Energy storage cell and production method

Abstract

An energy storage cell (100) comprises an electrode-separator composite (104) in the form of a cylindrical winding having two terminal end faces (104a, 104b), wherein a longitudinal edge (106a) of an anode current collector (106) emerges from one of the terminal end faces (104a, 104b) and a longitudinal edge (109a) of a cathode current collector (109) emerges from the other of the terminal end faces (104a, 104b) of the electrode-separator composite (104). The composite (104) is enclosed by a housing comprising a metallic housing cup (101) having an inner side (101d) and an outer side (101e), and also comprising a cover component (102). A sheet-metal component (112), optionally including a separate electrical conductor (133) fixed to the sheet-metal part, electrically connects a longitudinal edge (106a; 109a) of one of the current collectors (106; 109), said longitudinal edge emerging from the first terminal end face (104a), to the cover component (102). It is proposed that at least one insulating element (150; 160; 170; 180) composed of an electrically insulating material protects the sheet-metal component (112) and / or the longitudinal edge (106a, 109a) of the current collector (106; 109) emerging from the first terminal end face (104a), and / or the separate electrical conductor (133) fixed to the sheet-metal part, against direct contact with the inner side (101d) of the housing cup (101). Furthermore, a method for producing an energy storage cell is proposed, in which an energy storage cell (100) is subjected to a height calibration.

Description

[0001] Energy storage cell and manufacturing process

[0002] FIELD OF APPLICATION AND STATE OF THE ART

[0003] The invention described below relates to an energy storage cell and a method for producing an energy storage cell.

[0004] Electrochemical energy storage elements are capable of converting stored chemical energy into electrical energy through a redox reaction. The simplest form of an electrochemical energy storage element is the electrochemical cell. It comprises a positive and a negative electrode separated by a separator. During a discharge, electrons are released at the negative electrode through an oxidation process. This results in an electron current that can be tapped by an external electrical load, for which the electrochemical cell serves as an energy supplier. At the same time, an ion current corresponding to the electrode reaction occurs within the cell. This ion current passes through the separator and is enabled by an ion-conducting electrolyte.

[0005] If the discharge is reversible, meaning it is possible to reverse the conversion of chemical energy into electrical energy during the discharge and recharge the cell, it is called a secondary cell. The commonly used designation for secondary cells is the negative electrode, the anode, and the positive electrode, the cathode, which refers to the discharge function of the electrochemical cell.

[0006] Secondary lithium-ion cells are now used as energy storage elements for many applications because they can provide high currents and are characterized by a comparatively high energy density. They are based on the use of lithium, which can migrate back and forth between the cell's electrodes in the form of ions. The negative and positive electrodes of a lithium-ion cell are usually formed by so-called composite electrodes, which include both electrochemically active and electrochemically inactive components.

[0007] In principle, any material capable of absorbing and releasing lithium ions can be used as electrochemically active components (active materials) for secondary lithium-ion cells. Carbon-based particles, such as graphitic carbon, are used for the negative electrode. Lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), or derivatives thereof can be used as active materials for the positive electrode. The electrochemically active materials are usually contained in the electrodes in particle form.

[0008] As electrochemically inactive components, the composite electrodes generally comprise a flat and / or ribbon-shaped current collector, for example a metallic foil, which serves as a carrier for the respective active material. The current collector for the negative electrode (anode current collector) can be made of copper or nickel, for example, and the current collector for the positive electrode (cathode current collector) can be made of aluminum, for example. Furthermore, the electrodes can comprise an electrode binder (e.g., polyvinylidene fluoride (PVDF) or another polymer, such as carboxymethyl cellulose), conductivity-enhancing additives, and other additives as electrochemically inactive components. The electrode binder ensures the mechanical stability of the electrodes and often also the adhesion of the active material to the current collectors.

[0009] Lithium-ion cells typically contain electrolytes consisting of solutions of lithium salts such as lithium hexafluorophosphate (LiPF6) in organic solvents (e.g. ethers and esters of carbonic acid).

[0010] During the production of a lithium-ion cell, the composite electrodes are combined with one or more separators to form an electrode-separator assembly, in which the electrodes are connected to each other via the separator. The electrodes and separators are bonded together with or without pressure, if necessary by lamination or adhesive bonding. The basic functionality of the cell can then be achieved by impregnating the assembly with the electrolyte.

[0011] In many embodiments, the electrode-separator composite is formed in the form of a coil or processed into a coil. In the first case, for example, a strip-shaped positive electrode and a strip-shaped negative electrode as well as at least one strip-shaped separator are fed separately to a winding machine and wound spirally therein into a coil with the sequence positive electrode / separator / negative electrode. In a coil formed in this way, the electrodes are connected to one another via the separator. However, gluing or a similarly strong connection of the electrodes to the separator is not expedient in the vast majority of cases. In the second case, a strip-shaped positive electrode and a strip-shaped negative electrode as well as at least one strip-shaped separator are first combined to form an electrode-separator composite, for example by applying the aforementioned pressure. In a further step, the composite is then wound up.For applications in the automotive sector, for e-bikes or for other applications with high energy requirements, such as in tools, lithium-ion cells with the highest possible energy density are required, which at the same time are capable of being loaded with high currents during charging and discharging.

[0012] Cells for these applications are often designed as cylindrical round cells, for example, with a form factor of 21 x 70 (diameter times height in mm). Cells of this type always comprise a composite body in the form of a coil. Modern lithium-ion cells of this form factor can already achieve an energy density of up to 270 Wh / kg. However, this energy density is considered only an intermediate step. The market is already demanding cells with even higher energy densities.

[0013] The housing of cylindrical round cells typically comprises a housing cup, which serves to accommodate the wound electrode-separator assembly, and a cover component that closes the opening of the housing cup. A seal is arranged between the cover component and the housing cup. This seal serves to seal the cell housing and also electrically insulate the cover component and the housing cup from each other. The seal is usually pulled over the edge of the cover component for assembly. To close the round cells, the opening edge of the housing cup is generally bent radially inward over the edge of the cover component enclosed by the seal (flanging process), so that the cover component, including the seal, is positively fixed in the opening of the housing cup.

[0014] WO 2017 / 215900 A1 describes cylindrical round cells in which the electrode-separator assembly and its electrodes are strip-shaped and in the form of a coil. The electrodes each have strip-shaped current collectors loaded with electrode material. Oppositely polarized electrodes are arranged offset from one another within the electrode-separator assembly, so that longitudinal edges of the current collectors of the positive electrodes emerge from the coil on one side and longitudinal edges of the current collectors of the negative electrodes emerge from another side. To electrically contact the current collectors, the cells have sheet metal parts that sit flat on the end faces of the coil and are welded to the longitudinal edges of the current collectors. This makes it possible to electrically contact the current collectors and thus also the associated electrodes over their entire length.Cells with windings contacted in this way exhibit significantly reduced internal resistance. As a result, large currents can be absorbed much more effectively, and heat can also be dissipated more effectively from the winding.

[0015] In the case of contact plate design / front-end winding contact, very solid metallic contact elements are preferred to provide large cross-sections for high electrical and thermal conductivities. However, cells with such solid internal contact elements are susceptible to short circuits, which can result particularly from deformation of the housing as a result of external mechanical forces. For cells used in the automotive sector, for example, the risk of such damage is very real. Furthermore, height calibration may be required during cell production, in which the cells are deliberately compressed. The axial forces applied here can also cause short circuits within the cells.

[0016] TASK AND SOLUTION

[0017] The object of the present invention was to provide energy storage cells characterized by high energy density. Furthermore, the energy storage cells should also be characterized, in particular, by improved safety.

[0018] This object is achieved by the energy storage cell having the features of claim 1 and by the method having the features of claim 14. Preferred embodiments of the invention can be found in the dependent claims 2 to 13 and 15.

[0019] The energy storage cell according to the invention always has the directly following features a. to n.: a. The cell comprises an electrode-separator assembly with the sequence anode / separator / cathode. b. The anode of the electrode-separator assembly is strip-shaped and comprises a strip-shaped anode current collector which has a first longitudinal edge and a second longitudinal edge parallel thereto. c. The strip-shaped anode current collector comprises a main region which is loaded with a layer of negative electrode material, and a free edge strip which extends along its first longitudinal edge and which is not loaded with the negative electrode material. d. The cathode of the electrode-separator assembly is strip-shaped and comprises a strip-shaped cathode current collector which has a first longitudinal edge and a second longitudinal edge parallel thereto. e.The strip-shaped cathode current collector comprises a main region loaded with a layer of positive electrode material, and a free edge strip extending along its first longitudinal edge which is not loaded with the electrode material. f. The electrode-separator assembly is in the form of a cylindrical coil with a first terminal end face delimited by a circumferential edge and a second terminal end face delimited by a circumferential edge, with a coil jacket lying between them, and comprises the anode and the cathode in a spirally wound form. g. The anode and the cathode are arranged within the electrode-separator assembly such that the first longitudinal edge of the anode current collector emerges from one of the terminal end faces and the first longitudinal edge of the cathode current collector emerges from the other terminal end face of the electrode-separator assembly. h.The cell comprises an airtight and liquid-tight housing which has a metallic housing cup with a base and a circular opening at the end, and a cover component with a circular edge which closes the circular opening at the end. i. The electrode-separator assembly is arranged in an axial alignment in the housing cup, with the first end face facing the cover component and the second end face facing the base, optionally being in direct contact with the base. j. The cell comprises an annular seal made of an electrically insulating material which encloses the circular edge of the cover component and electrically insulates the housing cup and the cover component from one another. k.The housing cup comprises an inner side and an outer side and, in axial sequence, the base, a central section and a closure section, wherein the central section is cylindrical and, in the central section, the winding jacket of the electrode-separator assembly formed as a winding is in contact with the inner side of the housing cup, and, in the closure section, the annular seal is in press contact with the cover component and the inner side of the housing cup. l. The central section and the closure section are separated by an indentation which runs annularly around the outer side of the housing cup. m.The cell comprises a sheet metal component, optionally including a separate electrical conductor fixed to the sheet metal part, which is welded to the first longitudinal edge of the current collector emerging from the first terminal end face and via which this current collector is electrically connected to the cover component. The cell is particularly characterized by the following feature: n. The cell comprises at least one insulating element made of an electrically insulating material, which protects the sheet metal component and / or the first longitudinal edge of the current collector emerging from the first terminal end face and / or the separate electrical conductor fixed to the sheet metal part from direct contact with the inside of the housing cup, in particular in the region of the indentation.

[0020] This measure ensures that the risk of a short circuit in the cell's internal contact area is reduced. Axial forces occurring, for example, during height calibration, generally no longer lead to direct contact between oppositely polarized cell components. This is prevented by at least one insulating element.

[0021] The base of the housing cup is preferably circular. The housing cup is usually formed by deep drawing. However, it is also possible, for example, to form the cup by welding a base into a tubular half-section.

[0022] Preferably, the housing cup has a wall thickness in the range of 0.1 mm to 2 mm.

[0023] The housing cup is preferably made of aluminum, an aluminum alloy, or sheet steel, such as nickel-plated steel. Stainless steel is also preferred.

[0024] Suitable aluminum alloys for the housing cup include aluminum 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 above 99.5%.

[0025] The energy storage cell according to the invention is preferably a cylindrical round cell. The height of an energy storage cell according to the invention configured 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 suitable, for example, for supplying power to electric drives in motor vehicles.

[0026] The electrode-separator assembly is preferably manufactured using two strip-shaped separators. The assembly preferably has the sequence separator / anode / separator / cathode or anode / separator / cathode / separator. The separator(s) then enclose either the anode or the cathode. Their function is to prevent direct electrical contact between oppositely polarized electrodes within the coil while simultaneously allowing an exchange of ions between the electrodes.

[0027] Lithium-ion cell version

[0028] In a particularly preferred embodiment of the invention, the energy storage cell according to the invention is a lithium-ion cell.

[0029] Basically, all electrode materials known for secondary lithium-ion cells can be used for the electrodes of the energy storage cell.

[0030] Carbon-based particles such as graphitic carbon or non-graphitic carbon materials capable of intercalating lithium, preferably also in particle form, can be used as active materials in the negative electrodes. Alternatively or additionally, lithium titanate (Li4Ti50i2) or a derivative thereof can also be contained in the negative electrode, preferably also in particle form. Furthermore, the negative electrode can contain as active material at least one material from the group consisting of silicon, aluminum, tin, antimony, or a compound or alloy of these materials that can reversibly intercalate and release lithium, for example silicon oxide (in particular SiO xwith 0 < x < 2), optionally in combination with carbon-based active materials. Tin, aluminum, antimony, and silicon are capable of forming intermetallic phases with lithium. The lithium absorption capacity, particularly in the case of silicon, exceeds that of graphite or comparable materials by several times. Mixtures of silicon- and carbon-based storage materials are often used. Silicon-carbon composites (SiC), for example, are particularly suitable. Thin anodes made of metallic lithium are also suitable.

[0031] For the positive electrodes, suitable active materials include lithium metal oxide compounds and lithium metal phosphate compounds such as LiCoO2 and LiFePO4. Lithium nickel manganese cobalt oxide (NMC) with the molecular formula LiNi is also particularly suitable. x Mn y Co zO2 (where x + y + z is typically 1), lithium manganese spinel (LMO) with the molecular formula LiMn2O4, or lithium nickel cobalt aluminum oxide (NCA) with the molecular formula LiNi x Co y Al z O2 (where x + y + z is typically 1). Derivatives thereof, for example lithium nickel manganese cobalt aluminum oxide (NMCA) with the molecular formula Lii.n(Ni.sub.4oMno.sub.39Coo.sub.i6Alo.sub.o5)o.sub.89O2 or Lii +xM-0 compounds and / or mixtures of the materials mentioned can be used. The cathodic active materials are also preferably used in particulate form. In addition, the electrodes of an energy storage cell according to the invention preferably contain an electrode binder and / or an additive to improve electrical conductivity. The active materials are preferably embedded in a matrix made of the electrode binder, with adjacent particles in the matrix preferably being in direct contact with one another. Conductive agents serve to increase the electrical conductivity of the electrodes. Common electrode binders are based, for example, on polyvinylidene fluoride (PVDF), (Li-)polyacrylate, styrene-butadiene rubber, or carboxymethyl cellulose, or mixtures of different binders. Common conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes, and metal powder.

[0032] The energy storage cell according to the invention preferably comprises an electrolyte, in the case of a lithium-ion cell, in particular an electrolyte based on at least one lithium salt, such as lithium hexafluorophosphate (LiPF6), dissolved in an organic solvent (e.g., in a mixture of organic carbonates or a cyclic ether such as THF or a nitrile). Other usable lithium salts include, for example, lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(oxalato)borate (LiBOB).

[0033] The nominal capacity of a lithium-ion-based energy storage cell according to the invention, designed as a cylindrical round cell, is preferably up to 15,000 mAh. With a form factor of 21 x 70, the energy storage cell in one embodiment as a lithium-ion cell preferably has a nominal capacity in the range of 1,500 mAh to 7,000 mAh, particularly preferably in the range of 3,000 to 5,500 mAh. With a form factor of 18 x 65, the cell in one embodiment as a lithium-ion cell preferably has a nominal capacity in the range of 1,000 mAh to 5,000 mAh, particularly preferably in the range of 2,000 to 4,000 mAh.

[0034] In the European Union, manufacturers' specifications regarding the nominal capacities of secondary batteries are strictly regulated. For example, specifications regarding the nominal capacity of secondary nickel-cadmium batteries must be based on measurements according to the standards IEC / EN 61951-1 and IEC / EN 60622; specifications regarding the nominal capacity of secondary nickel-metal hydride batteries must be based on measurements according to the standard IEC / EN 61951-2; specifications regarding the nominal capacity of secondary lithium batteries must be based on measurements according to the standard IEC / EN 61960; and specifications regarding the nominal capacity of secondary lead-acid batteries must be based on measurements according to the standard IEC / EN 61056-1. Any specifications regarding nominal capacities in this application are preferably also based on these standards. as a sodium ion cell Alternatively, the energy storage cell according to the invention can also be a sodium ion cell, a potassium ion cell, a calcium ion cell, a magnesium ion cell or an aluminum ion cell.In further possible embodiments, the energy storage cell according to the invention comprises a sodium ion cell, a potassium ion cell, a calcium ion cell, a magnesium ion cell, or an aluminum ion cell. Among these variants, energy storage cells with sodium ion cell chemistry are particularly preferred according to the invention.

[0035] The negative electrode material of an energy storage element according to the invention based on sodium ions is, for example, one of the following materials:

[0036] - Carbon, especially preferred hard carbon (pure or with nitrogen and / or phosphorus doping) or soft carbon or graphene-based materials, carbon nanotubes, graphite

[0037] - Phosphorus or sulfur

[0038] - Polyanions such as Na2Ti3O7, Na3Ti2(PO4)3, TiP2O7, TiNb2O7, Na-Ti-(PO4)3, Na-V-(PO4)3

[0039] - Transition metal oxides such as V2O5, MnO2, TiO2, Nb2O5, Fe2O3, Na2Ti3O7, NaCrTiO4, Na4Ti50i2

[0040] Alternatively, a Na metal anode can also be used on the anode side.

[0041] The positive electrode material of an energy storage element according to the invention based on sodium ions is, for example, one of the following materials:

[0042] - Polyanions: NaFePO4(triphylite type), Na2Fe(P2O7), Na4Fe3(PO4)2(P2O7), Na2FePO4F, Na / Na2[Fei / 2Mni / 2]PO4F, Na3V2(PO4)2F3, Na3V2(PO4)3, NaCoPO4, Na2CoPO4F

[0043] - Silicates: Na2MnSiO4, Na2FeSiO4

[0044] - Layered oxides: NaCoO2, NaFeO2, NaNiO2, NaCrO2, NaVO2, NaTiO2, Na(FeCo)O2, Na(NiFeCo)3O2, Na(NiFeMn)O2, and Na(NiFeCoMn)O2, Na(NiMnCo)O2

[0045] As with lithium-ion cells, sodium-ion-based electrodes can also contain an electrode binder and / or an additive to improve electrical conductivity. Suitable electrode binders are based, for example, on polyvinylidene fluoride (PVDF), (Li-)polyacrylate, styrene-butadiene rubber, or carboxymethyl cellulose, or even mixtures of different binders. Suitable conductive materials include carbon black, fine graphite, carbon fibers, carbon nanotubes, and metal powder.

[0046] An energy storage cell according to the invention based on sodium ions preferably comprises an electrolyte which comprises at least one of the following solvents and at least one of the following conductive salts:

[0047] - Suitable solvents are particularly organic carbonates, ethers, nitriles and mixtures thereof.

[0048] - Preferred conducting 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.

[0049] In preferred embodiments, additives may be added to the electrolyte.

[0050] The nominal capacity of a sodium-ion-based energy storage cell according to the invention, designed as a cylindrical round cell, is preferably up to 12,000 mAh. With a form factor of 21 x 70, the energy storage cell in one embodiment as a lithium-ion cell preferably has a nominal capacity in the range of 1,200 mAh to 5,500 mAh, particularly preferably in the range of 2,500 to 4,500 mAh. With a form factor of 18 x 65, the cell in one embodiment as a lithium-ion cell preferably has a nominal capacity in the range of 800 mAh to 4,500 mAh, particularly preferably in the range of 1,600 to 3,200 mAh.

[0051] Protection of the front edges of the electrode-separator assembly

[0052] In a first particularly preferred embodiment, the energy storage cell according to the invention is characterized by at least one of the immediately following features a. to c.: a. The at least one insulating element is or comprises an insulating tape which is applied to the edge which delimits the end face and protects this from direct contact with the inner side. b. The at least one insulating element is or comprises an annular molded part made of plastic with a preferably L-shaped cross-section, which is applied to the edge which delimits the end face and protects this from direct contact with the inner side. c. The insulating tape or the annular molded part made of plastic has a thickness in the range from 10 pm to 200 pm.

[0053] It is preferred that the immediately above features a. and c., as well as b. and c., are implemented in combination. The insulating tape can be, for example, a Kapton / polyimide adhesive tape.

[0054] The ring-shaped plastic part, preferably with an L-shaped cross-section, can be manufactured by injection molding, for example, and slid onto the edge to be protected. It can be made of Teflon or polyamide, for example.

[0055] Protection of the inside of the housing cup

[0056] In a second particularly preferred embodiment, the energy storage cell according to the invention is characterized by at least one of the immediately following features a. to c.: a. The at least one insulating element is or comprises an annular insulating element made of plastic, which rests against the inside of the housing cup in the region of the indentation and protects it from direct contact with the sheet metal component. b. The annular insulating element is a partial section of the annular seal. c. The annular insulating element made of plastic has a thickness in the range of 20 μm to 400 μm.

[0057] It is preferred that the immediately above features a. and b. are implemented in combination. Features a. to c. are particularly preferred that they are implemented in combination.

[0058] The annular insulating element can also be an injection-molded part, as can the annular seal. The thickness of the insulating element is preferably in the range of 20 μm to 400 μm.

[0059] The annular insulating element can be made of, for example, Teflon, polyamide, polybutylene terephthalate or a perfluoroalkoxy polymer.

[0060] Protection of the sheet metal component welded with the current ko Hector emerging from the first end face

[0061] In a third particularly preferred embodiment, the energy storage cell according to the invention is characterized by at least one of the immediately following features a. to d.: a. The at least one insulating element is or comprises an annular plastic part which encloses the sheet metal component and protects it from direct contact with the inside of the housing can in the region of the indentation. b. The annular plastic part is hollow-cylindrical, comprises a casing and is delimited on each end side by a circumferential edge. c. The annular plastic part is hollow-cylindrical, comprises a casing and is delimited on each end side by a circumferential edge, one of the edges being designed as an outwardly directed annular collar and sitting on the sheet metal component. d. The annular plastic part has a thickness in the range from 20 μm to 600 μm.

[0062] It is preferred that the immediately preceding features a. and b., particularly preferably features a. and b. and d., are implemented in combination. Particularly preferably, the immediately preceding features a. and c. and d. are implemented in combination.

[0063] The ring-shaped plastic part can also be an injection-molded part. The thickness of the plastic part is preferably in the range of 20 μm to 600 μm.

[0064] The plastic part can be made of, for example, Teflon, polyamide, polybutylene terephthalate or a perfluoroalkoxy polymer.

[0065] Protection of the edge of the sheet metal component

[0066] In a fourth particularly preferred embodiment, the energy storage cell according to the invention is characterized by at least one of the immediately following features a. to d.: a. The at least one insulating element is or comprises an electrically insulating plastic coating that surrounds an edge of the sheet metal component and protects it from direct contact with the inside of the housing cup, particularly in the region of the indentation. b. The electrically insulating coating is formed by overmolding the edge of the sheet metal component.

[0067] It is preferred that the immediately above features a. and b. are implemented in combination.

[0068] Basically, any thermoplastic material with electrically insulating properties is suitable for overmolding the edge of a sheet metal component. Polyamide, for example, is suitable.

[0069] Protective combinations Combinations of the four particularly preferred embodiments described are also according to the invention. The cell is particularly preferably characterized by a combination of two or more of the four immediately following features a. to d.: a. The at least one insulating element comprises an insulating strip or annular molded part made of plastic, which is applied to the edge that delimits the end face and protects this from direct contact with the inside, i.e. an insulating strip or annular molded part according to the first particularly preferred embodiment, and / or b. the at least one insulating element comprises an annular insulating element that rests against the inside of the housing cup in the region of the indentation and protects this from direct contact with the sheet metal component, i.e. an annular insulating element according to the second particularly preferred embodiment, and / or c.the at least one insulating element comprises an annular plastic part which encloses the sheet metal component and protects it from direct contact with the inside of the housing cup in the region of the indentation, i.e. an annular plastic part according to the third particularly preferred embodiment, and / or d. the at least one insulating element is or comprises an electrically insulating plastic coating which encloses an edge of the sheet metal component and protects it from direct contact with the inside of the housing cup, in particular in the region of the indentation, i.e. a plastic coating according to the fourth particularly preferred embodiment.

[0070] It is preferred that the cell according to the invention is characterized by at least one of the following features a. to c.: a. The housing cup has an identical maximum outer diameter in the central section and the closure section. b. In the region of the indentation, the outer diameter of the housing cup is reduced by 4 to 20 times the wall thickness of the housing cup in this region.

[0071] It is preferred that the immediately above features a. and b. are implemented in combination. Electrical connection of the sheet metal component with the cover component

[0072] There are two preferred variants for electrically connecting the sheet metal component, which is connected by welding to the first longitudinal edge of the current ko Hector emerging from the first terminal end face, to the cover component.

[0073] According to variant A, the cell according to the invention is characterized by at least one of the immediately following features a. to c.: a. The sheet metal component is directly connected to the cover component. b. The sheet metal component comprises a first section that sits flat on the first longitudinal edge of the current collector emerging from the first terminal end face and extends parallel to the end face. c. The sheet metal component comprises a second section that adjoins the first section at an angle and via which the first section is electrically connected to the cover component.

[0074] It is preferred that the immediately above features a. and b. are implemented in combination. Particularly preferred are the immediately above features a. to c. in combination.

[0075] According to variant B, the cell according to the invention is characterized by at least one of the immediately following features a. and b.: a. The sheet metal component is connected to the cover component via the separate electrical conductor. b. The sheet metal component sits flat on the first longitudinal edge of the current collector emerging from the first terminal end face.

[0076] It is preferred that the immediately above features a. and b. are implemented in combination.

[0077] If the separate electrical conductor is used, it is preferably made of the same material as the sheet metal component itself.

[0078] Electrical contacting of the first longitudinal edge of the current collector emerging from the second terminal face. Of course, not only the first longitudinal edge of the current collector emerging from the first terminal face needs to be electrically contacted. Rather, the first longitudinal edge of the current collector emerging from the second terminal face must also be electrically contacted. According to the invention, the following two variants are preferred:

[0079] According to a variant C, the cell according to the invention is characterized by the immediately following feature a.: a. The first longitudinal edge of the current collector emerging from the second terminal end face sits directly on the bottom of the housing cup and is connected to it by welding.

[0080] According to a variant D, the cell according to the invention is characterized by the immediately following feature b.: b. The cell comprises a sheet metal component which is welded to the first longitudinal edge of the current collector emerging from the second terminal end face and via which this current collector is electrically connected to the bottom of the housing cup.

[0081] In both cases, the longitudinal edge of the current collector emerging from the second terminal face can ideally be electrically and / or thermally connected over its entire length, as in the case of the current collector emerging from the first terminal face.

[0082] The cell according to the invention is particularly preferably characterized by the following feature a.: a. The current collector emerging from the first terminal end face is the anode current collector and the current collector emerging from the second end face is the cathode current collector.

[0083] This configuration is particularly advantageous when the housing, as described above, is made of aluminum or an aluminum-containing alloy. Since the cathode current collector is also preferably made of aluminum, see below. of the sheet metal component

[0084] In a particularly preferred embodiment of the invention, the sheet metal component electrically connected to the anode current collector is characterized by at least one of the following features a. or b.: a. The sheet metal component is made of nickel or copper or titanium or a nickel, copper, or titanium alloy or stainless steel, for example, type 1.4303 or 1.4404 or type SUS304, or nickel-plated copper. b. The sheet metal component is made of the same material as the anode current collector.

[0085] It is preferred that the immediately above features a. and b. are implemented in combination.

[0086] In embodiments in which the cathode current collector is also electrically connected via a sheet metal component, this sheet metal component is characterized by at least one of the following features a. and b.: a. The sheet metal component is made of aluminum or an aluminum alloy. b. The sheet metal component is made of the same material as the cathode current collector.

[0087] It is preferred that the immediately above features a. and b. are implemented in combination.

[0088] Sheet metal components which can be used according to the invention for contacting the longitudinal edges of the current collectors are particularly preferably characterized by at least one of the immediately following features a. to g.: a. They have a preferably uniform thickness in the range from 50 μm to 600 μm, preferably in the range from 150 μm to 350 μm. b. They have two opposite flat sides and extend essentially only in one dimension. c. They are designed as a disk or as a polygonal plate or comprise such a disk or plate. d. They are dimensioned such that they cover at least 50%, preferably at least 60%, particularly preferably at least 70% of the first terminal and / or the second terminal end face. e. They have at least one opening, in particular at least one hole and / or at least one slot. f.They have at least one bead, which appears as an elongated depression on one flat side of the sheet metal component and as an elongated elevation on the opposite flat side, with the flat side bearing the elongated elevation resting on the first longitudinal edge of the respective current collector. g. They are welded to the first longitudinal edge of the respective current collector in the region of the bead, in particular via one or more weld seams arranged in the bead.

[0089] It is particularly preferred that the immediately above features a., b., and d. are implemented in combination with one another. In a preferred embodiment, features a., b., and d. are implemented in combination with one of features c. or e., or features f. and g. Particularly preferably, all features a. to g. are implemented in combination with one another.

[0090] Covering the front side as extensively as possible is important for the thermal management of the energy storage cell according to the invention. The larger the cover, the easier it is to contact the first longitudinal edge of the respective current collector over its entire length. Heat generated in the electrode-separator assembly can thus be effectively dissipated via the sheet metal component(s).

[0091] In some embodiments, it has proven advantageous to pretreat the longitudinal edge of a current collector before a sheet metal component is mounted. In particular, at least one recess can be crimped into the longitudinal edge, corresponding to the at least one bead or elongated elevation on the corresponding flat side of the sheet metal component.

[0092] The longitudinal edges of the current collectors can also be subjected to directional deformation through pretreatment. For example, they can be bent in a defined direction.

[0093] The at least one opening in the sheet metal components can be useful, for example, to enable the electrode-separator assembly to be impregnated with an electrolyte. the current collectors

[0094] The anode current collector, the cathode current collector and the separator or separators of the cell according to the invention preferably have the following dimensions:

[0095] A length in the range of 0.5 m to 25 m

[0096] A width in the range 40 mm to 145 mm

[0097] To produce the electrode-separator assembly, it is preferred that the strip-shaped electrodes, together with the strip-shaped separator(s), be fed to a winding device and wound spirally therein, preferably around a winding axis. In some embodiments, the electrodes and the separator(s) are wound onto a cylindrical or hollow-cylindrical winding core, which sits on a winding mandrel and remains in the winding after winding.

[0098] The winding sleeve can be formed, for example, by a plastic film or an adhesive tape. It is also possible for the winding sleeve to be formed by one or more separator windings.

[0099] The current collectors of the energy storage cell according to the invention serve to electrically contact electrochemically active components contained in the respective electrode material over as large an area as possible. The current collectors are preferably made of a metal or at least have a metallized surface.

[0100] In the case of an energy storage cell according to the invention designed as a lithium-ion cell, suitable metals for the anode current collector include, for example, copper or nickel or other electrically conductive materials, in particular copper and nickel alloys or nickel-coated metals. 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. Suitable nickel alloys include, in particular, alloys of the types NiFe, NiCu, CuNi, NiCr, and NiCrFe. Suitable nickel alloys include, in particular, alloys of the types NiFe, NiCu, CuNi, NiCr, and NiCrFe. Stainless steel is also generally suitable, for example, type 1.4303 or 1.4404 or type SUS304.

[0101] In the case of an energy storage cell according to the invention designed as a lithium-ion cell, aluminum or other electrically conductive materials, including aluminum alloys, are particularly suitable as the metal for the cathode current collector. In the case of an energy storage cell according to the invention designed as a sodium-ion cell, the anode current collector and the cathode current collector can both be made of aluminum or an aluminum alloy.

[0102] Suitable aluminum alloys for the cathode current collector include aluminum 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 above 99.5%.

[0103] Preferably, the anode current collector and / or the cathode current collector are each a strip-shaped metal foil with a thickness in the range of 4 pm to 30 pm. In this case, the current collectors are also referred to as current collector foils.

[0104] In addition to foils, other strip-shaped substrates such as metallic or metallized nonwovens or open-pored metallic foams or expanded metals can also be used as current collectors.

[0105] The current collectors are preferably loaded on both sides with the respective electrode material.

[0106] In some embodiments, it is preferred—primarily for reasons of thermal connection—for the outer winding layer to consist of uncoated metal foils that are in direct contact with the housing. For example, in the case of an aluminum housing, a terminal section of an aluminum current collector foil of the cathode that is not coated with electrode material can form the outer turn of the winding and at the same time directly adjoin the aluminum housing. In the case of a housing made of nickel-plated steel, for example, a terminal section of an anode current collector foil made of copper or nickel that is not coated with electrode material can form the outer turn of the winding and adjoin the housing.

[0107] In these cases, the winding jacket is formed by the terminal section of the respective current collector foil.

[0108] It is preferred that the longitudinal edges of the separator(s) form the end faces of the electrode-separator assembly formed as a coil.

[0109] Method according to the invention The method according to the invention serves to produce an energy storage cell and is characterized by the following features and steps: a. An energy storage cell is provided as described above, in particular an energy storage cell with the features a. to n. of claim 1. b. The energy storage cell is subjected to a height calibration by which the closure section and the central section are pushed against one another with plastic deformation of the indentation, so that the distance between the sheet metal component, which is connected by welding to the first longitudinal edge of the current collector emerging from the first terminal end face, and the cover component becomes smaller.

[0110] During production of an energy storage cell of the type described above, it is almost unavoidable that a dead volume will form between the sheet metal component, which is welded to the first longitudinal edge of the current collector emerging from the first terminal end face, and the cover component, which reduces the energy density of the energy storage cell. According to the invention, this is counteracted by the aforementioned height calibration, during which the closure section and the central section are pushed against each other by preferably axial forces. In conventional cells, this step is a very critical one, since the axial forces can cause deformations of the wall of the housing can, of the sheet metal component welded to the first longitudinal edge of the current collector emerging from the first terminal end face, and of the separate electrical conductor connecting the sheet metal component to the cover component.As a result of these deformations, short circuits can occur within the energy storage cell.

[0111] The inventive design of the described energy storage cell with at least one insulating element allows for height calibration with a significantly reduced risk of short circuits. For example, it is possible to initially assemble a 21700 cell with a height of > 700 mm and, in a subsequent step, reduce the resulting dead volume during the aforementioned height calibration. This allows cells with increased energy density to be manufactured.

[0112] Preferably, the distance between the sheet metal component (112) and the cover component (102) is reduced by at least 10%, particularly preferably by at least 20%, further preferably by at least 30%, relative to the distance prior to height calibration. In absolute terms, the reduction in distance can range, for example, from 0.5 mm to 5 mm, depending on the dimensions of the cell. In contrast to so-called elastic deformation, the person skilled in the art understands the aforementioned plastic deformation to be a permanent deformation that is structurally reflected in the height-calibrated product. This particularly applies to the indentation arranged between the central section and the closure section.

[0113] In preferred embodiments, an energy storage cell according to the invention, which has been subjected to the described height calibration, is characterized by the immediately following feature a.: a. The indentation comprises an annular opening slot and an annular cavity with an undercut accessible via the opening slot.

[0114] According to the invention, such an undercut is formed by the height calibration, since according to the invention, the closure section and the central section can be pushed further toward each other than is the case with conventional cells. Preferably, the indentation in the region of the opening slot has a lower height in the axial direction than in the region of the undercut.

[0115] Even better results can be achieved if the indentation is designed asymmetrically before the height calibration. In preferred embodiments, an energy storage cell according to the invention is distinguished by the immediately following features a. to e. before it is subjected to the described height calibration: a. The housing of the energy storage cell is essentially cylindrical and the energy storage cell has a central axis which runs perpendicularly through the bottom of the housing cup. b. The housing cup has an identical maximum outer diameter in the central section and the closure section, while the outer diameter is reduced in the region of the indentation. c. A housing cup segment in which the outer diameter is reduced in the region of the indentation extends over a height S1. d.A plane E1, which passes through the deepest point of the recess and intersects the central axis perpendicularly, divides the housing cup segment into an upper sub-segment facing the cover component with a height S2 and a lower sub-segment facing the electrode-separator assembly with a height S3. e. S3 > S2.

[0116] Particularly preferably, S3 is at least 20%, further preferably at least 30%, in particular at least 40%, longer than S2.

[0117] BRIEF DESCRIPTION OF THE DRAWINGS

[0118] Further features and advantages of the invention will become apparent from the claims and the following description of preferred embodiments of the invention in conjunction with the drawings. The individual features may be implemented individually or in combination with one another.

[0119] The drawings show schematically

[0120] Fig. 1 shows a first embodiment of an energy storage cell according to the invention (cross-sectional view),

[0121] Fig. 2 shows a second embodiment of an energy storage cell according to the invention,

[0122] Fig. 3 shows a third embodiment of an energy storage cell according to the invention (cross-sectional view),

[0123] Fig. 4 shows several embodiments of a sheet metal component which is suitable for contacting the first longitudinal edge of the current collector emerging from the first terminal end face of an energy storage cell according to the invention (perspective view),

[0124] Fig. 5 shows an electrode-separator assembly which is a component of an energy storage cell according to the invention, as well as its components (top view and perspective view),

[0125] Fig. 6 further embodiments of the sheet metal component which is suitable for contacting the first longitudinal edge of the current collector emerging from the first terminal end face of an energy storage cell according to the invention (perspective view),

[0126] Fig. 7 Photos of a longitudinal section through an energy storage cell according to the invention (partial) and

[0127] Fig. 8 drawings of a longitudinal section through another energy storage cell according to the invention (also in detail).

[0128] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0129] Fig. 1 shows an energy storage cell 100 according to the invention with a housing sealed in a vent- and liquid-tight manner, comprising a metallic housing cup 101 with a circular opening at its end and a cover component 102 with a circular edge 102a that closes 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 cover component 102 and electrically insulates the housing cup 101 and the cover component 102 from each other.The housing cup 101 comprises, in axial sequence, a base 101a, a central section 101b, and a closure section 101c, wherein the central section 101b is cylindrical and, in the central section 101b, the winding jacket 104c of the electrode-separator assembly 104 formed as a winding is in contact with the inner side lOld of the housing cup 101, and in the closure section 101c, the annular seal 103 is in press contact with the cover component 102 and the inner side of the housing cup 101. The central section 101b and the closure section 101c are separated by an indentation 111, which runs annularly around the outer side lOle of the housing cup 101.

[0130] The cell 100 also includes an electrode-separator assembly 104 in the form of a cylindrical coil with the anode / separator / cathode sequence, which, however, is not shown in detail here. Only the longitudinal edge 106a of the anode current collector 106, which emerges from the end face 104a of the electrode-separator assembly 104, and the longitudinal edge 109a of the cathode current collector 109, which emerges from the end face 104b of the electrode-separator assembly 104, can be seen. The longitudinal edge 109a is welded directly to the housing base 101a, preferably over its entire length. The longitudinal edge 106a is welded directly to the sheet metal component 112, preferably over its entire length. The sheet metal component 112 is in turn connected to the cover component 102 via the electrical conductor 133.

[0131] The cell 100 preferably has a height in the range of 60 mm to 100 mm, and its diameter is 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.

[0132] The cell comprises an electrically insulating plastic coating 180 as an insulating element, which surrounds an edge of the sheet metal component 112 and protects it from direct contact with the inner side lOld of the housing cup 101, particularly in the region of the indentation 111. The electrically insulating coating 180 is formed by overmolding the edge of the sheet metal component 112. Furthermore, the cell 100 comprises an annular plastic part 170 as an insulating element, which surrounds the separate electrical conductor 133 fixed to the sheet metal part and protects it from direct contact with the inner side lOld of the housing cup 101 in the region of the indentation 111. Consequently, the cell 100 is excellently protected against short circuits even in the event of deformation of the housing as a result of an external mechanical force.

[0133] Fig. 2 shows an energy storage cell 100 according to the invention with a sealed, airtight and liquid-tight housing comprising a metallic housing cup 101 with a circular opening at its end and a cover component 102 with a circular edge 102a that closes the circular opening. The cell further comprises an annular seal 103 made of an electrically insulating material that surrounds the circular edge 102a of the cover component 102 and electrically insulates the housing cup 101 and the cover component 102 from each other.The housing cup 101 comprises, in axial sequence, a base 101a, a central section 101b and a closure section 101c, wherein the central section 101b is cylindrical and in the central section 101b the winding jacket 104c of the electrode-separator assembly 104 designed as a winding is in contact with the inner side lOld of the housing cup 101 (Attention: Solely for reasons of clarity, the electrode-separator assembly 104 is shown spaced from the inner side lOld, but in fact it presses against it, as is shown, for example, in Fig. 1), and in the closure section 101c the annular seal 103 is in press contact with the cover component 102 and the inner side of the housing cup 101. The central section 101b and the closure section 101c are separated by an indentation 111 which runs annularly around the outer side lOle of the housing cup 101.

[0134] The cell 100 also includes an electrode-separator assembly 104 in the form of a cylindrical coil with the anode / separator / cathode sequence, which, however, is not shown in detail here. Only the longitudinal edge 106a of the anode current collector 106, which emerges from the end face 104a of the electrode-separator assembly 104, and the longitudinal edge 109a of the cathode current collector 109, which emerges from the end face 104b of the electrode-separator assembly 104, can be seen. The longitudinal edge 109a is welded directly to the housing base 101a, preferably over its entire length. The longitudinal edge 106a is welded directly to the sheet metal component 112, preferably over its entire length. The sheet metal component 112 is in turn connected to the cover component 102 via the electrical conductor 133.

[0135] The cell 100 preferably has a height in the range of 60 mm to 100 mm, and its diameter is 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.

[0136] The cell comprises, as an insulating element, an annular molded part made of plastic 150 with an L-shaped cross-section, which is applied to the edge that delimits the end face 104a and protects it from direct contact with the inner side lOld of the housing cup 101. Furthermore, the cell comprises an annular insulating element 160 made of plastic, which rests against the inner side lOld of the housing cup 101 in the region of the indentation 111 and protects it from direct contact with the electrical conductor 133. This can also be a partial section of the annular seal 103, which can be sufficiently high to also cover the indentation 111 from the inside.

[0137] As a result, the cell 100 is excellently protected against short circuits even in the event of deformation of the housing as a result of an external mechanical force.

[0138] Instead of the annular molded part made of plastic 150 with an L-shaped cross-section, the edge that defines the end face 104a can also be covered with an insulating tape, for example, a Kapton tape 150. Ideally, this can be applied to the edge during the formation of the winding and protects the edge just as effectively from direct contact with the inner side lOld.

[0139] Fig. 3 shows an energy storage cell 100 according to the invention with a sealed, airtight and liquid-tight housing comprising a metallic housing cup 101 with a circular opening at its end and a cover component 102 with a circular edge 102a that closes the circular opening. The cell further comprises an annular seal 103 made of an electrically insulating material that surrounds the circular edge 102a of the cover component 102 and electrically insulates the housing cup 101 and the cover component 102 from each other.The housing cup 101 comprises, in axial sequence, a base 101a, a central section 101b, and a closure section 101c, wherein the central section 101b is cylindrical and, in the central section 101b, the winding jacket 104c of the electrode-separator assembly 104 formed as a winding is in contact with the inner side lOld of the housing cup 101, and, in the closure section 101c, the annular seal 103 is in press contact with the cover component 102 and the inner side of the housing cup 101. The central section 101b and the closure section 101c are separated by an indentation 111, which runs annularly around the outer side lOle of the housing cup 101.

[0140] The cell 100 also includes an electrode-separator assembly 104 in the form of a cylindrical coil with the anode / separator / cathode sequence, which, however, is not shown in detail here. Only the longitudinal edge 106a of the anode current collector 106, which emerges from the end face 104a of the electrode-separator assembly 104, and the longitudinal edge 109a of the cathode current collector 109, which emerges from the end face 104b of the electrode-separator assembly 104, can be seen. The longitudinal edge 109a is welded directly to the sheet metal component 134, preferably over its entire length. The sheet metal component 134 is in turn connected to the base 101a by welding. The longitudinal edge 106a is welded directly to the sheet metal component 112, preferably over its entire length. The sheet metal component 112 is in turn connected to the cover component 102 via the electrical conductor 133.

[0141] The cell 100 preferably has a height in the range of 60 mm to 100 mm, and its diameter is 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.

[0142] The cell comprises an insulating element, an annular plastic part 170, which laterally encloses the electrical conductor 133 and protects it from direct contact with the inner side lOld of the housing cup 101 in the region of the indentation 111. The annular plastic part 170 is hollow-cylindrical and comprises a jacket 171 perpendicular to the sheet metal component 112. One of its edges is designed as an outwardly directed annular collar 171 and sits on the sheet metal component 112.

[0143] As a result, the cell 100 is excellently protected against short circuits even in the event of deformation of the housing as a result of an external mechanical force.

[0144] Fig. 4 shows several embodiments of a sheet metal component 112 which is suitable for contacting the first longitudinal edge 106a of the current collector 106 emerging from the first terminal end face 104a of an energy storage cell 100 according to the invention.

[0145] Embodiment A shows a circular and essentially flat metal disk with a circumferential edge 102a as sheet metal component 112. This is characterized by a central hole 142 and three offset beads 141. Such a component can be used in the cells according to Figures 1 to 3 for electrically contacting the edge 106a of the anode current collector 106. However, it is also suitable for use as sheet metal component 134 in the cell according to Figure 3. When using such a metal disk for contacting the longitudinal edge 106a, the separate conductor 133 shown in Figures 1 to 3 is generally required to bridge the distance to the cover component 102.

[0146] Embodiment B is different. Here, the sheet metal component 112 comprises a first section 112a, which can sit flat on the first longitudinal edge of the current collector emerging from the first terminal end face 104a and which then extends parallel to the end face 104a. In addition, however, it additionally comprises a second section 112b, which adjoins the first section 112a at an angle and via which the first section 112a is electrically connected to the cover component 102. When using such a sheet metal component, no separate conductor 133 is required. The sheet metal component is further characterized by a hole 142 and two beads 141. The welding of the sheet metal component to the longitudinal edge of the respective current collector preferably takes place in these beads.

[0147] Embodiments C and D differ from embodiment B in that section 112a comprises three and four strips, respectively, extending in different directions. Each of the strips has a bead 141. In addition, the sheet metal parts each have two holes 142.

[0148] The structure of the electrode-separator composite 104 is illustrated in Fig. 5. The composite 104 comprises the strip-shaped anode 105 with the strip-shaped anode current collector 106, which has 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. This comprises a strip-shaped main region loaded with a layer of negative electrode material 107, as well as a free edge strip 106b that extends along its first longitudinal edge 106a and is not loaded with the electrode material 107. Furthermore, the composite 104 comprises the strip-shaped cathode 108 with the strip-shaped cathode current collector 109, which has a first longitudinal edge 109a and a second longitudinal edge parallel thereto. The cathode current collector 109 is an aluminum foil.It comprises a band-shaped main region loaded with a layer of positive electrode material 110, as well as a free edge strip 109b extending along its first longitudinal edge 109a and not loaded with the electrode material 110. Both electrodes are shown individually in the unwound state.

[0149] The anode 105 and the cathode 108 are arranged offset from one another within the electrode-separator assembly 104, so that the first longitudinal edge 106a of the anode current collector 106 extends from the first terminal end face 104a, and the first longitudinal edge 109a of the cathode current collector 109 extends from the second terminal end face 104b of the electrode-separator assembly 104. The offset arrangement is evident from the illustration at the bottom left. Also shown there are the two band-shaped separators 116 and 117, which separate the electrodes 105 and 108 from one another in the winding.

[0150] The illustration at the bottom right shows the electrode-separator assembly 104 in wound form, as it can be used in an energy storage cell according to one of Figures 1 to 4. The electrode edges 106a and 109a emerging from the end faces 104a and 104b are clearly visible. The winding jacket 104c is formed by a plastic film. Figure 6 shows further embodiments of the sheet metal component 112, which is suitable for contacting the first longitudinal edge 106a of the current collector 106 emerging from the first terminal end face 104a of an energy storage cell 100 according to the invention.

[0151] The embodiments BD shown here differ from the sheet metal components shown in the embodiments BD of Fig. 4 essentially only in that section 112b is not folded in a Z shape, but rather bent into a U shape. Such sheet metal components can replace the sheet metal component 112 and the electrical conductor 133 in the cells according to Figures 1 to 3.

[0152] Fig. 7 shows photographs of a longitudinal section through a preferred embodiment of an energy storage cell according to the invention before (A) and after (B) a calibration process. To create the images, the cells were cut lengthwise using a saw. An enlarged section is shown, particularly showing details of the closure section 101c and the recess 111.

[0153] The cover assembly 102 can be seen. This comprises the metal disk 113, which is in direct electrical contact with the pole cap 117, which closes off the cover assembly 102 to the outside. The edge of the metal disk 113 is folded over in a U-shape around the edge of the pole cap 117. The cover assembly 102 also comprises the metallic inner contact disk 115 and the insulator 116. The contact disk 115 is connected at the top by welding to a metallic membrane (not visible here), which is centrally integrated into the metal disk 113, and at the bottom to the separate electrical conductor 133 (connection also not shown), which is welded to the sheet metal component 112. The sheet metal component 112 is in turn connected by welding to the first longitudinal edge 106a of the current collector emerging from the first terminal end face.

[0154] Before the calibration process, the indentation 111 is approximately symmetrical. An insulating tape 150 is applied to the edge of the sheet metal component 112 and protects it and the first longitudinal edge 106a from direct contact with the inside of the housing cup 101. The insulating tape 150 extends upward into a dead volume between the cover assembly 102 and the sheet metal component 112.

[0155] During height calibration, the closure section and the central section are pushed against each other by axial forces, whereby the closure section 101c and the central section 101b are pushed against each other under plastic deformation of the indentation 111, so that the distance d between the sheet metal component 112 and the cover component 102 becomes significantly smaller. This significantly reduces the dead volume between the cover assembly 102 and the sheet metal component 112. The plastic deformation of the indentation 111 is clearly visible. This presses the insulating tape 150 almost onto the sheet metal component 112, reliably preventing a short circuit by the insulating tape 150. Furthermore, the deformation forms an undercut 144 (hatched area below the line L).Overall, as a result of the height calibration, the indentation has an annular opening slot with the height hl and an annular cavity with the undercut 144 accessible via the opening slot.

[0156] After altitude calibration, the displayed cell has the format 21700.

[0157] Fig. 8 shows a longitudinal section through another energy storage cell according to the invention before (A) and after (B) height calibration. This is an enlarged detail, particularly showing details of the closure section 101c and the recess 111.

[0158] The structure of the energy storage cell essentially corresponds to the cell shown in Fig. 7, with one important exception: the indentation is asymmetrical prior to height calibration. The housing of the energy storage cell is essentially cylindrical, and the energy storage cell has a central axis that runs vertically through the bottom of the housing cup (not shown here). The housing cup has an identical maximum outer diameter in the central section 101b and the closure section 101c, while the outer diameter is reduced in the region of the indentation 111. A housing cup segment, in which the outer diameter is reduced in the region of the indentation, extends over a height

[0159] 51. A plane El, which is laid through the lowest point of the indentation and intersects the central axis perpendicularly, divides the housing cup segment into an upper sub-segment facing the cover component with a height S2 and a lower sub-segment facing the electrode-separator assembly with a height S3.

[0160] Due to the asymmetrical design of the indentation 111, S3 has a significantly higher value than

[0161] 52. This allows for advantageous deformation of the recess 111 during height calibration.

[0162] Here, too, it can be seen that the dead volume between the cover assembly 102 and the sheet metal component 112 is significantly reduced (see decrease in distance d from A -> B). The plastic deformation of the indentation 111 is clearly visible. This presses the insulating tape 150 almost onto the sheet metal component 112, whereby a short circuit is reliably prevented by the insulating tape 150. Furthermore, an undercut 144 is also formed here as a result of the deformation (shaded area below the line L). Overall, as a result of the height calibration, the indentation here too has an annular opening slot with the height hl and an annular cavity with the undercut 144 accessible via the opening slot.

Claims

PATENT CLAIMS Energy storage cell (100) with the following features: a. The cell comprises an electrode-separator assembly (104) with the sequence anode (105) / separator (116) / cathode (108). b. The anode (105) of the electrode-separator assembly (104) is ribbon-shaped and comprises a ribbon-shaped anode current collector (106) having a first longitudinal edge (106a) and a second longitudinal edge parallel thereto. c. The ribbon-shaped anode current collector (106) comprises a main region loaded with a layer (107) of negative electrode material and a free marginal strip extending along its first longitudinal edge (106a) that is not loaded with the negative electrode material. d. The cathode (108) of the electrode-separator assembly (104) is ribbon-shaped and comprises a ribbon-shaped cathode current collector (109) having a first longitudinal edge (109a) and a second longitudinal edge parallel to it.The ribbon-shaped cathode current collector (109) comprises a main region loaded with a layer of positive electrode material (110) and a free marginal strip extending along its first longitudinal edge (109a) that is not loaded with the electrode material (110). f. The electrode-separator assembly (104) is in the form of a cylindrical winding with a first terminal end face (104a) bounded by a circumferential edge and a second terminal end face (104b) bounded by a circumferential edge, and an intermediate winding sheath (104c), and comprises the anode (105) and the cathode (108) in a spirally wound form. g.The anode (105) and the cathode (108) are arranged within the electrode-separator assembly (104) such that the first longitudinal edge (106a) of the anode current collector (106) emerges from one of the terminal end faces (104a, 104b) and the first longitudinal edge (109a) of the cathode current collector (109) emerges from the other terminal end face (104a, 104b) of the electrode-separator assembly (104). The cell comprises an airtight and liquid-tight housing, which has a metallic housing cup (101) with a base (101a) and a terminal circular opening, and a lid component (102) with a circular rim (102a) that closes the terminal circular opening. Page 31 i. The electrode-separator assembly (104) is arranged axially in the housing cup, with the first end face (104a) facing the lid component and the second end face (104b) facing the base (101a), optionally in direct contact with the base (101a). j. The cell comprises an annular seal (103) made of an electrically insulating material, which surrounds the circular rim (102a) of the lid component (102) and electrically insulates the housing cup (101) and the lid component (102) from each other. k.The housing cup (101) comprises an inner side (1Old) and an outer side (1Ole) and, in axial sequence, the base (101a), a central section (101b), and a closure section (101c), wherein the central section (101b) is cylindrical and the winding sheath (104c) of the coiled electrode-separator assembly (104) is in contact with the inner side (1Old) of the housing cup (101) in the central section (101b), and the annular seal (103) is in press contact with the lid component (102) and the inner side of the housing cup (101) in the closure section (101c). The central section (101b) and the closure section (101c) are separated by a recess (111) which runs annularly around the outer side (1Ole) of the housing cup (101).The cell comprises a sheet metal component (112), optionally including a separate electrical conductor (133) fixed to the sheet metal component, which is welded to the first longitudinal edge of the current collector emerging from the first terminal end face (104a) and via which this current collector is electrically connected to the cover component (102). The cell comprises at least one insulating element (150; 160; 170; 180) made of an electrically insulating material, which protects the sheet metal component (112) and / or the first longitudinal edge (106a, 109a) of the current collector (106, 109) emerging from the first terminal end face (104a) and / or the separate electrical conductor (133) fixed to the sheet metal component from direct contact with the inside (101) of the housing cup (101), particularly in the area of ​​the recess (111). Energy storage cell according to claim 1 with at least one of the following additional features:. Page 32 a. The at least one insulating element is or comprises an insulating tape (150) applied to the edge bounding the end face (104a) and protecting it from direct contact with the inner surface (1Old). b. The at least one insulating element is or comprises an annular molded part made of plastic (150) with a preferably L-shaped cross-section, applied to the edge bounding the end face (104a) and protecting it from direct contact with the inner surface (1Old). c. The insulating tape or the annular molded part made of plastic has a thickness in the range of 10 pm to 200 pm.

3. Energy storage cell according to claim 1 with at least one of the following additional features: a. The at least one insulating element is or comprises an annular insulating element (160) made of plastic, which rests against the inside (lOld) of the housing cup (101) in the area of ​​the indentation (111) and protects it from direct contact with the sheet metal component (112). b. The annular insulating element (160) is a section of the annular seal (103). c. The annular insulating element (160) made of plastic has a thickness in the range of 50 pm to 500 pm.

4. Energy storage cell according to claim 1 with at least one of the following additional features: a. The at least one insulating element is or comprises an annular plastic part (170) that surrounds the sheet metal component (112) and protects it from direct contact with the inside (101) of the housing cup (101) in the area of ​​the recess (111). b. The annular plastic part (170) is hollow cylindrical, comprises a shell (171), and is bounded at each end face by a circumferential rim. c. The annular plastic part (170) is hollow cylindrical, comprises a shell (171), and is bounded at each end face by a circumferential rim, one of which is formed as an outwardly directed annular collar (171) and rests on the sheet metal component (112). Page 33 d. The ring-shaped plastic part (170) has a thickness in the range of 20 pm to 600 pm. Energy storage cell according to claim 1 with at least one of the following additional features: a. The at least one insulating element is or comprises an electrically insulating plastic coating (180) that surrounds an edge of the sheet metal component (112) and protects it from direct contact with the inside (lOld) of the housing cup (101), particularly in the area of ​​the indentation (111). b. The electrically insulating coating (180) is formed by overmolding the edge of the sheet metal component (112). Energy storage cell according to claim 1 with at least one of the following additional features: a. The at least one insulating element comprises an insulating tape (150) or a ring-shaped molded part made of plastic (150) that is applied to the edge that delimits the end face (104a) and protects it from direct contact with the inside (lOld). b.The at least one insulating element comprises an annular insulating element (160) that rests against the inner surface (1Old) of the housing cup (101) in the area of ​​the indentation (111) and protects it from direct contact with the sheet metal component (112). c. The at least one insulating element comprises an annular plastic part (170) that surrounds the sheet metal component (112) and protects it from direct contact with the inner surface (1Old) of the housing cup (101) in the area of ​​the indentation (111). d. The at least one insulating element is or comprises an electrically insulating plastic coating (180) that surrounds an edge of the sheet metal component (112) and protects it from direct contact with the inner surface (1Old) of the housing cup (101), particularly in the area of ​​the indentation (111). Energy storage cell according to one of the preceding claims with at least one of the following additional features: Page 34 a. The housing cup (101) has an identical maximum outer diameter in the central section (101b) and the closure section (101c). b. In the area of ​​the indentation (111), the outer diameter of the housing cup (101) is reduced by 4 to 12 times the wall thickness of the housing cup (101) in this area.

8. Energy storage cell according to one of the preceding claims with at least one of the following additional features: a. The sheet metal component (112) is directly connected to the cover component (102). b. The sheet metal component (112) comprises a first section (112a) that rests flat on the first longitudinal edge of the current exiting from the first terminal end face (104a) and extends parallel to the end face (104a). c. The sheet metal component (112) comprises a second section (112b) that connects to the first section at an angle and through which the first section is electrically connected to the cover component (102).

9. Energy storage cell according to one of claims 1 to 7 with at least one of the following additional features: a. The sheet metal component (112) is connected to the cover component (102) via the separate electrical conductor (133). b. The sheet metal component (112) sits flat on the first longitudinal edge of the current collector emerging from the first terminal end face (104a).

10. Energy storage cell according to one of the preceding claims with one of the following additional features: a. The first longitudinal edge of the current collector exiting the second terminal end face (104b) rests directly on the base (101a) of the housing cup (101) and is welded to it. b. The cell comprises a sheet metal component (134) that is welded to the first longitudinal edge of the current collector exiting the second terminal end face (104b) and through which this current collector is electrically connected to the base (101a) of the housing cup (101). Page 35 Energy storage cell according to one of the preceding claims with the following additional feature: a. The current collector exiting the first terminal end face (104a) is the anode current collector (106) and the current collector exiting the second end face (104b) is the cathode current collector (109). Energy storage cell according to one of the preceding claims with one of the following additional features: a. The housing cup is made of aluminum or an aluminum alloy. b. A terminal section of a current collector foil made of aluminum or an aluminum alloy, not coated with electrode material, forms the outer turn of the winding and simultaneously rests directly against the housing cup made of aluminum or the aluminum alloy. Energy storage cell according to one of the preceding claims with one of the following additional features: a.The housing cup is made of copper or nickel or a copper or nickel alloy. b. A terminal section of a current collector foil made of copper or nickel or a copper or nickel alloy, not coated with electrode material, forms the outer turn of the winding and simultaneously rests directly against the housing cup made of copper or nickel or the copper or nickel alloy. Method for manufacturing an energy storage cell comprising the following steps: a. An energy storage cell (100) is provided having the features a. to n. of claim 1. b. The energy storage cell is subjected to height calibration, whereby, under plastic deformation of the indentation (111), the closure section (101c) and the central section (101b) are pushed against each other, so that the distance d between the sheet metal component (112), which is connected to the first longitudinal edge of the... Page 36, the first terminal end face (104a) of the current collector exiting is connected by welding, and the cover component (102) becomes smaller. Method according to claim 14, characterized by the following additional feature: a. The distance d between the sheet metal component (112) and the cover component (102) is reduced by at least 10%.

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