Sodium metal halide electrochemical cell and method of manufacture thereof

Abstract

The present invention relates to sodium metal halide electrochemical cells, particularly sodium nickel chloride cells, for high performance batteries in electric vehicles and other demanding stationary applications. The problem addressed by the present invention is to provide a sodium metal halide electrochemical cell having a current collector (1) with a maximum surface area to cross-sectional ratio, which can be manufactured in a simple manner, and which allows for the filling of the cell's electrodes in a simple manner. This problem is solved according to the present invention by the following: the metallic cathode-side current collector (1), elongated in the cathode chamber (21) around the central axis (51), is made from a metal tube (11) having high electrical conductivity; in the part of the current collector (1) pressed into the separator (3), the current collector has formed tubular sections (11, 12) with elements (15, 16, 18, 19) for increasing the surface area of ​​the current collector (1); and in the transition between the uncompressed tubular section and the compressed tubular section (12), which serves as the filling tube (13), the current collector has at least one through-hole (14) opening the filling tube (13) outward, so that the filling tube (13) can be used as a filling opening for the porous mixture of the cathode (2) and the second electrolyte (22).

Description

[Technical Field]

[0001] The present invention relates to a sodium metal halide electrochemical cell and a method for manufacturing the same, which comprises a case having a central axis, a separator extending equidistantly about the case axis and electrically insulating and hermetically separating an anode compartment from a cathode compartment as a solid first electrolyte, the separator being permeable to sodium ions, a cathode filling the cathode compartment and comprising a porous mixture of metal powder granules and metal halide powder granules, a second electrolyte impregnating the cathode compartment and the porous mixture and comprising a molten salt of sodium metal halide, and a metallic cathode-side current collector extending longitudinally within the cathode compartment about the central axis. The present invention is preferably for sodium metal halide batteries, particularly sodium nickel chloride batteries, for use in high-power batteries for electric vehicles and demanding stationary applications.

[0002] The electrochemical cell includes an anode made of at least one metal in a charged state, a cathode, often porous, made of transition metals and metal halides (e.g., sodium, nickel, iron, copper, aluminum), which is immersed in a liquid, ionically conducting molten salt at least in an operating state, and a metallic current collector in electrical contact with the cathode. [Background technology]

[0003] From the prior art of storage or secondary batteries, electrochemical cells based on sodium metal halide chemistry are known to be used in high-power batteries, particularly for electric vehicles and demanding stationary applications, due to their exceptionally high power and energy densities and long cycle life. These are thermal batteries, in which the anode is formed by a thermally liquefied alkali metal (sodium), and the cathode is formed by a molten salt impregnated with a porous material consisting of a metal and a metal halide (e.g., nickel chloride, sodium chloride). The two electrodes are separated by an electrically insulating separator that acts as a solid electrolyte (e.g., sodium-β-alumina with as large a "β" phase as possible, which is highly conductive, i.e., permeable to sodium ions, above 270°C). Such batteries have no electrochemical self-discharge and have an energy efficiency of approximately 90% and a coulombic efficiency of 100%.

[0004] In this regard, Patent Document 1 describes a current collector for a sodium metal halide battery, in which the current collector's sheet-like formation allows for high power and cost reduction of the electrochemical cell. The current collector has at least one flat, elongated fin made of a conductive material, which is bent with respect to its dominant longitudinal axis and welded or soldered by its bent upper end to a flat metal ring. The metal ring allows the current collector to be attached to the cell lid with the fin precisely centered within the cell axis. In a preferred embodiment, two complementary slotted sheets are arranged crosswise, with a central portion left open for a carbon felt. However, disadvantageously, on the one hand, in all different embodiments of the current collector, the sheets must be materially (adhesively) and precisely bonded to the metal ring. On the other hand, for the storage of liquid molten salt, a carbon felt of considerable size must be placed between the metal sheets, which is only limitedly fixed in position. The carbon felt itself takes up space, reducing the storage capacity of Na / MCl2 batteries. Inaccurate placement of the carbon felt can lead to locally different current densities and restrict the cathode regions to different thicknesses, which can lead to battery performance variations from cell to cell. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2015 / 0004456 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention is based on the object of finding new possibilities for realizing sodium metal halide electrochemical cells, which allow the formation of current collectors with a maximum surface area to cross-sectional area ratio, and which allow for an arrangement along the axis of symmetry of the electrochemical cell in order to achieve a uniform current density distribution in the electrodes around the current collector, and a simplified manufacturing process for the production of the sodium metal halide electrochemical cell, as well as a simplified installation of the sodium metal halide electrochemical cell with respect to the filling of the electrode components. A further object of the present invention is to integrate the function of spatial intermediate storage of molten salt into the current collector. [Means for solving the problem]

[0007] According to the present invention, the object is to provide a sodium metal halide electrochemical cell comprising a case having a central axis, a separator extending equidistantly about the case and centered on the central axis of the case, the separator separating the anode chamber from the cathode chamber in an electrically insulating and hermetic manner as a solid first electrolyte, the separator being permeable to sodium ions, a cathode filling the cathode chamber and consisting of a porous mixture of metal powder granules and metal halide powder granules, a second electrolyte impregnating the cathode chamber and the porous mixture, the second electrolyte consisting of a molten salt of sodium metal halide, and a metallic cathode-side current collector formed in the cathode chamber and extending longitudinally about the central axis, wherein the current collector has a σ>10 6The aforementioned object is achieved by a sodium metal halide electrochemical cell comprising a metal tube having a high electrical conductivity of S / m, the metal tube being immersed in a porous mixture of cathode granules and a second electrolyte within a separator, the metal tube being formed as a pressed tube section with a narrowed interior so that the cathode granules cannot penetrate therein and only the second electrolyte can penetrate therein, the metal tube having an element on the exterior for expanding the surface area of ​​the current collector, the current collector having an unpressed tube section above the immersed pressed tube section as a filling tube for filling the cathode chamber, and at least one through-hole opening the filling tube to the outside being present at the transition section from the pressed tube section to the unpressed tube section of the filling tube, whereby the filling tube can be used to fill the cathode chamber only on the outside of the pressed tube section with the porous mixture of cathode granules and to fill the entire cathode chamber with the second electrolyte.

[0008] Advantageously, the current collector has, within the pressing tube, a carbon felt inserted into the pressing tube before pressing.

[0009] Preferably, the current collector has a carbon felt inside the pressed tube section, which carbon felt can be inserted into the pressed tube section from the side after pressing and after cutting off the crushed end of the pressed tube section.

[0010] Preferably, the current collector has punched holes, preferably in the form of through-holes, in the pressed tube as elements for increasing the surface area, whereby the current collector has metal tufts of metal strips or wires suitably fixed in the through-holes in the pressed tube, which metal tufts consist of a metal that is not corroded by the electrochemical processes of the battery and has a high electrical conductivity comparable to that of the metal tube of the current collector.

[0011] Preferably, commercially available nickel, aluminum, or copper tubes are used as the current collector.

[0012] The current collector is provided with surface area-enlarging elements, which include at least one element from the group consisting of punched through holes or other relief-forming structures with crushed edges, metal tufts, fins, or folded metal sheets, with the metal tufts preferably being made from nickel or molybdenum metal strip or wire.

[0013] It has been found to be particularly advantageous if the metal tufts of metal strips or metal wires are arranged in such a way that local resistance gradients are minimized within the cathode chamber or are uniformly distributed over the cross section of the cathode chamber.

[0014] In a further advantageous embodiment, the metal strip or wire used for the metal tuft has a length that is selected to be shorter the greater the capacity of the battery to be achieved, and longer up to the separator the greater the power output to be extracted from the battery.

[0015] Preferably, the non-pressed tube section of the current collector's filled tube is closed by a metal circular plate or a deep-drawn section fixed by a material bonding method after filling with the cathode porous mixture and the second electrolyte. Alternatively, the non-pressed tube section of the current collector's filled tube is preferably crushed at the upper end of the filled tube or hermetically closed by soldering or welding after filling with the cathode porous mixture and the second electrolyte.

[0016] Preferably, the pressed tube portion of the current collector can be pressed flat by the application of force from two collinear directions.

[0017] In a further advantageous embodiment, the pressed tube section of the current collector is pressed from at least three directions equally offset around the central axis to form a star-shaped cross section.

[0018] The pressed tube of the current collector is preferably pressed with the force so that the internal space formed as a reservoir for the second electrolyte is exactly the same volume of second electrolyte required to completely wet the current collector when the battery is in a fully charged state.

[0019] It has been found to be even more advantageous if a metal tube with radial fins is added below the pressed tube section of the current collector, the radial fins being inserted into equidistant slots in the tangential direction of the metal tube.

[0020] In another advantageous embodiment, a metal tube with radial fins is added below the pressed tube section of the current collector, which metal tube is made from equidistantly folded sheet metal and then bent axially symmetrically.

[0021] Furthermore, the problem is solved by a method for manufacturing a sodium metal halide electrochemical cell, the method comprising the steps of: - providing a case for forming an anode compartment, a separator for separating the anode compartment from the cathode compartment, the separator being insertable equidistantly into the case as a first electrolyte, an electrically insulating solid that is permeable only to sodium ions, a cathode consisting of a porous mixture of metal powder granules and metal halide granules, and a second electrolyte for immersing the porous mixture of the cathode; - manufacturing a cathode-side current collector from a metal tube, from which a pressed tube section of the current collector is formed by a force acting radially on a central axis, leaving a non-pressed tube section at its upper end as a fill tube, and at least one transition section from the pressed tube section to the fill tube having at least one through-hole provided as an outlet opening of the fill tube for filling the cathode chamber; - fabricating a cell closure from a cathode closure having a central opening for passing a current collector fill tube through the central opening of the cathode closure, materially bonding the cathode closure to an insulator bond ring, and materially attaching an anode closure to the insulator bond ring; - positioning the current collectors collinearly with the central axis in the separator and in a case equidistantly arranged around the separator, using a cell closure consisting of an insulator joining ring and an anode closure, by a one-step joining process and material bonding of the joints; - filling a porous mixture of cathode metal powder granules and metal halide powder granules into the cathode chamber inside the separator, only outside the current collector, through the fill tube of the current collector and at least one through-hole of the fill tube, followed by filling with a liquid second electrolyte under oxygen exclusion conditions; - final hermetic closure of the electrochemical cell by materially bonding the filling tube.

[0022] Preferably, the elements for increasing the surface area of ​​the current collector are introduced into the pressed tube section at equal distances in the form of through holes, but they can also be introduced into the non-pressed tube section and / or formed into the pressed or non-pressed tube section as elements from the group of crushed edges, metal tufts, fins or other relief-forming structures with folded sheet metal.

[0023] It has proven particularly advantageous to insert metal tufts made of metal strips or metal wires into the through-holes of the pressed tube sections.

[0024] The pressed tube section of the current collector is preferably formed flat by the application of collinear radial forces.

[0025] In another alternative variant, the pressed tube section of the current collector is advantageously formed into a star shape by the action of a plurality of radial forces equally distributed around the central axis.

[0026] In another preferred embodiment of the current collector, radial fins inserted into equidistant slots in the tangential direction are attached to the metal tube below the pressed tube section in order to increase the surface area of ​​the current collector.

[0027] Furthermore, to increase the surface area of ​​the current collector, radial fins can be made on the metal tube below the pressed tube section by folding a metal sheet, which is wrapped around the metal tube or bent on itself into an object with a tubular-shaped interior space.

[0028] The filling tube is preferably closed by welding or soldering the upper end of the tube with a metal circular plate, or alternatively, by crushing the upper end of the tube and finally welding or soldering the crushed upper end of the tube.

[0029] The present invention demonstrates how to form current collectors for sodium metal halide electrochemical cells to achieve axisymmetric current distribution within the electrolyte material, simple filling of the cathode components, and technically simple and inexpensive current collector fabrication and attachment to the electrochemical cell. By increasing the surface area of ​​the current collector, contact resistance with the metal components of the cathode can be reduced, thereby reducing the internal resistance or power loss of the cell and improving performance.

[0030] The present invention will be described in more detail below with reference to examples and drawings. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic principle diagram of a cathode-side current collector according to the invention, which is manufactured from a partially pressed metal tube with punched holes. [Figure 2] FIG. 2 shows a further embodiment of the cathode-side current collector according to FIG. 1 with round punched holes through which metal wire tufts pass. [Figure 3]2 is a schematic cross-sectional view of part A of FIG. 1 with a punched hole passing through in the transition region from the filled tube to the pressed tube section of the current collector. [Figure 4] 3 is a diagram schematically illustrating the current distribution in the cathode chamber in a radial plane B shown in FIG. 2 that intersects with the holes into which the metal wire bundles are inserted in the pressed tube portion of the current collector. FIG. [Figure 5] FIG. 1 shows a preferred embodiment of a sodium metal halide electrochemical cell having a separator made of sodium-beta-alumina and a cathode current collector made of nickel-plated copper tubing. [Figure 6] 10 shows a further embodiment of a current collector according to the invention, which has a crushed end removed on only one side, preferably after the metal tube has been pressed, for the insertion of carbon felt. FIG. [Figure 7] 7 shows the current collector embodiment of FIG. 6 after filling with cathode material, with the top end of the fill tube finally crushed and fused. [Figure 8] 10 shows a further embodiment of a current collector according to the present invention, in which the lower pressed tube section of the metal tube is centrally crushed from multiple non-parallel radial directions, with the upper end of the filled tube finally crushed and fused. [Figure 9] 9 is a cross-sectional view of an embodiment of the current collector according to FIG. 8, in which the lower pressed tube section is pressed from four orthogonal radial directions, two of which are oriented collinearly and oppositely to the tube axis. [Figure 10] FIG. 9 shows a further embodiment of the current collector according to the present invention shown in FIG. 8, in which a fill tube with a final crushed upper tube end is attached to a metal tube separately pressed from four orthogonal radial directions as the lower tube section, in which the difference in cross section between the fill tube and the radially pressed metal tube replaces the punched holes for the fill openings. [Figure 11] FIG. 10 shows a further embodiment of a current collector according to the present invention comprising a metal tube with a filled tube, a pressed tube section, and radial fins, with a reservoir of second electrolyte inside the metal tube. [Figure 12] 12 shows a further embodiment of the current collector according to FIG. 11, in which the fins are modeled by equidistantly folded sheet metal and the metal tube is modeled by axially symmetrically folded sheet metal. [Figure 13] 6 is a cross-sectional view of a double-cell configuration of an electrochemical cell, expanded relative to FIG. 5, having a double-walled separator containing an anode compartment, and inner and outer cathode compartments with respective current collectors. DETAILED DESCRIPTION OF THE INVENTION

[0032] In an exemplary basic structure, a sodium metal halide electrochemical cell according to the present invention comprises a cathode-side current collector 1, a cathode 2 consisting of a sodium salt and a further metal halide, a separator 3 as a solid first electrolyte separating the cathode compartment 21 from the anode compartment 41, a second electrolyte 22 intermixing (entering) the current collector 1 into the cathode compartment 21, an anode 4, and a case 5 as the anode-side current collector.

[0033] FIG. 1 shows a preferred embodiment of the cathode-side current collector 1. The cathode-side current collector 1 is made of a metal with good electrical conductivity (σ>10 6 Starting from a tubular substrate (metal tube 11) made of a material such as PTFE (S / m), the cathode chamber 21 is divided into a lower pressed tube section 12 extending along the central axis 51 of the separator 3, and an upper unpressed tube section forming a filled tube 13 for cathode material above the cathode chamber 21. The cross sections of the initial unpressed metal tube 11 and the filled tube 13 as is can be formed into shapes other than circles, such as squares, polygons, or wave patterns.

[0034] The press tube section 12 temporarily stores the second electrolyte 22 in an amount necessary to completely wet the porous cathode 2 in a fully charged state. The cathode 2 can be replenished with the liquid second electrolyte 22 from the inside of the current collector 1 during charging, during which the volume of the porous cathode granules decreases by approximately 20%. To improve the electronic conductivity of the Na / metal halide battery and thereby reduce the internal resistance, it is desirable to position the length of the current collector 1 as close as possible to the base surface of the separator 3. Therefore, its length should be significantly greater than 70% of the length of the separator 3. In this case, tubular Na / metal halide batteries are preferably manufactured with lengths between 50 mm and 500 mm. The storage capacity is determined by the cathode chamber 21 filled with the porous cathode 2 between the outer shell of the current collector 1 and the inner wall of the separator 3. Thereby, it is particularly advantageous to select a diameter of the current collector 1 between 4 mm and 50 mm when the diameter of the separator 3 is between 15 mm and 90 mm. If the current collector 1 is fitted with an element for increasing the surface area, as will be explained in more detail below, a suitable diameter of the outer periphery of the current collector 1 between 10 mm and 80 mm can also be used for the above-mentioned assumed diameter of the separator 3.

[0035] Nickel or nickel alloys or even molybdenum can be used as material for the current collector 1. For a more cost-effective production of the current collector 1, metal tubes 11 made of, for example, copper or copper alloys are advantageously used, which are commercially available from mass production. These are, inter alia, easy to form (press, punch, bend), inexpensive and also have a very high electrical conductivity, which reduces the resistance of the electrochemical cell.

[0036] From the perspective of battery chemistry, after forming the metal tube 11 and punching the slots or through-holes 14, the current collector 1 is protected from chemical corrosion by a nickel coating. For example, when using a cathode 2 with ZnCl or FeCl granules, the current collector 1 can be made entirely of copper if the battery voltage is selected to be lower than the voltage at which copper reacts with salt via the second electrolyte 22 to form CuCl or CuCl (approximately 2.6 V). However, the use of nickel or molybdenum as a protective layer is a reliable means to ensure corrosion protection of the current collector 1, so an aluminum tube can also be used. However, other material combinations can also be selected depending on the battery chemistry (e.g., CuCl, CoCl, CrCl, or ZnCl).

[0037] If additional metal strands 15, for example in the form of metal strips or wires made of nickel or molybdenum, are introduced into the through holes 14 made in the metal tube 11 (for example before, during or after pressing), the surface area of ​​the current collector 1 is considerably increased, and in particular in the case of a flat pressed tube section 12, it is approximated to a cylindrical outer shell. Also, metal rods (not shown) can be used equally well instead of metal wires. The use of molybdenum instead of nickel allows for a higher maximum charging voltage when using a cathode 2 of, for example, FeCl2, and also for a higher conductivity (Mo: 18.2·10 6 S / m, Ni: 13.9·10 6 S / m), the battery performance can be improved.

[0038] By changing the wire length, diameter, number and direction of the metal tufts 15, the resistance of the cathode 2 in the cathode chamber 21 toward the separator 3 can be reduced very uniformly.

[0039] The performance of the battery can be greatly influenced by minimizing the number and size (length and diameter of the wires) and thereby optimizing the Na / MCl2 battery for storage capacity, or by using a larger number of wires of metal cells 15 that fit into the cathode compartment 21, which then results in a decrease in capacity but an increase in performance. The metal cells 15 arriving close to the separator 3 also means that electrons can no longer take a route via individual metal particles that are in contact with each other (as is usual according to the prior art), but can be rapidly transported through the wires of metal cells 15 as a solid, since in the charged state the amount of non-chlorinated conductive metal is reduced and the charge or discharge reaction always starts at the shortest distance from the separator 3.

[0040] As an example, if the metal tube 11 is approximately 300 mm long and 5 mm in diameter, the active surface area (270 mm high and in contact with the cathode 2) is approximately 42.6 cm 2 If 13 through holes 14 are provided in the metal tube 11, and each through hole 14 (except the top through hole 14 in contact with the filling tube 13) is provided with a metal tuft 15 made of 13 wires each having a thickness of 0.7 mm and a length of approximately 32 mm, the surface area of ​​the metal tuft 15 will be an additional 110 cm 2 Additional, if the wire thickness is 1mm, an additional 160cm 2 This has the added benefit of providing a high-speed electron coupling path (wire) to the separator 3. The formation of the current collector 1 according to this embodiment increases the surface area of ​​the cathode-side current collector 1 by five times (approximately 40 cm 2 From 200cm 2 Instead of metal wire, it is also possible to attach, bond or press a sheet metal strip to the metal tube 11.

[0041] To obtain a sufficient current carrying capacity, the material cross section of the metal tube 11 must be adapted to the requirements.

[0042] If pressing, spreading, or bending the wires or metal sheets (possibly with additional coatings) of the metal tufts 15 to the pressed tube section 12 is not sufficient to secure them against slippage or to sufficiently reduce the contact resistance, they can be fixed by a welding or soldering process. Materials with a lower conductivity than copper can also be used as the substrate for the wires, metal rods, or metal sheets of the metal tufts 15, in which case, with an appropriate adaptation of the battery chemistry and therefore the charging voltage, these can be provided with a chemically resistant protective layer, for example made of nickel or molybdenum, along with the pressed tube section 12. To further increase the conductivity, a substrate made of, for example, copper or nickel can be coated with graphene.

[0043] The provision of metal tufts 15 (preferably made of metal wire) used to increase the surface area in the pressed current collector 1 has the additional essential advantage that the current distribution is more homogeneous within the preferably used cylindrical separator 3, since the radial resistance gradient differences resulting from the flat shape of the pressed tube section 12 are minimized or are more uniformly distributed around the central axis 51. Such a homogenized current distribution of the current collector 1 according to the invention within the cylindrical separator 3 is qualitatively shown in FIG. 4. A similar behavior of the current distribution can be obtained by star-pressing the metal tube 11 for the current collector 1 according to FIG. 9. Furthermore, the pressed shape of the metal tube 11 can also be adapted to the contour of the separator 3.

[0044] The most uniform current density distribution in the cathode chamber 21, which can be achieved in a rotationally symmetric separator 3, is ensured by a current collector 1 in the form of an unpressed metal tube 11, which is also circular and located in the center of the cathode chamber 21. In this filling tube 13, it is possible to press only the upper part of the pressed tube section 12, which is only a few millimeters long, leaving the area designated as the filling tube 13 for filling the cathode chamber 21 and, at the same time, the internal volume of the current collector 1 below the pressed tube section 12 as a reservoir 24 for the second electrolyte 22 free. The tubular current collector 1 is then closed in its lowermost region by pressing, so that only the molten salt of the second electrolyte 22 can penetrate into the reservoir 24. Alternatively, the metal tube 11 can be lightly pressed a few centimeters above the lowermost region, and a carbon felt 23 can be inserted up to this stop to prevent the entry of the cathode 2, which is filled, for example, as granules.

[0045] In a further embodiment, the carbon felt 23 is arranged in the current collector 1 in the region A up to the pressed tube section 12, which is a few millimeters long, so that the carbon felt 23 protrudes from or closes the metal tube 11. The metal tube 11 does not need to have a closed contour, as long as it is ensured that the reservoir 24 is permeated with the second electrolyte 22 and that the granules of the cathode 2 do not penetrate. Therefore, slots along or across the central axis of the metal tube 11 are also permitted, but not in the fill tube 13 in the region from the cathode closure 61 to the outside of the battery (due to the requirement for hermeticity of the battery).

[0046] In a further embodiment, the metal tube 11 may be filled with wound carbon felt 23 before pressing, so that only the upper tube section, the fill tube 13, remains empty. The current collector 1 with the carbon felt 23 is then pressed and punched into the metal tube 11 that will later be in contact with the cathode 2, and preferably (according to the embodiment of FIG. 2) a metal tuft 15 of metal wire is attached. In this case, the uppermost through-hole 14 in the transition area between the pressed tube section 12 and the fill tube 13 remains free, i.e., no metal tuft is inserted, because this through-hole 14 is provided for filling with granules of the cathode 2 (as can be seen in the enlarged detail A of FIG. 1 in FIG. 3) and subsequent liquid infiltration of the second electrolyte 22.

[0047] The pressed tube section 12 or the non-pressed metal tube 11 may have at least one additional through-hole 14 below the top through-hole 14 provided for filling the cathode, which does not contain a metal tuft 15. This allows the second electrolyte 22 from the carbon felt 23 or from a reservoir 24 in the non-pressed metal tube 11 to additionally flow out from the inside of the current collector 1 and uniformly wet the granules of the cathode 2.

[0048] Instead of pressing the metal tube 11 of the current collector 1 flat, additional features (waves, grooves, indentations, slots, etc.) can be stamped into the metal to increase the surface area.

[0049] The filling process of the cathode 2 is carried out by pouring a pressed granule of metal powder and metal halide powder, as shown in a simplified form in FIG. 3. The cathode 2 is a mixture of granular metal powder, such as nickel, iron, aluminum, or even copper, cobalt, chromium, or zinc, which is converted into a metal halide only during subsequent charging of the battery, and a sodium halide, such as sodium chloride, sodium iodide, sodium bromide, or sodium fluoride. The granules of the cathode 2 then strike the pressing tube section 12 and are preferably deflected laterally by the two openings of the uppermost, unpressed through-hole 14. For good flowability, the dimensions of the through-hole 14 or of the additional through-holes 14 in the filling tube 13 must be adapted to the size of the granules of the cathode 2.

[0050] The larger the surface area of ​​the cathode-side current collector 1 formed, the lower the contact resistance between the porous metal network (eg, formed by non-chlorinated nickel or iron in the cathode granules) and the current collector 1 .

[0051] For this purpose, if the current collector 1 is formed as a metal tube 11 with an enlarged diameter, and the internal cavity of the metal tube 11 is made available as a reservoir 24 for the second electrolyte 22, the conductive surface area will be increased, but this may unnecessarily reduce the storage capacity, because above a certain internal volume of the metal tube 11, more second electrolyte 22 than is necessary for the charging process will accumulate in the reservoir 24, reducing the cathode chamber 21 left for the granules of the cathode 2.

[0052] The present invention therefore provides a preferred form of cathode-side current collector 1 with a reduced internal volume, an enlarged surface area, and an outer shape that is spatially adapted to the cylindrically assumed separator 3. In a preferred embodiment formed by a flat pressed tube section 12 with through-holes 14 and inserted metal strands 15 of metal strip or wire, as can be seen from the cross-sectional view in plane B of Fig. 2 in Fig. 4, the metal strip or wire inserted into the through-holes 14 as pressed strands can be subsequently fanned and crushed to fit the cylindrical outer shape of the current collector 1. This results in a uniform resistance distribution in the cathode chamber 21 in the radial direction of the separator 3.

[0053] The diameter of the metal tube 11 is determined according to the size and flowability of the granules of the cathode 2 or the diameter of the through-holes 14 formed as filling ports required for the filling time to be observed. However, the through-holes 14 used to increase the surface area of ​​the current collector 1 may be different. By varying the length, diameter, number and orientation of the wires, a very uniform and precise resistance drop can be achieved within the cathode 2.

[0054] 5 shows a preferred embodiment of an electrochemical cell according to the present invention in a schematic (not to scale) view of an axial cross section of the cell, in which the essential components of the electrochemical cell are shown in their principal spatial arrangement and, by way of specific example, implemented in terms of a particular cell chemistry.

[0055] In the cell configuration according to FIG. 5, the cathode-side current collector 1 is made from a nickel-coated copper tube to increase its chemical resistance. The use of copper or aluminum as the base material for the metal tube 11 reduces the electrical resistance of the current collector 1 due to its high electrical conductivity. The cathode 2 manufactured as a thin-walled hollow structure, and compared to a solid pure nickel body, reduces manufacturing costs and simplifies shaping (pressing, punching) due to a smaller wall thickness despite a larger surface area than a non-hollow body. In an alternative embodiment, the current collector 1 can be made entirely from nickel.

[0056] As an alternative to the cell configuration shown in Figure 5, it is also possible to arrange the cathode 2 on the outside of the separator 3. In this case, the cathode 2 can either be arranged exclusively on the outside of the separator 3, i.e., in the opposite direction compared to the configuration of Figure 5 (not shown), or, in the case of a double-walled embodiment of the separator 3 with an enclosed anode compartment 41 as shown in Figure 13, the cathode 2 can be arranged both inside and outside this double-walled configuration, as is known in principle from WO 2018 / 138740.

[0057] The cathode-side current collector 1, made of a nickel-plated copper tube according to FIG. 5, is manufactured in the shape shown in FIG. 2 and is arranged collinearly with the axis of the separator 3. The separator 3 divides the internal volume of the case 5, which serves as the anode-side current collector, into an outer anode chamber 41 and an inner cathode chamber 21. In this example, the anode chamber 41 is filled with metallic sodium as the anode 4 in a charged state. The cathode chamber 21 is filled with granules made of nickel / NaCl (uncharged state) or nickel / NiCl2 (fully charged state) injected through the upper tube part of the current collector 1, the so-called filling tube 13. To ensure rapid filling of the cathode chamber 21 with the cathode granules and to achieve low internal resistance, the cross-sectional areas of the metal tube 11 and the through-holes 14 must be adapted to the volume of the cathode 2 and the overall dimensions of the battery.

[0058] In the present embodiment shown in FIG. 5, the pressed tube portion 12 of the current collector 1 has punched through-holes 14 into which metal tufts 15 made of metal wire are fitted. The metal tufts 15 used to increase the surface area can be made of nickel or molybdenum wire. The through-holes 14 can be punched, for example, before, during, or after pressing the metal tube 11, allowing subsequent filling of the metal tube 11 with metal tufts 15 made of, for example, nickel or molybdenum, thereby significantly increasing the surface area of ​​the current collector 1. Plating the current collector 1 and its metal tufts 15 with gold further reduces the resistance of the current collector 1, but increases manufacturing costs.

[0059] Furthermore, the cathode chamber 21 inside the separator 3 made of sodium-β-alumina as the solid first electrolyte is filled with a liquid second electrolyte 22, which in this embodiment is sodium tetrachloroaluminate (NaAlCl). To ensure that only the second electrolyte 22 enters the inside of the current collector 1 below the fill tube 13 and that Ni / NaCl granules do not enter, the metal tube 11 contains carbon felt 23 inserted into and pressed together with the metal tube 11 before pressing, or the gap dimension of the pressed tube portion 12 below the fill tube 13 and the gap dimension at the lowest end of the pressed tube portion 12 are sufficiently small.

[0060] The installation of the cathode current collector 1 in the electrochemical cell can be advantageously carried out as a one-step joining process, which is carried out in suitable furnaces at different pressures and temperatures depending on the design. In this one-step joining process, the ceramic-ceramic bond between the separator 3 and the ceramic insulator joining ring 63, for example made of corundum, and the metal-ceramic bond between the separator 3 and the metallic cathode and anode closures 61 and 64, which serve to hermetically close the electrochemical cell, are achieved in a single joining step. For this purpose, the metallic closures 61 and 64 are advantageously produced by deep drawing. The cathode closure 61, which closes the cathode chamber 21, has a central opening into which the current collector 1, which has, for example, a pressed tube section 12 including a metal tuft 15 according to one of the embodiments of the present invention, is inserted. The pressed tube section 12 is welded or soldered to the non-pressed tube section (filled tube 13) before joining. In another embodiment, the dosing tube 13 is soldered to the metallic cathode closure 61 during one-step bonding or welded to the metallic cathode closure 61 only subsequent to the bonding process.

[0061] During the bonding step of the one-step bonding, the separator 3 surrounding the cathode chamber 21, or for example the case 5, determines the required free space in the furnace by its dimensions. Therefore, arranging the current collector 1 inside the separator 3 does not increase the required free space and is not disadvantageous.

[0062] During the one-step joining, the anode closure 64, which is a separate, e.g., deep-drawn metallic part, is also joined to the insulator joining ring 63 at a suitable location. The case 5 (as the anode-side current collector) can then also be welded to the metallic anode closure 64 following the joining process, thereby forming a sealed anode chamber 41. If carbon felt 23 is installed in the current collector 1, the one-step assembly or high-temperature soldering process can preferably be carried out only in the absence of oxygen, since otherwise the carbon would oxidize. After the welding process associated with the one-step joining, the electrochemical cell has only one opening, i.e., the open tube end of the fill tube 13 of the cathode-side current collector 1, or multiple openings in the case of multiple current collectors 1, 1′. Through this opening in the fill tube 13, the granular mixture of the cathode 2 is introduced into the cathode chamber 21 of the electrochemical cell. Under exclusion of oxygen and water (e.g., under vacuum or by inert gas purging), the second electrolyte is then introduced in liquid form into the cathode compartment 21 of the battery through the same opening in the fill tube 13. Finally, the opening in the battery is welded closed at the protruding end of the current collector 1 (e.g., using a deep-drawn part or metal circular plate 62 to close the upper end of the fill tube 13).

[0063] In a further embodiment of the final cell installation, shown diagrammatically in Figures 6 and 7, the fill tube 13 of the current collector 1 protrudes so far from the cathode closure 61 that it can be crushed and cut off on the outside of the filled cell, and the resulting narrow frontal surface can be closed by direct welding.

[0064] 6 and 7 show a further refinement of the current collector 1, which is used to introduce carbon felt 23 into the metal tube 11 even after the metal tube 11 has been pressed. For this purpose, after production of the pressed tube section 12, the crushed end 16 is opened, for example by cutting or milling, so that the strip of carbon felt 23 can be introduced via the laterally cut crushed end 17.

[0065] Another embodiment of the current collector 1 is shown in Figures 8 and 9. In this embodiment, in order to increase the surface area of ​​the metal tube 11 (shown only in Figure 1), the pressed tube portion 12 of the current collector 1 is pressed in four radial directions relative to the central axis 51. Two of the four directions are collinear and opposite to each other. As a result, the cross section of the pressed tube portion 12 has a star shape, as shown in Figure 9.

[0066] As further alternative cross sections, the star shape can also be formed as a three-pointed star, a five-pointed star, a six-pointed star, etc. (not shown). Also, although not shown in Fig. 8, in this embodiment, to further increase the surface area, through holes 14 with metal tufts 15 or slots with metal sheets as shown in Fig. 11 can also be additionally introduced.

[0067] A further improvement to fabricating a star-shaped cross section of the pressed tube section 12, as shown in FIG. 10, can be achieved by first forming the metal tube 11 into a star shape as shown in FIG. 9 and then welding the non-pressed tube section to the pressed tube section 12 as the fill tube 13. As a result, the four through holes 14 for filling the cathode granules are automatically formed due to the different cross-sectional shapes of the pressed tube section 12 and the cylindrical fill tube 13, and in this case, punching is not required. Furthermore, to prevent Ni / NaCl granules from penetrating into the pressed tube section 12, the upper pressed area and the lower opening of the current collector 1 can be fabricated with sufficiently small gaps, or carbon felt 23 can be inserted for sealing.

[0068] In a further embodiment of the current collector 1 advantageously arranged in the axial direction of the cathode chamber 21, as shown in FIG. 11 , a tubular base (metal tube 11) made of a good electrical conductor is divided into a lower pressed tube section 12 and an upper, unpressed, filled tube section 13 for filling the cathode chamber 21. The pressed tube section 12 allows the cathode 2 to be filled only into the cathode chamber 21 via the through-holes 14 without reaching the second electrolyte reservoir 24 inside the metal tube 11. Fins 18 made of inserted sheet metal can be inserted through slots in the metal tube 11 below the pressed tube section 12. The fins 18 are welded, pressed, or soldered to the metal tube 11. The fins 18 can be continuous, individually attached, or deformed so that the sheet metal conforms to the contours of the metal tube 11 on the inside, thereby forming at least two fins 18.

[0069] In a further embodiment according to FIG. 12, the fins 18 can also be formed solely by sheet metal 19 folded accordion-like (serpentine).

[0070] As can be seen in FIG. 12 , the star-shaped or wave-shaped cross-sectional profile of the second electrolyte reservoir 24 can also be formed from a folded metal sheet 19. The metal sheet 19 is welded, soldered, or pressed onto the metal tube 11 of the current collector 1, which is divided into the open fill tube 13 and the pressed tube section 12. For this purpose, the folded metal sheet 19 can first be manufactured with a fin-like structure and then bent internally into a tubular structure, for example, and then bonded to the fins 18. Instead of a single folded metal sheet 19, multiple folded metal sheets 19 can be used for forming. The gap dimensions between the formed fins 18 must be small enough to prevent the cathode 2 from penetrating into the second electrolyte reservoir 24. Even if the internal dimensions of the resulting star-shaped cross-sectional profile are smaller or larger than the lower opening of the metal tube 11, the second electrolyte reservoir 24 must still be free of granules of the cathode 2. Also, the remaining opening must be closed sufficiently narrow, for example by further pressing at least the lower end of the metal tube 11, or one or more carbon felts 23 must be introduced.

[0071] FIG. 13 shows a further measure for increasing the power output of an electrochemical cell, configured as a radial double cell. In this case, an additional current collector 1' is provided in the space between the case 5 and the outer wall of the separator 3, which in this example is double-walled, for contact with an additional cathode 2'. The separator includes an anode chamber 41 for the anode 4 in a cylindrical annular gap. Advantageously, the current collector 1', used in addition to the current collector 1 arranged as an unpressed metal tube 11 (not shown in FIG. 13) on the central axis 51, can substitute for the carbon felt 23 by forming a second electrolyte reservoir 24' between the current collector 1' and the inner wall of the case 5. Meanwhile, direct contact of the additional cathode 2' granules with the case wall is prevented, while electrical contact is made via the current collector 1'. This reduces the electrochemical corrosion requirements for the actual case 5. Similarly, when forming a further current collector 1', its surface area can be further increased, i.e. by adding additional folded metal sheets 19 arranged towards the central axis 51, or by the metal sheets themselves having a shape similar to the case contour and forming fins 18 arranged towards the central axis 51.

[0072] In this case, if an additional current collector 1', manufactured as a metal tube 11, for example made of nickel or, depending on the battery chemistry, of nickel-plated copper, and having a diameter smaller than the inner diameter of the case 5, is used, it is possible to create an additional second electrolyte reservoir 24' in electrical contact with the electrochemically active cathode 2' while at the same time not requiring carbon felt 23 beyond the fill level of the cathode 2'. The additional carbon felt 23' arranged in the base region of the case 5 prevents the granules of the cathode 2' from coming into direct contact with the wall of the case 5.

[0073] The additional current collector 1' arranged in the outer region of the additional cathode chamber 21' can also be formed by a sheet metal strip folded in the base region of the case 5 instead of a tube with folded edges at the base. The sheet metal strip is then directly connected to the base of the case 5 (e.g., spot-welded or soldered) and either represents a separate part from the case 5 or is manufactured as an integral part by deep-drawing the case 5. To further reduce the contact resistance of the additional current collector 1' to the case 5, the individual sheet metal strips of the additional current collector 1' can be made extra long so that they are each additionally folded and then come into even flatter contact with the inner wall of the case 5 (not visible in the drawing). Alternatively, the current collector 1' can be welded to the case 5 in the upper closure region of the battery or to another part of the closure region. All of the above-mentioned variations of the current collector 1 are still possible. However, the configurations of FIGS. 11 and 12 can preferably be used.

[0074] The present invention provides a particularly low-cost electrochemical cell, consisting of a small number of components that is easy to manufacture and assemble. In particular, the novel shape of the current collector 1 allows for easy and efficient filling of the cell with metal granules of the cathode 2 and second electrolyte 22 after the cell has been assembled and hermetically welded. By manufacturing the current collector 1 as a single unit and enabling direct cell-to-cell contact via a pressed and welded fill tube 13, the joining process is unnecessary and contact resistance is further reduced. The current collector 1, in its separate internal volume, is inaccessible to Ni / NaCl granules but easily permeable to the second electrolyte 22, thereby replacing the carbon felt 23's function as a second electrolyte reservoir 24. Furthermore, the special surface area enhancement of the current collector 1 achieves uniform radial current distribution in the cathode chamber 21. [Explanation of symbols]

[0075] 1,1' (cathode side) current collector 11 Metal tube 12 Pressed pipe section 13 Filled pipe / unpressed pipe section 14 Punched / Through Holes 15 Metal tufts (made of metal strips or metal wires) 16 Crushed end 17 Cutting and crushing edge 18 Finn 19 Folded sheet metal 2,2' cathode 21,21' cathode chamber 22 Second Electrolyte 23,23' (carbon) felt 24, 24' (second electrolyte) reservoir 3 Separator (solid first electrolyte) 4 anodes 41 Anode chamber 5 cases 51 Center axis 6 Battery compartment 61 (metallic) cathode closure 62 Metal circular plate 63 (ceramic) insulator joint ring 64 Anode Closure

Claims

1. 1. A sodium metal halide electrochemical cell comprising: a case (5) having a central axis (51); a separator (3) extending equidistantly about the central axis (51) of the case (5), the separator (3) serving as a solid first electrolyte, electrically insulating and sealingly separating the anode chamber (41) from the cathode chamber (21), and permeable to sodium ions; a cathode (2) filling the cathode chamber (21) and consisting of a porous mixture of metal powder granules and metal halide powder granules; a second electrolyte (22) consisting of a molten salt of a sodium metal halide, which immerses the porous mixture in the cathode chamber (21) and the cathode (2); a metallic cathode-side current collector (1) formed in the cathode chamber (21) and extending in the longitudinal direction around the central axis (51), The current collector (1) has a resistance of σ>10 ６ a metal tube (11) having a high electrical conductivity of S / m, the metal tube being immersed in the porous mixture of granules of the cathode (2) and the second electrolyte (22) located in the separator (3), and formed as a pressed tube section (12) with a narrowed interior so that the granules of the cathode (2) cannot penetrate and only the second electrolyte (22) can penetrate, and the metal tube has elements (15, 16, 18, 19) on the exterior for increasing the surface area of ​​the current collector (1); 1. A sodium metal halide electrochemical cell comprising: a current collector (1) having, above the immersed pressed tube section (12), an unpressed tube section (13) serving as a filling tube (13) for filling the cathode chamber (21); and at least one through-hole (14) opening the filling tube (13) to the outside is present in the filling tube (13) at the transition from the pressed tube section (12) to the unpressed tube section, thereby enabling the filling tube (13) to be used to fill the cathode chamber (21) only outside the pressed tube section (12) with a porous mixture of the granules of the cathode (2) and to fill the entire cathode chamber (21) with a second electrolyte (22).

2. 2. The electrochemical cell according to claim 1, wherein the current collector (1) comprises, within the pressed tube (12), a carbon felt (23) inserted into the pressed tube (12) before pressing.

3. 2. The electrochemical cell according to claim 1, wherein the current collector (1) has a carbon felt (23) inside the pressed tubular section (12), the carbon felt being insertable into the pressed tubular section (12) from the side after pressing and after cutting off the flattened end (16) of the pressed tubular section (12).

4. 4. The electrochemical cell according to claim 1, wherein the current collector (1) has punched holes in the pressed tubular section (12) in the form of further through-holes (14).

5. 5. The electrochemical cell according to claim 4, characterized in that the current collector (1) has a metal tuft (15) of metal strip or metal wire fixed in the pressed tube section (12) within the through-hole (14), the metal tuft consisting of a metal that is not corroded by the electrochemical processes of the battery and has a high electrical conductivity comparable to that of the metal tube (11) of the current collector (1).

6. 6. The electrochemical cell according to claim 1, wherein the current collector (1) is a nickel tube, an aluminum tube, or a copper tube.

7. 2. The electrochemical cell according to claim 1, characterized in that the surface area-enlarging elements are formed on the current collector (1) with at least one element from the group consisting of punched through holes (14) or other relief-forming structures with crushed edges (16), metal tufts (15), fins (18) or folded metal sheets (19).

8. Electrochemical cell according to claim 5 or 7, characterized in that the metal tufts (15) of metal strip or wire are made from nickel or molybdenum.

9. 8. An electrochemical cell according to claim 5 or 7, characterized in that the metal tufts (15) of metal strip or metal wire are arranged in such a way that local resistance gradients are minimized within the cathode chamber (21) or are uniformly distributed over the cross section of the cathode chamber (21).

10. 10. The electrochemical cell according to claim 1, wherein the non-pressed tube section of the fill tube (13) of the current collector (1) is closed by a metal circular plate (62) or a deep-drawn section, which is bonded to the fill tube (13).

11. 10. The electrochemical cell according to claim 1, wherein the non-pressed tube portion of the fill tube (13) of the current collector (1) is crushed at the tube upper end of the fill tube (13) or is hermetically closed by soldering or welding.

12. Electrochemical cell according to any one of claims 1 to 11, characterized in that the pressed tubular section (12) of the current collector (1) is pressed flat from two collinear directions.

13. 12. The electrochemical cell according to claim 1, wherein the pressed tube portion (12) of the current collector (1) is pressed from at least three directions equally offset around the central axis (51) to form a star-shaped cross section.

14. 14. An electrochemical cell according to claim 12 or 13, characterized in that the pressed tube (12) of the current collector (1) is pressed by the action of force in such a way that the internal space formed as a reservoir (24) for the second electrolyte is exactly the same volume of the second electrolyte (22) required to completely wet the current collector (1) in the fully charged state of the cell.

15. 12. The electrochemical cell according to claim 1, further comprising a metal tube (11) below the pressed tube section (12) of the current collector (1), the metal tube (11) being provided with radial fins (18) arranged in tangentially equidistant slots in the metal tube (11).

16. 12. The electrochemical cell according to claim 1, wherein a metal tube (11) with radial fins (18) is added below the pressed tube section (12) of the current collector (1), the metal tube being made from an equidistantly folded sheet metal (19) and then axially symmetrically folded.

17. 1. A method for manufacturing a sodium metal halide electrochemical cell, comprising: preparing a case (5) for forming an anode chamber (41); a separator (3) for separating the anode chamber (41) from a cathode chamber (21), the separator (3) being insertable equidistantly into the case (5) as an electrically insulating solid first electrolyte that is permeable only to sodium ions; a cathode (2) consisting of a porous mixture of metal powder granules and metal halide granules; and a second electrolyte (22) for immersing the porous mixture of the cathode (2); a step of producing a cathode-side current collector (1) from a metal tube (11), in which a pressed tube section (12) of the current collector (1) is formed from the metal tube (11) by a force acting radially on a central axis (51), leaving a non-pressed tube section at its upper end as a filling tube (13), and providing at least one through-hole (14) in at least one transition section from the pressed tube section (12) to the filling tube (13), the through-hole serving as an outlet opening of the filling tube (13) for filling the cathode chamber (21); manufacturing a cell closure (6) from the cathode closure (61) having a central opening for passing the fill tube (13) of the current collector (1) through the central opening of the cathode closure (61), materially bonding the cathode closure (61) to an insulator bonding ring (63), and materially attaching an anode closure (64) to the insulator bonding ring (63); Positioning the current collector (1) collinearly with the central axis (51) within the separator (3) and within the case (5) equidistantly arranged around the separator (3) using the cell closure (6) consisting of an insulator joining ring (63) and an anode closure (64) by a one-step joining process that achieves ceramic-ceramic or metal-ceramic bonding and a material bonding bonding of the joining sites different from the one-step joining process; filling the porous mixture of metal powder granules and metal halide powder granules of the cathode (2) into the cathode chamber (21) inside the separator (3) only on the outside of the current collector (1) through the filling tube (13) of the current collector (1) and the at least one through-hole (14) of the filling tube (13), and then filling the second electrolyte (22) in a liquid state in a state where oxygen and water are excluded; and finally hermetically closing said electrochemical cell by materially bonding closure of said fill tube (13).

18. A method for manufacturing a sodium metal halide electrochemical cell, comprising: preparing a case (5) for forming an anode chamber (41); a separator (3) for separating the anode chamber (41) from a cathode chamber (21), the separator (3) being insertable equidistantly into the case (5) as an electrically insulating solid first electrolyte that is permeable only to sodium ions; a cathode (2) consisting of a porous mixture of metal powder granules and metal halide granules; and a second electrolyte (22) for immersing the porous mixture of the cathode (2); a step of producing a cathode-side current collector (1) from a metal tube (11), in which a pressed tube section (12) of the current collector (1) is formed from the metal tube (11) by a force acting radially on a central axis (51), leaving a non-pressed tube section at its upper end as a filling tube (13), and providing at least one through-hole (14) in at least one transition section from the pressed tube section (12) to the filling tube (13), the through-hole serving as an outlet opening of the filling tube (13) for filling the cathode chamber (21); the filling tube (13) of the current collector (1) is passed through the central opening of the cathode closure (61) and materially fixed therein, and then a battery closure (6) is produced from the cathode closure (61) having the central opening, materially bonding the cathode closure (61) to an insulator bonding ring (63), and materially attaching an anode closure (64) to the insulator bonding ring (63); Positioning the current collector (1) in the separator (3) and in the case (5) collinearly with the central axis (51) by a one-step joining process that achieves ceramic-ceramic or metal-ceramic bonding using the cell closure (6) consisting of an insulator joining ring (63) and an anode closure (64) and a material bonding bonding of the joining site different from the one-step joining process; filling the porous mixture of metal powder granules and metal halide powder granules of the cathode (2) into the cathode chamber (21) inside the separator (3) only on the outside of the current collector (1) through the filling tube (13) of the current collector (1) and the at least one through-hole (14) of the filling tube (13), and then filling the second electrolyte (22) in a liquid state in a state where oxygen and water are excluded; and finally hermetically closing said electrochemical cell by materially bonding closure of said fill tube (13).

19. A method for manufacturing a sodium metal halide electrochemical cell, comprising: preparing a case (5) for forming an anode chamber (41); a separator (3) for separating the anode chamber (41) from a cathode chamber (21), the separator (3) being insertable equidistantly into the case (5) as an electrically insulating solid first electrolyte that is permeable only to sodium ions; a cathode (2) consisting of a porous mixture of metal powder granules and metal halide granules; and a second electrolyte (22) for immersing the porous mixture of the cathode (2); a step of producing a cathode-side current collector (1) from a metal tube (11), in which a pressed tube section (12) of the current collector (1) is formed from the metal tube (11) by a force acting radially on a central axis (51), leaving a non-pressed tube section at its upper end as a filling tube (13), and providing at least one through-hole (14) in at least one transition section from the pressed tube section (12) to the filling tube (13), the through-hole serving as an outlet opening of the filling tube (13) for filling the cathode chamber (21); manufacturing a cell closure (6) from the cathode closure (61) having a central opening for passing the fill tube (13) of the current collector (1) through the central opening of the cathode closure (61), materially bonding the cathode closure (61) to an insulator bonding ring (63), and materially attaching an anode closure (64) to the insulator bonding ring (63); a one-step joining process using the cell closure (6) consisting of an insulator joining ring (63) and an anode closure (64) to achieve a ceramic-ceramic or metal-ceramic bond, and then arranging the current collector (1) collinearly in the separator (3) and in the case (5) arranged equidistantly around the separator (3) and collinearly with the central axis (51), and then fixing the current collector (1) by a material bonding bond at a joining site different from that of the one-step joining process; filling the porous mixture of metal powder granules and metal halide powder granules of the cathode (2) into the cathode chamber (21) inside the separator (3) only on the outside of the current collector (1) through the filling tube (13) of the current collector (1) and the at least one through-hole (14) of the filling tube (13), and then filling the second electrolyte (22) in a liquid state in a state where oxygen and water are excluded; and finally hermetically closing said electrochemical cell by materially bonding closure of said fill tube (13).

20. A method for manufacturing a sodium metal halide electrochemical cell, comprising: preparing a case (5) for forming an anode chamber (41); a separator (3) for separating the anode chamber (41) from a cathode chamber (21), the separator (3) being insertable equidistantly into the case (5) as an electrically insulating solid first electrolyte that is permeable only to sodium ions; a cathode (2) consisting of a porous mixture of metal powder granules and metal halide granules; and a second electrolyte (22) for immersing the porous mixture of the cathode (2); a step of producing a cathode-side current collector (1) from a metal tube (11), in which a pressed tube section (12) of the current collector (1) is formed from the metal tube (11) by a force acting radially on a central axis (51), leaving a non-pressed tube section at its upper end as a filling tube (13), and providing at least one through-hole (14) in at least one transition section from the pressed tube section (12) to the filling tube (13), the through-hole serving as an outlet opening of the filling tube (13) for filling the cathode chamber (21); after materially fixing the fill tube (13) of the current collector (1) to the central opening of the cathode closure (61), fabricating a cell closure (6) from the cathode closure (61) having the central opening, materially bonding the cathode closure (61) to an insulator bonding ring (63), and materially attaching an anode closure (64) to the insulator bonding ring (63); Using the cell closure (6) consisting of an insulator joining ring (63) and an anode closure (64), the current collector (1) is positioned in the separator (3) collinearly with the central axis (51) by a one-step joining process that achieves a ceramic-ceramic or metal-ceramic bond, followed by positioning the case (5) equidistant from the separator (3) and collinearly with the central axis (51), and fixing the case (5) by a material bonding bond at the joining site different from that of the one-step joining process; filling the porous mixture of metal powder granules and metal halide powder granules of the cathode (2) into the cathode chamber (21) inside the separator (3) only on the outside of the current collector (1) through the filling tube (13) of the current collector (1) and the at least one through-hole (14) of the filling tube (13), and then filling the second electrolyte (22) in a liquid state in a state where oxygen and water are excluded; and finally hermetically closing said electrochemical cell by materially bonding closure of said fill tube (13).

21. 21. The method according to claim 17, wherein elements for increasing the surface area of ​​the current collector (1) are introduced into the pressed tube section (12) at equal distances in the form of through holes (14).

22. 22. The method according to claim 21, wherein a metal tuft (15) made of a metal strip or metal wire is inserted into the through-hole (14) of the pressed tube section (12).

23. The method according to any one of claims 17 to 22, wherein the pressed tube section (12) of the current collector (1) is formed flat by collinear radial force action.

24. 23. The method according to any one of claims 17 to 22, wherein the pressed tube section (12) of the current collector (1) is formed into a star shape by a plurality of radial force actions equally distributed around the central axis (51).

25. 21. The method according to any one of claims 17 to 20, wherein radial fins (18) inserted in tangentially equidistant slots are attached to the metal tube (11) below the pressed tube section (12) in order to increase the surface area of ​​the current collector (1).

26. 21. The method according to claim 17, wherein radial fins (18) are formed on the metal tube (11) below the pressed tube section (12) by folding metal sheets (19) in order to increase the surface area of ​​the current collector (1).

27. A method according to any one of claims 17 to 26, wherein the filling tube (13) is closed by welding or soldering the upper end of the tube with a metal circular plate (62).

28. A method according to any one of claims 17 to 26, wherein the closure of the filling tube (13) is carried out by crushing the upper end of the tube and finally by welding or soldering the crushed upper end of the tube.

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