Energy storage cell and manufacturing process

Abstract

The energy storage cell (100) includes an electrode-separator assembly (104) in the form of a cylindrical wound body having two end faces (104a, 104b), wherein the longitudinal edge (106a) of the anode current collector (106) protrudes from one of the end faces (104a, 104b), and the longitudinal edge (109a) of the cathode current collector (109) protrudes from the other of the end faces (104a, 104b) of the electrode-separator assembly (104). The assembly (104) is encapsulated by a housing, which includes a metal housing cup (101) having an inner surface (101d) and an outer surface (101e), and a lid component (102). The metal sheet component (112) includes an optional separate electrical conductor (133) attached to this metal sheet component, and electrically connects the longitudinal edge (106a; 109a) of one of the current collectors (106; 109) protruding from the first end face (104a) to the lid component (102). At least one insulating element (150; 160; 170; 180) made of an electrically insulating material is proposed to prevent the metal sheet component (112), and / or the longitudinal edges (106a, 109a) of the current collectors (106, 109) protruding from the first end face (104a), and / or the separate electrical conductor (133) attached to the metal sheet component from coming into direct contact with the inner surface (101d) of the housing cup (101). Further, a method for manufacturing an energy storage cell is proposed, in which the energy storage cell (100) is subjected to height calibration.

Description

Technical Field

[0001] The present invention described below relates to an energy storage cell and a method for manufacturing the energy storage cell.

Background Art

[0002] An electrochemical energy storage device can convert stored chemical energy into electrical energy through an oxidation-reduction reaction. The simplest form of an electrochemical energy storage device is an electrochemical cell. An electrochemical cell includes a positive electrode and a negative electrode separated from each other by a separator. During discharge, as a result of the oxidation process, electrons are released at the negative electrode. This results in an electron current that can be drawn by an external electrical consumer, and the electrochemical cell acts as an energy supplier to the external electrical consumer. At the same time, an ionic current corresponding to the electrode reaction is generated inside the cell. This ionic current passes through the separator and is enabled by an ion-conducting electrolyte.

[0003] When the discharge is reversible, that is, when it is possible to reverse the conversion of chemical energy to electrical energy during discharge and recharge the cell again, this is called a secondary cell. In a secondary cell, the common nomenclature of calling the negative electrode the anode and the positive electrode the cathode refers to the discharge function of the electrochemical cell.

[0004] Currently, secondary lithium-ion cells are used as energy storage devices for many applications, because secondary lithium-ion cells can supply a large current and are characterized by a relatively high energy density. Secondary lithium-ion cells are based on the use of lithium, and lithium can move back and forth between the electrodes of the cell in the form of ions. The negative electrode and the positive electrode of a lithium-ion cell are generally formed by so-called composite electrodes, which include an electrochemically inactive constituent material and an electrochemically active constituent material.

[0005] In principle, any material that can absorb and release lithium ions can be used as an electrochemically active constituent material (active material) of a secondary lithium ion cell. For example, carbon-based particles such as graphite-like carbon are used as the negative electrode. The active material of the positive electrode can be, for example, lithium cobalt oxide (LiCoO 2 ), lithium manganese oxide (LiMn 2 O 4 ), lithium iron phosphate (LiFePO 4 ), or derivatives thereof. Electrochemically active substances are generally contained in the electrodes in the form of particles.

[0006] As an electrochemically inert constituent material, a composite electrode generally includes a flat and / or ribbon-shaped current collector, such as a metal foil, which serves as a carrier for each active material. The current collector of the negative electrode (anode current collector) can be made of, for example, copper or nickel, and the current collector of the positive electrode (cathode current collector) can be made of, for example, aluminum. Furthermore, the electrode can include an electrode binder (e.g., polyvinylidene fluoride (PVDF) or another polymer, such as carboxymethyl cellulose), a conductivity-improving additive, and other additives as electrochemically inert constituent materials. The electrode binder ensures the mechanical stability of the electrode and often also securely adheres the active material to the current collector.

[0007] As the electrolyte, a lithium ion cell generally includes a solution of a lithium salt, such as lithium hexafluorophosphate (LiPF 6 ) in an organic solvent (e.g., esters and ethers of carbonic acid).

[0008] When manufacturing a lithium ion cell, a composite electrode is 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 the separator are connected to each other with or without pressure, and in some cases, they are further connected by lamination or adhesion. Then, the basic function of the cell can be established by impregnating this assembly with an electrolyte.

[0009] In many embodiments, the electrode-separator assembly is formed in the form of a wound body or processed into a wound body. In the first case, for example, a ribbon-shaped positive electrode, a ribbon-shaped negative electrode, and at least one ribbon-shaped separator are separately fed into a bending machine and spirally wound into a coil having a sequence of positive electrode / separator / negative electrode. In the wound body thus formed, the electrodes are connected to each other via the separator. However, in most cases, it is not a good idea to adhere the electrodes to the separator with an adhesive or connect them in a similar way. In the second case, the ribbon-shaped positive electrode, the ribbon-shaped negative electrode, and at least one ribbon-shaped separator are first combined to form an electrode-separator assembly, for example, by applying the pressure described above. In a further step, this assembly is then fully wound.

[0010] There is a need for lithium-ion cells that have the highest possible energy density and can withstand high currents during charging and discharging for applications in the automotive industry, electric motorcycles, or other high-energy-requirement applications such as tools.

[0011] Cells for the aforementioned applications are often designed as cylindrical round cells having a form factor of, for example, 21×70 (in mm, diameter * height). This type of cell always includes an assembly in the form of a wound body. The latest 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 just an intermediate stage. In the market, cells with even higher energy densities are already being demanded.

[0012] The housing of a cylindrical round cell generally includes a housing cup that functions as a container for a wound electrode-separator assembly, and a lid component that closes the opening of the housing cup. A seal is disposed between the lid component and the housing cup, which on the one hand acts to seal the cell housing and on the other hand also has the function of electrically insulating the lid component and the housing cup from each other. The seal is usually attached to the edge of the lid component. To seal the round cell, the edge of the opening of the housing cup is generally bent radially inward (crimping process) to cover the edge of the lid component surrounded by the seal, and as a result, the lid component including the seal becomes firmly fixed to the opening of the housing cup.

[0013] WO 2017 / 215900 A1 pamphlet describes a cylindrical round cell in which the electrode-separator assembly and its electrodes are in the form of ribbons and are wound. Each electrode has a ribbon-shaped electrode loaded with an electrode material. Electrodes with opposite polarities are arranged offset from each other inside the electrode-separator assembly, and as a result, the longitudinal edge of the current collector of the positive electrode protrudes from one side of the wound body, and the longitudinal edge of the current collector of the negative electrode protrudes from the other side of the wound body. To make electrical contact with the current collector, the cell has a metal sheet component, which is placed flat on the end face of the wound body and is connected to the longitudinal edge of the current collector by welding. This enables electrical contact to be made with the current collector, and thus the associated electrode, over its entire length. A cell equipped with a wound body thus contacted has a significantly reduced internal resistance. As a result, the generation of a large current can be much better alleviated, and heat can also be dissipated better from the wound body.

[0014] In the case of contact plate design / end face wound body contact, in order to provide a large cross-section to increase electrical conductivity and thermal conductivity, a very solid metal contact element is preferred. However, a cell having such a solid internal contact element is susceptible to short circuits, which can occur, in particular, as a result of external mechanical forces causing deformation of the housing. For example, in the case of cells used in the automotive field, the risk of such damage is very real. Furthermore, during the manufacture of the cell, height calibration may also be required, where the cell is further compressed. The axial force applied here may cause a short circuit inside the cell. Summary of the Invention Problems to be Solved by the Invention

[0015] The object of the present invention was to provide an energy storage cell characterized by a high energy density. Furthermore, the energy storage cell should in particular also be characterized by an improved safety. Means for Solving the Problems

[0016] This object is achieved by an energy storage cell having the features of claim 1 and a method having the features of claim 14. Preferred embodiments of the invention can be found in dependent claims 2 to 13 and 15.

[0017] The energy storage cell according to the present invention always has the following features a. to n. directly below. a. The cell includes an electrode-separator assembly having a sequence of anode / separator / cathode. b. The anode of the electrode-separator assembly is ribbon-shaped and includes a ribbon-shaped anode current collector having a first longitudinal edge and a second longitudinal edge parallel thereto. c. The ribbon-shaped anode current collector includes a main region loaded with a layer of negative electrode material and a free edge strip extending along the first longitudinal edge of the anode current collector where no negative electrode material is loaded. d. The cathode of the electrode-separator assembly is ribbon-shaped and includes a ribbon-shaped current collector having a first longitudinal edge and a second longitudinal edge parallel thereto. e. The ribbon-shaped current collector includes a main region on which a layer of the positive electrode material is loaded and a free edge strip extending along the first longitudinal edge of the current collector where no electrode material is loaded. f. The electrode-separator assembly is in the form of a cylindrical wound body, which has a first end face bounded by a circumferential edge, a second end face bounded by a circumferential edge, and a wound body shell therebetween. Also, the electrode-separator assembly includes the anode and the cathode wound in a spiral form. g. The anode and the cathode are arranged inside the electrode-separator assembly in such a manner that the first longitudinal edge of the anode current collector protrudes from one of the end faces and the first longitudinal edge of the cathode current collector protrudes from the other end face of the electrode-separator assembly. h. The cell includes a hermetic and liquid-tight housing having a metal housing cup with a bottom and a terminal circular opening, and a lid component having a circular edge closing the terminal circular opening. i. Inside the housing cup, the electrode-separator assembly is arranged axially aligned, with the first end face facing the lid component and the second end face facing the bottom, and in certain cases in direct contact with the bottom. j. The cell includes an annular seal made of an electrically insulating material, which surrounds the circular edge of the lid component and electrically insulates the housing cup and the lid component from each other. k. The housing cup includes an inner surface and an outer surface, and axially in sequence includes a bottom, a central portion, and a closing portion. - The central portion is cylindrical, and in the central portion, the wound body shell of the electrode-separator assembly in the form of a wound body is in contact with the inner surface of the housing cup. - In the closing portion, the annular seal is in pressing contact with the lid component and the inner surface of the housing cup. l. The central part and the closed part are separated by a recess that circumferentially surrounds the outer surface of the housing cup. m. The cell includes a metal sheet component, which optionally includes a separate electrical conductor attached to this metal sheet component. The metal sheet component is connected by welding to the first longitudinal edge of a current collector protruding from the first end face. This current collector is electrically connected to the lid component via the metal sheet component.

[0018] The cell has the following features in particular. n. The cell includes at least one insulating element made of an electrically insulating material, which prevents the metal sheet component, and / or the first longitudinal edge of the current collector protruding from the first end face, and / or a separate electrical conductor attached to the metal sheet component from coming into direct contact with the inner surface of the housing cup, especially in the area of the recess.

[0019] By this measure, the risk of short - circuit in the internal contact area of the cell is reduced. For example, the axial forces occurring in connection with height calibration generally no longer cause direct contact between cell components with opposite polarities. These are prevented by at least one insulating element.

[0020] 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, for example, by welding the bottom to a tubular half - component.

[0021] The wall thickness of the housing cup is preferably in the range of 0.1 mm to 2 mm.

[0022] The housing cup is preferably made of aluminum, an aluminum alloy, or a thin steel sheet, such as a nickel - plated thin steel sheet. It is preferably possible to use stainless steel as well.

[0023] Aluminum alloys suitable for the housing cup are, for example, type 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55 Al alloys. AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg, and AlMg are also suitable. The aluminum content of these alloys preferably exceeds 99.5%.

[0024] The energy storage cell according to the present invention is preferably a cylindrical round cell. The height of the cylindrical round cell of the energy storage cell according to the present invention is preferably in the range of 50 mm to 150 mm. Its diameter is preferably in the range of 15 mm to 60 mm. The cylindrical round cell having these form factors is suitable, for example, for supplying power to the electric drive unit of an automobile.

[0025] The electrode-separator assembly is preferably manufactured using two ribbon-shaped separators. The assembly is preferably in the sequence of separator / anode / separator / cathode, or anode / separator / cathode / separator. Then, one or more separators enclose the anode or cathode. Their role is to avoid direct electrical contact between electrodes with opposite polarities inside the wound body, and at the same time, to enable ion exchange between the electrodes.

[0026] Lithium-ion cell version In a particularly preferred embodiment of the present invention, the energy storage cell according to the present invention is a lithium-ion cell. Basically, all electrode materials known for secondary lithium-ion cells can be used for the electrodes of this energy storage cell.

[0027] Carbon-based particles such as graphite-like carbon or non-graphite-like carbon materials that can intercalate lithium and are preferably in the form of particles can be used as the active material of the negative electrode. Instead of or in addition to this, lithium titanate (Li 4 Ti5 O 12 ) or its derivatives can also be preferably contained in the negative electrode in the form of particles. Further, the negative electrode can contain, as an active material, at least one material selected from the group consisting of silicon, aluminum, tin, antimony, or a compound or alloy of these materials that can reversibly store and release lithium, for example, silicon oxide (especially, SiO x , provided that 0 < x < 2), optionally in combination with a carbon-based active material. Tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. The receptability of lithium far exceeds the receptability of graphite or a material equivalent thereto, and is particularly remarkable in the case of silicon. A mixture of silicon and a carbon-based storage material is often used. For example, a silicon-carbon composite material (SiC) is also particularly suitable. A thin anode made of metallic lithium is also suitable.

[0028] As active materials suitable for the positive electrode, there are mentioned lithium metal oxide compounds such as LiCoO 2 and LiFePO 4 and lithium metal phosphate compounds. The lithium nickel manganese cobalt oxide (NMC) having the chemical formula LiNi x Mn y Co z O 2 (where x + y + z is usually 1) is also particularly suitable, and the lithium manganese spinel (LMO) having the chemical formula LiMn 2 O 4 or the lithium nickel cobalt aluminum oxide (NCA) having the chemical formula LiNi x Co y Al z O 2 (where x + y + z is usually 1) is 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 ) 0.89 O 2Lithium nickel manganese cobalt aluminum oxide (NMCA) having [specific content] or Li 1+x

[0029] Furthermore, the electrodes of the energy storage cell according to the present invention preferably contain additives and / or electrode binders for improving 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 based on, for example, polyvinylidene fluoride (PVDF), (Li-) polyacrylate, styrene-butadiene rubber, or carboxymethyl cellulose, or a mixture of different binders. Common conductive agents are carbon black, fine graphite, carbon fiber, carbon nanotubes, and metal powder.

[0030] The energy storage cell according to the present invention contains an electrolyte solution. In particular, in the case of a lithium-ion cell, it is present in a dissolved state in an organic solvent (for example, a mixture of organic carbonates, or a cyclic ether such as THF or nitrile), and contains an electrolyte solution based on at least one lithium salt such as lithium hexafluorophosphate (LiPF 6 )). Other lithium salts that can be used include, for example, lithium tetrafluoroborate (LiBF 4 ), 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 cell according to the present invention, designed as a cylindrical round cell, is preferably at most 15000 mAh. In the case of a form factor of 21×70, the energy storage cell in the form of a lithium-ion cell preferably has 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 form factor of 18×65, the cell in the form of a lithium-ion cell preferably has 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, the manufacturer information regarding the nominal capacity of secondary batteries is strictly regulated. For example, the information regarding the nominal capacity of secondary nickel-cadmium batteries must be based on measurements in accordance with the IEC / EN61951-1 and IEC / EN60622 standards, the information regarding the nominal capacity of secondary nickel-metal hydride batteries must be based on measurements in accordance with the IEC / EN61951-2 standard, the information regarding the nominal capacity of secondary lithium batteries must be based on measurements in accordance with the IEC / EN61960 standard, and the information regarding the nominal capacity of secondary lead-acid batteries must be based on measurements in accordance with the IEC / EN61056-1 standard. The information regarding the nominal capacity in the present application is also preferably based on these standards.

[0033] Embodiments of sodium-ion cells Alternatively, the energy storage cell according to the present invention may be a sodium-ion cell, a potassium-ion cell, a calcium-ion cell, a magnesium-ion cell, or an aluminum-ion cell. In a further possible embodiment, the energy storage cell according to the present invention includes a sodium-ion cell, a potassium-ion cell, a calcium-ion cell, a magnesium-ion cell, or an aluminum-ion cell. Among these variations, according to the present invention, an energy storage cell having the chemical properties of a sodium-ion cell is particularly preferred.

[0034] The negative electrode material of the sodium-ion-based energy storage device according to the present invention is, for example, one of the following materials. - Carbon, especially hard carbon (pure or doped with nitrogen and / or phosphorus), or soft carbon, or graphene-based materials, carbon nanotubes, graphite, - Phosphorus or sulfur, - Na 2 Ti 3 O 7 、Na 3 Ti 2 (PO 4 ) 3 、TiP 2 O 7 、TiNb 2 O 7 、Na-Ti-(PO 4 ) 3 、Na-V-(PO 4 ) 3 such as polyanions, - V 2 O 5 、MnO 2 、TiO 2 、Nb 2 O 5 、Fe 2 O 3 、Na 2 Ti3O 7 、NaCrTiO 4 、Na 4 Ti 5 O 12 such as transition metal oxides. Alternatively, a Na metal anode can also be used on the anode side.

[0035] The positive electrode material of the sodium-ion-based energy storage device according to the present invention is, for example, one of the following materials. - Polyanions: NaFePO 4 (triphylite type), Na 2 Fe(P 2 O 7 )、Na 4 Fe 3 (PO 4 ) 2 (P 2 O7 ) Na 2 FePO 4 F, Na / Na 2 [Fe 1 / 2 Mn 1 / 2 PO 4 F, Na 3 V 2 (PO 4 ) 2 F 3 , Na 3 V 2 (PO 4 ) 3 , NaCoPO 4 , Na 2 CoPO 4 , F -Silicate: Na 2 MnSiO 4 , Na 2 FeSiO 4 , -Layered Oxide: NaCoO 2 , NaFeO 2 , NaNiO 2 , NaCrO 2 , NaVO 2 , NaTiO 2 , Na(FeCo)O 2 , Na(NiFeCo) 3 O 2 , Na(NiFeMn)O 2 , and Na(NiFeCoMn)O 2 , Na(NiMnCo)O 2 .

[0036] Similar to lithium-ion cells, sodium-ion-based electrodes can also contain additives and / or electrode binders to improve electrical conductivity. Suitable electrode binders are based on, for example, polyvinylidene fluoride (PVDF), (Li-) polyacrylate, styrene-butadiene rubber, or carboxymethyl cellulose, or a mixture of different binders. Suitable conductive agents are carbon black, fine graphite, carbon fiber, carbon nanotubes, and metal powder.

[0037] The sodium-ion based energy storage cell according to the present invention preferably includes an electrolytic solution containing at least one of the following solvents and at least one of the following conductive salts: - As the solvent, organic carbonates, ethers, nitriles, and mixtures thereof are particularly suitable. - Preferred main salts are NaPF 6 , sodium difluoro(oxalate)borate (NaBOB), NaBF 4 , sodium bis(fluorosulfonyl)imide (NaFSI), sodium 2-trifluoromethyl-4,5-dicyanoimidazole (NaTDI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), NaAsF 6 , NaBF 4 , NaClO 4 , NaB(C 2 O 4 ) 2 , NaP(C 6 H 4 O 2 ) 3 ; NaCF 3 SO 3 , sodium triflate (NaTf), and Et 4 NBF 4 . In a preferred embodiment, additives may be added to the electrolytic solution.

[0038] The nominal capacity of the sodium-ion based energy storage cell according to the present invention, designed as a cylindrical round cell, is preferably at most 12000 mAh. In the case of a form factor of 21×70, the energy storage cell in the embodiment as a lithium-ion cell preferably has a nominal capacity in the range of 1200 mAh to 5500 mAh, particularly preferably in the range of 2500 to 4500 mAh. In the case of a form factor of 18×65, the cell in the embodiment as a lithium-ion cell preferably has a nominal capacity in the range of 800 mAh to 4500 mAh, particularly preferably in the range of 1600 to 3200 mAh.

[0039] Protection of the end face edge of the electrode-separator assembly In a first particularly preferred embodiment, the energy storage cell according to the invention is characterized by at least one of the following features a. to c. directly below. a. At least one insulating element is an insulating tape that is attached to the edge defining the boundary of the end face and prevents the end face from coming into direct contact with the inner surface, or includes such an insulating tape. b. At least one insulating element is preferably an annular molded part made of plastic with an L-shaped cross-section, which is applied to the edge defining the boundary of the end face and prevents the end face from coming into direct contact with the inner surface, or includes such an annular molded part. c. The insulating tape or the annular molded plastic part has a thickness in the range of 10 μm to 200 μm. It is preferable that the immediately preceding features a. and c. and b. and c. are realized in combination.

[0040] The insulating tape can be, for example, a Kapton / polyimide adhesive tape.

[0041] The annular molded plastic part, preferably having an L-shaped cross-section, can be, for example, injection molded and pressed against the edge to be protected. It can be made of, for example, Teflon or polyamide.

[0042] Protection of the inner surface of the housing cup In a second particularly preferred embodiment, the energy storage cell according to the invention is characterized by at least one of the following features a. to c. directly below. a. At least one insulating element is an annular insulating element made of plastic, which is arranged in contact with the inner surface of the housing cup in the recessed area and prevents the inner surface from coming into direct contact with the metal sheet part, or includes such an annular insulating element. b. The annular insulating element is part of an annular seal. c. The annular insulating element made of plastic has a thickness in the range of 20 μm to 400 μm.

[0043] The immediately preceding features a. and b. are preferably realized in combination. It is particularly preferable that the features a. to c. are realized in combination.

[0044] The annular insulating element can also be an injection-molded part, like the annular seal. The thickness of the insulating element is preferably in the range of 20 μm to 400 μm.

[0045] The annular insulating element can be made of, for example, Teflon, polyamide, polybutylene terephthalate, or perfluoroalkoxy polymer.

[0046] Protection of the metal sheet part welded to the current collector protruding from the first end face 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. At least one insulating element is an annular plastic part that surrounds the sheet metal component and prevents the sheet metal component from coming into direct contact with the inner surface of the housing cup in the recessed area, or includes such an annular plastic part. b. The annular plastic part is hollow cylindrical, includes a shell, and is bounded by a circumferential edge at the end face. c. The annular plastic part has a hollow cylindrical shape, includes a shell, and is respectively bounded by a circumferential edge at the end face. One of the edges is designed as an outward-facing annular flange and is placed on the sheet metal component. d. The annular plastic part has a thickness in the range of 20 μm to 600 μm.

[0047] The immediately preceding features a. and b., particularly preferably features a., b., and d., are preferably realized in combination. The immediately preceding features a., c., and d. are particularly preferably realized in combination.

[0048] The annular 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.

[0049] The plastic part can be made of, for example, Teflon, polyamide, polybutylene terephthalate, or perfluoroalkoxy polymer.

[0050] Protection of the edge of the metal sheet part In a fourth particularly preferred embodiment, the energy storage cell according to the invention is characterized by at least one of the following features a. to d. directly below. a. At least one insulating element is an electrically insulating plastic coating that surrounds the edge of the metal sheet part and prevents the metal sheet part from coming into direct contact with the inner surface of the housing cup, especially in the recessed area. Or it includes such an electrically insulating plastic coating. b. The electrically insulating coating is formed by overmolding the edge of the metal sheet part. It is preferred that the immediately preceding features a. and b. are realized in combination.

[0051] Basically, all thermoplastic substances having electrical insulation properties are suitable for overmolding the edge of the metal sheet part. For example, polyamide is suitable.

[0052] Combination of protection According to the invention, the combination of the above four embodiments is also particularly preferred. Therefore, it is particularly preferred that the cell is characterized by a combination of two or more of the following four features a. to d. directly below. a. At least one insulating element includes an insulating tape or a plastic annular molded part, which is applied to the edge defining the boundary of the end face and prevents the edge from coming into direct contact with the inner surface. That is, it is an insulating tape or an annular molded part according to the first particularly preferred embodiment. And / or, b. At least one insulating element includes an annular insulating element, which is arranged in contact with the inner surface of the housing cup in the recessed area to prevent the inner surface from coming into direct contact with the metal sheet part. That is, it is an annular insulating element according to a second particularly preferred embodiment. And / or, c. At least one insulating element includes an annular plastic part, which surrounds the metal sheet part to prevent the metal sheet part from coming into direct contact with the inner surface of the housing cup in the recessed area. That is, it is an annular plastic part according to a third particularly preferred embodiment. And / or, d. At least one insulating element is or includes an electrically insulating plastic coating, which surrounds the edge of the metal sheet part to prevent the metal sheet part from coming into direct contact with the inner surface of the housing cup, especially in the recessed area. That is, it is a plastic coating according to a fourth particularly preferred embodiment.

[0053] Preferred embodiments of the recess The cell according to the present invention preferably features at least one of the following features a. to c. a. The housing cup has the same maximum outer diameter at the central part and the closing part. b. In the recessed area, the outer diameter of the housing cup decreases by 4 to 20 times the wall thickness of the housing cup in this area. It is preferred that the immediately preceding features a. and b. be realized in combination.

[0054] Electrical connection between the metal sheet part and the lid part There are two preferred variants for electrically connecting a metal sheet part connected by welding to the first longitudinal edge of the current collector protruding from the first end face to the lid part.

[0055] According to Variant A, the cell according to the present invention features at least one of the following features a. to c. below. a. The metal sheet part is directly connected to the lid part. b. The metal sheet part includes a first portion, which is flatly arranged on the first longitudinal edge of the current collector protruding from the first end face and extends parallel to the end face. c. The metal sheet part includes a second portion, which is angularly connected to the first portion, and through this second portion, the first portion is electrically connected to the lid part. It is preferable that the immediately preceding features a. and b. are realized in combination. It is particularly preferable that the immediately preceding features a. to c. are realized in combination.

[0056] 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 metal sheet part is connected to the lid part via a separate electrical conductor. b. The metal sheet part is flatly arranged on the first longitudinal edge of the current collector protruding from the first end face. It is preferable that the immediately preceding features a. and b. are realized in combination.

[0057] When a separate electrical conductor is used, this conductor is preferably made of the same material as the metal sheet part itself.

[0058] Electrical contact of the first longitudinal edge of the current collector protruding from the second end face Of course, it is not only that the first longitudinal edge of the current collector protruding from the first end face must be electrically contacted. Rather, the first longitudinal edge of the current collector protruding from the second end face must also be electrically contacted. According to the invention, the following two variants are preferable. According to 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 protruding from the second end face is directly placed on the bottom of the housing cup and connected to the bottom by welding.

[0059] According to the deformation form D, the cell according to the invention is characterized by the following feature b. directly below it. b. The cell includes a metal sheet part, which is connected by welding to the first longitudinal edge of the current collector protruding from the second end face, and through this metal sheet part, the current collector is electrically connected to the bottom of the housing cup.

[0060] In either case, the longitudinal edge of the current collector protruding from the second end face may ideally be electrically and / or thermally connected over its entire length, similar to the case of the current collector protruding from the first end face.

[0061] The cell according to the invention preferably is characterized in particular by the following feature a. a. The current collector protruding from the first end face is an anode current collector, and the current collector protruding from the second end face is a cathode current collector.

[0062] This configuration is particularly advantageous when the housing is made of aluminum or an aluminum-containing alloy as described above. Since the cathode current collector preferably also consists of aluminum, see the following.

[0063] Preferred embodiments of the metal sheet part In a particularly preferred further development of the invention, the metal sheet part electrically connected to the anode current collector is characterized by at least one of the following features a. or b. directly below it. a. The metal sheet part consists of nickel, or copper, or titanium, or an alloy of nickel or copper or titanium, or stainless steel (for example, of type 1.4303 or 1.4404, or of type SUS304), or nickel-plated copper. b. The metal sheet part consists of the same material as the anode current collector. The above features a. and b. are preferably realized in combination.

[0064] In an embodiment where the cathode current collector is also electrically connected via a metal sheet component, this metal sheet component is characterized by at least one of the following features a. and b. directly below. a. The metal sheet component is made of aluminum or an aluminum alloy. b. The metal sheet component is made of the same material as the cathode current collector. The above features a. and b. are preferably realized in combination.

[0065] The metal sheet component that can be used according to the present invention to contact the longitudinal edges of those current collectors is particularly preferably characterized by at least one of the following features a. to g. directly below. a. The thickness of those metal sheet components is preferably uniform within the range of 50 μm to 600 μm, more preferably within the range of 150 μm to 350 μm. b. Those metal sheet components have two opposing flat surfaces and extend essentially only in one dimension. c. Those metal sheet components are in the shape of a disk or a polygonal plate, or include such a disk or plate. d. Those metal sheet components are sized in such a way as to cover at least 50%, preferably at least 60%, particularly preferably at least 70% of the first end face and / or the second end face. e. Those metal sheet components have at least one aperture, particularly at least one hole and / or at least one slot. f. Those metal sheet components have at least one bead, which appears as an elongated recess on one flat surface of the metal sheet component and as an elongated protrusion on the opposite flat surface, and the flat surfaces support this elongated protrusion while being placed on the first longitudinal edge of each current collector. g. Those metal sheet parts are welded to the first longitudinal edge of each current collector in the region of the bead, in particular via one or more weld seams arranged within the bead.

[0066] It is particularly preferred that the immediately preceding features a., b., and d. are realized in combination with each other. 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 each other.

[0067] Covering the end face as widely as possible is important for the thermal management of the energy storage cell according to the present invention. The wider the coverage, the easier it is, if possible, to bring the first longitudinal edge of each current collector into contact over its entire length. Therefore, the heat generated within the electrode-separator assembly can be dissipated well through the metal sheet parts.

[0068] In some embodiments, it has been proven beneficial to subject the longitudinal edge of the current collector to a pretreatment before placing the metal sheet part on the longitudinal edge of the current collector. In particular, at least one recess can be woven into the longitudinal edge, which corresponds to at least one bead or elongated ridge on the corresponding flat surface of the metal sheet part.

[0069] The longitudinal edge of the current collector may also be subjected to a directional forming process by pretreatment. For example, the longitudinal edge of the current collector may be bent in a defined direction.

[0070] At least one aperture within the metal sheet part may be useful, for example, to allow the electrode-separator assembly to be impregnated with an electrolytic solution.

[0071] Preferred embodiments of the current collector The anode current collector, cathode current collector, and one or more separators of the cell according to the present invention preferably have the following dimensions. Length within the range of -0.5 m to 25 m Width within the range of -40 mm to 145 mm

[0072] To manufacture a ribbon-shaped electrode-separator assembly, the ribbon-shaped electrode and the ribbon-shaped separator are preferably supplied together to a winding device and wound in a spiral around a winding axis within the winding device. In some embodiments, for this purpose, the electrode and one or more separators are wound around a cylindrical or hollow cylindrical winding core, which is mounted on a winding mandrel and remains within the winding body after winding.

[0073] The winding body shell can be formed, for example, by a plastic film or an adhesive tape. It is also possible to form the winding body shell by one or more separator winding bodies.

[0074] The current collector of the energy storage cell according to the present invention has the function of making electrical contact over as wide an area as possible with the electrochemically active constituent materials contained within each electrode material. The current collector is preferably made of metal or at least has a metal-coated surface.

[0075] In the case of a lithium-ion cell according to the present invention, metals suitable for the anode current collector are, for example, copper, or nickel, or other electrically conductive materials, in particular copper alloys 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 steel can also be considered, for example, of type 1.4303 or 1.4404, or type SUS304.

[0076] In the case of a lithium-ion cell designed as an energy storage cell according to the present invention, as the metal for the cathode current collector, aluminum or another electrically conductive material containing an aluminum alloy is particularly suitable.

[0077] In the case of an energy storage cell according to the present invention designed as a sodium-ion cell, both the anode current collector and the cathode current collector can be made of aluminum or an aluminum alloy.

[0078] Aluminum alloys suitable for the cathode current collector are, for example, Al alloys of type 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55. AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg, and AlMg are also suitable. The aluminum content of these alloys preferably exceeds 99.5%.

[0079] The ribbon-shaped anode current collector and / or cathode current collector are each preferably a ribbon-shaped metal foil having a thickness in the range of 4 μm to 30 μm. In this case, the current collector is also called a current collector foil.

[0080] However, in addition to the thin film, other strip-shaped base materials such as a metal or metal-coated non-woven fabric, or an open-pore metal foam, or an expanded metal mesh can also be used as the current collector.

[0081] These current collectors preferably have the respective electrode materials loaded on both sides.

[0082] In some embodiments, mainly for reasons of thermal coupling, the outer wound body layer preferably consists of an uncoated metal foil that is in direct contact with the housing. For example, in the case of an aluminum housing, the end portion of the cathode aluminum current collector foil that is not coated with the electrode material forms one turn on the outside of the wound body and can be arranged in direct contact with the aluminum housing at the same time. In the case of a nickel-plated steel housing, for example, the end portion of the anode current collector foil made of copper or nickel that is not coated with the electrode material forms one turn on the outside of the wound body and can be arranged in contact with the housing.

[0083] In these cases, the wound body shell is formed by the end portions of the respective current collector foils.

[0084] The longitudinal edges of one or more separators form the end faces of the electrode-separator assembly, which is preferably formed as a wound body.

[0085] The method according to the invention The method according to the invention is used for manufacturing an energy storage cell and is characterized by the following features and steps. a. The above-described energy storage cell is provided, in particular an energy storage cell having the features a. to n. described in claim 1 is provided. b. The energy storage cell is subjected to height calibration, whereby the closure part and the central part are pressed against each other under plastic deformation of the indentation, so that the distance between the metal sheet part and the lid part connected by welding to the first longitudinal edge of the current collector protruding from the first end face is shortened.

[0086] In the manufacture of an energy storage cell of the type described above, it is almost inevitable that a dead volume is formed between a metal sheet component connected by welding to a first longitudinal edge of a current collector protruding from a first end face and a lid component, whereby the energy density of the energy storage cell is reduced. According to the present invention, this is offset by the aforementioned height calibration, in which the closure part and the central part are preferably pushed against each other by an axial force. In conventional cells, this step is a very critical step because, as a result of the axial force, deformation may occur in the wall of the housing cup, in the metal sheet component protruding from the first end face by welding to the first longitudinal edge of the current collector, and in a separate electrical conductor connecting the metal sheet component to the lid component. As a result of these deformations, a short circuit may occur within the energy storage cell.

[0087] The design of the aforementioned energy storage cell having at least one insulating element according to the present invention enables the height calibration to be carried out with a significantly reduced risk of short circuit. For example, it is possible to first assemble a type 21700 cell with a height exceeding 700 mm and, in a subsequent step, reduce the resulting dead volume as part of the aforementioned height calibration. In this way, it is possible to manufacture a cell with an increased energy density.

[0088] The distance between the metal sheet component (112) and the lid component (102) preferably decreases by at least 10%, particularly preferably by at least 20%, and even more preferably by at least 30% compared to the distance before height calibration. In absolute terms, depending on the dimensions of the cell, the decrease in distance can be in the range of, for example, 0.5 mm to 5 mm.

[0089] A person skilled in the art will understand that, in contrast to so-called elastic deformations, the aforementioned plastic deformations are permanent deformations that are structurally reflected in the height-calibrated product. This particularly applies to the indentation located between the central part and the closure part.

[0090] In a preferred embodiment, the energy storage cell according to the invention that has been subjected to the aforementioned height calibration is characterized by the following feature a directly below. a. The indentation includes an annular opening slot and an annular cavity with an undercut accessible through this opening slot.

[0091] According to the invention, such an undercut is formed by height calibration because, according to the invention, the closure part and the central part may be pushed against each other even more than in the case of a conventional cell. The indentation preferably has a lower axial height in the region of the opening slit than in the region of the undercut.

[0092] Better results can be obtained if the indentation is formed asymmetrically before the height calibration. In a preferred embodiment, the energy storage cell according to the invention, before being subjected to the aforementioned height calibration, is characterized by the following features a. to e. directly below. a. The housing of the energy storage cell has a basically cylindrical shape, and the energy storage cell has a central axis that is guided vertically through the bottom of the housing cup. b. The housing cup has the same maximum outer diameter in the central part and the closure part, while the outer diameter decreases in the region of the indentation. c. The segment of the housing cup with a decreasing outer diameter in the region of the indentation extends over a height S1. d. A plane E1, which is arranged so as to pass through the deepest point of the indentation and intersects the central axis perpendicularly, divides the housing cup segment into an upper segment facing the lid part with a height S2 and a lower segment facing the electrode-separator assembly with a height S3. e. S3 > S2. It is particularly preferred that S3 is at least 20%, more preferably at least 30%, and especially at least 40% longer than S2.

Brief Description of the Drawings

[0093] Further features and advantages of the present invention will become apparent from the following description of the preferred examples of the invention in conjunction with the claims and the drawings. Individual features may be realized individually or in combination with each other. The drawings schematically show the following.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0094] Figure 1 shows an energy storage cell 100 according to the invention, with an airtight and liquidtight housing, which housing includes a metal housing cup 101 with a circular opening at the end, and a lid part 102 with a circular edge 102a closing the circular opening. The cell further includes an annular seal 103 made of an electrically insulating material, which surrounds the circular edge 102a of the lid part 102 and electrically insulates the housing cup 101 and the lid part 102 from each other. The housing cup 101 includes, in axial order, a bottom 101a, a central part 101b, and a closing part 101c. The central part 101b is cylindrical, and in the central part 101b, the winding body shell 104c of the electrode-separator assembly 104 formed as a winding body contacts the inner surface 101d of the housing cup 101. In the closing part 101c, the annular seal 103 is in pressing contact with the inner surfaces of the lid part 102 and the housing cup 101. The central part 101b and the closing part 101c are separated by a recess 111 that circumferentially surrounds the outer surface 101e of the housing cup 101 in an annular shape.

[0095] The cell 100 also includes an electrode-separator assembly 104 in the form of a cylindrical winding body in the sequence of anode / separator / cathode, but the details of this sequence are not shown here. Only the longitudinal edge 106a of the anode current collector 106 protruding from the end face 104a of the electrode-separator assembly 104, and the longitudinal edge 109a of the cathode current collector 109 protruding from the end face 104b of the electrode-separator assembly 104, are visible. The longitudinal edge 109a is preferably welded directly to the housing bottom 101a over its entire length. The longitudinal edge 106a is preferably welded directly to a metal sheet part 112 over its entire length. The metal sheet part 112 is then connected to the lid part 102 via an electrical conductor 133.

[0096] The height of the cell 100 is preferably in the range of 60 mm to 100 mm, and the diameter is preferably in the range of 20 mm to 50 mm. The wall thickness of the housing cup 101 is usually in the range of 0.1 mm to 0.3 mm at the central portion 101b.

[0097] As an insulating element, the cell includes an electrically insulating plastic coating 180 that surrounds the edge of the metal sheet part 112 and prevents the metal sheet part 112 from coming into direct contact with the inner surface 101d of the housing cup 101, particularly in the region of the recess 111. The electrically insulating coating 180 is formed by overmolding the edge of the metal sheet part 112. Further, the cell 100 includes an annular plastic part 170 as an insulating element, which surrounds a separate electrical conductor 133 fixed to the metal sheet part and prevents the electrical conductor 133 from coming into direct contact with the inner surface 101d of the housing cup 101 in the region of the recess 111.

[0098] As a result, the cell 100 is very well protected against short circuits even if the housing is deformed by an external mechanical force.

[0099] Figure 2 shows an energy storage cell 100 according to the invention, with a hermetic and liquid-tight housing, which housing includes a metal housing cup 101 with a circular opening at the end, and a lid part 102 with a circular edge 102a closing this circular opening. The cell further includes an annular seal 103 made of an electrically insulating material, which surrounds the circular edge 102a of the lid part 102 and electrically insulates the housing cup 101 and the lid part 102 from each other. The housing cup 101 includes axially in sequence a bottom 101a, a central part 101b, and a closing part 101c. The central part 101b is cylindrical, and in the central part 101b, the winding body shell 104c of the electrode-separator assembly 104 formed as a winding body is in contact with the inner surface 101d of the housing cup 101 (Note: for clarity, the electrode-separator assembly 104 is shown separated from the inner surface 101d, but in reality, it is pressed against the inner surface 101d, for example, as shown in Figure 1). In the closing part 101c, the annular seal 103 is in pressing contact with the inner surfaces of the lid part 102 and the housing cup 101. The central part 101b and the closing part 101c are separated by a recess 111 that circumferentially annularly surrounds the outer surface 101e of the housing cup 101.

[0100] The cell 100 also includes an electrode-separator assembly 104 in the form of a cylindrical winding body in the sequence of anode / separator / cathode, but the details of this sequence are not shown here. Only the longitudinal edge 106a of the anode current collector 106 protruding from the end face 104a of the electrode-separator assembly 104, and the longitudinal edge 109a of the cathode current collector 109 protruding from the end face 104b of the electrode-separator assembly 104, are visible. The longitudinal edge 109a is preferably welded directly to the housing bottom 101a over its entire length. The longitudinal edge 106a is preferably welded directly to a metal sheet part 112 over its entire length. The metal sheet part 112 is then connected to the lid part 102 via an electrical conductor 133.

[0101] The height of the cell 100 is preferably in the range of 60 mm to 100 mm, and the diameter is preferably in the range of 20 mm to 50 mm. The wall thickness of the housing cup 101 is usually in the range of 0.1 mm to 0.3 mm at the central portion 101b.

[0102] As an insulating element, the cell includes an annular molded plastic part 150 having an L-shaped cross section, which is applied to the edge defining the boundary of the end face 104a and prevents the end face 104a from directly contacting the inner surface 101d of the housing cup 101. Further, the cell includes an annular insulating element 160 made of plastic, which is arranged in contact with the inner surface 101d of the housing cup 101 in the region of the recess 111 and prevents the inner surface 101d from directly contacting the electrical conductor 133. This may be a part of the annular seal 103, and the annular seal 103 may be high enough to cover the recess 111 from the inner surface.

[0103] As a result, the cell 100 is very well protected from short circuits even if the housing is deformed by an external mechanical force.

[0104] Instead of the annular molded plastic part 150 having an L-shaped cross section, the edge defining the boundary of the end face 104a can also be covered with an insulating tape, such as Kapton tape 150. Ideally, this can be already pasted on the edge when the winding body is formed, and the edge efficiently prevents direct contact with the inner surface 101d.

[0105] Figure 3 shows an energy storage cell 100 according to the present invention with an airtight and liquidtight housing, which housing includes a metal housing cup 101 with a circular opening at the end and a lid part 102 with a circular edge 102a closing this circular opening. The cell further includes an annular seal 103 made of an electrically insulating material, which surrounds the circular edge 102a of the lid part 102 and electrically insulates the housing cup 101 and the lid part 102 from each other. The housing cup 101 includes axially in sequence a bottom 101a, a central part 101b, and a closing part 101c. The central part 101b is cylindrical, and in the central part 101b, the winding body shell 104c of the electrode-separator assembly 104 formed as a winding body contacts the inner surface 101d of the housing cup 101. In the closing part 101c, the annular seal 103 is in pressing contact with the inner surfaces of the lid part 102 and the housing cup 101. The central part 101b and the closing part 101c are separated by a recess 111 that circumferentially annularly surrounds the outer surface 101e of the housing cup 101.

[0106] The cell 100 also includes an electrode-separator assembly 104 in the form of a cylindrical winding body in the sequence of anode / separator / cathode, but the details of this sequence are not shown here. Only the longitudinal edge 106a of the anode current collector 106 protruding from the end face 104a of the electrode-separator assembly 104 and the longitudinal edge 109a of the cathode current collector 109 protruding from the end face 104b of the electrode-separator assembly 104 are visible. The longitudinal edge 109a is preferably welded directly to the metal sheet part 134 over its entire length. The metal sheet part 134 is then connected to the bottom 101a by welding. The longitudinal edge 106a is preferably welded directly to the metal sheet part 112 over its entire length. The metal sheet part 112 is then connected to the lid part 102 via an electrical conductor 133.

[0107] The height of the cell 100 is preferably in the range of 60 mm to 100 mm, and the diameter is preferably in the range of 20 mm to 50 mm. The wall thickness of the housing cup 101 is usually in the range of 0.1 mm to 0.3 mm at the central portion 101b.

[0108] The cell includes an annular plastic part 170 as an insulating element, which laterally surrounds the electrical conductor 133 and prevents the electrical conductor 133 from directly contacting the inner surface 101d of the housing cup 101 in the region of the recess 111. The annular plastic part 170 has a hollow cylindrical shape and includes a shell 171 perpendicular to the metal sheet part 112. One of its edges is formed as an annular flange 171 directed outward and is disposed on the metal sheet part 112.

[0109] As a result, the cell 100 is very well protected against short - circuits even if the housing is deformed by external mechanical forces.

[0110] Figure 4 shows some embodiments of the metal sheet part 112 suitable for contacting the first longitudinal edge 106a of the current collector 106 protruding from the first end face 104a of the energy storage cell 100 according to the present invention.

[0111] Embodiment A shows a circular and substantially flat metal disk with a circumferential edge 102a as the metal sheet part 112. This disk is characterized by a central hole 142 and three offset beads 141. Such components can be used within the cell for electrical contact with the edge 106a of the anode current collector 106 in each case according to FIGS. 1 - 3. However, it is also suitable for use as the metal sheet part 134 within the cell according to FIG. 3. When such a metal disk is used to contact the longitudinal edge 106a, the separate conductor 133 shown in FIGS. 1 - 3 is generally absolutely necessary to bridge the distance to the lid part 102.

[0112] Embodiment B is different. Here, the metal sheet component 112 includes a first portion 112a that can be disposed flat on the first longitudinal edge of the current collector protruding from the first end face 104a and extends parallel to the end face 104a at this time. However, further, the metal sheet component 112 includes a second portion 112b that is angularly adjacent to the first portion 112a, and through this second portion 112b, the first portion 112a is electrically connected to the lid component 102. Using such a metal sheet component eliminates the need for a separate conductor 133. The metal sheet component is further characterized by holes 142 and two beads 141. In these beads, it is preferred that the metal sheet component be welded to the longitudinal edges of the respective current collectors.

[0113] Embodiments C and D are different from Embodiment B in that the portion 112a includes three and four strips respectively that extend in different directions. Each strip has a bead 141. Further, each metal sheet component has two holes 142.

[0114] The structure of the electrode-separator assembly 104 is described with reference to FIG. 5. The assembly 104 includes a ribbon-shaped anode 105 having a ribbon-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 includes a strip-shaped main region loaded with a layer of the negative electrode material 107 and a free-edge strip 106b extending along the first longitudinal edge 106a and not loaded with the electrode material 107. Further, the assembly 104 includes a ribbon-shaped cathode 108 having 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 includes a strip-shaped main region loaded with a layer of the positive electrode material 110 and a free-edge strip 109b extending along the first longitudinal edge 109a and not loaded with the electrode material 110. Both electrodes are shown individually in an unrolled state.

[0115] The anode 105 and the cathode 108 are arranged offset from each other within the electrode-separator assembly 104 such that the first longitudinal edge 106a of the anode current collector 106 protrudes from the first end face 104a and the first longitudinal edge 109a of the cathode current collector 109 protrudes from the second end face 104b of the electrode-separator assembly 104. This offset arrangement can be seen in the lower left figure. Two ribbon-shaped separators 116 and 117 that separate the electrodes 105 and 108 from each other within the wound body are also shown there.

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

[0117] FIG. 6 shows a further embodiment of a metal sheet component 112 suitable for contacting a first longitudinal edge 106a of a current collector 106 protruding from a first end face 104a of an energy storage cell 100 according to the present invention.

[0118] The metal sheet components shown in Embodiments B - D of FIG. 4 differ essentially only in that in the embodiments B - D shown here, portion 112b is bent in a U - shape rather than being folded in a Z - shape. Such metal sheet components can replace the metal sheet component 112 and the electrical conductor 133 within the cell according to FIGS. 1 - 3.

[0119] FIG. 7 shows photographs of longitudinal cross - sections through preferred embodiments of an energy storage cell according to the present invention before (A) and after (B) a calibration process. For these photographs, the cell was cut longitudinally using a saw. Enlarged portions are shown, in particular showing details of the closure 101c and the recess 111.

[0120] The lid assembly 102 is visible and includes a metal disk 113 that is in electrical and direct contact with a pole cap 117 (closing the lid assembly 102 on the outside). The edge of the metal disk 113 is bent in a U - shape around the edge of the pole cap 117. The lid assembly 102 further includes a metallic inner contact disk 115 and an insulator 116. The contact disk 115 has its upper part connected by welding to a metal film and its bottom part connected (although not shown) to a separate electrical conductor 133. The metal film is not visible here and is incorporated in the center of the metal disk 113, and the separate electrical conductor 133 is welded to the metal sheet component 112. The metal sheet component 112 is then welded to the first longitudinal edge 106a of the current collector protruding from the first end face.

[0121] Before the calibration process, the indentation 111 is generally symmetrical. The insulating tape 150 is attached to the edge of the metal sheet part 112 to prevent the metal sheet part 112 and the first longitudinal edge 106a from directly contacting the inner surface of the housing cup 101. The insulating tape 150 protrudes upward into the dead volume between the lid assembly 102 and the metal sheet part 112.

[0122] During height calibration, the closing part and the central part are pushed against each other by an axial force, and the closing part 101c and the central part 101b are pushed against each other under the plastic deformation of the indentation 111. As a result, the distance d between the metal sheet part 112 and the lid part 102 is significantly reduced. Thereby, the dead volume between the lid assembly 102 and the metal sheet part 112 is significantly reduced. The plastic deformation of the indentation 111 can be clearly seen. Due to this deformation, the insulating tape 150 is substantially pressed against the metal sheet part 112, thereby reliably avoiding a short circuit through the insulating tape 150. Furthermore, an undercut 144 is formed by this deformation (the hatched area below the line L). Overall, as a result of height calibration, the indentation has an annular opening slot with a height h1 and an annular cavity with an undercut 144 accessible through this opening slot. After height calibration, the displayed cell will be in format 21700.

[0123] FIG. 8 shows longitudinal cross-sections through another energy storage cell according to the invention before (A) and after (B) height calibration. An enlarged portion is shown, and in particular, the details of the closing part 101c and the indentation 111 are shown.

[0124] The structure of this energy storage cell is basically the same as the cell shown in FIG. 7, with one major exception being that the indentation is asymmetric before height calibration. The housing of the energy storage cell is basically cylindrical, and the energy storage cell has a central axis (not shown here) that passes vertically through the bottom of the housing cup. The housing cup has the same maximum outer diameter at the central part 101b and the closing part 101c, while the outer diameter decreases in the region of the indentation 111. The segment of the housing cup with a decreasing outer diameter in the region of the indentation extends over a height S1. A plane E1, which is arranged to pass through the deepest point of the indentation and intersects the central axis perpendicularly, divides the housing cup segment into an upper segment facing the lid part with a height of S2 and a lower segment facing the electrode-separator assembly with a height of S3.

[0125] Due to the asymmetric design of the indentation 111, S3 becomes a significantly larger value than S2. This makes the deformation of the indentation 111 during height calibration advantageous.

[0126] Here, it can also be seen that the dead volume between the lid assembly 102 and the metal sheet part 112 has been significantly reduced (refer to the distance d decreasing from A to B). The plastic deformation of the indentation 111 can be clearly seen, and this deformation presses the insulating tape 150 almost against the metal sheet part 112, thereby reliably avoiding a short circuit through the insulating tape 150. Here, furthermore, an undercut 144 is also formed by this deformation (the hatched area under the line L). Overall, as a result of height calibration, the indentation also has an annular opening slot with a height of h1 and an annular cavity with an undercut 144 accessible through this opening slot.

Claims

1. An energy storage cell (100), having the following features: a. The cell includes an electrode-separator assembly (104) having a sequence of anode (105) / separator (116) / cathode (108), b. The anode (105) of the electrode-separator assembly (104) is ribbon-shaped and includes 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) includes a main region loaded with a layer of negative electrode material (107) and a free edge strip extending along the first longitudinal edge (106a) of the anode current collector where the negative electrode material is not loaded, d. The cathode (108) of the electrode-separator assembly (104) is ribbon-shaped and includes a ribbon-shaped cathode current collector (109) having a first longitudinal edge (109a) and a second longitudinal edge parallel thereto, e. The ribbon-shaped cathode current collector (109) includes a main region loaded with a layer of positive electrode material (110) and a free edge strip extending along the first longitudinal edge (109a) of the cathode current collector where the electrode material (110) is not loaded, f. The electrode-separator assembly (104) is in the form of a cylindrical wound body, the cylindrical wound body having a first end face (104a) bounded by a circumferential edge, a second end face (104b) bounded by a circumferential edge, and a wound body shell (104c) disposed therebetween, and the electrode-separator assembly (104) includes the anode (105) and the cathode (108) wound in a spiral shape, g. The anode (105) and the cathode (108) are disposed inside the electrode-separator assembly (104) in such a manner that the first longitudinal edge (106a) of the anode current collector (106) protrudes from one of the end faces (104a, 104b) and the first longitudinal edge (109a) of the cathode current collector (109) protrudes from the other end face (104a, 104b) of the electrode-separator assembly (104). h. The cell includes an airtight and liquidtight housing cup (101) having a bottom (101a) and a terminal circular opening, and a lid part (102) having a circular edge part (102a) that closes the terminal circular opening. i. Inside the housing cup, the electrode-separator assembly (104) is arranged axially aligned, the first end face (104a) is directed towards the lid part, and the second end face (104b) is directed towards the bottom (101a), and in certain cases is in direct contact with the bottom (101a). j. The cell includes an annular seal (103) made of an electrically insulating material, which surrounds the circular edge part (102a) of the lid part (102) and electrically insulates the housing cup (101) and the lid part (102) from each other. k. The housing cup (101) includes an inner surface (101d) and an outer surface (101e), and axially in sequence includes a bottom (101a), a central part (101b), and a closing part (101c). - The central part (101b) is cylindrical, and in the central part (101b), the winding body shell (104c) of the electrode-separator assembly (104) in the form of a wound body is in contact with the inner surface (101d) of the housing cup (101). - In the closing part (101c), the annular seal (103) is in pressing contact with the lid part (102) and the inner surface of the housing cup (101). l. The central part (101b) and the closing part (101c) are separated by a recess (111) that circumferentially annularly surrounds the outer surface (101e) of the housing cup (101). m. The cell includes a metal sheet part (112), which includes an optional separate electrical conductor (133) attached to the metal sheet part. The metal sheet part (112) is connected by welding to the first longitudinal edge of the current collector protruding from the first end face (104a). This current collector is electrically connected to the lid part (102) via the metal sheet part (112). n. The cell includes at least one insulating element (150; 160; 170; 180) made of an electrically insulating material, which prevents the metal sheet part (112), and / or the first longitudinal edge part (106a, 109a) of the current collector (106, 109) protruding from the first end face (104a), and / or the separate electrical conductor (133) attached to the metal sheet part from directly contacting the inner surface (101d) of the housing cup (101), especially in the area of the recess (111). An energy storage cell (100) having the above. **Claim 2** The following additional features: a. The at least one insulating element is an insulating tape (150) that is pasted on the edge defining the boundary of the end face (104a) and prevents the end face (104a) from directly contacting the inner surface (101d), or includes such an insulating tape (150). b. The at least one insulating element is preferably an annular molded part (150) made of plastic with an L-shaped cross-section, which is applied to the edge defining the boundary of the end face (104a) and prevents the end face (104a) from directly contacting the inner surface (101d), or includes such an annular molded part (150). c. The insulating tape or the annular molded plastic part has a thickness in the range of 10 μm to 200 μm. The energy storage cell according to claim 1, having at least one of the above. **Claim 3** The following additional features: a. The at least one insulating element is an annular insulating element (160) made of plastic, which is arranged in contact with the inner surface (101d) of the housing cup (101) in the area of the recess (111) and prevents the inner surface (101d) from directly contacting the metal sheet part (112), or includes such an annular insulating element (160). b. The annular insulating element (160) is a part of the annular seal (103). c. The annular insulating element (160) made of plastic has a thickness in the range of 50 μm to 500 μm. The energy storage cell according to claim 1, having at least one of the above. **Claim 4** The following additional features: a. The at least one insulating element is an annular plastic part (170) that surrounds the metal sheet part (112) and prevents the metal sheet part (112) from directly contacting the inner surface (101d) of the housing cup (101) in the region of the recess (111), or includes such an annular plastic part (170). b. The annular plastic part (170) has a hollow cylindrical shape, includes a shell (171), and is bounded by a circumferential edge at each end face. c. The annular plastic part (170) has a hollow cylindrical shape, includes a shell (171), and is bounded by a circumferential edge at each end face. One of the edges is designed as an outward-facing annular flange (171) and is placed on the metal sheet part (112). d. The annular plastic part (170) has a thickness in the range of 20 μm to 600 μm. The energy storage cell according to claim 1, having at least one of the above.

5. The following additional features: a. The at least one insulating element is an electrically insulating plastic coating (180) that surrounds the edge of the metal sheet part (112) and prevents the edge of the metal sheet part (112) from directly contacting the inner surface (101d) of the housing cup (101), particularly in the region of the recess (111), or includes such an electrically insulating plastic coating (180). b. The electrically insulating coating (180) is formed by overmolding the edge of the metal sheet part (112). The energy storage cell according to claim 1, having at least one of the above.

6. The following additional features: a. The at least one insulating element is an insulating tape (150) or a plastic annular molded part (150) that is applied to the edge defining the boundary of the end face (104a) and prevents the end face (104a) from directly contacting the inner surface (101d), including the insulating tape (150) or the plastic annular molded part (150). b. The at least one insulating element is an annular insulating element (160) that is disposed in contact with the inner surface (101d) of the housing cup (101) in the region of the recess (111) and prevents the inner surface (101d) from coming into direct contact with the metal sheet component (112). c. The at least one insulating element is an annular plastic component (170) that surrounds the metal sheet component (112) and prevents the metal sheet component (112) from coming into direct contact with the inner surface (101d) of the housing cup (101) in the region of the recess (111). d. The at least one insulating element is an electrically insulating plastic coating (180) that surrounds the edge of the metal sheet component (112) and prevents the edge of the metal sheet component (112) from coming into direct contact with the inner surface (101d) of the housing cup (101), particularly in the region of the recess (111), or includes the same. The energy storage cell according to claim 1, having at least one of the above.

7. The following additional features: a. The housing cup (101) has the same maximum outer diameter at the central portion (101b) and the closing portion (101c). b. In the region of the recess (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 region. The energy storage cell according to any one of claims 1 to 6, having at least one of the above.

8. The following additional features: a. The metal sheet component (112) is directly connected to the lid component (102). b. The metal sheet component (112) includes a first portion (112a) that is flatly disposed on the first longitudinal edge of the current collector protruding from the first end face (104a) and extends parallel to the end face (104a). c. The metal sheet component (112) includes a second portion (112b) that is angled adjacent to the first portion, and through the second portion, the first portion is electrically connected to the lid component (102). The energy storage cell according to any one of claims 1 to 7, having at least one of the above.

9. The following additional features: a. The metal sheet component (112) is connected to the lid component (102) via the separate electrical conductor (133). b. The metal sheet component (112) is flatly arranged on the first longitudinal edge of the current collector protruding from the first end face (104a). The energy storage cell according to any one of claims 1 to 7, having at least one of the above.

10. The following additional features: a. The first longitudinal edge of the current collector protruding from the second end face (104b) is directly arranged on the bottom (101a) of the housing cup (101) and is connected to the bottom (101a) by welding. b. The cell includes a metal sheet component (134), which is connected by welding to the first longitudinal edge of the current collector protruding from the second end face (104b). Through the metal sheet component (134), this current collector is electrically connected to the bottom (101a) of the housing cup (101). The energy storage cell according to any one of claims 1 to 9, having any one of the above.

11. The following additional features: a. The current collector protruding from the first end face (104a) is the anode current collector (106), and the current collector protruding from the second end face (104b) is the cathode current collector (109). The energy storage cell according to any one of claims 1 to 10, having the above.

12. The following additional features: a. The housing cup is made of aluminum or an aluminum alloy. b. The end portion of the current collector foil made of aluminum or an aluminum alloy, which is not coated with an electrode material, forms one turn on the outside of the wound body and is simultaneously arranged in direct contact with the housing cup made of the aluminum or the aluminum alloy. The energy storage cell according to any one of claims 1 to 11, having any one of the above.

13. The following additional features: a. The housing cup is made of copper or nickel or an alloy of copper or nickel. b. The end portion of the current collector foil made of copper or nickel or an alloy of copper or nickel, which is not coated with the electrode material, forms one turn on the outside of the wound body, and at the same time, is directly placed in contact with the housing cup made of the copper or nickel or the alloy of copper or nickel. The energy storage cell according to any one of claims 1 to 12, having any one of the following.

14. A method for manufacturing an energy storage cell, comprising the following steps: a. An energy storage cell (100) having the features a. to n. described in claim 1 is provided. b. The energy storage cell is subjected to height calibration, whereby the closing portion (101c) and the central portion (101b) are pressed against each other under the plastic deformation of the recess (111), whereby the distance d between the metal sheet component (112) and the lid component (102), which are connected by welding to the first longitudinal edge of the current collector protruding from the first end face (104a), is reduced. A method comprising the above.

15. The following additional features: a. The distance d between the metal sheet component (112) and the lid component (102) is reduced by at least 10%. The method according to claim 14, characterized by the above.

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