Seal, lid assembly, energy storage cell, and assembly of energy storage cells

Abstract

To provide a seal, a lid assembly, an energy storage cell, and an assembly of energy storage cells.SOLUTION: An annular seal (103) includes an outer annular segment (130). The outer annular segment continues, at one of two ends thereof, into an inward-facing collar (131) that narrows the outer annular segment (130) at the end. The collar (131) has an inner edge (131a) continuing into an inner annular segment (132). The outer annular segment (130) also has an inwardly pointing circumferential nose (133) provided with an undercut (132). Described herein are: a lid assembly (102), including the seal, of an energy storage cell (100); and the energy storage cell (100) having the lid (102). Further proposed are: an assembly of such energy storage cells (100); and a method of producing such an assembly.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The invention described below relates to a seal, a lid assembly provided with the seal, an energy storage cell, and an assembly of energy storage cells. [Background technology]

[0002] Electrochemical energy storage elements are capable of converting stored chemical energy into electrical energy via redox reactions. The simplest form of electrochemical energy storage element is the electrochemical cell. An electrochemical cell comprises a positive electrode and a negative electrode, between which a separator is placed. During discharge, as a result of an oxidation process, electrons are released at the negative electrode. The result is an electron flow that can be absorbed by an external consumer, for which the electrochemical cell serves as an energy source. At the same time, an ionic current corresponding to the electrode reactions is generated in the cell. This ionic current passes through the separator and is made possible by the ionically conductive electrolyte. The separator thus prevents direct contact between the electrodes. At the same time, however, the separator allows charge equalization between the electrodes.

[0003] If the discharge is reversible, i.e., it is possible to reverse the conversion of chemical energy to electrical energy during discharge and recharge the cell, the cell is called a secondary cell. In secondary cells, the common designation of the negative electrode as the anode and the positive electrode as the cathode refers to the discharge function of the electrochemical cell.

[0004] Secondary lithium-ion cells are used today in many applications as energy storage elements, since they can supply high currents and are characterized by a relatively high energy density. Secondary lithium-ion cells are based on the use of lithium, which can be transported back and forth in the form of ions between the electrodes of the cell. The negative and positive electrodes of lithium-ion cells are generally formed by so-called composite electrodes, which contain an electrochemically inactive component as well as an electrochemically active component.

[0005] In principle, all materials capable of absorbing and releasing lithium ions can be used as electrochemically active components (active materials) for secondary lithium-ion cells. For example, carbon-based particles such as graphitic carbon are used for the negative electrode. The active material for the positive electrode can be, for example, lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), or derivatives thereof. The electrochemically active material is generally contained in the electrode in particulate form.

[0006] As electrochemically inactive components, composite electrodes generally comprise flat and / or strip-shaped current collectors, e.g. metal foils, which act as carriers for the respective active materials: the current collector for the negative electrode (anode current collector) can be made, for example, of copper or nickel, the current collector for the positive electrode (cathode current collector) can be made, for example, of aluminum.

[0007] Additionally, the electrode may contain, as electrochemically inactive components, an electrode binder (e.g., polyvinylidene fluoride (PVDF) or another polymer, such as carboxymethylcellulose), conductivity improving additives, and other additives. The electrode binder ensures the mechanical stability of the electrode and, in many cases, the adhesion of the active material to the current collector.

[0008] As an electrolyte, lithium-ion cells typically contain a lithium salt solution, such as lithium hexafluorophosphate (LiPF6), in an organic solvent (e.g., ethers and esters of carbonic acid).

[0009] In manufacturing lithium-ion cells, the composite electrode is generally combined with one or more separators to form an electrode-separator assembly. The electrode and separator are usually bonded together under pressure, optionally further by lamination or bonding. The assembly can then be impregnated with an electrolyte to establish basic functionality of the cell.

[0010] In many embodiments, the electrode-separator assembly is formed in the form of a winding or processed into a winding. In the first case, for example, the ribbon-shaped positive and negative electrodes and at least one ribbon-shaped separator are fed separately to a winding machine and spirally wound into a winding having a positive electrode / separator / negative electrode sequence. In the second case, the ribbon-shaped positive and negative electrodes and at least one ribbon-shaped separator are first combined to form the electrode-separator assembly, for example by applying pressure as described above. Then, in a further step, the assembly is wound.

[0011] Applications in the automotive sector, for electric bicycles or other applications with high energy requirements, such as electric tools, require lithium-ion cells with the highest possible energy density that are also able to withstand high currents during charging and discharging.

[0012] Cells for the aforementioned applications are often designed as cylindrical round cells, with a form factor of, for example, 21 x 70 (diameter x height, in mm). This type of cell always comprises an assembly in the form of a wound body. Modern lithium-ion cells with this form factor are able to achieve energy densities of up to 270 Wh / kg.

[0013] WO 2017 / 215900 A1 describes an electrode-separator assembly and a cylindrical circular cell whose electrodes are ribbon-like and in the form of a winding. Each electrode has a current collector provided with an electrode material. The electrodes with opposite polarity are arranged offset from each other in the electrode-separator assembly, so that the longitudinal edge of the current collector of the positive electrode protrudes from one side of the winding and the longitudinal edge of the current collector of the negative electrode protrudes from the other side of the winding. For electrical contact of the current collectors, the cell has a contact sheet metal member that rests on one end face of the winding and is connected by welding to the longitudinal edge of one of the current collectors. This allows the current collector, and therefore also the associated electrode, to be electrically contacted over its entire length. This significantly reduces the internal resistance in the described cell. As a result, high currents can be absorbed much better and also the heat can be dissipated better from the winding.

[0014] Cylindrical round cells such as those in WO 2017 / 215900 A1 are often used as part of a cell array in which several cells are connected in series and / or in parallel. It is often desirable to only have to contact one of the cell's end faces in order to tap off the voltage. It is therefore advantageous to provide both a connection pole connected to the positive electrode of the cell and a connection pole connected to the negative electrode of the cell on one of the cell's end faces.

[0015] The housing of a cylindrical round cell generally comprises a housing cup containing a wound electrode-separator assembly and a lid assembly closing the opening of the housing cup. Between the lid assembly and the housing cup a seal is arranged, which on the one hand serves to seal the cell housing, but on the other hand also has the function of electrically insulating the lid assembly and the housing cup from each other. The seal is usually mounted on the edge of the lid assembly. To close the circular cell, the opening edge of the housing cup is generally bent radially inwards over the edge of the lid assembly surrounded (crimped) by the seal, so that the lid assembly including the seal is securely fixed in the opening of the housing cup.

[0016] An example of such a circular cell is shown in FIG. 3 of EP 3188280 A1. To integrate the illustrated cell into a cell assembly, it is relatively easy to weld the lid assembly (reference number 270) to a suitable conductor rail, and the protruding pole cap (reference number 217) provides the best conditions for this. However, the electrical connection of the housing cup is more difficult. If one attempts to contact the housing cup on the same end face as the end face on which the lid assembly is located, the conductor rail can only be welded to the radially inwardly bent opening edge (reference number 213) of the housing cup. The problem with this is that such a welding operation can easily damage the seal that is in direct contact with the bent opening edge, because the seal is sensitive to the thermal stresses that typically occur during welding. Therefore, circular cells with a classical cell housing as described in EP 3188280 A1 are generally not accessible for welding current conductors to the opening edge.

[0017] From the applicant's international patent application PCT / EP2022 / 083072 (published as WO 2023 / 094498 A1), an energy storage cell is known which comprises a housing in which the radially inwardly bent opening edge of the housing cup has an increased wall thickness. This ensures that the conductor rails can be welded onto the radially inwardly bent opening edge of the housing cup without the following problems with the seal: The increased thickness of the opening edge ensures a better distribution of the heat generated during welding, which makes it possible to avoid local overheating and melting of the seal. Summary of the Invention [Problem to be solved by the invention]

[0018] It is the object of the present invention to create an energy storage cell which is characterized by a high energy density and which can be efficiently integrated into a cell assembly. Moreover, the energy storage cell should also be characterized by an improved safety. In particular, the present invention is based on the task of further improving the cell described in the above-mentioned International Application No. PCT / EP2022 / 083072. [Means for solving the problem]

[0019] This object is achieved by a seal having the features of claim 1, a lid assembly having the features of claim 3 and an energy storage cell having the features of claim 5. An assembly of an energy storage cell having the features of claim 13 is also an object of the invention. Preferred embodiments of the invention can be found in the dependent claims 2, 4 and 6-12.

[0020] The seal has the following features a. to d.: The seal includes an outer annular segment. b. The outer annular segment continues at one of its two ends into an inwardly facing collar which narrows the outer annular segment at this end. c. The collar has an inner edge that continues into the inner annular segment. d. The outer annular segment has an inwardly facing circumferential nose with an undercut.

[0021] Such seals are used to close housings of the above mentioned type, for example as described in EP 3188280 A1. During assembly, in addition to the seal, a lid assembly is often used which comprises other individual parts held together by the seal. The seal may act as a retaining element for fixing the parts of the lid assembly in corresponding holders (described in more detail below). However, when the seal is compressed, the nose results in an asymmetric pressure distribution, which makes it difficult to form a flat shoulder of the cell suitable for welding onto a conductor.

[0022] Surprisingly, it has been found that this problem can be solved simply by providing an undercut in the nose, which creates a space in which the area of ​​the seal with the nose can expand during compression, eliminating the "nose interference factor" when closing the cell. This allows a flat annular surface to be formed at the shoulder of the cell during cell closure, which is available for electrical contact of the cell.

[0023] The seal is preferably characterized by at least one of the following additional features a. to f.: The outer annular segment is hollow cylindrical. b. The inner annular segment is hollow cylindrical or conically tapered. c. The undercut is designed as an annular groove-like recess. d. The nose is formed as an annular ridge on the inner surface of the outer annular segment. e. A nose with an undercut divides the outer annular segment into a center portion segment and a terminal portion segment. f. The collar has an annular ridge on its inner surface.

[0024] Preferably, the wall thickness of the outer annular segment is reduced in the region of the groove-like recess. It is also preferred that the wall thickness of the outer annular segment is increased in the region of the nose.

[0025] The lid assembly according to the present invention has the following features a. to i.: The lid assembly includes a pole cap having a circular edge. b. The lid assembly includes a first metal disk having a circular edge. c. The lid assembly includes a second metal disk having a circular edge. d. The lid assembly includes an annular seal. e. The lid assembly includes an annular insulator. f. The first metal disc is located between the pole cap and the second metal disc. g. The annular insulator electrically insulates the first metal disc and the second metal disc from each other. h. The first metal disk is in direct contact with the pole cap. i. An annular seal is mounted on the circular edge of the pole cap and / or on the circular edge of the first metal disc.

[0026] The lid assembly is characterized in particular by the following features j. to l.: j. The seal is designed as the seal described above. k. The circular edge of the pole cap and / or the circular edge of the first metal disc rests on the collar. l. The circular edge of the pole cap and / or the circular edge of the first metal disc is held in place by a nose.

[0027] Particularly preferably, the collar, the central part segment and the nose form a recess for the circular edge of the pole cap and / or the circular edge of the first metal disc.

[0028] The lid assembly is preferably characterized by at least one of the following additional features a. to d.: a. The annular seal is mounted on the circular edge of a first metal disk. b. An annular seal is mounted on the circular edge of the pole cap. c. An annular seal is mounted on the circular edge of the pole cap and on the circular edge of the first metal disc. d. The circular edge of the first metal disk is folded in a U-shape around the circular edge of the pole cap.

[0029] Feature a. is generally preferred when the diameter of the first metal disc is greater than the diameter of the pole cap. Feature b. is generally preferred when the diameter of the first metal disc is smaller than the diameter of the pole cap. Feature d. may be preferred when the diameter of the first metal disc is equal to the diameter of the pole cap. Feature d. is particularly preferred.

[0030] The energy storage cell according to the present invention has the following characteristics a. to f.: a. the energy storage cell comprises an electrode-separator assembly having an anode / separator / cathode sequence; b. the electrode-separator assembly is in the form of a cylindrical winding having a first terminal end face and a second terminal end face with a winding shell located therebetween; c. the cell comprises an air-tight and liquid-tight housing comprising a metal housing cup having a terminal circular opening and a lid assembly having a circular edge closing the circular opening; d. the lid assembly is formed as described above; e. the housing cup comprises, in axial sequence, a bottom section, a center section, and a closure section; the central section being cylindrical, and in the central section the wound shell of the electrode-separator assembly contacts the inner surface of the housing cup; In the closing section, the annular seal of the lid assembly is pressed against the edge of the pole cap and / or the edge of the first metal disk and the inner surface of the housing cup; f. The housing cup has an opening edge at the closure section defining a terminal circular opening, the opening edge bent radially inwardly over an edge of the pole cap and / or first metal disk surrounded by the seal to securely fasten the lid assembly, including the seal, within the circular opening of the housing cup.

[0031] The term "edge of the pole cap and / or the first metal disc" encompasses the above-mentioned embodiments, according to which the diameters of the pole cap and the metal disc are different or the same. For crimping, the component with the larger diameter is important, because the seal is in contact with it. Particularly preferred is an embodiment in which the circular edge of the first metal disc is folded in a U-shape around the edge of the pole cap.

[0032] In some particularly preferred embodiments, the radially inwardly curved opening edge of the housing cup has a greater wall thickness than the housing cup in the central section.

[0033] This ensures that the conductor rails can be welded onto the radially inwardly bent opening edge of the housing cup without problems with the seal. The increased thickness of the opening edge ensures a better distribution of the heat generated during welding, thereby avoiding local overheating and melting of the seal.

[0034] The same effect can be achieved by welding a ring-shaped washer onto the inwardly bent opening edge of the housing cup. The washer provides an annular flat surface that can act as a support for the conductor rail. Preferably, the washer has an outer diameter that does not exceed the outer diameter of the housing cup. For example, the outer diameter can be in the range of 1 cm to 10 cm, more preferably in the range of 1.5 cm to 7 cm. Of course, this depends on the absolute dimensions of the corresponding energy storage cell. The width of the annular flat surface is preferably in the range of 2 mm to 3 cm, preferably in the range of 4 mm to 2 cm, and in some particularly preferred embodiments in the range of 2 mm to 5 mm. The thickness of the washer is preferably in the range of 0.1 mm to 5 mm, preferably in the range of 0.5 mm to 3 mm. Preferably, the ring disk has a circular hole in its center, through which the pole cap is accessible from the outside, through which preferably the central ridge of the pole cap can protrude.

[0035] Preferably, the washer has a flat upper surface and a flat lower surface. In a particularly preferred embodiment, this means that there is a maximum height difference of 0.2 mm between the highest and lowest points of the upper and lower surfaces, more preferably a maximum height difference of 0.08 mm. In a further preferred embodiment, the annular disc forms an angle of 90° with the wall of the housing cup in the central section.

[0036] Preferably, the washer is welded onto the aperture edge such that the outer edge of the annular disc is a uniform distance from the aperture edge defining the circular aperture.

[0037] At this point it must be emphasized that the washer can be used completely independent of the design of the seal of the lid assembly. Welding onto the ring washer can be realized for any energy storage cell having features a. to c. as well as e. and f. of claim 5. Feature d. of claim 5 is optional.

[0038] The electrode-separator assembly is preferably in direct contact with the inner surface of the housing cup. It is particularly preferred that the electrode-separator assembly is in direct contact with the inner surface of the housing cup. However, in some embodiments, electrical insulation of the inner surface of the housing cup may be provided, for example by a film. In this case, the electrode-separator assembly is in contact with the inner wall via the film.

[0039] The bottom of the housing cup is preferably circular. The housing cup is preferably formed by deep drawing. However, it is also possible to form the cup by welding the bottom into the tubular half-piece.

[0040] The energy storage cell is preferably a cylindrical cell. The electrode-separator assembly preferably comprises an anode and a cathode in the form of a ribbon. Furthermore, the electrode-separator assembly preferably comprises one ribbon-shaped separator or two ribbon-shaped separators. The end faces of the cylindrical cell are preferably surrounded by circular edges.

[0041] The height of the cylindrical cells is preferably in the range of 50 mm to 150 mm. Their diameter is preferably in the range of 15 mm to 60 mm. Cylindrical round cells with these form factors are particularly suitable for powering electric drives in automobiles.

[0042] Lithium-ion cell embodiment In a particularly preferred embodiment of the invention, the energy storage cell is a lithium-ion cell. Essentially all electrode materials known for secondary lithium-ion cells can be used for the electrodes of the energy storage cell.

[0043] Carbon-based particles such as graphitic carbon or non-graphitic carbon materials capable of intercalating lithium, preferably also in particulate form, can be used as the active material in the negative electrode. Alternatively or in addition, lithium titanate (Li4Ti5O 12) Or its derivative can also be preferably contained in the negative electrode in a particulate form as well. Furthermore, the negative electrode contains, as an active material, at least one material selected from the group consisting of silicon, aluminum, tin, antimony, or a compound or alloy of these materials that can reversibly store or release lithium, for example, silicon oxide (specifically, SiO x , where 0 < x < 2), and can optionally contain it in combination with a carbon-based active material. Tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. The capacity to absorb lithium, especially in the case of silicon, far exceeds the capacity of graphite or equivalent materials. Mixtures of silicon and carbon-based storage materials are often used. Thin anodes made of metallic lithium are also suitable.

[0044] Suitable active materials for the positive electrode include lithium metal oxide compounds and lithium metal phosphate compounds, such as LiCoO2 and LiFePO4. Lithium nickel manganese cobalt oxide (NMC) having the chemical formula LiNi x Mn y Co z O2 (where x + y + z is typically 1), lithium manganese spinel (LMO) having the chemical formula LiMn2O4, or lithium nickel cobalt aluminum oxide (NCA) having the chemical formula LiNi x Co y Al z O2 (where x + y + z is typically 1) are also particularly suitable. Its derivatives, for example, lithium nickel manganese cobalt aluminum oxide (NMCA) having the chemical formula Li 1.11 (Ni 0.40 Mn 0.39 Co 0.16 Al 0.05 ) 0.89 O2, or Li 1+x M - O compounds, and / or mixtures of the above-described materials can also be used. The cathode active material is also preferably used in particulate form.

[0045] In addition, the electrodes of the energy storage cell preferably contain an electrode binder and / or additives to improve electrical conductivity. The active material is preferably embedded in the matrix of the electrode binder, and adjacent particles in the matrix are preferably in direct contact with each other. The conductive agent has the function of increasing the electrical conductivity of the electrode. Common electrode binders are, for example, based on polyvinylidene fluoride (PVDF), (Li-) polyacrylate, styrene butadiene rubber, or carboxymethyl cellulose, or a mixture of different binders. Common conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes, and metal powders.

[0046] The energy storage cell preferably comprises an electrolyte, in the case of a lithium-ion cell, in particular an electrolyte based on at least one lithium salt present dissolved in an organic solvent (for example in a mixture of an organic carbonate or a cyclic ether, such as THF or a nitrile), such as lithium hexafluorophosphate (LiPF6). Other usable lithium salts are, for example, lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(oxalato)borate (LiBOB).

[0047] Preferably, the nominal capacity of the lithium-ion based energy storage cells according to the invention is up to 15000mAh. For a 21mm x 700mm form factor, the lithium-ion cells according to the invention preferably have a nominal capacity in the range of 1500mAh to 7000mAh, particularly preferably in the range of 3000 to 5500mAh. For a 18mm x 650mm form factor, the lithium-ion cells according to the invention preferably have a nominal capacity in the range of 1000mAh to 5000mAh, particularly preferably in the range of 2000 to 4000mAh.

[0048] In the European Union, manufacturer standards regarding the nominal capacity of secondary batteries are highly regulated. For example, information regarding the nominal capacity of secondary nickel-cadmium batteries must be based on measurements according to the IEC / EN 61951-1 and IEC / EN 60622 standards, information regarding the nominal capacity of secondary nickel-hydrogen hybrid batteries must be based on measurements according to the IEC / EN 61951-2 standard, information regarding the nominal capacity of secondary lithium batteries must be based on measurements according to the IEC / EN 61960 standard, and information regarding the nominal capacity of secondary lead-acid batteries must be based on measurements according to the IEC / EN 61056-1 standard. Any information regarding nominal capacity in the present application is preferably based on these standards.

[0049] Sodium-Ion-Based Cells In further embodiments, the energy storage cell may be a sodium-ion cell, a potassium-ion cell, a calcium-ion cell, a magnesium-ion cell, or an aluminum-ion cell. Among these variations, energy storage cells having sodium-ion cell chemistry are particularly preferred. Preferably, the sodium-ion based energy storage cell comprises an electrolyte comprising at least one of the following solvents and at least one of the following conductive salts:

[0050] Organic carbonates, ethers, nitriles and mixtures thereof are particularly suitable as solvents. Preferred examples are: Carbonates: Propylene carbonate (PC), Ethylene carbonate-propylene carbonate (EC-PC), Propylene carbonate-dimethyl carbonate-ethyl methyl carbonate (PC-DMC-EMC), Ethylene carbonate-diethyl carbonate (EC-DEC), Ethylene carbonate-dimethyl carbonate (EC-DMC), Ethylene carbonate-ethyl methyl carbonate (EC-EMC), Ethylene carbonate-dimethyl carbonate-ethyl methyl carbonate (EC-DMC-EMC), Ethylene carbonate-dimethyl carbonate-diethyl carbonate (EC-DMC-DEC) Ethers: Tetrahydrofuran (THF), 2-methyltetrahydrofuran, dimethyl ether (OME), 1,4-dioxane (DX), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), tetraethyl glycol dimethyl ether (TEGDME) · Nitriles: Acetonitrile (ACN), Adiponitrile (AON), y-butyrolactone (GBL).

[0051] Trimethyl phosphate (TMP) and tris(2,2,2-trifluoroethyl) phosphate (TFP) can also be used.

[0052] Preferred conductive salts are NaPF6, sodium difluoro(oxalato)borate (NaBOB), NaBF4, sodium bis(fluorosulfonyl)imide (NaFSI), sodium 2-trifluoromethyl-4,5-dicyanoimidazole (NaTDI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), NaAsF6, NaBF4, NaClO4, NaB(C2O4)2, NaP(C6H4O2)3, NaCF3SO3, sodium triflate (NaTf), and Et4NBF4.

[0053] In a preferred embodiment, additives may be added to the electrolyte. Examples of preferred additives, especially for stabilization, are:

[0054] Fluoroethylene carbonate (FEC), trans-difluoroethylene carbonate (DFEC), ethylene sulfite (ES), vinylene carbonate (VC), bis(2,2,2-trifluoroethyl)ether (BTFE), sodium 2-trifluoromethyl-4,5-dicyanoimidazole (NaTDI), sodium bis(fluorosulfonyl)imide (NaFSI), aluminum chloride (AlCl3), ethylene sulfate (DTD), sodium difluorophosphate (NaPO2F2), sodium difluoro(oxalato)borate (NaODFB), sodium difluorobisoxalatophosphate (NaDFOP) and tris(trimethylsilyl)borate (TMSB).

[0055] The negative electrode material of the sodium-ion based energy storage cell is preferably at least one of the following materials: Carbon: in particular hard carbon (pure or doped with nitrogen and / or phosphorus) or soft carbon, or graphene-based materials (N-doped), carbon nanotubes, graphite Phosphorus or sulfur (conversion anode) ·Polyanion: Na2Ti3O7, Na3Ti2(PO4)3, TiP2O7, TiNb2O7, Na-Ti-(PO4)3, Na-V-(PO4)3 Prussian Blue: low sodium variant (for aqueous electrolyte systems) Transition metal oxides: V2O5, MnO2, TiO2, Nb2O5, Fe2O3, Na2Ti3O7, NaCrTiO4, Na4Ti5O 12 MXene: M=Ti, V, Cr, Mo or Nb, A=Al, Si and Ga, X=C and / or N, e.g., Ti3C2 · Organic: e.g., sodium terephthalate (Na2C8H2O4)

[0056] Alternatively, a sodium metal anode can be used on the anode side.

[0057] The positive electrode material of the sodium-ion based energy storage cell may include or be at least one of the following materials: Polyanions: NaFePO4 (triplyte type), Na2Fe(P2O7), Na4Fe3(PO4)2(P2O7), Na2FePO4F, Na / Na2[Fe 1 / 2 Mn 1 / 2 ]PO4F, Na3V2(PO4)2F3, Na3V2(PO4)3, Na4(CoMnNi)3(PO4)2P2O7, NaCoPO4, Na2CoPO4F Silicates: Na2MnSiO4, Na2FeSiO4 Layered oxides: NaCoO2, NaFeO2, NaNiO2, NaCrO2, NaVO2, NaTiO2, Na(FeCo)O2, Na(NiFeCo)3O2, Na(NiFeMn)O2, and Na(NiFeCoMn)O2, Na(NiMnCo)O2.

[0058] In addition, the electrodes of the sodium-ion cell may preferably contain electrode binders and / or additives to improve electrical conductivity. The active material is preferably embedded in the matrix of the electrode binder, and the active material is preferably used in the form of particles, with adjacent particles in the matrix preferably in direct contact with each other. The conductive agent has the function of increasing the electrical conductivity of the electrode. Common electrode binders are, for example, based on polyvinylidene fluoride (PVDF), (Na-) polyacrylate, styrene butadiene rubber, (Na-) alginate or carboxymethyl cellulose, or a mixture of different binders. Common conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes and metal powders.

[0059] In a particularly preferred embodiment of an energy storage cell based on sodium-ion technology, both the anode and cathode current collectors are constructed of aluminum or an aluminum alloy. The housing and contact sheet metal members, as well as any other current conductors within the housing, may also be constructed of aluminum or an aluminum alloy.

[0060] Preferred wall thickness of the housing cup Particularly preferably, the energy storage cell is characterized by at least one of the following characteristics a. to c.: a. The radially inwardly curved opening edge of the housing cup has a thickness in the range of 1.5 to 2 times that of the housing cup in the central section. b. The housing cup has a wall thickness in the range of 0.1 mm to 0.4 mm, preferably 0.25 mm to 0.3 mm, in the central section. c. The radially inwardly curved opening edge of the housing cup has a wall thickness in the range of 0.15 mm to 0.8 mm, preferably in the range of 0.375 mm to 0.6 mm.

[0061] It is preferred that the immediately preceding features a and b, and a and c, are realized in combination. It is particularly preferred that all three of the immediately preceding features a to c are realized in combination with one another. The bottom of the housing cup preferably has a thickness in the range of 0.2 mm to 2 mm.

[0062] Preferred variants for higher wall thicknesses of the opening edges To achieve a higher wall thickness of the opening edge, starting material can already be used in the production of the housing cup, which is thickened in the area where the opening edge is intended to be formed. However, to achieve a larger wall thickness, it is particularly preferred to reinforce the opening edge by bending or folding the wall of the housing cup.

[0063] Thus, preferred embodiments according to the invention are characterized by at least one of the following features a. to c.: a. The radially inwardly bent opening edge of the housing cup is double layered. b. The bi-layer opening edge is formed by folding or bending the opening edge. c. The opening edge of the bilayer has a U-shaped cross section, particularly as a result of folding or bending in accordance with immediately preceding feature b.

[0064] It is preferable that the immediately preceding features a. and b., and particularly preferable that the immediately preceding three features a. to c. are all realized in combination.

[0065] The folding or bending to form the bilayer aperture edge can be done outwardly or inwardly, resulting in different variations in the bilayer aperture edge.

[0066] Particularly preferably, the energy storage cell is characterized by at least one of the following characteristics a. to c.: a. The two-layer opening edge has a first layer that surrounds the edge of the lid assembly and directly contacts the seal, and a second layer that is parallel to the first layer on the side of the first layer that faces away from the seal. b. The first layer is bounded by a cut edge facing radially outward. c. The second layer is bounded by a cut edge facing radially outward.

[0067] Preferably, the immediately preceding features a. and b. or the immediately preceding features a. and c. are realised in combination.

[0068] In the variant having features a. and b., it is particularly advantageous that the outwardly facing cut edge is protected from corrosion since it is shielded from the cell environment by the second layer and the outer wall of the cup.

[0069] The housing cup is preferably constructed from aluminum, an aluminum alloy, or steel sheet, for example nickel-plated steel sheet.

[0070] Suitable aluminum alloys for the housing cup include Al alloys of types 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series), and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg, and AlMg. The aluminum content of these alloys is preferably greater than 99.5%.

[0071] Contact surface for conductors Particularly preferably, the energy storage cell is characterized by at least one of the features a. to d. immediately below: a. A radially inwardly curved opening edge, particularly a double layer opening edge, has an inner first surface in direct contact with the seal and a second surface facing away from the seal. b. The second surface has the shape of or includes an annular planar surface. c. The annular flat surface forms a ring having a ring width in the range of 1 mm to 5 mm, preferably in the range of 1 mm to 3 mm, and particularly preferably in the range of 1.2 mm to 1.3 mm. d. The annular flat surface forms a 90° angle with the wall of the housing cup at the central section.

[0072] It is preferable that the immediately preceding features a, b, and c, or the immediately preceding features a, b, and d, or the immediately preceding features a to d are realized in combination with each other.

[0073] In these preferred embodiments, the size and flatness of the radially inwardly bent opening edge can be optimized to facilitate welding onto a metallic electrical conductor, such as a metallic arrester bar or rail. Thus, an annular flat surface is preferably used for welding onto a metallic electrical conductor.

[0074] It is particularly advantageous if the annular flat surface is characterized by a high degree of flatness with respect to the electrical conductor to be welded. The energy storage cell according to the invention is particularly characterized by the following feature a.: a. There is a maximum height difference of 0.08 mm between the highest and lowest points of the annular flat surface.

[0075] Vice versa, the annular flat surface located on the second side of the bilayer opening edge is defined in a preferred embodiment by the fact that there is a maximum height difference of 0.08 mm between the highest and lowest points of the annular flat surface, or in other words, this degree of flatness preferably defines the boundary of the annular flat surface.

[0076] Preferably, for cells having a diameter with a width of 26 mm or less, the circular ring-shaped flat surface forms a ring with a ring width in the range of 0.5 mm to 1.5 mm, preferably 1 mm to 1.5 mm.

[0077] Preferably, for cells having a diameter with a width greater than 26 mm, the circular ring-shaped flat surface forms a ring with a ring width in the range of 0.8 mm to 3.5 mm, preferably 1 mm to 2.5 mm.

[0078] In a particularly preferred embodiment, the radially inwardly bent opening edge of the housing cup has a greater wall thickness everywhere in the area of ​​the annular flat surface, which is used for welding to the diverter, ensuring good shielding of the seal in this sensitive area.

[0079] Preferred Embodiments of the Housing Particularly preferably, the energy storage cell according to the invention is characterized by at least one of the following characteristics a. to c.: a. The center section and the closed section are separated by a recess that circumferentially surrounds the outer surface of the housing cup. b. The housing cup has the same maximum outside diameter in the center section and the closed section. c. In the region of the recess, the outer diameter of the housing cup is reduced by an amount between 4 and 12 times the wall thickness of the housing cup in this region.

[0080] It is preferable that at least the immediately preceding features a and b be realized in combination. It is particularly preferable that all three of the immediately preceding features a to c be realized in combination with one another.

[0081] Preferably, the annular seal is compressed in the closed section, the annular seal preferably being radially pressed against the circular edge of the pole cap and / or the first metal disc.

[0082] Electrical contact to the electrode As mentioned above, the present invention aims to provide an energy storage cell characterized by a high energy density, which is particularly possible when the wound electrodes are efficiently connected to the housing, as described for example in WO 2017 / 215900 A1.

[0083] Particularly preferably, the energy storage cell according to the invention is characterized by at least one of the following characteristics a. to e.: a. The anode of the electrode-separator assembly includes an anode current collector having a first longitudinal edge and a parallel second longitudinal edge. b. An anode current collector having a main area provided with a layer of negative electrode material and a free edge strip extending along a first longitudinal edge free of negative electrode material. c. The cathode of the electrode-separator assembly comprises a cathode current collector having a first longitudinal edge and a parallel second longitudinal edge. d. A cathode current collector having a main area provided with a layer of positive electrode material and a free edge strip extending along a first longitudinal edge free of electrode material. e. The anode and cathode are positioned within the electrode-separator assembly such that a first longitudinal edge of the anode current collector protrudes from a first terminal end face and a first longitudinal edge of the cathode current collector protrudes from a second terminal end face of the electrode-separator assembly.

[0084] It is preferable that all five of the immediately preceding features a. to e. be realized in combination with each other.

[0085] In a further development of this preferred embodiment, the energy storage cell according to the invention is preferably characterized by at least one of the following characteristics a. to d.: a. The energy storage cell comprises a contact sheet metal member mounted on a first longitudinal edge of the anode current collector, covering a first end face and connected to the first end face by a welded connection, or mounted on a first longitudinal edge of the cathode current collector, covering a second end face and connected to the second end face by a welded connection. b. A contact sheet metal member is connected to the first longitudinal edge of the anode current collector or the first longitudinal edge of the cathode current collector by a weld connection. c. The contact sheet metal member is connected to the bottom of the housing cup, in particular by a welded connection. d. The contact sheet metal member plate is electrically connected to the lid assembly.

[0086] It is preferable that at least the immediately preceding features a. to c. or features a., b. and d. are realized in combination.

[0087] In some particularly preferred embodiments, the energy storage cell comprises a contact sheet metal member located on a first longitudinal edge of the anode current collector and connected thereto by a welded connection, and a further contact plate located on a first longitudinal edge of the cathode current collector and connected thereto by a welded connection.

[0088] In a possible further development, the energy storage cell according to the invention is preferably characterized by the following feature a.: a. The first longitudinal edge of the anode current collector or the first longitudinal edge of the cathode current collector sits directly on the bottom of the housing cup and is connected to the bottom by a welded connection.

[0089] In this embodiment, one of the current collectors is directly connected to the housing or housing cup. In a preferred variation of this embodiment, a contact sheet metal member rests or rests on the longitudinal edge of the other current collector. This contact sheet metal member is then electrically connected to the lid assembly.

[0090] Preferred embodiments of contact sheet metal members In a particularly preferred embodiment of the invention, the contact sheet metal member electrically connected to the anode current collector is characterized by at least one of the following features a. and b.: a. The contact sheet metal members are constructed of nickel or copper or titanium, or nickel or copper or titanium alloys, or stainless steel, for example type 1.4303 or 1.4404, or type SUS304, or nickel plated copper. b. The contact sheet metal member is constructed from the same material as the anode current collector.

[0091] In a further particularly preferred embodiment of the present invention, the contact sheet metal member electrically connected to the cathode current collector is characterized by at least one of the following features a. and b.: a. The contact sheet metal member is constructed from aluminum or an aluminum alloy. b. The contact sheet metal member is constructed from the same material as the anode current collector.

[0092] Particularly preferably, the contact sheet metal member electrically connected to the anode current collector or the contact sheet metal member electrically connected to the cathode current collector is characterized by at least one of the following features a. to g.: a. The contact sheet metal member has a preferably uniform thickness in the range of 50 μm to 600 μm, preferably in the range of 150 μm to 350 μm. b. The contact sheet metal member has two opposing planar faces and extends essentially in only one dimension. c. The contact sheet metal member is a disk or plate, for example a circular plate or a polygonal plate. d. The contact sheet metal member is dimensioned to cover at least 60%, preferably at least 70%, particularly preferably at least 80% of the first terminal end face or of the second terminal end face. e. The contact sheet metal member comprises at least one aperture, particularly at least one hole and / or at least one slot. f. the contact sheet metal member has at least one bead, the bead appearing as an elongated depression on one planar surface of the contact sheet metal member and as an elongated ridge on the opposing planar surface, such contact sheet metal member preferably having a planar surface carrying the elongated ridge resting or resting on a first longitudinal edge of a corresponding current collector. g. The contact sheet metal member is welded to a first longitudinal edge of the corresponding current collector in the area of ​​a bead or in the area of ​​one of a plurality of beads, in particular via one or more weld seams or weld spots in the bead.

[0093] It is particularly preferred that the immediately preceding features a., b. and d. are realized in combination with one another. In a preferred embodiment, features a., b. and d. are realized in combination with one of features c. or e., or features f. and g. It is particularly preferred that all features a. to g. are realized in combination.

[0094] Covering as much of the end surface as possible is important for the thermal management of the energy storage cell according to the invention. The larger the coverage, the easier it is to contact the majority of the first longitudinal edge of the corresponding current collector, or even over its entire length. Thus, the heat generated in the electrode-separator assembly can be better dissipated through the contact sheet metal members.

[0095] In some embodiments, it has been found to be advantageous to pretreat the longitudinal edges of the current collector before the contact sheet metal member is placed thereon. In particular, at least one recess can be folded into the longitudinal edges, which corresponds to at least one bead or elongated ridge on the flat surface of the contact plate facing the first terminal end face.

[0096] The longitudinal edges of the current collector may be pre-formed to have a directionally shaped shape, for example, the longitudinal edges may be bent in a predetermined direction.

[0097] At least one aperture in the contact sheet metal member may be useful, for example, for impregnating the electrode-separator assembly with an electrolyte.

[0098] Preferred embodiments of the current collector and separator The anode current collector, cathode current collector, and separator of the cell according to the invention preferably have the following dimensions: Length ranging from 0.5m to 25m Width ranging from 40mm~145mm.

[0099] In the electrode-separator assembly, the ribbon-shaped anode, ribbon-shaped cathode, and ribbon-shaped separator are preferably wound in a spiral shape. To produce a ribbon-shaped electrode-separator assembly, the ribbon-shaped electrode and ribbon-shaped separator can be fed to a winding device, where they are wound in a spiral shape, preferably around a winding axis. It is generally not necessary to bond or contact the electrodes and separators at high temperatures. In some embodiments, the electrode and separator(s) are wound on a winding core, e.g., a cylindrical or hollow cylindrical core, which is seated on a winding mandrel and remains in the winding body after winding.

[0100] The shell of the wound body (wound shell) can be formed, for example, from a plastic film or an adhesive tape. The wound shell can also be formed by wrapping the separator around one or more times.

[0101] The current collectors of the energy storage cell according to the invention have the function of electrically contacting the electrochemically active components contained in the corresponding electrode material over as large an area as possible. Preferably, the current collectors are made of metal or at least have a metallized surface.

[0102] In the case of the lithium-ion cell of the present invention, the preferred metal for the anode current collector is copper or nickel, or other conductive materials, in particular alloys of copper and nickel, or nickel-coated metals. In particular, materials of the type EN CW-004A or EN CW-008A with a copper content of at least 99.9% can be used as copper alloys. Alloys of the type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable as nickel alloys. Alloys of the type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable as nickel alloys. Stainless steels, such as type 1.4303 or 1.4404 or type SUS304, can also be considered.

[0103] For lithium-ion cells, aluminum or other conductive materials, including aluminum alloys, are particularly suitable as metals for the cathode current collector.

[0104] Suitable aluminum alloys for the cathode current collector include, for example, Al alloys of types 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series), and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg, and AlMg. The aluminum content of these alloys is preferably greater than 99.5%.

[0105] Preferably, the anode current collector and / or the cathode current collector are each a ribbon-shaped metal foil having a thickness in the range of 4 μm to 30 μm.

[0106] However, in addition to foils, other strip-shaped substrates such as metallic or metallized nonwoven fabrics, or open-pore metal foams, or expanded metals can also be used as current collectors.

[0107] The current collector is preferably provided on both sides with a corresponding electrode material.

[0108] Preferably, the longitudinal edges of the separator(s) form the end faces of the electrode-separator assembly.

[0109] Preferred Embodiments of the Lid Assembly The cell according to the invention is preferably characterized by the fact that the CID function is integrated into the lid assembly, which ensures that if the pressure inside the cell becomes too high, the pressure can escape from the housing, while at the same time the electrical contact between the lid assembly and the electrode-separator assembly is interrupted.

[0110] Particularly preferably, the energy storage cell according to the invention is accordingly characterized by at least one of the characteristics a. and b. immediately below: A first metal disc of the lid assembly includes a metal membrane that bulges outwardly or bursts when a certain excess pressure occurs inside the housing. b. The first metal disk of the lid assembly, having the membrane, is in electrical contact with an electrical conductor that is electrically connected to either the anode current collector or the cathode current collector.

[0111] Preferably, features a. and b. immediately preceding are implemented in combination.

[0112] Anticipated design of the seal In addition, it is preferred to use a particularly heat-resistant plastic as the sealing material in order to limit the effects of the welding process on the seal.

[0113] In a further development of this preferred embodiment, it is accordingly preferred that the energy storage cell according to the invention is characterized by at least one of the following features a. and b.: a. The seal is made of a plastic material having a melting point above 200°C, preferably above 300°C, and particularly preferably above 300°C and below 350°C. b. The plastic material is polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfide (PPS), or polytetrafluoroethylene (PTFE), or polyamide (PA), or polyphthalamide (PPA), or polybutylene terephthalate (PBT), or perfluoroalkoxy polymer (PFA), or ethylene propylene diene rubber (EPDM).

[0114] Preferably, features a. and b. immediately preceding are implemented in combination.

[0115] Assembly of an energy storage cell according to the present invention The assembly of energy storage cells according to the invention is characterized by the following features: a. the assembly comprises at least two of the energy storage cells described above; b. The assembly comprises at least one electrical conductor made of metal connected by welding to the radially inwardly bent opening edges of the housing cups of the at least two energy storage cells.

[0116] The at least one conductor may for example be a conductor made of aluminum or an aluminum alloy, in particular a rail.

[0117] Suitable aluminum alloys for the conductor include Al alloys of types 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series), and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg, and AlMg. The aluminum content of these alloys is preferably greater than 99.5%.

[0118] In some preferred embodiments, the conductor is a metal sheet strip, for example made of aluminum, having a thickness in the range of 2-5 mm, particularly preferably 3.5 mm. [Brief description of the drawings]

[0119] Further features and advantages of the invention are apparent from the claims and from the following description of preferred embodiments of the invention taken in conjunction with the drawings. The illustrated features may be realized individually or in combination with other features. [Figure 1] 1 shows a general view (cross-section) of an energy storage cell according to the present invention; [Diagram 2] 1 illustrates an electrode-separator assembly that may be part of an energy storage cell according to the present invention, and its components. [Diagram 3] 1 shows an energy storage cell according to the present invention having two electrical conductors connected to a housing by a welded connection. [Figure 4] FIG. 4 is an enlarged view of the weld seam according to FIG. [Diagram 5] FIG. 2 is a top view of the lid of the cell according to the present invention shown in FIG. [Figure 6] 3 shows a cross-section through a lid assembly according to the invention with a seal according to the invention. [Figure 7] 7 is a photograph showing a cross section through a housing closed by a lid assembly as shown in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0120] 1 shows an energy storage cell 100 according to the invention, having an airtight and liquid-tight housing comprising a metal housing cup 101 with a terminal circular opening and a lid assembly 102 with a circular edge 102a closing the circular opening. The cell further comprises an annular seal 103 made of an electrically insulating material, which surrounds the circular edge 102a of the lid assembly 102 and electrically insulates the housing cup 101 and the lid assembly 102 from each other. The housing cup 101 comprises, in axial sequence, a bottom 101a, a central section 101b and a closed section 101c, the central section 101b being cylindrical, in which a wound shell 104c of an electrode-separator assembly 104 formed as a winding is in contact with the inner surface of the housing cup 101, and in which the closed section 101c the annular seal 103 is in pressure contact with the lid assembly 102 and the inner surface of the housing cup 101. In the closed section 101c, the housing cup 101 has an opening edge 101d defining a circular opening, which is bent radially inwardly over an edge 102a of the lid assembly 102 surrounded by the seal 103 to securely fasten the lid assembly 102, including the seal 103, within the circular opening of the housing cup 101. The radially inwardly bent opening edge 101d of the housing cup 101 has a greater wall thickness than the housing cup 101 in the central section 101b. As a result, it is possible to perform a welding process on the opening edge 101d without damaging the seal 103.

[0121] The seal has a nose 133 with an undercut. The nose is compressed with the seal and therefore deforms, forcing into the recess formed by the undercut (see FIG. 6).

[0122] The cell 100 also comprises an electrode-separator assembly 104 in the form of a cylindrical winding with an anode / separator / cathode sequence, which is shown here only diagrammatically. Only the longitudinal edge 106a of the anode current collector 106, which protrudes from the end face 104a of the electrode-separator assembly 104, and the longitudinal edge 109a of the anode current collector 109, which protrudes from the end face 104b of the electrode-separator assembly 104, are visible. The longitudinal edge 106a is welded directly, preferably over its entire length, to the housing bottom 101a. The longitudinal edge 109a is welded directly, preferably over its entire length, to a plate-like contact sheet metal member 112. The plate-like contact sheet metal member 112 is then connected to the lid assembly 102 via an electrical conductor 118, which will be described in more detail below.

[0123] The cell 100 preferably has a height in the range of 60 mm to 10 mm, and its diameter is preferably in the range of 20 mm to 50 mm. The housing cup 101 preferably has a wall thickness in the range of 0.1 mm to 0.3 mm in the central section 101b. The radially inwardly bent opening edge 101d of the housing cup 101 preferably has a thickness in the range of 1.5 to 2 times that of the housing cup 101 in the central section 101b. The opening edge comprises an inner first surface in direct contact with the seal 103 and a second surface facing away from the seal 103. The second surface comprises an annular flat surface 101p. This forms an annulus with a preferred annulus width in the range of 0.8 mm to 3 mm, forming an angle of 90° with the wall of the housing cup 101 in the central section 101b. There is a maximum height difference of 0.08 mm between the highest and lowest points of the annular flat surface.

[0124] The structure of the electrode-separator assembly 104 is shown with reference to FIG. 2. The assembly 104 comprises a ribbon-shaped anode 105 with a ribbon-shaped anode current collector 106, the anode current collector having a first longitudinal edge 106a and a second longitudinal edge parallel thereto. The anode current collector 106 is a foil made of copper or nickel. The anode current collector comprises a strip-shaped main area provided with a layer of negative electrode material 107 and a free edge strip 106b extending along its first longitudinal edge 106a and not provided with electrode material 107. Furthermore, the assembly 104 comprises a ribbon-shaped cathode 108 with a ribbon-shaped cathode current collector 109, the cathode current collector 109 having a first longitudinal edge 109a and a second longitudinal edge parallel thereto. The cathode current collector 109 is an aluminum foil. The cathode current collector comprises a strip-shaped main area provided with a layer of positive electrode material 110 and a free edge strip 109b extending along its first longitudinal edge 109a which is free of electrode material 110. Both electrodes are shown individually in an unwound state.

[0125] The anode 105 and cathode 108 are offset from one another within the electrode-separator assembly 104 such that a first longitudinal edge 106a of the anode current collector 106 protrudes from a first terminal end face 104a and a first longitudinal edge 109a of the cathode current collector 109 protrudes from a second terminal end face 104b of the electrode-separator assembly 104. The offset configuration is visible in the bottom left view, which also shows two ribbon-like separators 156 and 157, which separate the electrodes 105 and 108 from one another in the windings.

[0126] In the bottom right image, the electrode-separator assembly 104 is shown in a rolled form, as it can be used in an energy storage cell, for example according to one of Figures 1 and 3. Edges 106a and 109a protruding from end faces 104a and 104b are clearly visible. The rolled shell 104c is preferably formed from a plastic film.

[0127] Fig. 3 shows an energy storage cell 100 with a design according to Fig. 1, with two welded electrical conductors 140 and 141. Each of the electrical conductors 140 and 141 is made of metal and is connected by welding to the radially inwardly bent opening edge of the housing cup of the energy storage cell 100. Both electrical conductors 140 and 141 are welded onto the annular flat surface 101p of the opening edge. The energy storage cell 100 can be connected to adjacent cells of the same type via the electrical conductors 140 and 141.

[0128] Cell analysis showed that the seal located under flat surface 101p was not damaged by the welding process.

[0129] 4 shows the underside of the inwardly bent opening edge of the housing cup, on whose upper side an electrical conductor is welded according to the invention. Two weld seams (142a and 142b, and 142c and 142d) are arranged parallel to one another. Each weld seam is formed from several individual weld seams running parallel to one another. Such weld seams can be formed particularly efficiently using a laser.

[0130] Figure 5 shows a top view of the lid component of the energy storage cell shown in Figure 1. The annular flat surface 101p is visible, as well as the edge of the seal 103 and the pole cap 117. In the area of ​​the annular flat surface 101p, there is a maximum height difference of 0.08 mm between the highest and lowest points of the annular flat surface. The surface 101p extends to the inner edge of the inwardly bent opening edge, below which the seal 103 protrudes. The flat surface 101p adjoins the curved area 101k on the outside.

[0131] The lid assembly 102 shown in Figure 6 includes a pole cap 117, a first metal disc 113, a second metal disc 115, an annular seal 103, and an annular insulator 116. The first metal disc 113 is disposed between the pole cap 117 and the second metal disc 115. The annular insulator 116 electrically insulates the first metal disc 113 from the second metal disc 115, while the first metal disc 113 is in direct contact with the pole cap 117.

[0132] The annular seal 103 is mounted on the circular edge of a first metal disc 113 which is folded in a U-shape around the edge of the pole cap 117 .

[0133] The seal 103 comprises an outer annular segment 130 which is open at its lower end and continues into an inwardly facing collar 131 which narrows the outer annular segment 130 at this end. The collar 131 has an inner edge 131a which continues into an inner annular segment 132 which has a smaller diameter than the outer annular segment 130. The outer annular segment 130 has an inwardly facing circumferential nose 133 with an undercut 132.

[0134] The U-shaped edge of the first metal disc 113 , which is folded around the edge of the pole cap 117 , seats on a collar 131 and is held in place by a nose 133 .

[0135] The cross-sectional photograph according to Fig. 7 shows the closed section of the lid assembly according to Fig. 6 in the assembled state. The edges of the housing cup 101 are bent inwards to fix the lid assembly to the pole cap 117, the first metal disk 113 and the second metal disk 115 and the annular insulator 116. The seal 103 is compressed in the closed section. It is preferably pressed from below and above and radially against the circular U-shaped edge of the first metal disk 113. The collar 131 and the inner annular segment 132 are also clearly visible. The annular segment 132 is pulled down and shields the recess 111 towards the inner surface. The recess formed by the undercut 132 is also visible here, which is partially filled by the nose 133, which is deformed as a result of the compression and bending of the seal, which is clearly visible here.

Claims

1. 1. An annular seal (103) for a lid assembly (102) of an energy storage cell (100), comprising: a. the annular seal comprises an outer annular segment (130); b. the outer annular segment (130) continues at one of its two ends into an inwardly facing collar (131) which narrows the outer annular segment (130) at said one end; and c. said collar (131) having an inner edge (131a) continuing into an inner annular segment (132); whereby d. said outer annular segment (130) having an inwardly directed circumferential nose (133) with an undercut (132); The annular seal (103).

2. Additional features include: a. the outer annular segment (130) is hollow cylindrical; b. the inner annular segment (132) is hollow cylindrical or conically tapered; c. said undercut (132) is designed as an annular groove-like recess; d. said nose (133) being formed as an annular ridge on the inner surface of said outer annular segment (130); e. said nose (133) with said undercut (132) divides said outer annular segment (130) into a central portion segment (130a) and a terminal portion segment (130b); f. said collar (131) having an annular ridge (134) on an inner surface of said collar; The annular seal of claim 1 , comprising at least one of:

3. A lid assembly (102) for an energy storage cell (100), comprising: a. the lid assembly comprises a pole cap (117) having a circular edge; b. the lid assembly comprises a first metal disk (113) having a circular edge; c. the lid assembly comprises a second metal disc (115) having a circular edge; d. said lid assembly comprising an annular seal (103); and e. the lid assembly comprises an annular insulator (116); whereby f. the first metal disc (113) is disposed between the pole cap (117) and the second metal disc (115); g. the annular insulator (116) electrically insulates the first metal disk (113) and the second metal disk (115) from each other; h. said first metal disk (113) is in direct contact with said pole cap (117); and i. the annular seal (103) is mounted on the circular edge of the pole cap (117) and / or on the circular edge of the first metal disc (113); having j. the seal is formed in accordance with claim 1 or 2; k. the circular edge of the pole cap (117) and / or the circular edge of the first metal disc (113) rests on a collar (131); and l. held in place by nose (133); A lid assembly (102) comprising:

4. Additional features include: a. said annular seal (103) is mounted on said circular edge of said first metal disc (113); b. the annular seal (103) is mounted on the circular edge of the pole cap (117); c. the annular seal (103) is mounted on the circular edge of the pole cap (117) and on the circular edge of the first metal disc (113); d. the circular edge of the first metal disc (113) is folded in a U-shape around the circular edge of the pole cap (117); The lid assembly (102) of claim 3, further comprising one of:

5. An energy storage cell (100) having the following features: a. the energy storage cell comprises an electrode-separator assembly (104) having an anode (105) / separator (116) / cathode (108) sequence; b. the electrode-separator assembly (104) is in the form of a cylindrical winding having a first terminal end face (104a) and a second terminal end face (104b) with a winding shell (104c) located therebetween; c. the energy storage cell comprises an air-tight and liquid-tight sealed housing comprising a metal housing cup (101) having a terminal circular opening and a lid assembly (102) having a circular edge (102a) closing said circular opening; d. the lid assembly (102) is formed in accordance with claim 1 or 2; e. said housing cup (101) comprises, in axial sequence, a bottom section (101a), a middle section (101b) and a closing section (101c); the central section (101b) is cylindrical, and in the central section (101b) the wound shell (104c) of the electrode-separator assembly (104) contacts the inner surface of the housing cup (101); In the closed section (101c), the annular seal (103) of the lid assembly is in pressure contact with an edge of a pole cap (117) and / or an edge of a first metal disk (113) and the inner surface of the housing cup (101); and f) the housing cup (101) has an opening edge (101d) at the closure section (101c) that defines the terminal circular opening, the opening edge being bent radially inwardly over the edge of the pole cap (117) and / or the first metal disk (113) surrounded by the seal (103) to securely fasten the lid assembly (102), including the seal (103), within the circular opening of the housing cup (101); An energy storage cell (100) having

6. Additional features include: a. the radially inwardly turned opening edge (101d) of the housing cup (101) has a greater wall thickness than the housing cup (101) in the central section (101b); The energy storage cell (100) of claim 5, comprising:

7. Additional features include: a. said central section (101b) and said closed section (101c) are separated by a recess (111) circumferentially surrounding the outer surface of said housing cup (101); b. said housing cup (101) has the same maximum outer diameter in said central section (101b) and in said closed section (101c); c) in the region of the recess (111), the outer diameter of the housing cup (101) is reduced by an amount between 4 and 12 times the wall thickness of the housing cup (101) in said region; 7. The energy storage cell according to claim 5 or 6, comprising at least one of:

8. Additional features include: a. the anode (105) of the electrode-separator assembly (104) comprises an anode current collector (106) having a first longitudinal edge (106a) and a second longitudinal edge parallel thereto; b. said anode current collector (106) comprising a main area provided with a layer of negative electrode material (107) and a free edge strip extending along said first longitudinal edge (106a) and free of said negative electrode material; c. the cathode (108) of the electrode-separator assembly (104) comprises a cathode current collector (109) having a first longitudinal edge (109a) and a second longitudinal edge parallel thereto; d. said cathode current collector (109) comprising a main area provided with a layer of positive electrode material (110) and a free edge strip extending along said first longitudinal edge (109a) and free of said electrode material (110); e. the anode (105) and the cathode (108) are disposed within the electrode-separator assembly (104) such that the first longitudinal edge (106a) of the anode current collector (106) projects from the first terminal end face (104a) and the first longitudinal edge (109a) of the cathode current collector (108) projects from the second terminal end face (104b) of the electrode-separator assembly (104); The energy storage cell according to any one of claims 5 to 7, comprising at least one of:

9. Additional features include: the energy storage cell comprises a contact sheet metal member (112) mounted on the first longitudinal edge (109a) of the anode current collector, covering the first terminal end face and connected to the first terminal end face by a welded connection, or mounted on the first longitudinal edge (109a) of the cathode current collector (109), covering the second terminal end face (104b) and connected to the second terminal end face by a welded connection; b. the contact sheet metal member (112) is connected to the first longitudinal edge (109a) of the anode current collector or the first longitudinal edge (109a) of the cathode current collector (109) by a welded connection; c) said contact sheet metal piece (112) is connected to said bottom of said housing cup, in particular by a welded connection; d. said contact sheet metal member (112) is electrically connected to said lid assembly; 9. The energy storage cell of claim 8, comprising at least one of:

10. Additional features include: a. the first longitudinal edge (106a) of the anode current collector (106) or the first longitudinal edge of the cathode current collector sits directly on the bottom (101a) of the housing cup (101) and is connected to the bottom by a welded connection; 10. The energy storage cell according to claim 8 or 9, comprising at least one of:

11. Additional features include: a. the disk (113) of the lid assembly (102) includes a metal membrane (114) that bulges outwardly or bursts when a certain excess pressure occurs within the housing; b. the disk (113) carrying the membrane (114) is in electrical contact with an electrical conductor (118) that is electrically connected to the anode current collector or the cathode current collector (109); The energy storage cell according to any one of claims 5 to 10, comprising at least one of:

12. Additional features include: a. said seal (103) is made from a plastic material having a melting point above 200°C, preferably above 300°C; b. the plastic material is polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfide (PPS), or polytetrafluoroethylene (PTFE); The seal, lid assembly, or energy storage cell of any one of claims 1 to 11, comprising at least one of:

13. 1. An assembly of energy storage cells, comprising: a. the assembly comprises at least two energy storage cells (100) according to any one of claims 5 to 12; b) the assembly comprises electrical conductors made of metal connected by welded connections to the radially inwardly bent open edges of the housing cups of the at least two energy storage cells; 11. An assembly of energy storage cells comprising:

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