ENERGY STORAGE CELL, ARRAY OF ENERGY STORAGE CELLS, AND MANUFACTURING PROCESS - Patent application

Abstract

The energy storage cell (100) includes an electrode-separator assembly (104) in the form of a cylindrical winding having first and second end faces (104a, 104b) and a winding shell (104c) located therebetween. The assembly (104) has the following order: anode (105) / separator (156) / cathode (108). The cell further includes an air-tight and liquid-tight housing including a metallic housing cup (101) having a terminal circular opening and a lid assembly (102) having a circular edge (102a) closing the circular opening, as well as an annular seal (103) made of an electrically insulating material that seals 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) includes, in axial order, a bottom (101a), a central section (101b), and a closed section (101c), with the central section (101b) being cylindrical, and in the central section (101b), the winding shell (104c) of the electrode-separator assembly (104) is in contact with the inside of the housing cup (101), and in the closed section (101c), the annular seal (103) is in pressing contact with the lid assembly (102) and the inside of the housing cup (101). In the closed section (101c), the housing cup (101) has an opening edge (101d) defining a circular opening, the opening edge (101d) bent radially inwardly above the edge (102a) of the lid assembly (102) and sealed by a seal (103), and the opening edge (101d) secures the lid assembly (102) including the seal (103) at the circular opening of the housing cup (101). It is proposed that the wall thickness of the opening edge (101d) bent radially inwardly of the housing cup (101) is greater than the wall thickness of the housing cup (101) in the central section (101b). Furthermore, an array of such energy storage cells and a method for manufacturing such an array are proposed.

Description

[Technical field]

[0001] Application areas and prior art The invention described below relates to energy storage cells, arrays of energy storage cells, and methods of manufacture. [Background technology]

[0002] Electrochemical energy storage elements are capable of converting stored chemical energy into electrical energy through oxidation-reduction reactions. The simplest form of an electrochemical energy storage element is the electrochemical cell. An electrochemical cell comprises a positive electrode and a negative electrode separated from each other by a separator. During discharge, electrons are released at the negative electrode as a result of an oxidation process. This results in an electron flow that can be extracted by an external electrical consumer, for which the electrochemical cell serves as an energy source. At the same time, an ion flow corresponding to the electrode reactions occurs within the cell. This ion flow crosses the separator and is made possible by an ion-conducting electrolyte.

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

[0004] Secondary lithium-ion cells are currently used as energy storage elements in many applications, since they can supply high currents and are characterized by a relatively high energy density. They are based on the use of lithium, which in the form of ions can be transported back and forth 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 not only electrochemically active components, but also electrochemically inactive components.

[0005] In principle, any material capable of absorbing and releasing lithium ions can be used as an electrochemically active component (active material) in a secondary lithium-ion cell. 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 include flat and / or strip-shaped current collectors, e.g., metallic foils, that serve 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, and the current collector for the positive electrode (cathode current collector) can be made, for example, of aluminum. In addition, the electrodes can include an electrode binder (e.g., polyvinylidene fluoride (PVDF) or another polymer, e.g., carboxymethylcellulose), additives that improve conductivity, and other additives as electrochemically inactive components. The electrode binder ensures the mechanical stability of the electrode and in many cases also the adhesion of the active materials to the current collector.

[0007] As an electrolyte, lithium-ion cells generally contain a solution of a lithium salt, such as lithium hexafluorophosphate (LiPF6), in an organic solvent (e.g., ethers and esters of carbonic acid).

[0008] The composite electrode is combined with one or more separators to form an assembly when manufacturing a lithium-ion cell. For this purpose, the electrode and separator can be joined to each other under pressure, possibly also by lamination or bonding. Very often the electrodes and separators are combined in a winding machine. The basic functionality of the cell can then be established by impregnating the assembly with an electrolyte.

[0009] In many embodiments, the assembly is produced in the form of a winding or processed into a winding. The assembly generally includes the order positive electrode / separator / negative electrode. The assembly is often produced as a so-called bicell with the possible orders negative electrode / separator / positive electrode / separator / negative electrode or positive electrode / separator / negative electrode / separator / positive electrode.

[0010] Other applications with high energy requirements, such as applications in the automotive sector, electric bicycle applications or applications in tools, require lithium-ion cells with as high an energy density as possible that are also able to withstand high currents during charging and discharging.

[0011] Cells for the aforementioned applications are often designed as cylindrical round cells, for example with a form factor of 21x70 (diameter*height in mm). This type of cell always includes an assembly in the form of a winding. Modern lithium-ion cells of this form factor are already capable of achieving energy densities of up to 270Wh / kg. However, this energy density is considered to be only an intermediate step. The market already requires cells with even higher energy densities.

[0012] In WO 2017 / 215900 A1, a cylindrical round cell is described, in which the electrode-separator assembly is in the form of a winding and contains ribbon-shaped electrodes. Each of the electrodes has a current collector filled with electrode material. The oppositely polarized electrodes are arranged in an electrode-separator assembly in a staggered manner, so that the longitudinal edge of the current collector of the positive electrode protrudes from the winding on one side and the longitudinal edge of the current collector of the negative electrode protrudes from the winding on the other side. For the electrical contact of the current collectors, the cell has a contact plate placed on one end face of the winding and welded to one longitudinal edge of the current collector. This makes it possible to electrically contact the current collectors, and therefore also the associated electrodes, over their entire length. This significantly reduces the internal resistance in the above-mentioned cell. As a result, large current generation can be absorbed much better and heat can also be dissipated better from the winding.

[0013] Cylindrical round cells such as those described 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 desirable to contact the cells only on one of their end faces in order to tap 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 end faces.

[0014] The housing of a cylindrical round cell generally includes a housing cup that contains the wound electrode-separator assembly and a lid assembly that closes the opening of the housing cup. A seal is disposed between the lid assembly and the housing cup, which not only serves to seal the cell housing on the one hand, but also has the function of electrically insulating the lid assembly and the housing cup from each other. The seal is usually attached to the edge of the lid assembly. To close a round cell, the opening edge of the housing cup is generally bent radially inwardly above the edge of the lid assembly on which the seal is attached (crimped), so that the lid assembly including the seal is positively fixed in the opening of the housing cup.

[0015] An example of such a round cell is shown in FIG. 3 of EP 3188280 A1. To incorporate the illustrated cell into a cell array, it is relatively easy to weld the lid assembly (reference number 270) to a suitable conductor rail. The protruding electrode cap (reference number 217) provides the best conditions for this. However, the electrical connection of the housing cup is more difficult. If one wishes to contact the housing cup on the same end face where 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 the seal in direct contact with the bent opening edge can easily be damaged by welding, since it is subject to the thermal stresses that usually occur during welding. Therefore, a round cell with a conventional cell housing as illustrated in FIG. 3 of EP 3188280 A1 is not intended for welding conductors to the opening edge.

[0016] EP 3537496 A1 and JP 2012-174523 A disclose lithium-ion cells in which a lid assembly is inserted into an opening in a housing cup and folds back the edge of the housing cup in a U-shape at the end to protect it from corrosion.

[0017] JP 2007-234305 A discloses a cell housing for an alkaline cell that includes a housing cup with a thickened and reinforced edge, where the edge of the cup is thicker than the rest of the cup to prevent the edge from breaking during mechanical closure of the cell by crimping. Summary of the Invention [Problem to be solved by the invention]

[0018] Objectives and Solutions It is an object of the present invention to provide an energy storage cell which is characterized by a high energy density and which can be efficiently integrated into a cell array, and furthermore, which is characterized by an improved safety. [Means for solving the problem]

[0019] This object is achieved by an energy storage cell having the features of claim 1. An array of energy storage cells having the features of claim 13 and a manufacturing method having the features of claim 14 are also objects of the invention. Preferred embodiments of the invention are defined in the dependent claims 2 to 12.

[0020] Energy storage cell according to the present invention An energy storage cell according to the invention always has the following characteristics a. to f. a. The cell includes an electrode-separator assembly having the following order: anode / separator / cathode. b. The electrode-separator assembly is in the form of a cylindrical winding having a first end surface and a second end surface with a winding shell therebetween. c. The cell includes an air-tight and liquid-tight housing including a metal housing cup having a circular opening at one end and a lid assembly having a circular edge closing the circular opening. d. The cell includes an annular seal made of an electrically insulating material that seals the circular edge of the lid assembly and electrically insulates the housing cup and the lid assembly from each other. e. the housing cup includes, in axial order, a bottom section, a center section, and a closure section; the central section is cylindrical, and in the central section the winding shell of the electrode-separator assembly is in contact with the inside of the housing cup; In the closed section, the annular seal is in pressing contact with the lid assembly and the inside of the housing cup. f. In the closed section, the housing cup has an opening edge defining a circular opening, the opening edge bent radially inwardly above the edge of the lid assembly and sealed by a seal, and the opening edge secures the lid assembly including the seal at the circular opening of the housing cup. The energy storage cell according to the invention comprises in particular g. The wall thickness of the housing cup at the radially inwardly curved opening edge is greater than the wall thickness of the housing cup at the central section.

[0021] This measure ensures that the conductor rail can be welded to the radially inwardly bent opening edge of the housing cup without sealing problems. The increased thickness of the opening edge ensures an improved distribution of the heat generated during welding, thus avoiding local overheating and melting of the seal.

[0022] Preferably, the electrode-separator assembly is in direct contact with the inside of the housing cup, particularly preferably in direct contact with the inside of the housing cup, but in some embodiments the inside may be electrically insulated, for example with a foil, in which case the electrode-separator assembly is in contact with the inner wall via the foil.

[0023] The bottom of the housing cup is preferably circular. The housing cup is usually formed by deep drawing. However, it is also possible to form the cup by welding the bottom into a tubular half-piece.

[0024] The energy storage cell according to the invention is preferably a cylindrical round cell. Accordingly, the electrode-separator assembly preferably comprises an anode and a cathode in the form of a ribbon. In addition, it preferably comprises one ribbon-shaped separator or two ribbon-shaped separators. The end faces are preferably delimited by circular edges.

[0025] The height of the energy storage cell according to the invention, when designed as a cylindrical round cell, is preferably in the range of 50 mm to 150 mm. Its 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.

[0026] Lithium-ion cell embodiment In a particularly preferred embodiment of the invention, the energy storage cell according to the invention 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.

[0027] Carbon-based particles, such as graphite carbon or non-graphite carbon materials capable of intercalating lithium, are preferably also usable as the active material in the negative electrode even in particulate form. Alternatively, or additionally, lithium titanate (Li4Ti5O 12 ) or a derivative thereof may also preferably be included in the negative electrode even in particulate form. Further, the negative electrode can contain at least one material from the group including silicon, aluminum, tin, antimony, or a compound or alloy of these materials capable of reversibly storing and releasing lithium, for example, silicon oxide (particularly, SiO x , where 0 < x < 2), optionally in combination with a carbon-based active material, as the active material. Tin, aluminum, antimony, and silicon can form an intermetallic phase with lithium. The ability to absorb lithium far exceeds, especially in the case of silicon, the ability of graphite or comparable materials by several times. A mixture of silicon and a carbon-based storage material is often used. A thin anode made of metallic lithium is also suitable.

[0028] Active materials suitable 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. Their derivatives, for example, the chemical formula Li 1.11 (Ni 0.40 Mn 0.39 Co 0.16 Al 0.05 ) 0.89Lithium Nickel Manganese Cobalt Aluminum Oxide (NMCA) with O2, or Li 1+x MO compounds and / or mixtures of the aforementioned materials may also be used.The active material of the cathode is also preferably used in particulate form.

[0029] In addition, the electrodes of the energy storage cell according to the invention preferably contain an electrode binder and / or additives that increase 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), polyacrylic acid (lithium), styrene-butadiene rubber or carboxymethyl cellulose, or are mixtures of different binders. Common conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes and metal powders.

[0030] The energy storage cell according to the invention preferably comprises, in the case of a lithium-ion cell, an electrolyte, in particular an electrolyte based on at least one lithium salt present dissolved in an organic solvent (for example a mixture of organic carbonates or a cyclic ether such as THF or a nitrile), such as lithium hexafluorophosphate (LiPF6). Other lithium salts can be used, such as lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(oxalato)borate (LiBOB).

[0031] The nominal capacity of the lithium-ion based energy storage cells according to the invention, designed as cylindrical round cells, is preferably up to 15000 mAh. In the case of a 21×70 form factor, the energy storage cells in one embodiment as lithium-ion cells preferably have a nominal capacity in the range of 1500 mAh to 7000 mAh, particularly preferably in the range of 3000 to 5500 mAh. In the case of a 18×65 form factor, the cells in one embodiment as lithium-ion cells preferably have a nominal capacity in the range of 1000 mAh to 5000 mAh, particularly preferably in the range of 2000 to 4000 mAh.

[0032] In the European Union, information on the nominal capacity of a manufacturer's secondary batteries is strictly regulated. For example, information on the nominal capacity of secondary nickel-cadmium batteries must be based on measurements in accordance with the IEC / EN61951-1 and IEC / EN60622 standards, information on the nominal capacity of secondary nickel-metal hydride batteries must be based on measurements in accordance with the IEC / EN61951-2 standard, information on the nominal capacity of secondary lithium batteries must be based on measurements in accordance with the IEC / EN61960 standard, and information on the nominal capacity of secondary lead-acid batteries must be based on measurements in accordance with the IEC / EN61056-1 standard. All information on nominal capacity in the present application is preferably also based on these standards.

[0033] Sodium Ion-Based Embodiments In further embodiments, the energy storage cells according to the invention may also be sodium-ion, potassium-ion, calcium-ion, magnesium-ion or aluminum-ion cells. Among these variants, energy storage cells having sodium-ion cell chemistry are particularly preferred according to the invention.

[0034] A sodium-ion based energy storage cell according to the present invention preferably comprises an electrolyte comprising at least one of the following solvents and at least one of the following conductive salts:

[0035] Organic carbonates, ethers, nitriles and mixtures thereof are particularly suitable as solvents. -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 (THE), 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). Trimethyl phosphate (TMP) and tris(2,2,2-trifluoroethyl) phosphate (TFP) can also be used.

[0036] Suitable conductive salts are as follows: 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.

[0037] In a preferred embodiment, additives can be added to the electrolyte. Examples of suitable additives, especially for stabilization, are:

[0038] 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).

[0039] The negative electrode material of the sodium-ion based energy storage cell preferably comprises at least one of the following materials: Carbon, in particular hard carbon (pure carbon or doped with nitrogen and / or phosphorus) or soft carbon, or graphene-based materials (N-doped), carbon nanotubes, graphite -Phosphorus or sulfur (conversion anode) -Polyanions: Na2Ti3O7, Na3Ti2(PO4)3, TiP2O7, TiNb2O7, Na-Ti-(PO4)3, Na-V-(PO4)3 -Prussian Blue: Low Na variant (for systems using aqueous electrolytes) -Transition metal oxides: V2O5, MnO2, TiO2, Nb2O5, Fe2O3, Na2Ti3O7, NaCrTiO4, Na4Ti5O 12 - MXenes where M = Ti, V, Cr, Mo or Nb, A = Al, Si and Ga and X = C and / or N, e.g. TiC 32 -Organic: e.g., Na-terephthalate (Na2C8H2O4) Alternatively, it is also possible to use a Na metal anode on the anode side.

[0040] The positive electrode material of the sodium-ion based energy storage cell according to the invention comprises, for example, 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

[0041] In addition, the electrodes of the energy storage cell according to the invention preferably contain an electrode binder and / or additives that increase electrical conductivity. The active material is preferably embedded in the matrix of the electrode binder, whereby the active material is preferably used in the form of fine particles, 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), polyacrylic acid (sodium), styrene-butadiene rubber, alginate (sodium) or carboxymethylcellulose, or mixtures of different binders. Common conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes and metal powders.

[0042] In energy storage cells based on sodium-ion technology, it is particularly preferred that both the anode and cathode current collectors are made of aluminum or an aluminum alloy. The housing and contact plates, as well as any other electrical conductors within the housing, can be made of aluminum or an aluminum alloy.

[0043] Preferred wall thickness of the housing cup The energy storage cell according to the invention is particularly preferably characterized by at least one of the features a. to c. described immediately below: a. The radially inwardly turned open edge of the housing cup is in the range of 1.5 to 2 times thicker than the housing cup in the central section. b. The housing cup has a wall thickness in the central section in the range of 0.1 mm to 0.4 mm, preferably in the range of 0.25 mm to 0.3 mm. c. The radially inwardly turned 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.

[0044] It is preferred that the immediately preceding features a. and b. as well as a. and c. are realized in combination. It is particularly preferred that all three immediately preceding features a. to c. are realized in combination. The bottom of the housing cup preferably has a thickness in the range of 0.2 mm to 2 mm.

[0045] Preferred embodiments for larger wall thickness opening edges To achieve a larger wall thickness of the opening edge, the starting material can already be used in the production of the housing cup and thickened in the area where the opening edge is to be formed. However, it is particularly preferable to reinforce the opening edge by appropriately bending or folding back the wall of the housing cup to achieve the larger wall thickness.

[0046] Thus, the energy storage cell according to the invention is preferably characterized by at least one of the features a. to c. described immediately below: a. The opening edge of the housing cup that is bent radially inward is double layered. b. The double layered edge is formed by folding or bending the edge of the opening. c. The double-layered opening edge has a U-shaped cross section, in particular resulting from the folding or bending according to feature b. immediately above.

[0047] It is preferred that the immediately preceding features a. and b., and particularly preferred that all three immediately preceding features a. to c., are realized in combination.

[0048] The folding or bending to form the double layered edge can be done either outward or inward, resulting in different variations of the double layered edge.

[0049] The energy storage cell according to the invention is particularly preferably characterized by at least one of the features a. to c. described immediately below: a. The double layered opening edge has a first layer in direct contact with the seal that seals the edge of the lid assembly, and a second layer parallel to the first layer on the side of the first layer facing away from the seal. b. The first layer is bounded by a radially outwardly facing cut edge. c. The second layer is bounded by a radially outwardly facing cut edge.

[0050] It is preferred that the immediately preceding features a. and b., or the immediately preceding features b. and c., are implemented in combination.

[0051] In the variant having features a. and b., it is particularly advantageous that the cut edges facing outwards are protected from corrosion, since they are shielded from the surroundings of the cell by the second layer and the outer wall of the cup.

[0052] The housing cup is preferably made of aluminium, an aluminium alloy or sheet steel, for example nickel plated sheet steel.

[0053] Suitable aluminum alloys for the housing cup are, for example, Al alloys of type 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%.

[0054] Contact surface for conductors The energy storage cell according to the invention is particularly preferably characterized by at least one of the features a. to d. described immediately below: a. A radially inwardly curved opening edge, particularly a double-layered opening edge, includes a first, inner, surface that is in direct contact with the seal and a second surface that faces away from the seal. b. the second surface is or includes a toric flat surface. c. The annular flat surface forms a ring having a 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.

[0055] It is preferred 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, be implemented in combination.

[0056] In these preferred embodiments, the surfaces of the opening edges that are bent radially inwards are particularly enlarged and flat, facilitating welding to a metal conductor, for example a metal arrester bar, and therefore the annular flat surface is preferably used for welding to a metal conductor.

[0057] It is particularly advantageous if the toric surface of the conductor to be welded is characterized by a high degree of flatness. The energy storage cell according to the invention is characterized in particular by the feature a. described immediately below: a. There is a maximum height difference of 0.08 mm between the highest and lowest points of the annular flat surface.

[0058] Thus, the toric plane located on the second side of the double layered opening edge is preferably defined by a maximum height difference between the highest and lowest points of the toric flat surface of 0.08 mm, or in other words, this flatness preferably defines the toric surface.

[0059] For cells with a diameter of 26 mm or less in width, the annular flat surface preferably 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.

[0060] For cells with a diameter greater than 26 mm in width, the toric plane preferably 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.

[0061] In a particularly preferred embodiment, the radially inwardly turned opening edge of the housing cup has an increased wall thickness over the entire area of ​​the toroidal flat surface, which is used for welding to the conductor, thereby ensuring the shielding of the seal in this sensitive area.

[0062] Preferred Embodiments of the Housing The energy storage cell according to the invention is particularly preferably characterized by at least one of the features a. to c. described immediately below: a. The central section and the closed section are separated by a recess that circumferentially surrounds the outside 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 4 to 12 times the wall thickness of the housing cup in this region.

[0063] It is preferred that at least the immediately preceding features a. and b. are implemented in combination. It is particularly preferred that all three immediately preceding features a. to c. are implemented in combination.

[0064] Preferred embodiments of the sealing area The energy storage cell according to the invention is particularly preferably characterized by at least one of the features a. to c. described immediately below: a. The annular seal includes a first annular segment disposed between the recess and a surface of the lid assembly facing the inside of the housing, the first annular segment contacting, preferably in pressing contact, with the wall sections defining the recess and the surface of the lid assembly. b. The annular seal includes a second annular segment disposed between the opening edge, which is bent radially inward, and a surface of the lid assembly facing away from the inside of the housing, the second annular segment being pressed, preferably perpendicularly, against this surface of the lid assembly by the opening edge. c. The annular seal includes a third annular segment located between the housing cup and the edge of the lid assembly, the third annular segment being pressed against the edge of the lid assembly by the wall of the housing cup within the closure zone.

[0065] It is preferred that all three immediately preceding features a. to c. be realised in combination.

[0066] The annular seal is preferably compressed within the closure section and is preferably pressed against the edge of the lid assembly on several sides.

[0067] Electrical contact of electrodes As mentioned at the outset, the present invention aims to provide an energy storage cell that is characterized by a high energy density, which is particularly possible if the electrode windings are efficiently connected to the housing, as described, for example, in WO 2017 / 215900 A1.

[0068] The energy storage cell according to the invention is particularly preferably characterized by at least one of the features a. to e. described immediately below: 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. The anode current collector includes a main area filled with a layer of negative electrode material and a free edge strip extending along a first longitudinal edge thereof that is not filled with negative electrode material. c. The cathode of the electrode-separator assembly includes a cathode current collector having a first longitudinal edge and a second longitudinal edge parallel thereto. d. The cathode current collector includes a main area filled with a layer of positive electrode material and a free edge strip extending along a first longitudinal edge thereof that is not filled with 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 projects from a first end face and such that a first longitudinal edge of the cathode current collector projects from a second end face of the electrode-separator assembly. All five immediately preceding features a. to e. are preferably realized in combination.

[0069] In a possible development of this preferred embodiment, the energy storage cell according to the invention is preferably characterized by at least one of the following features a. to d., which are mentioned immediately below: a. The energy storage cell includes a contact sheet metal member positioned on a first longitudinal edge of the anode current collector, covering a first end face and welded to the first longitudinal edge of the anode current collector, or a contact sheet metal member positioned on a first longitudinal edge of the cathode current collector, covering a second end face and welded to the first longitudinal edge of the cathode current collector. b. A contact sheet metal member is welded to a first longitudinal edge of the anode current collector or a first longitudinal edge of the cathode current collector. c. The contact sheet metal member is connected to the bottom of the housing cup, particularly by welding. d. The contact sheet metal member is part of the lid assembly or is electrically connected directly or indirectly to the lid assembly.

[0070] It is preferred that at least the immediately preceding features a. to c., or features a., b. and d., are realised in combination.

[0071] In some particularly preferred embodiments, the energy storage cell includes a contact sheet metal member positioned on and welded to a first longitudinal edge of the anode current collector, and a further contact sheet metal member positioned on and welded to a first longitudinal edge of the cathode current collector.

[0072] In a possible further development, the energy storage cell according to the invention is preferably characterized by the following feature a., which is mentioned immediately below: a. The first longitudinal edge of the anode current collector or the first longitudinal edge of the cathode current collector is placed directly on the bottom of the housing cup and connected thereto by welding.

[0073] In this embodiment, one of the current collectors is therefore directly connected to the housing or to the housing cup. In a preferred further development of this embodiment, a contact sheet metal member is placed on the longitudinal edge of the other current collector. This is then electrically connected to the lid assembly.

[0074] 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 features a. and b. described immediately below: a. The contact sheet metal members consist of nickel or copper or titanium, or a nickel or copper or titanium alloy, or stainless steel, for example of type 1.4303 or 1.4404 or type SUS304, or nickel-plated copper. b. The contact sheet metal member is made of the same material as the anode current collector.

[0075] In a further particularly preferred embodiment of the invention, the contact sheet metal member electrically connected to the cathode current collector is characterized by at least one of the features a. and b. described immediately below: a. The contact sheet metal member is made of aluminum or an aluminum alloy. b. The contact sheet metal member is made of the same material as the anode current collector.

[0076] It is particularly preferred that the contact sheet metal member electrically connected to the anode current collector and / or the contact sheet metal member electrically connected to the cathode current collector is characterized by at least one of the features a. to g. described immediately below: a. The contact sheet metal members have 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 polygonal plate. d. The dimensions of the contacting sheet metal members are such that they cover at least 60%, preferably at least 70%, particularly preferably at least 80% of the first end surface or the second end surface. e. The contact sheet metal member has at least one aperture, in particular at least one hole and / or at least one slot. f. the contact sheet metal members have at least one bead which appears as an elongated depression on one flat surface of the contact sheet metal members and as an elongated ridge on the opposing flat surface of the contact sheet metal members, the flat surface having the elongated ridge resting against the first longitudinal edge of the respective current collector. g. The contact sheet metal element is welded to the first longitudinal edge of the respective current collector in the area of ​​the bead, in particular via one or more weld seams arranged in the bead.

[0077] 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 with one another.

[0078] Covering as many of the end faces as possible is important for the thermal management of the energy storage cell. The greater the coverage, the easier it is to contact the first longitudinal edge of each current collector over its entire length. Thus, the heat generated in the electrode-separator assembly can be better dissipated through the contact plate.

[0079] In some embodiments, it has been found to be advantageous to pretreat the longitudinal edges of the current collector before placing the contact sheet metal member thereon. In particular, at least one recess can be folded back into the longitudinal edge corresponding to at least one bead or elongated ridge on the flat surface of the contact sheet metal member facing the first end face.

[0080] The longitudinal edges of the current collector may also be pre-treated to provide orientation, for example by bending them in a defined direction.

[0081] At least one aperture in the contact sheet metal member may be useful, for example, to impregnate the electrode-separator assembly with electrolyte.

[0082] Preferred embodiments of the current collector and separator The anode current collector, cathode current collector and separator(s) of a cell according to the invention preferably have the following dimensions: - Lengths ranging from 0.5m to 25m - Widths ranging from 40mm to 145mm

[0083] The ribbon anode, ribbon cathode, and ribbon separator(s) are preferably spirally wound in an electrode-separator assembly formed as a winding. To produce the electrode-separator assembly, the ribbon electrode and ribbon separator(s) are preferably fed to a winding machine where they are spirally wound about a winding axis. Bonding or contacting the electrodes and separators at high temperatures is not typically required. In some embodiments, the electrodes and the separator(s) are wound on a cylindrical or hollow cylindrical winding core that is placed on a winding mandrel and remains on the winding after winding.

[0084] The winding shell can be formed, for example, by a plastic film or an adhesive tape. It is also possible for the winding shell to be formed by one or more separator windings.

[0085] 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 respective electrode materials over as large an area as possible. The current collectors preferably consist of a metal or are metallized at least on the surface.

[0086] For the energy storage cell designed as a lithium-ion cell according to the invention, suitable metals for the anode current collector include copper or nickel or other conductive materials, in particular copper and nickel alloys or metals coated with nickel. In particular, materials of 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 type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable as nickel alloys. Alloys of type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable as nickel alloys. Stainless steels, for example type 1.4303 or 1.4404 or type SUS304, can also be considered.

[0087] For energy storage cells designed as lithium-ion cells according to the present invention, aluminum or other conductive materials, including aluminum alloys, are particularly suitable as metals for the cathode current collector.

[0088] Suitable aluminum alloys for the cathode current collector are, for example, Al alloys of type 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%.

[0089] The anode current collector and / or the cathode current collector are each preferably a ribbon-shaped metal foil having a thickness in the range of 4 μm to 30 μm.

[0090] However, in addition to foils, other strip-like substrates such as metallic or metallized nonwoven fabrics, or open-pore metallic foams, or expanded metals, can also be used as current collectors.

[0091] The current collector is preferably filled on both sides with the respective electrode materials.

[0092] The longitudinal edges of one or more of the separators suitably form the end faces of an electrode-separator assembly formed as a winding.

[0093] Possible embodiments of the lid assembly The cell according to the invention preferably features a CID function 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 breaking the electrical contact between the lid assembly and the electrode-separator.

[0094] It is therefore particularly preferred that the energy storage cell according to the invention is characterized by at least one of the features a. to c. described immediately below: The lid assembly includes a metal disk with a metal membrane that expands or bursts outward in the event of excessive pressure inside the housing. b. The disk with the membrane is in electrical contact with a metal electrode cap that seals the lid assembly from the outside. c. The disk with the membrane is in electrical contact with an electrical conductor that is electrically coupled to an anode current collector or a cathode current collector. The immediately preceding features a. to c. are preferably implemented in combination.

[0095] Possible embodiments of the seal In order to further limit the influence of the welding process on the seal, it is preferred according to the invention to use a particularly heat-resistant plastic as sealing material.

[0096] In a further development of this preferred embodiment, it is correspondingly preferred that the energy storage cell according to the invention is characterized by at least one of the following features a. and b., which are mentioned immediately below: a. The seal is made of a plastic material having a melting point above 200°C, preferably above 300°C, particularly preferably above 300°C and below 350°C. b. The plastic material is polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfide (PPS), or polytetrafluoroethylene (PTFE). The immediately preceding features a. and b. are preferably implemented in combination.

[0097] Array of Energy Storage Cells An array of energy storage cells according to the invention is always characterized by the following features: a. the array includes at least two of the energy storage cells described above; b. The array includes at least one metallic electrical conductor welded to a radially inwardly bent open edge of a housing cup of at least two energy storage cells.

[0098] The at least one conductor may for example be a conductor made of aluminium or an aluminium alloy, in particular a rail.

[0099] 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%.

[0100] In some preferred embodiments, the conductor is a metal sheet strip, in particular made of aluminium, having a thickness in the range of 2 to 5 mm, particularly preferably 3.5 mm.

[0101] Method according to the invention The method according to the invention is always characterized by the following features: a. at least two of the energy storage cells described above and at least one metallic electrical conductor are provided; b. at least one metallic electrical conductor is connected by welding to the radially inwardly bent open edge of one of the energy storage cells and to the radially inwardly bent open edge of the other of the energy storage cells.

[0102] The welding is preferably carried out using a laser, however, welding by means of resistance welding is also possible.

[0103] In a preferred further development, in order to reduce the heat input, a weld seam consisting of several individual lines running parallel to one another is produced by means of at least one laser, which weld seam connects the metal conductor and the inwardly bent opening edge to one another. This may also make it possible to use seals with a low melting temperature, for example seals made of corresponding polybutylene terephthalate or perfluoroalkoxy polymers (PFA).

[0104] The weld seam includes a solidified molten zone in the area of ​​contact between the metal conductor and the inwardly bent edge of the opening.

[0105] The weld seams or individual lines mentioned above can also consist of a number of adjacent points in a row, which are also preferably formed using a laser. [Brief description of the drawings]

[0106] Further features and advantages of the invention are evident from the claims and from the following description of preferred embodiments of the invention in conjunction with the drawings. The illustrated features may be realized separately or in combination with other features. In the drawings, the following is shown diagrammatically: [Figure 1] 1 is a cross-sectional view of a first embodiment of an energy storage cell according to the invention; [Diagram 2] Overall view (cross-section) of the energy storage cell shown in Figure 1. [Diagram 3] FIG. 2 shows a second embodiment of an energy storage cell according to the invention (cross-sectional view). [Figure 4] FIG. 3 shows a third embodiment of an energy storage cell according to the invention (cross-sectional view). [Diagram 5] A lid assembly (cross-section) as used in an embodiment of an energy storage cell according to the invention as shown in Figures 1 to 4. [Figure 6] An electrode-separator assembly that is part of an energy storage cell according to the present invention, and components thereof. [Figure 7]An energy storage cell according to the present invention having two welded conductors. [Figure 8] Close-up of the weld seam. [Figure 9] FIG. 3 is a top view of a lid component of a cell according to the present invention as shown in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0107] 1 and 2 show an energy storage cell 100 according to the invention with an airtight and liquid-tight housing including a metallic 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 includes an annular seal 103 made of an electrically insulating material that seals 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 includes, in axial order, a bottom 101a, a central section 101b, and a closed section 101c, the central section 101b being cylindrical. In the central section 101b, a winding shell 104c of an electrode-separator assembly 104 formed as a winding is in contact with the inside of the housing cup 101, and in the closed section 101c, the annular seal 103 is in contact with the inside of the lid assembly 102 and 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 above the edge 102a of the lid assembly 102 and sealed by the seal 103, and which secures the lid assembly 102, including the seal 103, in 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, welding can be performed at the opening edge 101d without damaging the seal 103.

[0108] The cell 100 further comprises an electrode-separator assembly 104 in the form of a cylindrical winding having an anode / separator / cathode sequence, although this is not shown in detail herein. Only the longitudinal edge 106a of the anode current collector 106, which protrudes from an end face 104a of the electrode-separator assembly 104, and the longitudinal edge 109a of the anode current collector 109, which protrudes from an end face 104b of the electrode-separator assembly 104, are visible. The longitudinal edge 106a is preferably welded directly to the housing bottom 101a, in particular over its entire length. The longitudinal edge 109a is preferably welded directly to a contact plate 112, in particular over its entire length. The contact plate 112 is in turn connected to the lid assembly 102 via electrical conductors 118, which will be described in more detail below.

[0109] The cell 100 typically has a height in the range of 60 mm to 10 mm, and a diameter preferably in the range of 20 mm to 50 mm. The housing cup 101 typically has a wall thickness in the range of 0.1 mm to 0.3 mm in the central section 101b. The opening edge 101d of the housing cup 101, which is turned inwardly in the radial direction, is thicker by a factor of 1.5 to 2 than the housing cup 101 in the central section 101b. This opening edge comprises a first, inner surface in direct contact with the seal 103 and a second surface facing away from the seal 103. The second surface comprises a flat surface 101p of annular shape. The flat surface is shaped as a circular ring with a preferred ring width in the range of 0.8 mm to 3 mm. The flat surface preferably forms 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.

[0110] The cell 100 shown in Fig. 3 differs from the cell shown in Figs. 1 and 2 only in that the opening edge 101d is folded back, resulting in a two-layered opening edge 101d with a U-shaped cross section. The double-layered opening edge 101d has a first layer 101e in direct contact with the seal 103 sealing the edge 102a of the lid assembly 102, and a second layer 101f extending parallel to the first layer on the side of the first layer 101e facing away from the seal 103. The first layer 101e is bounded by a cut edge 101g facing radially outward, and is therefore very well protected from corrosion. This double-layered opening edge 101d includes a first, inner surface 101j in direct contact with the seal 103, and a second surface 101h facing away from the seal 103. The second surface 101h includes an annular, flat surface 101p having a ring width d ranging from 1.2 mm to 4 mm, the flat surface forming a 90° angle with the wall of the housing cup 101 in the central section 101b.

[0111] The cell 100 shown in Figure 4 differs from the cell shown in Figures 1 and 2 only in that the open edge 101d is folded over, resulting in a double layered, U-shaped cross section. The double layered open edge 101d has a first layer 101e in direct contact with the seal 103 sealing the edge 102a of the lid assembly 102, and a second layer 101f extending parallel to the first layer 101e on the side of the first layer 101e facing away from the seal 103. The second layer 101f is bounded by a cut edge 101g facing radially outward.

[0112] The radially inwardly turned opening edge 101d of the housing cup 101 includes a first, inner surface in direct contact with the seal 103 and a second surface facing away from the seal 103. The second surface includes an annular flat surface 101p. The annulus of the annular portion has a preferred annular width in the range of 0.8 mm to 3 mm and forms a 90° angle with the wall of the housing cup 101 at 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.

[0113] FIG. 5 shows a lid assembly 102 used in an embodiment of an energy storage cell 100 according to the invention as shown in FIGS. 1 to 4. It includes a disk 113 with a metal membrane 114 that expands outward or bursts in case of excessive pressure inside the housing. The disk 113 with the membrane 114 is in electrical and direct contact with an electrode cap 117 that closes the lid assembly 102 to the outside. The disk is also in electrical contact with an inner contact disk 115, but only through the membrane 114. The disks 113 and 115 are otherwise electrically insulated from each other by an insulator 116. If the membrane 114 expands outward as a result of excessive pressure that may act directly on the membrane through the aperture 115a, the electrical contact between the disks 113 and 115 is interrupted. At high pressures, the membrane may also burst.

[0114] The structure of the electrode-separator assembly 104 is described with reference to FIG. 6. The assembly 104 comprises a strip-shaped anode 105, which has a strip-shaped anode current collector 106 with 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. It comprises a strip-shaped main area filled with a layer of a negative electrode material 107 and a free edge strip 106b, which is not filled with the electrode material 107, extending along its first longitudinal edge 106a. Furthermore, the assembly 104 comprises a ribbon-shaped cathode 108, which has a ribbon-shaped cathode current collector 109 with a first longitudinal edge 109a and a second longitudinal edge parallel thereto. The cathode current collector 109 is an aluminum foil. It comprises a strip-shaped main area filled with a layer of positive electrode material 110 and a free edge strip 109b extending along its first longitudinal edge 109a that is not filled with electrode material 110. Both electrodes are shown in an unwound state.

[0115] The anode 105 and cathode 108 are staggered in the electrode-separator assembly 104 such that a first longitudinal edge 106a of the anode current collector 106 protrudes from a first end face 104a and a first longitudinal edge 109a of the cathode current collector 109 protrudes from a second end face 104b of the electrode-separator assembly 104. The staggered arrangement can be seen in the illustration on the lower left, where two ribbon-like separators 156 and 157 are also shown, which separate the electrodes 105 and 108 from each other within the winding.

[0116] In the illustration on the lower right, the electrode-separator assembly 104 is shown in wound form, as it can be used in an energy storage cell according to one of the figures 1 to 4. The edges 106a and 109a protruding from the end faces 104a and 104b are clearly visible. The winding shell 104c is formed by a plastic film.

[0117] Figure 7 shows an energy storage cell 100 according to the invention as shown in Figure 2 with two electrical conductors 140 and 141 welded onto it. Each of the electrical conductors 140 and 141 is made of metal and is welded onto the radially inwardly bent open 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 open edge. The energy storage cell 100 can be connected to adjacent cells of the same type via the electrical conductors 140 and 141.

[0118] Analysis indicates that the seal located under flat surface 101p was not damaged by the welding process.

[0119] 8 shows the underside of the inwardly bent opening edge of the housing cup, on whose upper side an electrical conductor has been welded according to the invention. It can be seen that two weld seams (142a and 142b, and 142c and 142d) are arranged parallel to one another. It can also be seen that the weld seams are each formed from several individual weld seams running parallel to one another. Such weld seams can be formed particularly efficiently using a laser.

[0120] Figure 9 shows a top view of a component of a lid of an energy storage cell according to the invention as shown in Figure 2. Not only the annular flat surface 101p is visible, but also the edge of the seal 103 and the electrode cap 117. In the area of ​​the annular flat surface 101p, there is a height difference of up to 0.08 mm between the highest and lowest points of the annular flat surface. The surface 101p extends to the inner edge of the opening edge, which is bent inwards, below which the seal 103 protrudes. Towards the outside, the flat surface 101p adjoins a curved area 101k.

Claims

1. An energy storage cell (100) having the following characteristics: a. the cell comprises an electrode-separator assembly (104) having the following order: anode (105) / separator (156) / cathode (108); b. the electrode-separator assembly (104) is in the form of a cylindrical winding having a first end surface (104a) and a second end surface (104b) and a winding shell (104c) located therebetween; c) the cell comprises an airtight and liquid-tight housing including a metal housing cup (101) having a terminal circular opening, and a lid assembly (102) having a circular edge (102a) closing the circular opening; d. the cell includes an annular seal (103) made of an electrically insulating material that seals the circular edge (102a) of the lid assembly (102) and electrically insulates the housing cup (101) and the lid assembly (102) from each other; e. the housing cup (101) comprises, in axial order, a bottom (101a), a central section (101b), and a closing section (101c); - said central section (101b) is cylindrical, in which the winding shell (104c) of the electrode-separator assembly (104) is in contact with the inside of the housing cup (101); and the annular seal is in pressing contact with the lid assembly and the inside of the housing cup in the closing section (101c); f. In the closing section (101c), the housing cup (101) has an opening edge (101d) that defines the circular opening, the opening edge (101d) is bent radially inward above the edge (102a) of the lid assembly (102) and is sealed by the seal (103), and the opening edge (101d) firmly secures the lid assembly (102) including the seal (103) in the circular opening of the housing cup (101). and g. An energy storage cell (100) characterized in that the wall thickness of the radially inwardly bent opening edge (101d) of the housing cup (101) is greater than the wall thickness of the housing cup (101) in the central section (101b).

2. The following additional features: a. The radially inwardly bent opening edge (101d) of the housing cup (101) is thicker than the housing cup (101) in the central section (101b) by a thickness in the range of 1.5 to 2 times; b. The housing cup (101) has a wall thickness in the central section (101b) ranging from 0.1 mm to 0.4 mm; c. The radially inwardly turned opening edge (101d) of the housing cup (101) has a wall thickness in the range of 0.15 mm to 0.8 mm; 10. The energy storage cell of claim 1, comprising at least one of:

3. The following additional features: a. The radially inwardly bent opening edge (101d) of the housing cup (101) is double-layered; b. The double-layered opening edge portion (101d) is formed by folding back the opening edge portion; c. The double-layered opening edge portion (101d) has a U-shaped cross section; 10. The energy storage cell of claim 1, comprising at least one of:

4. The following additional features: a) the double-layered opening edge (101d) has a first layer (101e) in direct contact with the seal (103) sealing the edge (102a) of the lid assembly (102), and a second layer (101f) parallel to the first layer on a surface of the first layer (101e) facing away from the seal (103); b. said first layer (101e) being bounded by a cutting edge (101g) directed radially outward; c. said second layer (101f) being bounded by a cutting edge (101g) directed radially outward; 4. The energy storage cell of claim 3, comprising at least one of:

5. The following additional features: the radially inwardly bent opening edge (101d) includes a first, inner surface (101j) in direct contact with the seal (103), and a second surface (101h) facing away from the seal (103); b. the second surface (101h) is or includes a circular toroidal flat surface; c. the annular portion has a width (d) in the range of 1 mm to 5 mm; d. The annular flat surface forms a 90° angle with the wall of the housing cup (101) in the central section (101b); 10. The energy storage cell of claim 1, comprising at least one of:

6. The following additional features: a. The central section (101b) and the closed section (101c) are separated by a recess (111) circumferentially surrounding the outside of the housing cup (101); b. The housing cup (101) has the same maximum outer diameter in the central section (101b) and the closed section (101c); c) the outer diameter of the housing cup (101) in the area of ​​the recess (111) is reduced in this area by 4 to 12 times the wall thickness of the housing cup (101); 10. The energy storage cell of claim 1, comprising at least one of:

7. The following additional features: the annular seal (103) includes a first annular segment (103a) disposed between the recess (111) and a surface of the lid assembly (102) facing the interior of the housing, the first annular segment being in pressing contact with the recess (111) and a wall section defining this surface of the lid assembly (102); b) the annular seal (103) includes a second annular segment (103b) disposed between the radially inwardly bent opening edge (101d) and the face of the lid assembly (102) facing away from the interior of the housing, the second annular segment being pressed against this face of the lid assembly (102) by the opening edge (101d); c) the annular seal (103) includes a third annular segment (103c) disposed between the housing cup (101) and the edge (102a) of the lid assembly (102), the third annular segment being pressed against the edge (102a) of the lid assembly (102) by the wall of the housing cup within the closing section (101c); 10. The energy storage cell of claim 1, comprising at least one of:

8. The following additional features: a. the anode (105) of the electrode-separator assembly (104) includes an anode current collector (106) having a first longitudinal edge (106a) and a second longitudinal edge parallel thereto; b. the anode current collector (106) comprises a main area filled with a layer of negative electrode material (107) and a free edge strip extending along its first longitudinal edge (106a) that is not filled with the negative electrode material; c. the cathode (108) of the electrode-separator assembly (104) includes 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 filled with a layer of positive electrode material (110) and a free edge strip extending along its first longitudinal edge (109a) that is not filled with 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) protrudes beyond the first end face (104a) and such that the first longitudinal edge (109a) of the cathode current collector (109) protrudes beyond the second end face (104b) of the electrode-separator assembly (104); 10. The energy storage cell of claim 1, comprising at least one of:

9. The following additional features: the energy storage cell includes a contact plate (112) placed on the first longitudinal edge (109a) of the anode current collector and covering the first end face (104b), or placed on the first longitudinal edge (109a) of the cathode current collector (109) and covering the second end face (104b), and connected to the first longitudinal edge by welding; b. the contact plate (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 welding; c. the contact plate (112) is connected to the bottom of the housing cup; d. The contact plate (112) is part of the lid assembly or is electrically connected directly or indirectly to the lid assembly; 9. The energy storage cell of claim 8, comprising at least one of:

10. The following additional features: a) the first longitudinal edge (106a) of the anode current collector (106) or the first longitudinal edge of the cathode current collector is placed directly on the bottom (101a) of the housing cup (101) and connected thereto by welding; 9. The energy storage cell of claim 8, comprising at least one of:

11. The following additional features: a. the lid assembly (102) includes a disk (113) having a metal membrane (114) that expands or bursts outward in the event of excessive pressure within the housing; b. the disc (113) with the membrane (114) is in electrical contact with an electrode cap (117) that seals the lid assembly (102) from the outside; c) the disk (113) carrying the membrane (114) is in electrical contact with an electrical conductor (118) electrically coupled to the anode current collector or the cathode current collector (109); 10. The energy storage cell of claim 1, comprising at least one of:

12. The following additional features: a. The seal (103) is made of a plastic material having a melting point above 300°C; b. The plastic material is polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfide (PPS), or polytetrafluoroethylene (PTFE); 10. The energy storage cell of claim 1, comprising at least one of:

13. 1. An array of energy storage cells, comprising: a. The array comprises at least two energy storage cells (100) according to any one of claims 1 to 10, and b) the array includes at least one metallic electrical conductor (140, 141) connected by welding to the radially inwardly bent opening edge of the housing cup of the at least two energy storage cells (100); an array of energy storage cells having

14. 1. A method of manufacturing an array of energy storage cells, comprising: a. providing at least two energy storage cells (100) according to any one of claims 1 to 7 and at least one metallic electrical conductor (140, 141); b) welding the at least one metallic electrical conductor (140, 141) to the radially inwardly bent opening edge of one of the energy storage cells (100) and to the radially inwardly bent opening edge of the other of the energy storage cells (100); A method comprising:

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