US20090301868A1 - Methods and systems for assembling electrolyzer stacks - Google Patents

Abstract

The present techniques provide systems and methods for assembling electrolyzers from parts which have internal structures that form fluid flow channels when placed adjacent to one another. In a contemplated embodiment, the assembly technique may use alignment bars, inserted through openings in the individual parts to hold the parts in alignment, while other structures apply pressure to hold the structure together. In another contemplated embodiment, the parts may be aligned by having ridges, or other protrusions, formed on the parts that mate with openings on adjacent parts. The applied pressure seals fluid flow channels formed in the electrolyzer and extending through the joined parts. The use of pressure to hold the structure together allows for the servicing and replacement of individual parts.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT
• This invention was made with Government support under contract number DE-FC07-06ID14789 awarded by the Department of Energy. The Government has certain rights in the invention.
BACKGROUND
• This invention generally relates to methods of assembling electrolyzer stacks, and in particular to a method of sealing electrolyzer cells together to form fluid channels in electrolyzer stacks.
• Electrochemical devices are useful in chemical reactions in which electrons may participate as reactants or products. For example, an electrolytic cell may use electrical energy to split lower energy reactants into higher energy products, which may then be used as materials, reactants, or in power generation. In another example, voltaic cells and fuel cells may be used to chemically combine higher energy products to form lower energy products, releasing electrons that may be used to power other devices. While in voltaic cells, the electrode may be consumed during the reaction, in a number of other electrochemical devices, such as electrolytic cells and fuel cells, the electrode is not intended to be a reactant, but merely to catalyze the reaction and collect or donate the current from the reaction.
• Electrolytic cells may be useful in a number of processes, such as the splitting of water into oxygen and hydrogen in an electrolyzer. The hydrogen generated may be used in chemical processes, such as hydroformulation or hydrocracking in refineries, or may be stored for later use, such as in the generation of energy in a fuel cell. Electrolyzers may be assembled from a stack of individual plastic components that are joined together to form a contiguous structure, generally by adhesives or welding.
• However, permanently joining the components may be disadvantageous for a number of reasons. For example, the failure of an individual part in an electrolyzer stack my require replacement of the entire electrolyzer stack, particularly if individual modules, sections or parts cannot be serviced or replaced. Accordingly, it would be desirable to have techniques for assembling electrolyzer stacks to form a hermetic seal between the individual parts in ways that permit disassembly, servicing, and replacement.
BRIEF DESCRIPTION OF THE INVENTION
• An embodiment of the present techniques provides an electrolyzer that includes a plurality of electrolyzer cells placed adjacent to one another to form a stack. Each electrolyzer cell includes an electrode assembly and a diaphragm assembly, and the diaphragm assembly of each electrolyzer cell is placed adjacent to an electrode assembly of another electrolyzer cell. An internal fluid channel through the stack is formed by an internal structure of each of the electrolyzer cell, and a mounting configured to maintain a compressive force on the stack seals the internal fluid channel.
• Another embodiment provides a method of assembling an electrolyzer that includes assembling a plurality of cells in an aligned stack. Each cell includes a metal plate and a diaphragm, and has apertures, that when aligned with an adjacent cell, form a fluid channel. The fluid channel is sealed by maintaining a compressive force on the stack.
• Another embodiment provides a method of assembling an electrolyzer, which includes assembling a plurality of electrolyzer cells. Each electrolyzer cell includes a metal plate and a diaphragm, and has a structure configured to form a fluid channel when aligned with other electrolyzer cells. The electrolyzer cells are aligned to form an electrolyzer stack having a first end, a second end, and an internal fluid channel. A body is placed around the electrolyzer stack and an end cap is placed over an end of the body. The end cap has an aperture aligned with the channel in the electrolyzer stack. A base plate over another end of the body to create a compressive force to seal the internal channel in the electrolyzer stack securing the end cap and the base plate to the body.
DESCRIPTION OF THE DRAWINGS
• These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawing.
• FIG. 1 is a diagrammatic representation of an electrolyzer system according to embodiments of the present techniques;
• FIG. 2 is a perspective view of an exemplary assembled electrolyzer;
• FIG. 3 is an exploded view of the electrolyzer ofFIG. 2, showing the individual parts of the assembly;
• FIG. 4 is a perspective view of an exemplary electrolytic cell that may be used in the electrolyzer ofFIG. 3;
• FIG. 5 is an exploded view of the electrolyzer ofFIG. 2, showing the use of a protruding lip on the end cap that may be used to place pressure on the electrolyzer stack;
• FIG. 6 is a magnified view of the protruding lip ofFIG. 5; and
• FIG. 7 is diagram illustrating exemplary steps in a method for assembling an electrolyzer in accordance with embodiments of the present techniques.
DETAILED DESCRIPTION
• As discussed in detail below, the present techniques provide systems and methods for assembling electrolyzers from parts which have internal structures that form fluid flow channels when placed adjacent to one another. In a contemplated embodiment, the assembly technique may use alignment bars, inserted through openings in the individual parts to hold the parts in alignment, while other structures apply pressure to hold the structure together. In another contemplated embodiment, the parts may be aligned by having ridges, or other protrusions, formed on the parts that mate with openings on adjacent parts. The applied pressure seals fluid flow channels formed in the electrolyzer and extending through the joined parts. The use of pressure to hold the structure together allows for the servicing and replacement of individual parts.
• An example of anelectrolyzer system10 that may be assembled by the present techniques is illustrated by the schematic diagram ofFIG. 1. In theelectrolyzer system10,water12 is split intohydrogen14 andoxygen16 by anelectrolyzer stack18. In operation, apump20 maintains a continuous flow of anelectrolyte solution22 through theelectrolyzer stack18. Generally, theelectrolyte solution22 is an aqueous solution of about 20 wt % to about 40 wt. %, or about 30 wt %, potassium hydroxide (KOH) or sodium hydroxide (NaOH), although any number of other ionic solutions may be used. For example, theelectrolyte solution22 may contain lithium hydroxide or other metals.
• As a portion of thewater12 is converted tohydrogen14 andoxygen16,additional water12 is added prior to returning theelectrolyte solution22 to theelectrolyzer stack18. As discussed in further detail below, theelectrolyzer stack18 produces ahydrogen stream24 containing bubbles ofhydrogen14 in theelectrolyte solution22. Thehydrogen stream24 is directed to ahydrogen separator26, where thehydrogen14 separates out and is collected for storage or use. Theelectrolyzer stack18 also produces aseparate oxygen stream28 containing bubbles ofoxygen16 in theelectrolyte solution22, which is directed to anoxygen separator30. In theoxygen separator30, theoxygen16 is separated from theelectrolyte solution22. Thehydrogen separator26 andoxygen separator30 may generally function as reservoirs for theelectrolyte solution22. From theseparators26,30 areturn electrolyte solution32 may be directed to thepump20, where it is circulated to theelectrolyzer stack18.
• In theelectrolyzer stack18, twoinlet channels34,35 direct theelectrolyte solution22 to a number ofindividual electrolyzer cells36. Theinlet channels34,35 are formed by adjacently aligned apertures formed in each of theelectrolyzer cells36. Theelectrolyzer cells36 are stacked and electrically connected in series by theelectrolyte solution22. Generally, theelectrolyzer cells36 are joined, for example, by welding, to form a single structure, in which theinlet channels34,35 form one of two sets of flow paths through the structure. However, embodiments of the present techniques allow for assembling anelectrolyzer stack18 without forming a permanent bond between theelectrolyzer cells36, by placing theelectrolyzer stack18 under pressure during assembly and use. This holds theelectrolyzer cells36 together with sufficient pressure to form a hermetic seal between theindividual electrolyzer cells36. Further, these techniques may allow theelectrolyzer stack18 to be serviced by the replacement of or access toindividual cells36.
• In the illustrated embodiment, theelectrolyzer stack18 contains 10electrolyzer cells36, although any number may be included, such as 50, 75, 100, ormore electrolyzer cells36 depending on the current available and the production rates desired. At one end of theelectrolyzer stack18, apositive source38 is connected to a positivecurrent collector40. At the other end of the stack, anegative source42 is connected to a negativecurrent collector44. Ametal plate46 disposed within each of theelectrolyzer cells36 functions as a bipolar electrode. As current is passed through theelectrolyte solution22, a positive charge is induced on the side of themetal plate46 closest to thepositive electrode38, forming ananodic surface48. Similarly, a negative charge is induced on the side of themetal plate46 closest to the negative electrode, forming acathodic surface50. Themetal plate46 may have a wire mesh welded to thesurfaces48,50 to increase the surface area.
• Generally, during electrolysis, the difference in charge between theanodic surface48 andcathodic surface50 may be on the order of about 1.5 volts to about 2.2 volts. Accordingly, as theelectrolyzer cells36 are in series, the voltage supplied to theelectrolyzer stack18 will be increased to accommodate the number ofelectrolyzer cells36 in the stack. For example, the voltage supplied to theelectrolyzer stack18 may range from about 15 to about 22 volts, for embodiments with 10electrolyzer cells36 and range from about 150 volts to about 220 volts, for embodiments with 100electrolyzer cells36. Other voltages, and indeed, other charge application schemes may also be envisaged.
• During operation of theelectrolyzer stack18, theelectrolyzer solution22 is passed over theanodic surface48 of themetal plate46 through achannel52 formed in each of theelectrolyzer cells36 and connected toinlet channel34. Asecond channel54 directselectrolyte solution22 frominlet channel35 over thecathodic surface50 of themetal plate46. Thewater12 in theelectrolyte solution22 is split intooxygen16 at theanodic surface48 andhydrogen14 at thecathodic surface50. The bubbles ofhydrogen14 andoxygen16 are isolated from each other by a liquidpermeable membrane56, which allows water and ions from theelectrolyte solution22 to flow conducting current, between theanodic surface48 and thecathodic surface50, but generally prevents the transfer of gas. The liquidpermeable membrane56 may be made from any number of hydrophilic polymers, including, for example, polysulfones, polyacrylamides, and polyacrylic acids, among others.
• Theoxygen stream28 formed at theanodic surface48 in each of theelectrolyzer cells36 is directed through anoxygen channel58 to anoxygen outlet channel60. From theoxygen outlet channel60, theoxygen stream28 is directed to theoxygen separator30. Similarly, thehydrogen stream24 formed at thecathodic surface50 of each of theelectrolyzer cells36 is directed through ahydrogen channel62 to ahydrogen outlet channel64. From thehydrogen outlet channel64, thehydrogen stream24 is directed to thehydrogen separator26. As for theinlet channels34,35, theelectrolyzer cells36 have adjacently aligned apertures that form theoutlet channels60,64 whenelectrolyzer cells36 are joined together to form the final structure. Accordingly, it is desirable that theelectrolyzer cells36 be hermetically sealed to each other to prevent mixing of thehydrogen14 andoxygen16 between theoutlet channels60,64, or other parts of theelectrolyzer stack18.
• Theelectrolyzer stack18 is generally mounted in an enclosure as illustrated inFIG. 2, forming anelectrolyzer66. Theelectrolyzer66 has connections for theinlet channels34,35 to allow the flow ofelectrolyte solution22 into theelectrolyzer66. Theelectrolyzer66 also has connections for theoxygen outlet channel60 to allow theoxygen stream28 to be removed, and thehydrogen outlet channel64 to allow thehydrogen stream24 to be removed. In the illustrated embodiment, the structure forms a pressure vessel, and the connections are flanged connections for interfacing with mating piping. Other physical configurations may, of course, be envisaged. Generally, in a presently contemplated embodiment, thethickness68 of theelectrolyzer66 may be about 150 cm, but the actual size and dimensions will vary depending upon the number of electrolyzer cells used. The details of theelectrolyzer66 may be seen more clearly inFIG. 3.
• FIG. 3 illustrates an explodedview70 showing the individually components of theelectrolyzer66. As shown in this view, the electrolyzer has anend cap72, which has connections to theinlet channels34,35 andoutlet channels60,64. Thebody74 of the electrolyzer has a number ofconnectors76 mounted along the periphery to allow pressure to be applied during operation. The pressure applied is outside of the electrolyzer stack18 (within the body74) to reduce hoop stress on theelectrolyzer stack18 by generally equalizing or reducing the pressure differential between the interior and exterior regions of the stack.
• Theelectrolyzer stack18 is assembled by stacking theelectrolyzer cells36 together to form a single unit, with the apertures in each of theelectrolyzer cells36 aligned to form theinlet channels34,35 andoutlet channels60,64. The alignment of theelectrolyzer cells36 may be performed by inserting analignment bar78 through the parts, for example, through thehydrogen outlet channel64, as shown. Other alignment bars (not shown) may be inserted through theother channels34,35, and60 to further improve the alignment. Further, theelectrolyzer cells36 may be aligned by mating protrusions (not shown) in the surface of theelectrolyzer cell36 with corresponding indentations onadjoining electrolyzer cells36.
• Abase plate80 is mounted against thebody74 opposite theend cap72. Thebase plate80 may havedepressions81 into which thealignment bar78 may be inserted, aligning thebase plate80 with the rest of theelectrolyzer66. Theend cap72,base plate80, andbody74 may be constructed from any suitable materials, such as stainless steel, hastalloy, nickel, and so forth. Further, the parts do not have to be made from metal, as a high performance plastic may provide sufficient properties. Suitable high performance plastics may include, for example, polyphenylene sulfide (PPS) or poly(ether-ether-ketone) (PEEK), among others. Moreover the parts may be made of the same material or may be of different materials. For example, theend cap72 and thebase plate80 may be made from stainless steel, while thebody74 may be made from a high-performance plastic, thereby insulating theend cap72 from thebase plate80. Theend cap72 may also be insulated from thebase plate80 by the use of gaskets (not shown) betweenend cap72, thebody74, and thebase plate80.
• To place theelectrolyzer cells36 under pressure, one ormore spacer plates82 may be inserted insulate theelectrolyzer stack18 from theend cap72. Further, agasket84 may be inserted to add additional pressure, and/or to insulate the stack from thebase plate80. The pressure applied to theelectrolyzer stack18 may be controlled by the number and thickness of thespacer plates82. For example, twospacer plates82 may provide a pressure of about 6.89 bar (100 psi). Other pressures that may be used in embodiments depend on the materials used, as discussed further below. Other ways of imposing pressure on theelectrolyzer stack18 may be used, including anend cap72 with a protruding lip, as discussed with respect toFIG. 5 below.
• The entire assembly may be held together bybolts86 inserted through theend cap72 andbase plate80, which are threaded intonuts88 after insertion through thebase plate80. Thebolts86 will apply the pressure used to seal theelectrolyzer cells36 against each other, forming theinlet channels34,35 andoutlet channels60,64. Apower terminal90 may be welded onto theend cap72 which may then function as one of thecurrent collectors40,44. Anotherpower terminal92 welded onto thebase plate80 may allow thebase plate80 to function as the oppositely charged current collector.
• It should be noted that additional elements may also be placed between the cells to aid in assembly and/or sealing. For example, the cells may be mated through the intermediary of a seal or seal assembly (not shown) that may be placed between adjacent cells or cell elements (i.e., adjacent electrode and diaphragm assemblies). Such seals may be disposed on a surface of one or both of the adjacent elements, or may be recessed in grooves or other structures formed or machined into the elements.
• Anindividual electrolyzer cell36 that may be used in theelectrolyzer stack18 is shown in the perspective view ofFIG. 4. Theelectrolyzer cell36 generally includes two parts, anelectrode assembly94 mounted to adiaphragm assembly96. Bothassemblies94,96 have apertures which align with one another, and with other electrolyzer cells to form theinlet channels34,35 and theoutlet channels60,64. Theelectrode assembly94 holds themetal plate46 that forms the bipolar electrode. One side of theelectrode assembly94 has thechannel54 molded in to direct flow of the electrolyte from one of theinlet channels35 across thecathodic surface50 of themetal plate46. The flow with entrained hydrogen bubbles is then directed to thehydrogen outlet channel64 viahydrogen channel62, which may also be molded into theelectrode assembly94. An analogous set of channels on the opposite side of themetal plate46 directs the flow ofoxygen16.
• Theelectrode assembly94 and thediaphragm assembly96 may be made from any number of materials, and in a presently contemplated embodiment, include a peripheral frame made of a non-conductive, chemically resistant plastic. The plastic material may generally be chemically resistant to an oxidative environment, a reducing environment, an acidic environment, a basic environment, or any combination thereof. For example, the frames of theassemblies94,96, may be made from polyimides, polyamides, polyetheretherketones, polyethylenes, fluorinated polymers, polypropylenes, polysulfones, polyphenylene oxides, polyphenylene sulfides, polyphenylethers, polystyrenes, polyether imides, epoxies, polycarbonates, impact-modified polyethylene, impact-modified fluorinated polymers, impact-modified polypropylenes, impact-modified polysulfones, impact-modified polyphenylene oxides, impact-modified polyphenylethers, impact-modified polyphenylene sulfides, impact-modified polystyrene, impact-modified polyetherimide, impact-modified epoxies, impact-modified polycarbonates, or any combinations thereof. Other polymers that may be used include high performance blends, such as Noryl, which is a blend of polyphenylether and polystyrene (PS) (available from SABIC Innovative Plastics of Pittsfield, Mass.).
• The materials selected for theelectrode assembly94 anddiaphragm assembly96 will determine the pressure that needs to be applied to theelectrolyzer stack18 to form a hermetic seal between eachelectrolyzer cell36. Specifically, the compliance, or modulus, of the plastic will determine what applied pressure will result in formation of a seal. If the pressure is too low relative to the compliance, the plastic may not adequately seal, allowing thehydrogen14 andoxygen16 to mix through leaks between theoutlet channels60,64. If the pressure is too high, the plastic may crack, also allowing leaks to form. In presently contemplated embodiments, the pressure applied to theelectrolyzer stack18 may be about 2 bar, 3 bar, 5 bar, 7 bar, 9 bar, or higher.
• Thediaphragm assembly96 may be permanently joined to theelectrode assembly94 to form theelectrolyzer cell36. The twoassemblies94,96 may be joined by any number of techniques including adhesives, ultrasonic welding, thermal welding, compression, and so forth. Thediaphragm assembly96 holds the liquidpermeable membrane56, which prevents mixing ofoxygen16 formed on theanodic surface48 of themetal plate56 withhydrogen14 formed on thecathodic surface50 of an adjoining metal plate. In other contemplated embodiments, theelectrode assembly94 anddiaphragm assembly96 may be left as separate units, and held together by pressure in the final assembledelectrolyzer66.
• Theelectrolyzer cell36 may be slid onto alignment bars98,100 inserted through thechannels34 and35 to align theelectrolyzer cell36 withadjoining electrolyzer cells36, forming theelectrolyzer stack18. Other alignment bars (not shown) may be inserted throughchannels60 and64. The alignment bars may generally be cylindrical, but any shape that makes sufficient contact with the sides of thechannels34,35,60, and64 may be used. The alignment bars may be plastic rods or cylinders and may also include plastic tubing and pipe. As previously mentioned, other techniques may be used to align theelectrolyzer cells36. Protrusions (not shown) may be molded or machined into theelectrode assembly94 or thediaphragm assembly96, and designed to interface with matching holes or surface depressions in adjoining parts. The use of mating protrusions may be used in addition to or in place of the alignment bars.
• In addition to the use ofspacer plates82, described above, another presently contemplated technique that may be used to apply pressure to theelectrolyzer stack18 is shown in the top view of theelectrolyzer66 inFIG. 5. In this configuration, theend cap72 has aprotruding lip102 machined into the lower surface. The protrudinglip102 has an o-ring104 set into a channel machined into the protrudinglip104. The procedure is generally the same as described forFIG. 3, with analignment bar78 placed through at least one of thechannels64 formed by the aligned apertures in theelectrolyzer cells36. Thespacer plates82 andgasket84 may be used to further increase the pressure on theelectrolyzer stack18. The protrudinglip102 is designed the closely fit within thebody74 of theelectrolyzer66, with the o-ring104 forming a seal.
• A closer view of the protrudinglip102 may be seen in the magnified view ofFIG. 6, taken along cut line6-6 inFIG. 5. InFIG. 6, it can be seen that the protrudinglip102 may be only slightly within theinside edge106 of thebody74. This tight fit may enable the o-ring104 to securely engage theinside edge106 of thebody74 forming the seal. As the nuts88 are tightened onto thebolts86, the protrudinglip102 may function as a piston, applying pressure to theelectrolyzer stack18, and sealing thechannels34,35,60, and64.
• Amethod108 for assembling anelectrolyzer66 is illustrated in the flow chart inFIG. 7. Themethod108 begins with the formation of the sub-assemblies (block110). The sub-assemblies include theelectrolyzer cells36 which are made by joining anelectrode assembly94 to adiaphragm assembly96, as described above. Once the sub-assemblies are made, they are placed onto an alignment bar78 (block112), to form anelectrolyzer stack18. Any other parts desired are then placed onto the alignment bars, such as thespacer plates82 andgasket84. In other contemplated embodiments, protrusions on each of theelectrolyzer cells36 may be matched to indentations onadjoining electrolyzer cells36 to align thefluid channels34,35,60,64. In this contemplated embodiment, matching protrusions and indentations may also be formed into thespacer plates82,gasket84. In this embodiment, matching indentations or protrusions may also be machined into theend cap72 and thebase plate74.
• The alignedelectrolyzer stack18 is then assembled into the body74 (block114). The alignment bars are placed through theend cap72 to align thechannels34,35,60, and64 with theend cap72. The opposite end of the alignment bars may be placed into depressions in thebase plate80 to align thebase plate80 with the rest of the parts. After all parts are assembled, thebolts86 are placed through theend cap72 andbase plate80, and the nuts88 are ed onto the bolts86 (block116).
• Once thebolts86 are attached to the nuts88, they are tightened to apply pressure to the electrolyzer stack18 (block118). The pressure seals theelectrolyzer cells36 to each other, forming theinlet channels34,35 andoutlet channels60,64. Once the assembly is complete, the alignment bars are removed by pulling them from thechannels34,35,60, and64 in the end cap72 (block120), leaving a fully assembled electrolyzer unit.
• While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims (20)

1. An electrolyzer, comprising:

a plurality of electrolyzer cells placed adjacent to one another to form a stack, wherein each electrolyzer cell comprises an electrode assembly and a diaphragm assembly, and wherein the diaphragm assembly of each electrolyzer cell is placed adjacent to an electrode assembly of another electrolyzer cell;

an internal fluid channel through the stack formed by an internal structure of each of the electrolyzer cells;

a mounting configured to maintain a compressive force on the stack sufficient to seal the internal fluid channel.

2. The electrolyzer ofclaim 1, wherein the compressive force creates a pressure between cells of between about 3 bar and a pressure less than the maximum allowable compressive load of the cell material.

3. The electrolyzer ofclaim 1, wherein the mounting is configured to be opened to permit access to any one of the plurality of electrolyzer cells.

4. The electrolyzer ofclaim 1, wherein either the electrode assembly, the diaphragm assembly, or both, comprises a plastic material that is chemically resistant to an oxidative environment, a reducing environment, an acidic environment, a basic environment, or any combination thereof.

5. The electrolyzer ofclaim 1, wherein either the electrode assembly, the diaphragm assembly, or both, comprises polyimides, polyamides, polyether ether ketones, polyethylenes, fluorinated polymers, polypropylenes, polysulfones, polyphenylene oxides, polyphenylene sulfides, polyphenylene ethers, polystyrenes, polyether imides, epoxies, polycarbonates, impact-modified polyethylene, impact-modified fluorinated polymers, impact-modified polypropylenes, impact-modified polysulfones, impact-modified polyphenylene oxides, impact-modified polyphenylene sulfides, impact-modified polystyrene, impact-modified polyetherimide, impact-modified epoxies, impact-modified polycarbonates, or any combination thereof.

6. The electrolyzer ofclaim 1, wherein the mounting comprises a body around the stack, an end cap comprising a manifold configured to be in fluid contact with the internal fluid channel, and a base plate, wherein the end cap and the base plate are configured to maintain the compressive force.

7. The electrolyzer ofclaim 6, wherein the end cap comprises a lip configured to extend into the body and maintain the compressive force.

8. The electrolyzer ofclaim 6, comprising a spacer between the stack and the end cap, wherein the spacer plate maintains the compressive force.

9. The electrolyzer ofclaim 1, wherein the electrode assembly and the diaphragm assembly of each electrolyzer cell form a single unit.

10. The electrolyzer ofclaim 1, wherein the electrode assembly and the diaphragm assembly of each electrolyzer cell are held together by the compressive force.

11. The electrolyzer ofclaim 1, comprising an inlet channel for introducing an electrolyte solution into the electrolyzer, a hydrogen outlet channel, an oxygen outlet channel, or any combination thereof.

12. A method of assembling an electrolyzer, comprising:

assembling a plurality of cells in an aligned stack, each cell comprising a metal plate and a diaphragm, and each cell having aligned apertures forming a fluid channel when aligned with an adjacent cell; and

maintaining a compressive force on the stack to seal the fluid channel.

13. The method ofclaim 12, comprising placing an alignment bar through the cells to align the plurality of cells.

14. The method ofclaim 12, comprising mating a protrusion on each cells with a depression on each adjacent cell to align the plurality of cells.

15. The method ofclaim 12, wherein the compressive force creates a pressure between cells of between about 3 bar and about 9 bar.

16. The method ofclaim 12, wherein the compressive force is maintained by a spacer.

17. The method ofclaim 12, wherein the compressive force is maintained on the device by a lip on an end cap disposed adjacent to the stack.

18. The method ofclaim 12, comprising releasing the pressure to access one of the plurality of cells.

19. A method of assembling an electrolyzer, comprising:

assembling a plurality of electrolyzer cells, wherein each electrolyzer cell comprises a metal plate and a diaphragm, and wherein each electrolyzer cell has a structure configured to form a fluid channel when aligned with other electrolyzer cells;

aligning the plurality of electrolyzer cells to form an electrolyzer stack having a first end, a second end, and an internal fluid channel;

placing a body around the electrolyzer stack;

placing an end cap over an end of the body, the end cap having an aperture aligned with the channel in the electrolyzer stack;

placing a base plate over another end of the body to create a compressive force to seal the internal channel in the electrolyzer stack securing the end cap and the base plate to the body.

20. The method ofclaim 19, comprising disposing at least one spacing element in contact with the electrolyzer stack to create the compressive force.

Images