Electrolysis cell with support members

Abstract

A half shell (5) for an electrolysis cell is provided. The half shell comprises a backwall plate (5a), a backwall frame (5b) extending from a periphery of the backwall plate (5a) so as to define a volumetric space for a cathode or anode chamber, the backwall frame (5b) having a flange portion at an end opposite to the backwall plate, and one or more raised features (10) for stiffening the half shell (5) arranged in the backwall plate (5a) and / or the backwall frame (5b), each raised feature (10) being shaped by a recess on its opposite side.

Description

[0001] ELECTROLYSIS CELL WITH SUPPORT MEMBERS

[0002] Technical Field

[0003] The present invention relates to a half shell for an electrolysis cell and a method of manufacturing the same. More specifically, it involves the design and production of half shells for cathode and anode, which reduce material usage, enhance the efficiency of electrochemical reactions, improve fluid handling, and / or ensure the integrity of the half shell over its lifecycle.

[0004] Background

[0005] Conventional single-element electrolysis cells are divided into cathode and anode half shells. The existing designs face several challenges, including the need for efficient electrochemical reactions, optimal fluid handling, and being leakage proof throughout the lifecycle. Further, these half shells must resist electrolytes, especially alkaline electrolytes, and often require costly materials to be used such as pure nickel.

[0006] Conventional production involves a complex, multistep process, e.g., laser cutting, bending, followed by laser or arc welding. This approach limits functional optimizations such as stiffening for material reduction, fluid flow enhancement, and electrolyte (e.g., KOH) usage efficiency. The conventional shell design lacks the integration of additional functions due to the complexities and limitations of the existing production methods.

[0007] Moreover, the differential construction of the conventional cell design complicates series production. So called “undercut”, which is a gap between a collecting channel for gas and / or liquid collection arranged at the top side of the cell and an opposing backwall frame portion (i.e., the top side of the electrolysis cell), may be necessary to minimize size of gas pocket whilst defining the filling level. The backwall frame portion is inclined both outwards and upwards with respect to the horizontal plane as seen from the electrolytic membrane.However, forming the undercut may preclude easy removal of forming tool, leading to a complex multistep process.

[0008] Additionally, the conventional bending process necessitates downstream welding of corners, requiring testing via dye penetrant methods. This testing is manual, infrastructure-intensive, and presents a production bottleneck. Scaling up production quantities in the existing setup only increases the number of production lines without realizing cost degression or scaling effects. As such, the conventional method introduces production bottlenecks, particularly during ramp-up phases of annual quantities.

[0009] Summary

[0010] The present invention aims at solving one or more of the abovementioned drawbacks in the conventional shell design and production thereof.

[0011] The present invention is defined by independent claims 1 and 8 as appended. Further preferable embodiments are given in the dependent claims.

[0012] In particular, the half shell according to the present invention is directed to an enhanced structural design. The half shell incorporates one or more raised feature as stiffening features that allow material usage to be reduced whilst maintaining structural integrity. The raised feature may also be referred to as “bead” in the description. The stiffened design thus allows to reduce the use of expensive materials such as pure nickel, without compromising performance.

[0013] One embodiment provides an improved half shell for electrolysis cells and an efficient manufacturing method. One embodiment may feature a robust and optimized half shell design that integrates multiple functional enhancements whilst facilitating high-volume production. The half shell may be designed to be resistant to electrolytes and may utilize rare materials such as pure nickel efficiently.In some embodiments, the one or more raised features allow improvements in fluid flow management within the shell, thereby enhancing electrochemical reaction and reducing the required quantity of electrolytes such as KOH.

[0014] Each raised feature may have a geometric shape of cross, square, circle or triangle, or a geometric shape of corrugation in plan view. Depending on the planar shape of the raised feature, different technical effects can be expected. For example, the raised feature having crossed shape may effectively reinforce the half shell in two different directions. The raised feature having circular shape may have fewer wrinkles associated with the formation of the raised feature. The raised feature having wavy or corrugation shape may function as improved flow guidance or management for electrolyte in the chamber.

[0015] When multiple raised features are formed, the raised features may be arranged in a staggered manner with respect to each other in plan view. Alternatively, the multiple raised features may be aligned in the cell width and / or cell height directions. The former allows for the formation of more raised features, whereas the latter is expected to have a greater effect in reduced flow resistance against the electrolyte in the chamber.

[0016] In a preferable arrangement, each raised feature is located where no support element for electrode is mounted on the backwall plate. This facilitates the attachment of the support element to the backwall plate. Alternatively, each raised feature may be so located as to be adjacent to the support element for electrode to be mounted on the backwall plate. Such a raised feature is advantageous in a welded or mechanical (e.g., clinching) connection to the support element.

[0017] The raised feature may take various dimensions depending on the required functionality. Preferably, the height of the raised feature ranges from 1.2 mm to 7 mm, the width of the raised feature ranges from 10 mm to 37 mm, and / or the radius (if applicable) of the raised feature ranges from 6 mm to 15 mm.In one example, the one or more raised features may be used to reduce the volume of the chamber. For this reason, the raised feature may have a relatively wide raised surface. Preferably, the height of the raised feature is constant (i.e. the raised surface of the raised feature 10 is flat). More preferably, each raised feature has a low profile, namely, the height of the raised feature is 50% or less of the minimum width of the raised feature, more preferably 25% or less. With these raised features, the volume of the volumetric space may be reduced by 2.5% or more, preferably up to 15%, compared to the volume where no raised feature is provided.

[0018] In one embodiment, the backwall frame may include a part tilted towards the volumetric space towards the flange portion. This creates a gap between the sloping backwall frame and the collecting channel as mentioned above.

[0019] The one or more raised features may provide not only the strengthening function but also clamping or joining function for add-on parts inside the cathode or anode chamber. That is, the raised features may be used to secure or aid in securing add-on parts such as support elements for electrode or collecting channel to the half shell. For example, if the raised feature is formed adjacent to the add-on part, the add-on part may be welded to the raised feature easily with less gap. Alternatively, the add-on part may be mounted to the half shell by clinching the raised feature, requiring no fasteners or welding.

[0020] The method of manufacturing a half shell according to the invention is characterized by deep drawing, which allows simplified manufacturing processes as well as high-volume production, enabling efficient scale-up.

[0021] The method may enable the incorporation of additional functions without the need for extra production steps. This reduces complexity and bottlenecks associated with traditional multistep processes.

[0022] In one example, multiple functions may be integrated into a single production step, reducing costs and production complexity.Furthermore, the method may eliminate the necessity of some of manual testing such as dye penetrant testing for the welded corners of the half shell.

[0023] The method may include forming the one or more raised features as discussed above. Such raised features may be formed by embossing the same time of the deep-drawing step.

[0024] As discussed above, the half shell may include a tilted part on the top side of the shell. More specifically, the backwall frame may include a tilted or sloping part towards the volumetric space towards its flange portion. Such a half shell with the tilted part may be easily produced even through the deep drawing process if a punch is moved laterally towards a die after a blank material sheet is formed into a pan shape having the backwall plate and the backwall frame. Likewise, after forming the tilted part, the punch may be withdrawn from the die whilst being moved laterally away from the die.

[0025] Brief Description of the Drawings

[0026] Figure 1 shows cross sectional view of an electrolysis cell comprising a pair of half shell assemblies and associated components.

[0027] Figure 2 shows various beading geometries into the backwall plate.

[0028] Figure 3A shows an exemplary half shell comprising a plurality of cross-shaped raised features.

[0029] Figure 3B shows a cross-section along A-A line in figure 3A.

[0030] Figure 4 shows an exemplary half shell comprising a plurality of raised features in corrugation shape, which are designed for optimized flow guidance.

[0031] Figure 5A shows an exemplary half shell comprising a plurality of raised features in square shape, which are designed for volume reduction of the half shell.Figure 5B shows a cross section along line B-B in figure 5A.

[0032] Figure 5C shows an enlarged view from C-C in figure 5A.

[0033] Figure 6A shows an exemplary half shell comprising a plurality of raised features, which are designed for serving as thermal joining aids.

[0034] Figure 6B shows a cross section along line D-D in figure 6A.

[0035] Figure 7 A shows an exemplary half shell comprising a plurality of raised features, which are designed for serving as mechanical joining aids.

[0036] Figure 7B shows a cross section along line E-E in figure 7A.

[0037] Figure 8A shows an exemplary half shell comprising a plurality of raised features, which are designed for fixing a collecting channel to the half shell.

[0038] Figure 8B shows a cross section along line G-G in figure 8A.

[0039] Figure 8C shows an enlarged view from part F in figure 8A.

[0040] Figure 9A shows an exemplary half shell having a stamped collar on the backwall frame for enabling a more stable welding process of a nozzle.

[0041] Figure 9B shows a cross section along H-H line in figure 9A.

[0042] Figure 10 illustrates an exemplary operation to form an undercut into the half shell using a slidable punch. For eased understanding, all embossed bead designs were left out in the drawing.

[0043] Detailed Description

[0044] The invention addresses critical challenges in the design and manufacturing of electrolysis cell half shells through a transformative change in the basic functional product design. This new design allows for a shift to alternativeproduction technologies and system layouts capable of scaling to high series production volumes. The key aspects of the product design and production optimizations that achieve these goals are detailed as follows:

[0045] 1. Forming of Raised features with Various Geometries

[0046] The half shell design incorporates one or more raised features such as embossed beads with various geometries that serve multiple product optimization purposes including:

[0047] (la) Stiffening Function: The one or more raised features in the half shell provides structural reinforcement, enhancing the rigidity and stability of the half shell. This stiffening allows for the use of thinner materials whilst maintaining strength, thereby reducing the overall material costs and improving the mechanical performance of the half shell.

[0048] (lb) Improved Flow Guidance: The geometry of the raised feature may be designed to improve the flow of electrolytes within the half shell during use, i.e. , cathode or anode chamber. This leads to improved fluid dynamics, ensuring efficient distribution and movement of electrolytes, which enhances the electrochemical reaction efficiency.

[0049] (lc) Volume Reduction Without Cell Pitch Reduction: the one or more raised features may reduce the internal volume of the half shell without affecting the cell pitch. This design helps in reducing the use of expensive electrolytes whilst maintaining the overall performance and dimensions of the cell. This design may particularly be advantageous in combination with the improved flow guidance as discussed immediately above.

[0050] 2. Production Process Optimization

[0051] The present invention also focuses on optimizing the production process through deep drawing technology, preferably in combination with embossing the one or more raised features.(2a) Suitable Geometries for Assembly and Joining Aids: The embossing process via deep drawing may create geometries that act as aids for joining additional parts within the half shell. These features simplify the assembly process and reduce the need for complex post-production operations.

[0052] (2b) Simplified Assembly: The deep drawing process may emboss geometries that facilitate easier and more accurate assembly of the half shell. This reduces assembly time and complexity, contributing to a more streamlined production workflow.

[0053] (2c) Integrated Weld Collars: The production may include beading welded collars as a stamping part of the deep drawing operation. These collars serve as joining aids for attaching additional components such as nozzles, thereby simplifying production and enabling a more stable welding process of a nozzle.

[0054] 3. Enhanced Durability and Increased Lifespan

[0055] The new design of the half shell enhances its durability and operational lifespan: The deep-drawn half shell may feature rounded corners and the elimination of weld seams, which reduces stress concentrations and potential points of failure. This design improvement leads to a longer operational lifespan by enhancing the overall structural integrity of the half shell.

[0056] 4. Production Technology Adaptations for Deep Drawing Production

[0057] The invention may include specific adaptations to the production technology, ensuring efficient and scalable manufacturing:

[0058] (4a) Realization of an undercut: The undercut necessary for the electrolysis cell may be achieved using slider functions and increased radii in moulding mechanism. This adaptation makes the design compatible with deep drawing processes, enabling more straightforward production.(4b) Reduced Stretching: Adopting a more octagonal layout for the sheet metal, adjusting radii to achieve smoother geometry, and incorporating specific design features such as drawing beads may be incorporated to reduce stretching during the deep drawing process. These features ensure that the material deformation is controlled, reducing deep drawing defects like wrinkling or cracks.

[0059] (4c) Tribological System Demands: Materials with sufficient KOH-resistance are accounted for demands on the tribological system during deep drawing, such as lubrication and friction management, ensuring smooth and efficient material flow during forming.

[0060] (4d) Exploitation of Deep Drawing Advantages: The production process takes advantage of deep drawing capabilities, including integrated punching and forming operations, which allow formation of the raised feature having a geometric shape of cross, corrugation, square, circle or the like, in plan view. This integration streamlines production steps, reduces costs, and enhances efficiency.

[0061] In summary, the inventive design and manufacturing method for the half shell of an electrolysis cell may provide significant advancements over the conventional design and production and overcome critical challenges related to structural integrity, fluid dynamics, production efficiency, and scalability. These solutions enable a shift to high-volume production with enhanced performance, reduced costs, and improved operational lifespan of the electrolysis cells.

[0062] Figure 1 shows an exemplary electrolysis cell comprising a pair of half shell assemblies 1. Each half shell assembly 1 may include an electrode 2 accommodated in a chamber 3. A sheet-like separator or membrane 7, such as ion exchange membrane or diaphragm, may be arranged between the opposing electrodes 2.

[0063] The half shell assembly 1 includes a half shell 5. The half shell 5 includes a backwall plate 5a and a backwall frame 5b. The backwall plate 5a extends in the cell height direction as well as the cell width direction and faces the electrode 2 when assembled. The backwall frame 5b extends from the periphery of thebackwall plate 5a so as to define a volumetric space for the chamber 3. The backwall frame 5b has a flange portion 5c at its end that is an opposite end to the backwall plate 5a.

[0064] The half shell assembly 1 may further include a collecting channel 6 for gas and liquid discharge. The collecting channel 6 may be arranged inside the chamber 3 to face the top side of the backwall frame 5b.

[0065] The electrode 2 is arranged within the chamber 3 defined by the half shell 5, serving as the site for electrochemical reactions. Depending on which side the electrode 2 is arranged with respect to the separator or membrane 7, the electrode 2 functions as either the cathode or the anode of the electrolysis cell.

[0066] The electrode 2 is typically made of materials that exhibit high conductivity and corrosion resistance, such as nickel, titanium, or other suitable alloys. It is designed to enhance the surface area for electrochemical reactions, often featuring a mesh or porous structure to enhance reaction efficiency and facilitate the movement of ions.

[0067] The electrode 2 is positioned within the half shell and may securely be mounted to ensure consistent electrical contact and stability during operation. The electrode 2 shall be oriented to face the opposite electrode 2 in the paired half shell 5, creating the electrolysis cell. The distance between the electrodes 2 and the separator 7 may be reduced to achieve so called “zero-gap electrolyser”.

[0068] The half shell assembly 1 may further include one or more support elements that provide mechanical support to the electrode 2, ensuring its stability and alignment within the half shell 5. The one or more support elements may include webs or web structures 4 (see, e.g., figures 2 and 7) and support blades (not shown). The support blades are typically arranged horizontally, i.e. , in the cell width direction, depending on the design of the electrolysis cell. Each support blade may extend through the webs 4 to enhance the overall rigidity and strength of the web structures. The web structures may be designed towithstand the operational stresses and thermal expansion that occur during electrolysis.

[0069] The webs 4 are typically ribbed formations or brackets that extend from the backwall plate 5a towards the electrode 2. The webs 4 are typically arranged vertically, i.e. , in the cell height direction. The webs 4 may be spaced evenly across the electrode surface to provide uniform support. The web structures 4 may be designed to distribute mechanical loads evenly and minimize deformation under operational conditions. The web structures 4 may be made from the same material as the half shell or other compatible materials that provide adequate mechanical strength and chemical resistance as well as good conductivity.

[0070] The backwall plate 5a and backwall frame 5b are the primary structural elements of the half shell 5, defining a volumetric space for the cathode or anode chamber 3 thereinside. The backwall plate 5a may provide a mounting surface for the support elements or the like. The backwall frame 5b extends from the periphery of the backwall plate 5a. The backwall plate 5a and the backwall frame 5b may be made from a robust, corrosion-resistant material such as pure nickel. Pure nickel (nickel content: 99.0% or more), such as Ni200 or Ni201, shows excellent corrosion resistance in alkaline solutions.

[0071] The collecting channel 6 may be a part of the half shell assembly 1 , designed to manage the collection and flow of gas and liquid produced during the electrolysis process. The collecting channel 6 is typically located within the chamber 3 and to face the top side of the backwall frame 5b. The channel 6 is designed to gather gases (such as hydrogen or oxygen) and liquids (such as electrolytes) generated during the electrolysis process. The channel 6 may include a profile to direct the flow of collected gases and liquids towards an outlet or manifold system.

[0072] Other associated components, such as an inlet nozzle 8 and outlet nozzle 9 (see, figure 5) may also be provided. These nozzles may be welded to the half shell 5.With reference to figures 2a to 2g, various half shell designs according to the present invention are shown. As discussed above, the half shell 5 includes the backwall plate 5a and the backwall frame 5b. The backwall frame 5b extends from the periphery of the backwall plate 5a so as to define a volumetric space for the cathode or anode chamber 3, the backwall frame 5b having the flange portion 5C at the end opposite to the backwall plate 5a. The half shell 5 further includes one or more raised features 10 or beads. The one or more raised features 10 may be embossed by deep drawing without further process costs with beneficial effects on product functionality. Different bead geometries like bent or curved lines, squares, corrugations or crosses in plan view are depicted in figures 2A to 2G. In these drawings, various conceivable bead geometries in plan view are shown. The geometries may be designed to fulfil functions such as component stiffening, optimization of the fluid flow in the chamber, reduction of the chamber volume (i.e., the volumetric space), enabling a more stable welding process or prevention of bulging or thermal warpage of the backwall plate 5a as a result of downstream laser welding.

[0073] Stiffening function

[0074] The purpose of embossing the raised features 10 or beads into sheet metal components usually lies in the associated increase in sheet metal rigidity. The inertia or resistance torque is increased and thus the resistance of the sheet against elastic and plastic deformation is reinforced.

[0075] The conventional half shell for alkaline water electrolysis features no stiffening beads.

[0076] The raised features 10 or beads with various geometries may be embossed into the backwall plate 5a and / or the backwall frame 5b by deep drawing without further process costs. The stiffening function is dependent on the geometric function of the beads.

[0077] The stiffening effect can be assessed on the basis of the bending stiffness. The bending stiffness is calculated from the product of the modulus of elasticity (e.g.,about 205 GPa at 20°C for Nickel 201) and the moment of inertia of the bead geometry.

[0078] Variable geometries such as, rectangular forms, crosses, circles with beading depths, lines show positive effects on stiffness of the overall structure and negate thermal warpage of further joined components such as the web structure.

[0079] Figure 3A shows an exemplary half shell comprising a plurality of cross-shaped raised features 10. Figure 3B shows a cross-section along A-A line in figure 3A. Each raised feature 10 is embossed into the backwall plate 5a.

[0080] The introduction of the raised features 10 significantly increases the bending stiffness of the component.

[0081] In order to effectively increase the rigidity of the half shell, thereby reducing deformation under operational stresses and allowing for thinner walls, it is preferable that:, the height of the raised feature ranges from 1.2 mm to 7 mm, the width of the raised feature ranges from 10 mm to 37 mm, and / or the radius (if applicable) of the raised feature ranges from 6 mm to 15 mm, in cross sectional view. As shown in figure 3, the height of a raised feature 10 may be measured in cross-section along a line normal to the plane of the backwall plate 5a or backwall frame 5b on which the raised feature is located. The height is denoted by H in figure. The width of a raised feature 10 may be the distance, in cross-section, between two points where the backwall frame or backwall plate on which the raised feature is located deviates from a plane thereof. The width is denoted by L in figure 3. In case where a raised feature is arc shaped, the radius of the raised feature refers to the radius of the arc. The radius is denoted R in figure 3. Of course, the cross-sectional shape of the raised features is not limited to being arc-shaped, but may be rectangular, triangular or the like. It is also clear from figure 3B that on the other side of the raised feature 10, there is a corresponding recess. In other words, the raised feature 10 is an embossed feature and the corresponding recess is a debossed feature. This is beneficial that the half shell 5 does not require extra material to form the raised features 10.In one example, the raised features 10 or beads with a cross shape in plan view (e.g., figure 2C or 3) may have a height ranging from 1.2 mm to 7 mm, a width ranging from 10 mm to 37 mm, and / or a radius ranging from 6 mm to 15 mm, thereby achieving a suitable geometry for the component for the stiffening purpose. Of course, other shapes and dimensions of the raised feature 10 may be applied.

[0082] Therefore, the stiffening beads embossed into the half shell can be employed to reduce the thickness of used sheet material and thus reduce product costs, e.g., by about 5% to 10% in some examples. A reduction of sheet thickness, e.g., by 10% to 12.5% can be achieved in some examples.

[0083] Optimized flow guidance

[0084] Figure 4 shows an exemplary half shell 5 with raised features 10 having a geometric shape of corrugation or a sine curve in plan view. Each raised feature 10 may continuously extend from the bottom of the shell 5 to the top of the shell 5. However, the raised feature 10 may be divided into multiple parts in the cell height direction.

[0085] Preferably, the raised feature 10 extends continuously from the lower part to the upper part of the shell 5 as shown. The wavelength Lw of the raised feature 10, which is the distance between adjacent peaks, may be 100% or less of the extension length Lt of the raised feature 10, preferably 90% or less, more preferably 80% or less, more preferably 70% or less, more preferably 60% or less, more preferably 50% or less, more preferably 40% or less, and most preferably 35% to 25%. Preferably, the plurality of raised features 10 are adjacent to each other in the cell width direction and extend in parallel to each other. The number of the raised features 10 is not limited to the example as shown in figure 4.

[0086] Through the corrugated raised features 10 into the backwall plate 5a the flow regime can be altered.

[0087] The conventional half shell for alkaline water electrolysis features no flow fields.The mass and heat transfer inside the half shell 5 and thus the process efficiency can e.g., be optimized by embossing geometries such as corrugations to employ a turbulent flow regime potentially increasing with beading depth and thickness.

[0088] In order for the effective mass and heat transfer inside the half shell 5, it is preferable that: the height of the raised feature ranges from 1.2 mm to 7 mm, the width of the raised feature ranges from 10 mm to 37 mm, and / or the radius (if applicable) of the raised feature ranges from 6 mm to 15 mm, in cross sectional view.

[0089] Volume reduction without cell pitch reduction

[0090] Figures 5A and 5B illustrate the volume reduction aspect by exemplary raised features 10 on the backwall plate 5a.

[0091] The volume of the conventional half shell design is limited by the cell height or pitch given by the diameter of the inner piping and the geometric restrictions given by bending. Lower volume would result in decreased electrolyte material costs and lower consumption because of a lower throughput of the electrolyte. In figure 5A, the possible geometries of raised features 10 or beads in the half shell 5 is shown. The raised features 10 in this figure are primarily designed to reduce the volume of the chamber 3. Depending on the height of the cell the volume of the electrolyte can be reduced from 2,5% to maximum 15%. In one example, the raised features 10 have a rectangular shape in both plan and cross-sectional views. In this example, the raised features 10 are formed in the backwall plate 5a. In plan view, the width or length L of the raised feature 10 may be in the range from 38 mm to 100 mm to ensure the volume reduction whilst maintaining adequate spacing for the support elements. In cross-sectional view, the height H of the raised feature 10 may be within the range of 1 mm to 5 mm. In one example, the backwall plate 5a may include multiple rows of raised features 10 and multiple columns of raised features 10.

[0092] Deep drawing can be employed to emboss such larger raised areas into the backwall plate 5a. The raised features 10 may be square shaped, triangle shaped, circular shaped, elliptic shaped or the like in plan view, or have lengthy shapes in the cell height direction or cell width direction. It is preferable that each raised feature 10 has a low profile in which the height H of the raised feature 10 is equal to, or smaller than, 50% of the minimum width L (in figure 5B, the length Lw of the raised feature 10 in the cell width direction as the lengthLw of the raised feature 10 in the cell width direction is smaller than the length Lh of the raised feature 10 in the cell height direction). This provides the volume reduction for the chamber 3 whilst maintaining low flow resistance inside the chamber 3 during use. More preferably, the height H of the raised feature 10 is equal to, or smaller than, 25% of the minimum width L of the raised feature 10. For yet lower flow resistance during use, the height H of the raised feature 10 may be constant.

[0093] It is further preferable that the raised surface of the raised feature 10 is flat, i.e. , the height of the raised feature 10 is constant across the raised surface. This allows reduced flow resistance during use whilst achieving the reduced chamber volume.

[0094] Furthermore, deviations of the rectangular shape of the backwall plate 5a can be deep drawn to form restrictions and to reduce the volume of the half shell 5. A difficulty to overcome is to still ensure the electrical contact between the electrolysis cells inside the cell rack. An altered embossed geometry for the anode and cathode half shell resulting in a form fit can serve as a solution ensuring a sufficient electrical contact.

[0095] Figure 5C, which is a C-C view in figure 5A, shows that a bulge 5d is included in the half shell as an inlet or outlet nozzle 8, 9 attached beneath does not allow for a slimmer construction of the lower side of the half shell 5.

[0096] Suitable geometries embossed via deep drawing as joining aids for add-on parts Joining steps of the half shell internals such as the webs 4 to the backwall plate 5a can be described as time intensive and challenging to produce in a process stable way due to the tight tolerances required.

[0097] The lengthy connection along the cell height direction between the backwall plate 5a and the webs 4 can be either joined by thermal joining processes such as arc or laser welding or mechanical joining processes such as clinching.

[0098] For the thermal joining processes, the embossing of linear raised features 10 or beads may be performed as shown in figure 6 to ensure centered positioning of the webs 4, thereby minimizing the welding gap. Furthermore, the geometry may be beneficial for the weld seam quality regarding weld pool dynamics. The linear raised features 10 or beads may continuously extend in a shell height direction that is also the cell height direction.After placing the webs 4 between the adjacent linear raised features 10 or beads, the webs 4 may be joined to the backwall plate 5a by arc or laser welding.

[0099] Alternatively, as shown in figures 7A and 7B, the support elements such as the webs 4 may be mounted on the backwall plate 5a via a mechanical joining process on the basis of clinching the raised features 10 and the webs 4. This requires no additional steps such as welding to fix the support elements to the backwall plate 5a. As shown in figure 7B, this joining process may be performed by a punch 12 and a die 14. The die 14 includes a recess 14a to receive the punch 12 with a portion of the backwall plate 5a and a portion of the web 4 interposed therebetween. Preferably, the backwall plate 5a is deepdrawn to have a raised feature 10 prior to the clinching process so that the raised feature 10 overhangs the recess 14a for clinching (in other words, the width L of the raised feature 10 is larger than the width L14a of the recess 14a). The web 4 may include an extended base 4a for clinching. Preferably, the raised feature 10 extends in the cell height direction and has the width L equal to, or larger than, the width of the extended base of the web 4. Then, the backwall plate 5a with the deep-drawn linear raised feature 10 is placed on the die 14, and thereafter the extended base of the web 4 is placed on the raised feature 10 of the backwall plate 5a. The punch 12 is then pushed down into the recess 14a of the die 14, allowing the extended base of the web 4 to be clinched by the raised feature 10 of the backwall plate 5a. In this way, the raised features 10 serves as mechanical joining aids by clinching.

[0100] Embossed Geometries via deep drawing to simplify assembly

[0101] Functions of adjacent components that cannot be realised by serial production technologies such as continuous casting or continuous tube forming are integrated into the central component of the assembly, the half shell. This reduces the production costs of adjacent components by changing the production technology and simplifying the design. In addition, this results in a fundamentally new cell design with new design principles, which arises from the premise of shifting as much geometric complexity as possible to one central part of the subassembly of the half shell, which will be the backwall plate.

[0102] For example, as shown in figure 8, the collecting channel 6 as an add-on component inside the half shell 5 may be arranged within the half shell 5, preferably with a fixed distance or gap Gp between the top side of the channel 6and the opposing backwall frame 5b. The collecting channel 6 may extend in the cell width direction. The functionality of the gap holders of the fixed collecting channel 6 can be integrated into the backwall frame 5b and the backwall plate 5a by means of the raised features 10 or beads. The gap Gp keeps more gas and / or liquid therein, which drops into the collection channel 6. The raised features 10 to position the collecting channel 6 as well as to create the gap Gp between the collecting channel 6 and the opposing backwall frame 5b is not a separate element from the half shell 5 but a monolithic part thereof. The monolithic part is more robust and more easily produced than separate components attached to the half shell5. Furthermore, no additional element is necessary for positioning the collecting channel 6. The raised features 10 may be shaped into a triangle in cross section. However, the shape of the raised feature 10 is not limited thereto as long as they are able to fix or position add-on components.

[0103] The raised features 10 may be embossed by deep drawing and via an undercut forming step to fixate the collecting channel 6 horizontally. Here, the term "undercut" refers to a space S sandwiched between the base of the backwall frame 5b and the backwall plate 5a, which is formed by tilting or sloping the upper part of the backwall frame 5b (the flange side) towards the volumetric space of the half shell 5.

[0104] Figure 8C shows that the embossed raised features 10 clamps the collecting channel 6 and positively locks the same in the operating state. The corner may include a cutout area 5e required for removal of an embossing tool for the raised feature 10.

[0105] Weld collar beaded as part of deep drawing operation as Joining aids for add-on parts

[0106] As shown in figure 9, beading of the nozzle cut outs during tool bound stamping (part of the forming operation) is aiding the weld situation of the inlet / outlet nozzle 8, 9 to the half shell 5. Forming a collar 15 leads to more material for weld seam and eased gap bridging with respect to the inlet / outlet nozzle 8, 9. Such a collar 15 may be formed by stamping in line with the deep drawing.

[0107] Collars 15 from 1.5 mm to 4 mm protrusion may be suitable to meet quality requirements for welding such as DIN EN ISO 13919. This was experimentally explored for thin nickel sheet metal with collars ranging from 2-4 mm, which were laser welded to the respective nozzle.Longer lifetime of deep drawn half shell resulting from rounding of deep drawn half shell and elimination of weld seams

[0108] Although not shown, a FEM simulation result shows the corners of a half shell as the most stressed area in load cycle analysis. The FEM simulation is based on the unbeaded half shell.

[0109] A FEM simulation study was able to show that the greatest stresses occurs in the corner of the half shell. The stress maxima comes almost exclusively from the cyclic temperature load. Through the deep drawn design according to the invention, there may be provided a rounded geometry in the critical corner areas, making it less prone to pressure related stress than an acute angled design. Additionally, no corner weld seam is needed which also leads to a weld seam factor of 1. In particular, the corner has the maximum stress.

[0110] Due to the forming process (deep drawing), the wall thickness in the critical upper corner area of the half shell is increased by approximately 10-20%, according to the simulation results. The thickening therefore occurs in the area of interest and results in lower stress.

[0111] Overall, the results show that the deep drawn design according to the invention has a significantly longer lifespan than the conventional design with a bent half shell and welded seams. The deep drawn design according to the invention can withstand up to 50 times more load cycles then the conventional, bent and welded half shell.

[0112] Realisation of Undercut with slider function and increased radii in the moulding As discussed above, the undercut or inclined backwall frame portion may be provided within the half shell 5. The undercut is formed by tilting a part of the backwall frame 5b inwardly, i.e. , towards the volumetric space of the half shell 5 towards the flange portion 5c of the backwall frame 5b. This tilting may also be performed by the deep drawing. Due to the tilted wall part, however, some forming tool, e.g., a punch, cannot easily be removed from the formed half shell 5. More specifically, one significant challenge is the lack of a continuous draft of the component in a specific direction due to the undercut.

[0113] In order to address this issue, a slide function with a two-stage tool for the shaping of the undercut may be introduced. More specifically, in a first forming step as shown in figure 10A, a punch 20 moves towards the a die 21 whilst the sheet material 5’ is pressed against the die 21 by a blank holder 22, therebydeep drawing the sheet material 5’ into a square pan shape including the backwall frame 5b and the backwall plate 5a. The arrows indicate applied forces. The backwall frame 5b extends substantially at a right angle from the backwall plate 5a via a rounded corner.

[0114] In a second forming step as shown in in figures 10B and 10C, another punch 23 and die 24 each having a tilted forming surface 23a, 24a are used. The angles of tilted forming surfaces align with that of the tilted part of the formed backwall frame 5b. The punch 23 is brought closer to the die 24 whilst the punch 23 is moved or shifted laterally towards the die 24 to perform a second drawing operation. The punch 23 travels diagonally to come closer to the die 24. When removing the punch 23 from the die 24, the punch 23 moves or shifts in the opposite direction. In other words, the punch 23 travels diagonally away from the die 24. This facilitates removal of the punch 23 from the formed half shell 5. Preferably, the sliding punch 23 advances and retracts at a 45 degree angle relative to a normal to the plane of the die 24 that faces the backwall plate 5a.

[0115] Exploit advantages through deep drawing (integrated punching) Conventionally, the flexible process chain employed for producing the subassembly half shell can only be scaled up to full capacity through duplication. This process chain relies on a combination of production technologies, including laser cutting, bending, and arc / laser welding, enabling the production of three-dimensional geometries akin to the origami technique. In contrast, utilizing deep drawing eliminates bottlenecks, with limitations only imposed by the number of shifts in the press shop or exceptionally high annual quantities in the million range. This is primarily attributed to the short cycle time of tool-based production technologies. Additionally, the plant technology employed can further be utilized for subsequent deep drawing processes or punching processes, such as collecting channel side framing.

[0116] Streamlining quality checks, the elimination of weld seams in corner regions obviates the need for dye penetrant testing, a previously essential step.

[0117] Conventionally, the dye penetration test stands as a significant bottleneck in the quality checking process.Innovatively, the deep drawing process including embossing the raised features 10 or beads are now being integrated into electrolyser development and production.

[0118] Reference sign list

[0119] 1 half shell assembly

[0120] 2 electrode

[0121] 3 chamber

[0122] 4 web

[0123] 5 half shell

[0124] 5a backwall plate

[0125] 5b backwall frame

[0126] 5c flange portion

[0127] 6 collecting channel

[0128] 7 separator

[0129] 8 inlet nozzle

[0130] 9 outlet nozzle

[0131] 10 raised feature

[0132] 12, 20, 23 punch

[0133] 14, 21 , 24 die

[0134] 15 collar

Claims

22 / 25230414P10WOClaims1. A half shell (5) for an electrolysis cell comprising:a backwall plate (5a); anda backwall frame (5b) extending from a periphery of the backwall plate (5a) so as to define a volumetric space for a cathode or anode chamber (3), the backwall frame (5b) having a flange portion at an end opposite to the backwall plate (5a),further comprising:one or more raised features (10) for stiffening the half shell (5) arranged in the backwall plate (5a) and / or the backwall frame (5b), each raised feature (10) being shaped by a recess on its opposite side.

2. The half shell (5) according to claim 1 , wherein each raised feature (10) has a geometric shape of cross, square, circle or triangle, or a geometric shape of corrugation in plan view, andoptionally, each raised feature (10) is located where no support element (4) for electrode is mounted on the backwall plate (5b), or each raised feature (10) is so located as to be adjacent to a support element (4) for electrode to be mounted on the backwall plate (5b).

3. The half shell (5) according to claim 1 or 2, wherein:a height of the raised feature (10) ranges from 1.2 mm to 7 mm, a width of the raised feature (10) ranges from 10 mm to 37 mm, and / or a radius of the raised feature (10) ranges from 6 mm to 15 mm, in cross sectional view.

4. The half shell (5) according to claim 1 or 2, wherein the one or more raised features (10) protrude into the volumetric space to reduce a volume of the volumetricspace by 2.5% or more, preferably up to 15%, and preferably, each raised feature (10) has a width of 38 mm or more but 100 mm or less.

5. The half shell (5) according to any one of claims 1 to 4, wherein the backwall frame (5b) includes a part tilted towards the volumetric space towards the flange portion.

6. The half shell (5) according to any one of claims 1 to 5, wherein the one or more raised features (10) are configured to provide a clamping function or joining aid for addon parts inside the cathode or anode chamber.

7. The half shell (5) according to any one of claims 1 to 6, wherein the half shell (5) is made of pure nickel.

8. A method of manufacturing a half shell (5) for an electrolysis cell, comprising steps of:cutting out a rectangular blank from a sheet material; anddeep-drawing the blank to form a backwall plate (5a) and a backwall frame (5b), the backwall frame extending from a periphery of the backwall plate (5a) so as to define a volumetric space for a cathode or anode chamber, the backwall frame (5b) having a flange portion at an end opposite to the backwall plate.

9. The method according to claim 8, further comprising a step of:embossing one or more raised features (10) in either the rectangular blank, or the backwall plate (5a) and / or the backwall frame (5b).

10. The method according to claim 9, wherein each raised feature (10) has a geometric shape of cross, square, circle or triangle, or a geometric shape of corrugation in plan view, andoptionally, each raised feature (10) is located where no support element (4) for electrode is mounted on the backwall plate (5b), or each raised feature (10) is so located as to be adjacent to a support element (4) for electrode to be mounted on the backwall plate (5b).

11. The method according to 9 or 10, wherein:a height of the raised feature (10) ranges from 1.2 mm to 7 mm, a width of the raised feature (10) ranges from 10 mm to 37 mm, and / or a radius of the raised feature (10) ranges from 6 mm to 15 mm, in cross sectional view.

12. The method according to any one of claims 9 to 11, wherein the one or more raised features (10) protrude into the volumetric space to reduce a volume of the volumetric space by 2.5% or more, preferably up to 15%, and preferably, each raised feature (10) has a width of 38 mm or more but 100 mm or less.

13. The method according to any of claims 8 to 12, wherein the step of deep drawing includes tilting a part of the backwall frame (5b) towards the volumetric space towards the flange portion.

14. The method according to claim 13, wherein the tilting is performed by bringing a punch closer to a die whilst moving the punch laterally towards the die.

15. The method according to claim 14, wherein after forming the tilted part, the punch is withdrawn from the die whilst being moved laterally away from the die.

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