Cathode current collector assembly for aluminum electrolysis cell

Abstract

The present invention relates to a cathode current collector assembly for an aluminum electrolysis cell, a kit of parts for manufacturing the cathode current collector assembly, and an aluminum electrolysis cell comprising the cathode current collector assembly.

Description

[Technical Field]

[0001] The present invention relates to a cathode current collector assembly for an aluminum electrolysis cell, a kit of parts for manufacturing the cathode current collector assembly, and an aluminum electrolysis cell comprising the cathode current collector assembly. [Background technology]

[0002] Aluminum is produced by the Hall-Heoldt process, which involves dissolving aluminum oxide in a cryolite-based electrolyte and electrolyzing it at temperatures up to 1000 °C. A typical Hall-Heoldt cell consists of a steel shell, an insulating layer of refractory material, and a carbon cathode that holds the liquid metal. The cathode consists of multiple cathode blocks with collector rods embedded in the bottom to extract the current.

[0003] Several patent applications have proposed different approaches to minimizing the voltage drop from the liquid metal to the tip of the collector rod. WO 2008 / 062318 discloses the use of a highly conductive material to complement existing steel collector rods, while WO 02 / 42525, WO 01 / 63014, WO 01 / 27353, WO 2004 / 031452, and WO 2005 / 098093 describe solutions using copper inserts within the collector rod. U.S. Patent 4,795,540 employs a structure that divides the cathode and collector rod into sections. WO 2001 / 27353 and WO 2001 / 063014 use highly conductive materials within the collector rod. U.S. Patent 2006 / 0151333 involves the use of collector rods with different electrical conductivities. WO 2007 / 118510 proposes a method for modifying the current distribution on the cathode surface by increasing the cross-sectional area of ​​the collector rods as they move toward the center of the cell. US Pat. Nos. 5,976,333 and 6,231,745 present a technique using copper inserts within steel collector rods. EP 2133446 A1 describes a technique for adjusting the cathode surface geometry by modifying the cathode block arrangement to stabilize the metal pad surface waves and thereby minimize the ACD (anode-to-cathode distance). WO 2011 / 148347 describes a carbon cathode for an aluminum production cell that includes a highly electrically conductive insert sealed within the carbon cathode. These inserts modify the conductivity of the cathode body but are not used for current collection or extraction by the collector rods. The electrical conductivity of molten cryolite is relatively low, and the occurrence of magneto-hydrodynamic instabilities causes waves at the metal-bath (metal-cryolite electrolyte) interface, preventing a significant reduction in the ACD. The occurrence of waves reduces the current efficiency of the process, making it impossible to reduce energy consumption below a critical value. In the aluminum industry, the average current density results in a minimum voltage drop across the ACD of 0.3 V / cm. Since the ACD thickness is 3 cm to 5 cm, the voltage drop across the ACD is typically 1.0 V to 1.5 V. The magnetic field within the liquid metal is generated by the current flowing through the external bus bar and the internal current.The internal local current density within the liquid metal is primarily determined by the cathode geometry and its local electrical conductivity. The magnetic field and current density generate a Lorentz force field, which shapes the metal surface contour and the metal velocity field, defining the basic environment for magnetohydrodynamic cell stability. Cell stability can be expressed as the ability to reduce ACD without generating unstable waves on the surface of the metal pad. The level of stability depends on the current density and magnetic field induction, but also on the liquid metal pool geometry. The pool geometry depends on the cathode surface and step geometry. While conventional solutions can meet a certain level of magnetohydrodynamic conditions required to achieve good cell stability (low ACD), solutions using copper inserts often require complex processing steps.

[0004] Therefore, in recent years, there has been a trend to replace steel collector rods with copper inserts with pure copper collector rods. Copper collector rods typically consist of a central section positioned below the central section of the carbon cathode, usually directly in the cathode slot or through-hole. At least the upper outer surface of this central section of the copper collector rod is in direct electrical contact with the carbon cathode, or through an electrically conductive interface formed by an electrically conductive adhesive, or through an electrically conductive flexible foil or sheet applied to the surface of the copper collector rod. The copper collector rod consists of one or two outer sections adjacent to, on one or both sides of, the central section, and a terminal end or groups of terminal ends extending outward from the outer sections. Each of these copper collector rod ends is electrically connected in series with a steel conductor rod of larger cross-sectional area than the copper collector rod, which extends outward for connection to an external current supply bus bar.

[0005] Typically, the carbonaceous block with collector rods is placed on a refractory solid support. Because of the time constraints of cathode layering, it is difficult to achieve sufficient flatness to support the block evenly, so a powder bedding layer is often applied on top of the solid support. The two components of the layer, the solid support and the powder layer, are usually made of refractory materials with similar properties to prevent aluminum and impurities from penetrating through the voids in the cell components and into the rod material from below, causing alloying and contamination.

[0006] However, especially in the case of copper collector rods, the detrimental effects caused by the diffusion of aluminum and other products during cell operation are still observed, which affects the performance and long-term stability of electrolysis cells. The diffusion of metals such as aluminum and sodium into the copper rods not only causes alloying processes that reduce cell performance, but also hinders recovery at the end of the cell's life.

[0007] For additional protection of the copper current collector rods, it is known to increase the height of the groove, place the current collector rods within the grooves, and fill the remaining void with carbon-based ramming paste or a steel beam, ensuring that the grooves are flush with the surface of the carbon-based cathode. However, introducing this additional protective layer reduces the effective height of the carbonaceous cathode, thereby shortening the cell's lifespan and increasing its operating voltage. In the case of ramming paste, a layer of at least 35 mm in height is required to provide sufficient protection. On the other hand, the use of a steel beam can lead to cracking due to differences in thermal expansion coefficients when the cell is heated. Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the present invention to provide a cathode current collector assembly for an aluminum electrolysis cell, and in particular to provide a cathode current collector assembly for an aluminum electrolysis cell that has high performance and stability over the life of the cell, reduces energy consumption, maximizes current efficiency, and can be operated for longer periods at lower voltages. Another object of the present invention is to facilitate recycling of the current collector system. [Means for solving the problem]

[0009] The above problems are solved by a cathode current collector disposed in a layer of the aluminum electrolysis cell. The cathode current collector comprises: a) a current collector system made of copper or a copper alloy; b) a carbonaceous cathode having a groove for receiving a first portion of a current collector system; A first portion of the current collector system is disposed in a groove of the carbonaceous cathode, and the cathode current collector further comprises: c) a cover element at least partially covering the groove with the first portion of the current collector system disposed in the groove; d) a filler selected from carbonaceous and / or carbide-based materials, the filler being disposed between the cover element and the first part of the current collector system made of copper or a copper alloy.

[0010] The cathode current collector has a carbonaceous cathode with a groove formed in one of its surfaces, in which a current collector system is at least partially disposed. Electrical contact between the carbonaceous cathode and the current collector system is achieved over the entire embedded area. Electrical current flows from the carbonaceous cathode to the copper current collector system, which is connected to an external current supply bus bar, for example via an additional transition element (e.g., a steel conductor element (steel conductor rod)), to conduct the current to the next cell.

[0011] The grooves and corresponding ("negative electrode") current collector systems can have different shapes. Typically, the current collector systems are rod-shaped, especially rectangular rod-shaped, although oval or round shapes may also be possible. Preferably, the carbonaceous cathode has a rectangular shape, and the current collector systems (preferably also rectangular rod-shaped) are arranged in grooves extending along the longitudinal surface of the carbonaceous cathode.

[0012] The current collector system may consist of one or more elements, in particular rod-shaped elements. Preferably, the current collector system consists of at least two longitudinal rectangular rod-shaped elements.

[0013] In the present invention, "carbonaceous" refers to all types of materials based on anthracite and / or graphite and / or coke, whether these cathodes are calcined or graphitized or not.

[0014] In a preferred embodiment of the invention, the cathode current collector and connector assembly includes a conductor element located at an end portion of the current collector system, i.e., connected between the current collector system and the connection point of the external power bus bar, the conductor element preferably having a recess in which the second portion of the current collector system is located.

[0015] In the present invention, the term "carbide material" refers to a hard chemical compound consisting of a metal or semi-metal and carbon, which has the properties of a ceramic or refractory material.

[0016] In the present invention, "carbide-based material" means any kind of material or combination of materials containing at least 50%, preferably at least 80%, of carbide material. Particularly preferred is when the carbide-based material consists of carbide material.

[0017] In the present invention, the term "filler" refers to a material capable of filling the gap between the current collector system and the cover element.

[0018] The combination of the cover element and the carbonaceous and / or carbide-based filler material provides improved protection against the diffusion of aluminum and / or impurities, while at the same time preventing cracking of the carbonaceous cathode when the cell is heated. By effectively preventing the diffusion and alloying of the copper collector system with metals such as aluminum, the benefits of using copper as a collector material (e.g., optimized current distribution in the liquid metal and / or carbonaceous cathode, allowing the cell to operate at lower voltages) can be maximized and realized over the entire life of the cell.

[0019] The combination of the inventive cover element and the carbonaceous or carbide-based filler allows cathode current collector assemblies having a ramming paste layer covering the current collector system to achieve the same or better protection while reducing the height of the protective ramming paste layer from a minimum of 45 mm to approximately 10 mm. As a result, the position of the cathode collector rod can be lowered (see cross-section in operating position), increasing the amount of abradable material between the liquid aluminum and the collector rod, i.e., increasing the effective height of the carbonaceous cathode. As a result, the life of the cathode current collector assembly can be extended.

[0020] In a preferred embodiment of the invention, the cover element is formed from at least one plate (one or more plates), which is at least partially, preferably completely, positioned in the groove, so that the current collector system and the filler are positioned between the cathode and the at least one plate.

[0021] Preferably, the cover elements (e.g., plate-shaped) are placed in the grooves so that the grooves are flush with the recessed surface of the carbonaceous cathode. If the cover elements are connected to the cathode by fastening means, these fastening means are also preferably placed so that the grooves are flush with the recessed surface of the carbonaceous cathode. This simplifies the placement of the cathode current collector assembly on the layer.

[0022] In another preferred embodiment, the cover element is formed from at least one plate which is at least partially, preferably completely, positioned on the surface of the cathode recessed with the grooves and current collector system, i.e. the at least one plate is in direct contact with the surface of the cathode.

[0023] When the cover element is at least one plate, the thickness of the plate is preferably in the range of 0.5 mm to 10 mm, more preferably in the range of 1 mm to 8 mm, most preferably in the range of 2 mm to 6 mm.

[0024] Preferably, the carbonaceous cathode has a block shape, and the cover element is arranged parallel to the horizontal surface of the block and is arranged to cover the groove formed in the horizontal surface.

[0025] Preferably, the cover element covers at least 50% of the groove, more preferably at least 70%, even more preferably at least 80%, and most preferably at least 90%. In a particularly preferred embodiment, the cover element completely covers the groove.

[0026] Preferably, the cover element covers at least 50% of the cross section of the groove in which the current collection system is disposed, more preferably at least 70%, even more preferably at least 80%, and most preferably at least 90%. In a particularly preferred embodiment, the cover element completely covers the cross section of the groove in which the current collection system is disposed.

[0027] Preferably, at least 50% of the space between the cover element and the current collector system is filled with the layer of carbonaceous or carbide material, preferably at least 70%, more preferably at least 80%, and most preferably at least 90%. In particularly preferred embodiments, the carbonaceous and / or carbide-based material completely fills the space between the cover element and the current collector system. Most preferably, the height of the layer of carbonaceous or carbide-based material filling the space between the cover element and the current collector system is at least 8 mm, more preferably at least 10 mm, or even more preferably at least 15 mm throughout, to ensure compression. However, the height of this layer is preferably less than 35 mm, more preferably less than 25 mm. Particularly preferred ranges are 8 mm to 35 mm, more preferably 10 mm to 30 mm, and most preferably 15 mm to 25 mm. "Height" in this context refers to the vertical extension of the protective layer of carbonaceous and / or carbide-based packing material in the operating position of the cathode current collector assembly.

[0028] The above-described preferred features further enhance the protection effect of the invention.

[0029] Preferably, the cover element is made of or consists of a material selected from metals or alloys (for example steel, carbon fiber reinforced carbon, graphite, concrete, ceramics, or mixtures thereof).

[0030] Particularly preferred are steels selected from carbon steel, low carbon steel, chromium-based steel, nickel-based steel, or chromium-nickel-based steel or alloy steel.

[0031] Without being bound by this theory, the inventors believe that the protective effect of the metal cover element is particularly significant because the combination of the metal (cover element) and the carbon-based filler prevents the diffusion of various metals and impurities that may be present and accumulate during the electrolysis process.

[0032] In a preferred embodiment, the groove has a dovetail cross section, which can further enhance the beneficial effects of the invention.

[0033] Particularly preferred is the use of a carbon-based material as a filler between the cover element and the copper or copper alloy current collector system.

[0034] Particularly preferred are ramming pastes and / or electrically conductive adhesives containing a carbonaceous material and / or a carbide material as a filler, which further contain a binder, for example, an unmodified or modified tar- or PAH-free (polycyclic aromatic hydrocarbon)-free ramming paste binder.

[0035] Fillers are solid particles mixed with a liquid (binder) to form a paste, adhesive, or cement.

[0036] In another preferred embodiment, the filler is a carbide material, which is a ceramic or refractory hard chemical compound consisting of a metal or semimetal and carbon. Particularly preferred is SiC, which has high hardness and oxidation stability.

[0037] Of course, the use of a combination of carbonaceous and carbide-based materials is also within the scope of the present invention.

[0038] The form of the filler is preferably selected from a cloth, a mesh, a foam, a paste, a foil, a fabric, an adhesive layer, or a combination thereof, most preferably an adhesive layer or a paste, which allows for thermal expansion during the heating process of the cell.

[0039] In a preferred embodiment of the invention, the cathode is a rectangular cathode block having rectangular grooves extending along the longitudinal surfaces of the cathode block.

[0040] Preferably, the current collector system comprises a current collector rod, preferably rectangular in shape.

[0041] In a preferred embodiment of the present invention, the current collector system is at least partially coated with a protective steel layer.

[0042] Preferably, at least 50% of the current collector system surface is covered with the protective steel layer, more preferably at least 60%, even more preferably at least 70%, and most preferably at least 80%. In a particularly preferred embodiment, the current collector system surface is completely covered with the protective steel layer. If the current collector system comprises a conductor element, the above values ​​apply to the surface without taking into account the second portion arranged in the recess of the conductor element.

[0043] Preferably, at least 50% of the surface of the first portion of the current collector system is coated with the protective steel layer, more preferably at least 60%, even more preferably at least 70%, and most preferably at least 80%. In a particularly preferred embodiment, the surface of the first portion of the current collector system is completely coated, thereby reducing the deleterious effects of diffusion of aluminum or other products produced during operation of the electrolytic cell.

[0044] Preferably, the volume ratio of copper or copper alloy to the protective steel layer in the current collector system is at least 200%, preferably at least 300%, more preferably at least 400%.

[0045] Preferably, the thickness of the protective steel layer is 0.05 mm to 6 mm, more preferably 0.15 mm to 4 mm, and even more preferably 1.5 mm to 3 mm.

[0046] The thin protective steel layer may be made of or consist of a steel selected from carbon steel, low carbon steel, chromium-based steel, nickel-based steel or chromium-nickel-based steel or alloy steel.

[0047] In a preferred embodiment of the invention, the copper or copper alloy is in the form of a rod of rectangular cross section, protected by a protective steel layer on at least one surface facing the cathode, preferably on all surfaces facing the cathode, most preferably on all surfaces.

[0048] If the current collector system comprises a protective steel layer, i.e. is at least partially coated with a protective steel layer, the protective steel layer is in direct contact with the walls of the grooves of the carbonaceous cathode.

[0049] Preferably, the protective steel layer is coated with an additional upper and / or lower layer of copper, nickel, chromium, or graphite paint or film layer, more preferably the thickness of the additional upper and / or lower layer is between 1 μm and 1 mm.

[0050] The surface of the current collector system may be roughened or formed with recesses or protrusions such as grooves, fins or ribs to increase the surface area between the cathode and the current collector system and improve contact between the elements.

[0051] In a preferred embodiment of the invention, the current collector system is at least partially coated with a layer of insulating material, in particular alumina, insulating glue or cement, or an insulating material that can withstand up to 1200°C.

[0052] In a preferred embodiment of the invention, the current collector system, and / or the steel protective layer if the current collector system is at least partially coated, is in direct contact with the carbonaceous cathode.

[0053] In a preferred embodiment of the invention, a cover element at least partially covering the groove in which the current collector system is arranged is fixed to the cathode via fixing means.

[0054] The fastening means may be, for example, a screw, bolt, key, stud, rivet, anchor, nail, pin or insert, most preferably a bean-shaped screw to prevent thermal expansion.

[0055] In a preferred embodiment of the present invention, the cathode current collector assembly is configured so that the groove is located in the bottom surface of the cathode current collector assembly when the cathode current collector assembly is in an operating position within the electrolytic cell.

[0056] The present invention also relates to a kit of parts, i.e., a system of separate elements, for manufacturing the inventive cathode current collector assembly. The kit of parts comprises: a) a current collector system made of copper or a copper alloy; b) a carbonaceous cathode having a groove for receiving a first portion of a current collector system; c) a cover element; d) a filler selected from carbonaceous and / or carbide-based materials.

[0057] The present invention further relates to a cathode current collector and connector assembly for an aluminum electrolysis cell, which combines the inventive cathode current collector assembly with an additional conductor element (e.g., rod-shaped), preferably made of or consisting of steel. The steel conductor rod is connected at a connection point to an external current supply bus rod, allowing current to be extracted outside the cell. Preferably, the conductor rod has a larger cross-sectional area than the collector rod, thereby limiting heat flow from the cell and preventing freezing of the cryolite.

[0058] The present invention also relates to an aluminum electrolysis cell having an inventive cathode current collector.

[0059] The invention also relates to the use of the cathode current collector of the invention in the electrolytic production of aluminum, where the cover element protects the cathode current collector system in the groove from the ingress of aluminum produced in the electrolytic process.

[0060] The present invention further relates to the use of a cover element for at least partially covering a groove of a carbonaceous cathode of an aluminum electrolysis cell, with a current collector system disposed therein, to protect the cathode current collector system from aluminum infiltration during the electrolysis process.

[0061] example The present invention will now be described in more detail with reference to specific embodiments according to the invention and the accompanying drawings.

[0062] Examples of inventions A cathode block with a copper current collection system measuring 550 x 450 x 3200 mm (width x height x length) was fitted with a rectangular groove measuring 40 x 95 mm (width x depth). The copper current collector system (40 x 80 mm cross-sectional dimensions) was placed in the groove, leaving a 15 mm high gap above the current collector rod system. This gap was filled with carbide ram paste compacted with a conventional pneumatic ram tool. After filling the gap, a 2 mm thick, 80 mm wide, and 3200 mm long stainless steel plate was placed over the groove, covering the entire length of the cathode block with a 20 mm overhang on each side. The steel plate was secured to the cathode block with steel bolts spaced 500 mm apart, starting 100 mm from each end.

[0063] Comparative Example A cathode block with a copper current collection system having external dimensions of 550 x 450 x 3200 mm (width x height x length) is provided with a rectangular groove with dimensions of 40 x 125 mm (width x depth). A rectangular copper current collection system (cross-sectional dimensions 40 x 80 mm) is placed in the groove, leaving a 45 mm high gap above the current collector rod system. This gap is filled with carbide casting paste compacted with a conventional pneumatic casting tool.

[0064] The inventive example extends cell life by 9% over the comparative example. [Brief explanation of the drawings]

[0065] Furthermore, additional advantages, features and possible applications will become apparent from the description of the preferred embodiments and the associated drawings.

[0066] [Figure 1] FIG. 1 shows a cross-sectional view of a cathode current collector assembly according to the prior art. [Figure 2] FIG. 2 shows a cross-sectional view of an inventive cathode current collector assembly having a cover element that is flush with the cathode surface. [Figure 3] FIG. 3 shows a cross-sectional view of a cathode current collector assembly of the present invention having a cover element disposed on top of the cathode surface. [Figure 4] FIG. 4 shows a cross-sectional view of a cathode current collector assembly of the present invention having two cover elements that are flush with the cathode surface. [Figure 5] FIG. 5 shows a cross-sectional view of an inventive cathode current collector assembly having a cover element flush with the cathode surface and a cutter-shaped groove flush with the cathode surface. DETAILED DESCRIPTION OF THE INVENTION

[0067] FIG. 1 shows a cross-sectional view of a prior art cathode current collector assembly. The assembly is shown rotated 180° in its manufacturing position compared to its final operating position in an electrolysis cell. In this assembly, a rectangular cathode block 1 has a recessed groove in its horizontal surface into which a current collector rod 2 is placed. Typically, the current collector rod is in direct contact with the cathode block, or a conductive carbonaceous layer, e.g., ramming paste, is placed between the surfaces. The groove is filled with ramming paste 3 as a filler material, flush with the top surface of the cathode.

[0068] Figure 2 shows a cross-sectional view of a cathode current collector assembly of the present invention, including a cover element 7. In this assembly, the cathode block 1 has a recessed groove in its horizontal surface, in which a current collector rod 2 is positioned. Typically, the current collector rod is in direct contact with the cathode block, or a conductive carbonaceous layer, such as ramming paste, may be placed between the surfaces. The groove is filled with ramming paste 3 as a filler, but the layer does not completely fill the groove. Instead, a plate-like cover element 7 is placed to close the groove and be flush with the cathode surface. Compared to the prior art shown in Figure 1, the height h14 of the ramming paste layer has been significantly reduced. As a result, the height h25 of the groove and the height h36 of the abradable cathode material have also been significantly increased.

[0069] FIG. 3 shows a cross-sectional view of a cathode current collector assembly of the present invention, including a cover element 7. In this assembly, a cathode block 1 has a recessed groove in its horizontal surface, in which a current collector rod 2 is placed. Typically, the current collector rod is in direct contact with the cathode block, or a conductive carbonaceous layer, e.g., ramming paste, is placed between the surfaces. The groove is filled with ramming paste 3 as a filler material, completely filling the groove. A cover element 7 is placed on top of the layer and the surface of the cathode block and secured by fastening means (not shown). Compared to the prior art shown in FIG. 1, the height h14 of the ramming paste layer has been significantly reduced. As a result, the height h25 of the groove and the height h36 of the abradable cathode material have also been significantly increased.

[0070] FIG. 4 shows a cross-sectional view of a cathode current collector assembly of the present invention with two cover elements 7. In this assembly, a cathode block 1 has four parallel grooves in its horizontal plane, with a current collector rod 2 positioned in each groove. Typically, the current collector rods are in direct contact with the cathode block, or a conductive carbonaceous layer, e.g., ramming paste, is placed between the surfaces. The grooves are filled with ramming paste 3 as a filler (not shown), completely filling the grooves. Two cover elements 7 are placed on top of the layer and on the surface of the cathode block, each covering two complete grooves, and are fixed with fixing means 8. At the terminal ends (inside and outside the projection plane), the current collector rods are connected to external bus bars, preferably via optional intervening conductor elements (e.g., steel conductor rods).

[0071] FIG. 5 shows a cross-sectional view of a cathode current collector of the present invention having a dovetail-shaped groove and a cover element 7 that is flush with the cathode surface. In this device, the cathode block 1 has a groove in which a current collector rod 2 is disposed. Typically, the current collector rod is in direct contact with the cathode block, or a conductive carbonaceous layer, e.g., ramming paste, is disposed between the surfaces. The groove is filled with ramming paste 3 as a filler, but the layer does not completely fill the groove. Instead, the cover element 7 closes the groove and is flush with the cathode surface. [Explanation of symbols]

[0072] 1 cathode block 2 current collector rods 3 Ramming paste layer 4 Ramming paste layer height h1 5 Groove height h2 6 Height of wearable cathode material h3 7 Cover Elements 8 Fixing means

Claims

1. 1. A cathode current collector for an aluminum electrolysis cell, comprising: a) a current collector system made of copper or a copper alloy; b) a carbonaceous cathode having a groove for receiving at least a first portion of the current collector system; Equipped with at least a first portion of the current collector system is disposed in a groove of the carbonaceous cathode; The cathode current collector assembly further comprises: c) a cover element at least partially covering the groove with a first portion of the current collector system disposed in the groove; d) a filler material selected from carbonaceous and / or carbide-based materials, the filler material being disposed between the cover element and the first part of the copper or copper alloy current collector system; 1. A cathode current collector assembly for an aluminum electrolysis cell, comprising:

2. 10. The cathode current collector assembly of claim 1, wherein the cover element is a plate at least partially disposed in the groove, such that the current collector system and the filler material are disposed between the carbonaceous cathode and the plate.

3. 10. The cathode current collector assembly of claim 1, wherein the cover element is a plate disposed at least partially on a surface of the cathode, whereby the current collector system and filler material are disposed between the carbonaceous cathode and the plate.

4. 4. A cathode current collector assembly according to claim 1, wherein the cover element comprises or consists of a material selected from the group consisting of steel, carbon fiber reinforced carbon, graphite, ceramics or mixtures thereof.

5. The cathode current collector assembly of any of claims 1 to 4, wherein the groove has a dovetail-shaped cross section.

6. The cathode current collector assembly according to any of claims 1 to 5, wherein the carbonaceous and / or carbide based material is selected from the group consisting of ramming paste and conductive adhesive.

7. A cathode current collector assembly according to any of claims 1 to 6, wherein the cathode is a rectangular cathode block and / or the current collector system is a current collector bar, preferably having a rectangular shape.

8. The cathode current collector assembly according to any one of claims 1 to 7, wherein the current collector system is at least partially coated with a protective steel layer.

9. 9. The cathode current collector assembly according to claim 1, wherein the current collector system and / or, if the current collector system is at least partially coated with a protective steel layer, the protective steel layer is in direct contact with the cathode.

10. 10. The cathode current collector assembly according to claim 1, wherein a cover element at least partially covering the groove with the current collector system arranged in the groove is fixed to the cathode via fixing means.

11. 11. The cathode current collector assembly of claim 1, wherein the cathode current collector assembly is configured such that, in the operating position of the cathode current collector assembly, the groove is located on a bottom surface of the cathode current collector assembly.

12. A kit of parts for manufacturing a cathode current collector assembly according to any one of claims 1 to 11, comprising: a) a current collector system made of copper or a copper alloy; b) a carbonaceous cathode having a groove for receiving at least a first portion of the current collector system; c) a cover element at least partially covering the groove with the current collector system disposed in the groove; d) a filler selected from carbonaceous and / or carbide-based materials; A parts kit comprising:

13. An aluminum electrolytic cell comprising a cathode current collector assembly according to any one of claims 1 to 11.

14. Use of a cover element at least partially covering a groove of a carbonaceous cathode of an aluminum electrolysis cell having a current collector system disposed in the groove to protect the cathode current collector from penetration of aluminum during the electrolysis process.

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