half-cell assembly of F-1, wherein the membrane sub-gasket assembly is hot melt sealed to the bipolar plate assembly, thereby completely encapsulating the cathode electrode within a hermetically sealed hydrogen region.
  • F-3. The half-cell assembly of F-2, wherein a hot melt seal is formed between the sub-gasket assembly and a hydrogen seal of the bipolar plate assembly.
  • F-4 The half-cell assembly of F-2 to F-3, wherein the hot melt seal is formed from thermoplastic materials having compatible properties to allow homogeneous mixing at the interface during hot melt processing thereby eliminating a potential bond line between layers after processing.
  • G-1. An anode-gasket assembly for an electrochemical cell comprising
  • a water seal,
  • anode electrode, and
  • an anode flow field,
  • wherein the water seal comprises a thermoplastic material.
  • G-2. The anode-gasket assembly of G-1, wherein the thermoplastic material is hot bonded to the water seal, anode electrode, and anode flow field such that the components form a unitized assembly for accuracy in component alignment and ease of handling in manufacturing.
  • G-3. The anode-gasket assembly of G-1 to G-2, wherein the thermoplastic material is a hot melt thermoplastic material.
  • G-4. The anode-gasket assembly of G-1 to G-3, wherein the thermoplastic material is UV cross-linkable to enhance high temperature mechanical properties in-situ.
  • G-5. The anode-gasket assembly of G-1 to G-4, wherein the thermoplastic material comprises a low elastic modulus.
  • G-6. The anode-gasket assembly of G-1 to G-5, wherein UV cross-linking occurs post lamination and post-slug recycling to allow processing at low temperatures for manufacturing while achieving necessary in-situ mechanical properties.
  • H-1. An integrated cell assembly comprising
  • a half-cell assembly according to any of F-1 to F-4, and
  • an anode-gasket assembly according to any of G-1 to G-6.
  • H-2. The integrated cell assembly of H-1, wherein the half-cell assembly and anode gasket assembly are hot bonded into a unitized assembly for accuracy in component alignment and ease of handling in manufacturing.
  • H-3. The integrated cell assembly of H-1 to H-2, wherein the hot bond completely encapsulates the anode electrode and flow field within a hermetically sealed water region.
  • H-4. The integrated cell assembly of H-1 to H-3, wherein the hot bonded seal is disposed between the sub-gasket of the membrane sub-gasket assembly and the water seal of the anode-gasket assembly.
  • H-5. The integrated cell assembly H-1 to H-4, wherein the materials for the at least one reinforcement border layer and water seal are selected from thermoplastic materials of compatible properties to allow homogeneous mixing at the interface during hot melt processing thereby eliminating a potential bond line between layers after processing.
  • I-1. A method of manufacturing an electrolysis cell with improved electrical isolation, comprising:
  • providing an electrically conductive bipolar plate with water plenum features;
  • providing an electrically conductive flow field with water plenum features;
  • providing an electrically non-conductive sub-gasket with water plenum features dimensioned smaller than the corresponding water plenum features of the bipolar plate and flow field; and
  • laminating the bipolar plate, flow field, and sub-gasket such that their respective water plenum features align and create a non-conductive edge extension between conductive components and a water plenum.
  • I-2. The method of I-1, further comprising:
  • providing an electrically non-conductive water seal with water plenum features dimensioned smaller than the corresponding water plenum features of the bipolar plate; and
  • laminating the water seal to provide electrical isolation for at least three edges of the water plenum.

I-3. The method of I-1 to I-2, further comprising forming a flap in the sub-gasket and wrapping the flap around the bipolar plate to encapsulate a fourth edge of the water plenum with non-conductive material.

The foregoing description of preferred embodiments has been presented for purposes of illustration and description only. It is not intended to be exhaustive or to limit the application to the precise form disclosed, and modifications and variations are possible and/or would be apparent in light of the above teachings or may be acquired from practice of the application. The embodiments were chosen and described in order to explain the principles of the application and its practical application to enable one skilled in the art to utilize the application in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the application be defined by the claims appended hereto and that the claims encompass all embodiments of the application, including the disclosed embodiments and their equivalents.