Energy storage element and manufacturing process

Abstract

The energy storage element (100) includes a housing closed in an airtight and liquidtight manner and an electrode-separator assembly (104) disposed therein, the electrode-separator assembly (104) including an anode current collector (106) loaded with a layer of anode material (107) and a cathode current collector (109) loaded with a layer of cathode material (110). The housing includes a metal cup-shaped housing part (101) having a housing bottom (101a), a peripheral sidewall, and a terminal opening, and a lid part (102) closing the terminal opening of the cup-shaped housing part (101). A first edge (106a, 109a) of the anode current collector (106) or the cathode current collector (109) is electrically connected to the housing bottom (101a). The housing bottom (101a) of the cup-shaped housing part (101) comprises a primary protection against internal overpressure in the form of an aperture (101b) closed by a metal membrane (114) and a secondary protection against internal overpressure in the form of at least one groove (101c) on its inner or outer side. The lid part (102) comprises a metallic lid plate (102a) and a connection pole (102b) guided through an aperture in the lid plate (102a) and electrically insulated from the lid plate (102). This structure allows electrical contact with the electrodes of the electrode-separator assembly (104) only through the lid part (102). Since the aforementioned protection devices are not integrated in the lid part as in many conventional cells, but instead in the housing bottom, it is also possible to build the lid part (102) very compactly. The lid part (102) can be manufactured during the housing assembly.

Description

[Technical field]

[0001] The invention described below relates to an energy storage element and a method of manufacture. [Background technology]

[0002] Electrochemical energy storage elements are capable of converting stored chemical energy into electrical energy by means of redox reactions. The simplest form of electrochemical energy storage element is the electrochemical cell. It comprises a positive electrode and a negative electrode, between which a separator is placed. During discharge, electrons are released at the negative electrode as a result of an oxidation process. This results in an electronic current that can be drawn off by an external electrical consumer, for which the electrochemical cell acts as an energy supplier. At the same time, an ionic current corresponding to the electrode reactions is generated in the cell. This ionic current crosses the separator and is made possible by the ionically conductive electrolyte. The separator thus prevents direct contact between the electrodes. However, it simultaneously allows for the equalization of the charge between the electrodes.

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

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

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

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

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

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

[0009] The composite electrode is generally combined with one or more separators to form an electrode-separator assembly when making a lithium-ion cell. The electrodes and separators are often, but not necessarily, joined together under pressure, possibly by lamination or gluing. Basic function of the cell can then be established by impregnating the assembly with an electrolyte.

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

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

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

[0013] WO 2017 / 215900 A1 describes an electrode-separator assembly and a cylindrical circular cell whose electrodes are ribbon-like and in the form of a winding. The electrodes have current collectors, each loaded with an electrode material. The oppositely polarized electrodes are arranged offset from each other in the electrode-separator assembly, such that the longitudinal edge of the positive current collector protrudes from the winding on one side and the longitudinal edge of the negative current collector protrudes from the winding on the other side. For electrical contact of the current collectors, the cell has a contact sheet metal part that sits on one end face of the winding and is connected by welding to one longitudinal edge of the current collector. This makes it possible to electrically contact the current collectors and therefore also the associated electrodes over their entire length. This significantly reduces the internal resistance in the described cell. As a result, the generation of large currents can be absorbed much better and also heat can be dissipated better from the winding.

[0014] Cylindrical round cells such as those in WO 2017 / 215900 A1 are usually used as part of a cell assembly in which several cells are connected in series and / or in parallel. In many cases, it is desirable to only have to contact the cells at one of their end faces in order to tap off the voltage. It is therefore advantageous to provide both a connection pole connected to the positive pole of the cell and a connection pole connected to the negative pole of the cell at one of the end faces.

[0015] A lithium-ion circular cell comprising an electrode-separator assembly formed as a winding in a cylindrical housing is known from US 2006 / 0019150 A1. The housing comprises a metallic cylindrical housing cup with an opening that is closed by a metallic lid part. The bottom of the housing cup is electrically connected to the positive pole of the winding, and therefore the housing cup is positively polarized. Both housing parts are in direct contact with each other, which is why the lid part is also positively polarized. The positive metal connection pole is welded onto the lid part. On the other hand, the negative pole of the winding is connected to the negative metal terminal pole, which is guided through an aperture in the lid part and is electrically insulated from it. The positive and negative connection poles are therefore arranged adjacent to each other on the same side of the cell, so that the cell can be easily integrated into a cell assembly via corresponding current conductors.

[0016] In addition to its good contact, the cell described in US 2006 / 0019150 A1 is also characterized by an integrated overpressure protection. For this purpose, the bottom is separated from the annular residual area of ​​the bottom by a circumferential weakening line and has a central circular area to which a bent arrester strip is welded inside, said electrical contact of the bottom to the positive pole of the windings via the arrester strip. In the event of an overpressure occurring inside the housing, the circular area can be blown off from the bottom. The annular insulator ensures that the annular residual area does not come into contact at all with the electrode-separator assembly in the form of a winding, thus interrupting the electrical connection between the positive pole and the annular residual area and between all parts in electrical contact with the annular residual area, including the positive terminal pole.

[0017] The negative pole of the winding is electrically contacted through a multi-fold arrester strip, the upper end of which is bonded to the negative terminal.

[0018] From an energy point of view, the cell design described in US 2006 / 0019150 A1 is not optimal: there are dead volumes at both ends of the windings, which must be bridged by the arrester strips mentioned above, which have a negative effect on the energy density of the cell. Summary of the Invention [Problem to be solved by the invention]

[0019] The object of the present invention was to provide an energy storage element which is characterized by an improved energy density compared to the prior art and which can be efficiently processed into cell assemblies. Furthermore, the energy storage element should also be characterized by an improved safety. [Means for solving the problem]

[0020] This object is achieved by an energy storage element having the features of claim 1. An object of the invention is also a manufacturing method having the features of claim 10. Preferred embodiments of the energy storage element according to the invention and the method according to the invention are defined in the dependent claims.

[0021] Energy storage element according to the present invention The energy storage element according to the present invention has the following characteristics a. to o. The energy storage element includes an air-tight and liquid-tight housing and an electrode-separator assembly disposed therein. b. The housing includes a metal cup-shaped housing portion having a housing bottom, a peripheral sidewall, and a terminal opening. c. The housing includes a lid component that closes the terminal opening in the cup-shaped housing portion. d. The lid part includes a metallic lid plate and a connection terminal guided through an aperture in the lid plate and electrically insulated from the lid plate. e. The electrode-separator assembly includes a first flat terminal end surface and a second flat terminal end surface. f. The electrode-separator assembly includes an anode having an anode current collector having a first edge and a parallel second edge. g. The anode current collector includes a main area loaded with a layer of negative electrode material and a free edge strip extending along a first edge thereof that is not loaded with electrode material. h. The electrode-separator assembly includes a cathode having a cathode current collector having a first edge and a parallel second edge. i. The cathode current collector includes a main area loaded with a layer of positive electrode material and a free edge strip extending along a first edge thereof that is not loaded with electrode material. j. The anode and cathode are positioned within the electrode-separator assembly such that a first edge of the anode current collector protrudes from a first terminal end face of the electrode-separator assembly, and a first edge of the cathode current collector protrudes from a second terminal end face. k. The energy storage element includes a contact sheet metal portion that seats directly on the first edge of the anode current collector or the first edge of the cathode current collector. l. The contact sheet metal portion is electrically connected to a connecting pole which is routed through an aperture in the cover plate. m. The first edge of the cathode current collector or the anode current collector that is not in direct contact with the contact sheet metal portion is electrically connected to the housing bottom. n. The housing bottom of the cup-shaped housing section has a primary protection against internal overpressure in the form of an aperture closed by a metal membrane. o. The housing bottom of the cup-shaped housing part has a secondary protection device against internal overpressure in the form of at least one groove on its inside or outside.

[0022] The advantage of such an energy storage element is that it is possible to make electrical contact with both the anode and the cathode through the lid part. The aforementioned safety features are not integrated in the lid part, as is the case in many conventional cells, but instead in the housing bottom, so that the lid part can also be constructed very compactly. It is also not necessary to preassemble the lid part. Instead, the lid part can be manufactured during the housing assembly, as described in more detail below.

[0023] In particularly preferred embodiments, the energy storage element according to the invention is characterized by at least one of the features a. to e. immediately below. A cover plate is welded into the terminal opening of the cup-shaped housing portion. b. The contact sheet metal portion is connected to the first edge of the anode current collector or the first edge of the cathode current collector by welding. c. The first edge of the anode or cathode current collector that is not in direct contact with the contact sheet metal rests directly on the housing bottom. d. The first edge of the anode current collector or cathode current collector that is not in direct contact with the contact sheet metal portion is connected to the housing bottom by welding. e. At least one groove is located on the inside of the housing bottom.

[0024] Preferably, the immediately preceding features a. to d., and particularly preferably the immediately preceding features a. to e., are realized in combination.

[0025] The primary protector functions to provide controlled pressure equalization in the event that an unacceptable overpressure occurs above a predetermined threshold, in which case the membrane is blown open or dislodged by the pressure, allowing gas that is building up inside the housing to escape through an aperture in the bottom of the housing.

[0026] The secondary protection device is intended for cases where pressure equalization via the primary protection device does not occur quickly enough, in which case the housing bottom can tear open due to excessive pressure along the grooves, which does nothing but weaken the structure of the housing bottom and creates an outlet opening with a relatively large cross section through which gases formed inside the housing can escape.

[0027] Such safety solutions are already known per se: the pressure at which the protective device is triggered can be set precisely by suitable design of the groove and the membrane.

[0028] In many cases, the cup-shaped housing part is preferably positively polarized and the connection pole is the negative connection pole. In these cases, the energy storage element according to the invention is characterized by the immediately following feature a., optionally in combination with at least one other feature of the immediately following features b. to e. a. The cup-shaped housing portion is electrically connected to the cathode. b. A contact sheet metal portion is seated on a first edge of the anode current collector and connected thereto by welding. c. The cup-shaped housing portion is made of aluminum or an aluminum alloy. d. The cover plate is made of aluminum or an aluminum alloy. e. The contact sheet metal part is in direct contact with the connecting pole which is guided through an aperture in the cover plate and is connected thereto, preferably by welding.

[0029] The immediately preceding features a. to e. are particularly preferably realized in combination.

[0030] In this embodiment, the housing of the energy storage element consists of a substantial part made of aluminum or an aluminum alloy. This has various advantages: the formation of localized elements is excluded if the outside of the cell comes into contact with moisture. The housing itself can essentially serve as a positive connection pole on all its sides. However, it is particularly preferred that the cell is only contacted via the lid part, in which the negative connection pole is also located. For this purpose, the current arrester can be welded directly to the lid plate or alternatively fixed to a separate connection pole, for example by welding.

[0031] Suitable aluminum alloys for the cup-shaped housing part and the cover plate are, for example, Al alloys of type 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg and AlMg. The aluminum content of these alloys is preferably greater than 99.5%.

[0032] In further cases, it may be preferred that the cup-shaped housing part is negatively polarized and the connection pole is a positive connection pole. In these cases, the energy storage element according to the invention is characterized by the immediately following feature a., optionally in combination with at least one other feature of the immediately following features b. to e. a. The cup-shaped housing portion is electrically connected to the anode. b. A contact sheet metal portion is seated on a first edge of the cathode current collector and connected thereto by welding. c. The cup-shaped housing portion is made of copper or nickel or a copper or nickel alloy or steel or nickel plated steel. d. The cover plate is made of copper or nickel or a copper or nickel alloy or steel or nickel-plated steel. e. The contact sheet metal part is in direct contact with the connecting pole which is guided through an aperture in the cover plate and is connected thereto, preferably by welding.

[0033] The immediately preceding features a. to e. are particularly preferably realized in combination.

[0034] In this embodiment, the housing of the energy storage element consists of main parts made of copper or nickel or copper or nickel alloys or steel or nickel-plated steel. Suitable stainless steels are, for example, stainless steels of type 1.4303 or 1.4404 or type SUS304 or nickel-plated steel. 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. Nickel alloys of the type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable.

[0035] Preferred design of the housing bottom In a preferred embodiment, the energy storage element according to the invention is characterized by at least one of the following characteristics a. to f. a. The housing bottom has at least one bead that appears as an elongated recess on its exterior and as an elongated ridge on its interior, and a first edge of the anode current collector or a first edge of the cathode current collector rests on the interior. b. The housing bottom is welded to the first edge of the anode current collector or the first edge of the cathode current collector in the area of ​​the bead. c. The aperture is positioned in the center of the bottom of the housing. d. The at least one bead comprises several linear beads, particularly three beads, arranged in a star configuration around the aperture. e. At least one groove includes several linear subsections arranged in a star-shaped configuration around the aperture. f. At least one groove includes a subsection that extends around the aperture connecting linear subsections that are arranged in a star shape.

[0036] Preferably, the immediately preceding features a and b, c and d, and c, e, and f are realized in combination. Particularly preferably, the immediately preceding features a to f are realized in combination.

[0037] As a result of the welding in the region of the bead, there are preferably one or more weld seams in the bead. The star-shaped bead and the star-shaped linear subsections of the groove each preferably form an angle of 120°.

[0038] In some embodiments, it has proven advantageous to provide a pretreatment to the edge of the current collector that sits inside the housing bottom so as to improve the contact between the housing bottom and the current collector. In particular, at least one recess can be folded into the edge, which corresponds to at least one bead or elongated ridge on the flat side of the contact sheet metal part facing the first terminal end face.

[0039] The edge of the current collector may also be directionally shaped by pretreatment, for example it may be bent in a defined direction.

[0040] In some embodiments, the bottom of the cup-shaped housing part is welded, i.e. manufactured separately and assembled to the side wall by welding, but in most cases the cup-shaped housing part is manufactured by deep drawing.

[0041] Prismatic embodiment In a preferred embodiment, the energy storage element according to the invention is designed as a prismatic or cylindrical round cell or button cell.

[0042] In this embodiment, the housing is prismatic. In this embodiment, the bottom and lid parts of the cup-shaped housing part preferably have a polygonal, particularly preferably rectangular, base. The shape of the terminal openings in the cup-shaped housing part corresponds to the shape of the bottom and lid parts. In addition, the housing comprises several, preferably four, rectangular sides connecting the bottom and lid parts to each other.

[0043] In this embodiment, the electrode-separator assembly is also preferably prismatic, in which case it is preferably a prismatic stack of several anodes, cathodes and at least one separator, so that the electrode-separator assemblies within a stack always have the order anode / separator / cathode.

[0044] At least the anode and cathode preferably have rectangular base surfaces, and the current collectors of the anode and cathode each have a first edge and a parallel second edge, and each have a free edge strip along their first edges that is not coated with the respective electrode material.

[0045] If there are several separators between the anodes and cathodes, the separators also preferably have a rectangular base surface, but it is also possible to use ribbon-shaped separators separating several anodes and cathodes within the stack.

[0046] The first and second flat terminal end faces of the stack are, for example, two opposing or adjacent side faces of the stack. A first edge of the anode current collector projects from one of these end faces, and a first edge of the cathode current collector projects from the other. Contact sheet metal parts seat on the first edges of the anode current collectors and are assembled thereto by welding.

[0047] Cylindrical round cell or button cell embodiment In this embodiment of the invention, the energy storage element according to the invention is preferably characterized by at least one of the immediately following features a. to p. a. The terminal opening in the cup-shaped housing portion is circular and the peripheral sidewall of the cup-shaped housing portion includes or forms a cylindrical housing shell. b. The lid piece closing the circular opening of the cup-shaped housing portion has a circular periphery. c. The electrode-separator assembly is in the form of a cylindrically wound body having first and second flat terminal end faces, as well as a wound shell located between the end faces. d. In the housing, the electrode-separator assembly is axially aligned so that the wound shell abuts the inside of the cylindrical housing shell. e. The anode and anode current collector are ribbon-shaped, the anode current collector including a first longitudinal edge, a second longitudinal edge, and two end portions. f. The first and parallel second edges of the anode current collector are the longitudinal edges of the ribbon anode current collector. g. The major area of ​​the anode current collector onto which the layer of negative electrode material is loaded is in the form of a strip. h. A free edge strip extends along the first longitudinal edge of the anode current collector. i. the cathode and cathode current collector are ribbon-shaped, the cathode current collector including a first longitudinal edge, a second longitudinal edge, and two end portions. j. The first and parallel second edges of the cathode current collector are the longitudinal edges of the ribbon-shaped cathode current collector. k. The major area of ​​the cathode current collector onto which the layer of positive electrode material is loaded is in the form of a strip. l. A free edge strip extends along the first longitudinal edge of the cathode current collector. m. One or more of the separators of the electrode-separator assembly is in the form of a ribbon. n. The anode and cathode are positioned within the electrode-separator assembly such that a first longitudinal edge of the anode current collector protrudes from a first terminal end face of the electrode-separator assembly, and a first longitudinal edge of the cathode current collector protrudes from a second terminal end face. o. A contact sheet metal portion seats on the first longitudinal edge of the anode current collector or on the first edge of the cathode current collector and is connected thereto by welding. p. A first longitudinal edge of the anode current collector or cathode current collector that is not in direct contact with the contact sheet metal portion is electrically connected to the housing bottom.

[0048] Particularly preferably, the energy storage element according to the invention is characterized by all combinations of the immediately preceding features a. to p.

[0049] In this embodiment, the electrode-separator assembly preferably includes one ribbon-shaped separator or two ribbon-shaped separators, each having first and second longitudinal edges and two ends. An electrode-separator assembly includes an electrode and one or more separators, always in the order anode / separator / cathode.

[0050] In this embodiment, a lid part having a circular periphery is preferably positioned within the circular opening of the cup-shaped housing part such that its edge abuts the inside of the cup-shaped housing part along a circumferential contact zone, and the edge of the lid part is joined to the cup-shaped housing part by a circumferential weld seam.

[0051] Preferably, the height of the energy storage element designed as a cylindrical round cell according to the invention is in the range of 50 mm to 150 mm. The diameter of the cylindrical round cell is preferably in the range of 15 mm to 60 mm. Cylindrical round cells with these form factors are particularly suitable for powering electric drives in motor vehicles.

[0052] If the energy storage element according to the invention is designed as a button cell, it preferably has a diameter of up to 25 mm and a height of up to 15 mm.

[0053] In embodiments in which the cell according to the invention is a cylindrical circular cell, the anode current collector, cathode current collector and one or more separators preferably have the following dimensions: - Length ranging from 0.5m~25m, - Widths ranging from 30mm to 145mm.

[0054] The free edge strips extending along the first longitudinal edge and not loaded with electrode material preferably have a width of less than or equal to 5000 μm in these cases.

[0055] Preferred embodiments of the separator Preferably, one or more separators are formed from an electrically insulating plastic film. The separator is preferably permeable to the electrolyte. For this purpose, the plastic film used may, for example, have micropores. The film may, for example, consist of polyolefins or polyetherketones. Nonwovens and fabrics made from plastic materials or other electrically insulating fabrics may also be used as separators. Separators having a thickness in the range of 5 μm to 50 μm are preferred.

[0056] Some particularly preferred embodiments utilize separators that are coated or impregnated on one or both sides with ceramic particles (eg, Al2O3 or SiO2).

[0057] In particular, in prismatic embodiments of the energy storage element, one or more separators of the assembly can also be one or more layers of solid electrolyte.

[0058] Preferred construction of the electrode-separator assembly in the form of a winding The ribbon-shaped anode, ribbon-shaped cathode and ribbon-shaped separator are preferably spirally wound in an electrode-separator assembly formed as a winding body. To manufacture the ribbon-shaped electrode-separator assembly, the ribbon-shaped electrode is preferably fed together with the ribbon-shaped separator to a winding device and is preferably spirally wound in the winding device around a winding shaft. In some embodiments, the electrode and separator are wound on a cylindrical or hollow cylindrical winding core for this purpose, which sits on a winding mandrel and remains in the winding body after winding.

[0059] The winding shell can be formed, for example, by a plastic film or an adhesive tape. It is also possible for the winding shell to be formed by one or more separator windings.

[0060] Preferred Electrochemical Embodiments In a further particularly preferred embodiment of the present invention, the energy storage element according to the present invention is characterized by one of the following features a. and b. a. The energy storage element is a lithium-ion cell. b. The energy storage element includes a lithium-ion cell.

[0061] Feature a. particularly refers to the described embodiment of the energy storage element according to the present invention as a cylindrical circular cell or button cell. In this embodiment, the energy storage element preferably comprises exactly one electrochemical cell or is one electrochemical cell.

[0062] Feature b. particularly refers to the described prismatic embodiment of the energy storage element according to the present invention. In this embodiment, the energy storage element may also include two or more electrochemical cells.

[0063] Basically, all electrode materials known for secondary lithium-ion cells can be used for the electrodes of the energy storage element.

[0064] Carbon-based particles such as graphite-like carbon or non-graphite-like carbon materials that can intercalate lithium can preferably be used as the active material in the negative electrode even in particle form. Alternatively or additionally, lithium titanate (Li4Ti5O 12 ) or its derivatives can preferably be contained in the negative electrode even in the form of particles. Further, the negative electrode may optionally contain, as the active material, at least one material from the group including silicon, aluminum, tin, antimony, or compounds or alloys of these materials that can reversibly store and release lithium, such as silicon oxide (especially SiO x , 0 < x < 2), in combination with a carbon-based active material. Tin, aluminum, antimony, and silicon can form intermetallic compound phases with lithium. The ability to accept lithium is many times higher than that of graphite or equivalent materials, especially in the case of silicon. Mixtures of silicon and carbon-based storage materials are often used. Thin anodes made of metallic lithium are also suitable.

[0065] Suitable active materials for the positive electrode include lithium metal oxide compounds and lithium metal phosphate compounds, such as LiCoO2 and LiFePO4. The chemical formula is LiNi x Mn y Co z Lithium nickel manganese cobalt oxide (NMC) with the formula LiMn2O4 (where x+y+z is usually 1), lithium manganese spinel (LMO) with the formula LiMn2O4 or lithium manganese spinel with the formula LiNi x Co y Al z Lithium nickel cobalt aluminum oxide (NCA) having the formula LiO2 (where x+y+z is usually 1) is also particularly suitable. 1.11 (Ni 0.40 Mn 0.39 Co 0.16 Al 0.05 ) 0.89 Lithium Nickel Manganese Cobalt Aluminum Oxide (NMCA) or Li 1+x Mixtures of MO compounds and / or the aforementioned materials may also be used. The cathode active material is also preferably used in particulate form.

[0066] Furthermore, the electrodes of the energy storage element according to the present invention preferably contain an electrode binder and / or additives to improve electrical conductivity. The active material is preferably embedded in the matrix of the electrode binder, and adjacent particles in the matrix are preferably in direct contact with each other. The conductive agent has the function of increasing the electrical conductivity of the electrode. Common electrode binders are, for example, based on polyvinylidene fluoride (PVDF), (Li-) polyacrylate, styrene-butadiene rubber or carboxymethyl cellulose or mixtures of different binders. Common conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes and metal powders.

[0067] The energy storage element 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), present dissolved in an organic solvent, for example a mixture of organic carbonates or cyclic ethers such as THF or nitriles. Other lithium salts that can be used are, for example, lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(oxalato)borate (LiBOB).

[0068] The nominal capacity of the lithium-ion based energy storage element according to the invention, designed as a cylindrical round cell, is preferably at most 15000 mAh. In a 21x70 form factor, the energy storage element in the embodiment as 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 a 18x65 form factor, the cell in the embodiment as 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.

[0069] In the European Union, manufacturer information on the nominal capacity of secondary batteries is strictly regulated. For example, information on the nominal capacity of nickel-cadmium secondary batteries must be based on measurements in accordance with the IEC / EN61951-1 and IEC / EN60622 standards, information on the nominal capacity of nickel-hydrogen secondary batteries must be based on measurements in accordance with the IEC / EN61951-2 standard, information on the nominal capacity of lithium secondary batteries must be based on measurements in accordance with the IEC / EN61960 standard, and information on the nominal capacity of lead-acid secondary batteries must be based on measurements in accordance with the IEC / EN61056-1 standard. Any information on nominal capacity in the present application is preferably based on these standards.

[0070] Further preferred electrochemical embodiments Alternatively, the energy storage cell according to the invention can 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 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.

[0071] The negative electrode material of the sodium ion-based energy storage element according to the invention is, for example, one of the following materials: carbon, in particular hard carbon (pure or doped with nitrogen and / or phosphorus) or soft carbon or graphene-based materials, carbon nanotubes, graphite, - phosphorus or sulfur, - Polyanions such as Na2Ti3O7, Na3Ti2(PO4)3, TiP2O7, TiNb2O7, Na-Ti-(PO4)3, Na-V-(PO4)3, etc. - V2O5, MnO2, TiO2, Nb2O5, Fe2O3, Na2Ti3O7, NaCrTiO4, Na4Ti5O 12 and other transition metal oxides. Alternatively, a Na metal anode can be used on the anode side.

[0072] The positive electrode material of the sodium ion-based energy storage element according to the invention is, for example, one of the following materials: - Polyanions: NaFePO4 (triplyte type), Na2Fe(P2O7), Na4Fe3(PO4)2(P2O7), Na2FePO4F, Na / Na2[Fe 1 / 2 Mn 1 / 2 ]PO4F, Na3V2(PO4)2F3, Na3V2(PO4)3, NaCoPO4, Na2CoPO4F, - Silicates: Na2MnSiO4, Na2FeSiO4, - Layered oxides: NaCoO2, NaFeO2, NaNiO2, NaCrO2, NaVO2, NaTiO2, Na(FeCo)O2, Na(NiFeCo)3O2, Na(NiFeMn)O2 and Na(NiFeCoMn)O2, Na(NiMnCo)O2.

[0073] Similar to lithium-ion cells, sodium-ion based electrodes may also contain electrode binders and / or additives to improve electrical conductivity. Suitable electrode binders are, for example, based on polyvinylidene fluoride (PVDF), (Li-) polyacrylate, styrene-butadiene rubber or carboxymethyl cellulose or mixtures of different binders. Suitable conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes and metal powders.

[0074] A sodium ion based energy storage cell according to the present invention preferably comprises an electrolyte comprising at least one of the following solvents and at least one of the following conductive salts: Organic carbonates, ethers, nitriles and mixtures thereof are particularly suitable as solvents. Preferred conductive salts are NaPF6, sodium-difluoro(oxalato)borate (NaBOB), NaBF4, sodium bis(fluorosulfonyl)imide (NaFSI), sodium-2-trifluoromethyl-4,5-dicyanoimidazole (NaTDI), sodium-bis(trifluoromethanesulfonyl)imide (NaTFSI), NaAsF6, NaBF4, NaClO4, NaB(C2O4)2, NaP(C6H4O2)3; NaCF3SO3, sodium trifuran (NaTf) and Et4NBF4. In a preferred embodiment, an additive may be added to the electrolyte.

[0075] Preferred embodiments of the current collector The current collector of the energy storage element serves to electrically contact the electrochemically active components contained in the respective electrode materials over as large an area as possible. Preferably, the current collector is made of a metal or has at least a metallized surface.

[0076] In the case of an energy storage element designed as a lithium-ion cell according to the invention, suitable metals for the anode current collector are, for example, copper or nickel or other conductive materials, in particular copper and nickel alloys or metals coated with nickel. In particular, materials of type EN CW-004A or EN CW-008A with a copper content of at least 99.9% can be used as copper alloys. As nickel alloys, alloys of the type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable. As nickel alloys, alloys of the type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable. Stainless steels, for example type 1.4303 or 1.4404 or type SUS304, can also be considered.

[0077] For energy storage elements designed as lithium-ion cells according to the invention, aluminum or other conductive materials, including aluminum alloys, are particularly suitable as metals for the cathode current collector.

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

[0079] For sodium-ion cells, in a preferred embodiment, both the cathode and anode current collectors are made of aluminum or an aluminum alloy.

[0080] Preferably, the anode current collector and / or the cathode current collector are each a metal foil having a thickness in the range of 4 μm to 30 μm and, in the case of the described configuration of the energy storage element as a cylindrical circular cell, a ribbon-shaped metal foil having a thickness in the range of 4 μm to 30 μm.

[0081] However, in addition to films, other strip-shaped substrates such as metal or metallized nonwoven fabrics or perforated metal foams or expanded metals can also be used as current collectors.

[0082] The current collector is preferably loaded on both sides with the respective electrode material.

[0083] In the described configuration of the energy storage element as a cylindrical circular cell, the longitudinal edges of one or more separators preferably form the end faces of an electrode-separator assembly formed as a wound body.

[0084] In the described prismatic configuration of the energy storage element, the edges of the separators preferably form the end faces of the stack from which the edges of the current collectors project.

[0085] It is further preferred that the longitudinal edge or edges of the anode and / or cathode current collector which protrude beyond the terminal end face of the winding or beyond the side of the stack do not exceed 5000 μm, preferably 3500 μm or less.

[0086] Particularly preferably, the edge or longitudinal edge of the anode current collector protrudes from the side or end face of the stack by not more than 2500 μm, particularly preferably not more than 1500 μm, and particularly preferably, the edge or longitudinal edge of the cathode current collector protrudes from the side or end face of the stack by not more than 3500 μm, particularly preferably not more than 2500 μm.

[0087] Preferred embodiments of the lid part In a preferred embodiment, the energy storage element according to the invention is characterized by at least one of the following features a. to d. The connecting pole sits directly on the contact sheet metal part and is connected thereto by welding. b. The connection terminals are electrically insulated from the cover plate by a hardened potting compound made from an electrically insulating plastic material. c. There is an annular gap between the cover plate and the contact sheet metal which is filled with potting compound. d. The annular gap is limited radially outwardly by an O-ring shaped insulating washer made from an electrically insulating plastic material.

[0088] Particularly preferably, the energy storage element according to the invention is characterized by all combinations of the immediately preceding features a. to d.

[0089] A lid part of this design ensures that there is essentially no dead volume between the electrode-separator assembly and the metal lid plate. Any space between the contact sheet metal parts, the connecting pole, the lid plate, and optionally the O-ring-like insulating disk can be filled with potting compound. A lid part with the above mentioned features can be constructed very compactly.

[0090] In a further development of the energy storage element according to the invention, in which the cup-shaped housing part has a positive pole and the connecting pole is a negative connecting pole, the energy storage element is characterized by the immediately following features a. to e. The connecting pole sits directly on the contact sheet metal part and is connected thereto by welding. b. The contact sheet metal portion is made of nickel, copper, or titanium or a nickel, copper, or titanium alloy or stainless steel. c. The terminal electrode is a bimetallic terminal electrode and includes a lower pole part made of nickel, copper, or titanium, or a nickel, copper, or titanium alloy, or stainless steel, and an upper pole part made of aluminum or an aluminum alloy. d. The bottom of the pole is welded to the contact sheet metal part. e. The bottom part of the electrode, the contact sheet metal part and the anode current collector are made of the same material.

[0091] Particularly preferably, the energy storage element according to the present invention is characterized by a combination of the immediately preceding features a.-d., and in some embodiments by all combinations of the immediately preceding features a.-e.

[0092] In this embodiment, the energy storage element according to the invention is therefore characterized by a connecting pole comprising two different metallic materials: nickel, or copper, or titanium or a nickel, or copper, or titanium alloy or stainless steel on one side and aluminium or an aluminium alloy on the other side.

[0093] It is therefore possible to construct an energy storage element according to the invention in which the exterior of the housing is made entirely from aluminium or an aluminium alloy.

[0094] The upper pole section is accessible from the outside and can be welded, for example, to an aluminum conductor. Such an energy storage element offers the great advantage that it can be easily integrated into a cell assembly. In this case, the poles of several energy storage elements are interconnected via a common current conductor. From a production technology point of view, it can be advantageous to weld the poles of the cells to the current conductor using a laser. This is generally only possible without problems if the materials to be welded are the same. For example, it is difficult or impossible to weld a copper terminal pole to an aluminum conductor using a laser. However, with pole tops made of aluminum or an aluminum alloy, this is possible without any problems. This means that the negative connection pole of the cell can also be assembled by laser via a common aluminum conductor.

[0095] Suitable aluminum alloys are, for example, Al alloys of type 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg and AlMg. The aluminum content of the alloy is preferably more than 99.5%. Suitable stainless steels are, for example, stainless steels of type 1.4303 or 1.4404 or type SUS304 or nickel-plated steels. 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. Nickel alloys of the type NiFe, NiCu, CuNi, NiCr and NiCrFe are particularly suitable.

[0096] In a further development of the energy storage element according to the invention, in which the cup-shaped housing part has a negative pole and the connecting pole is a positive connecting pole, the energy storage element is characterized by the immediately following features a. to d. The connecting pole sits directly on the contact sheet metal part and is connected thereto by welding. b. The contact sheet metal portion is made of aluminum or an aluminum alloy. c. The connecting electrodes are made of aluminum or an aluminum alloy. d. The contact sheet metal portion, the connecting electrode, and the cathode current collector are made of the same material.

[0097] Particularly preferably, the energy storage element according to the present invention is characterized by a combination of the immediately preceding features a.-c., and in some embodiments also by all combinations of the immediately preceding features a.-d.

[0098] Thus, also in this embodiment it is possible to construct an energy storage element according to the invention in which the exterior of the housing is made entirely from aluminium or aluminium alloy.

[0099] Preferred embodiments of the connection of the contact sheet metal part / contact sheet metal part to the anode current collector and negative terminal electrode or the contact sheet metal part to the cathode current collector and positive terminal electrode The contact sheet metal part is electrically connected to the connecting pole passing through an aperture in the cover plate and electrically connected to either the anode current collector or the cathode current collector, in particular it is directly welded to the connecting pole and / or the respective current collector.

[0100] In a particularly preferred embodiment of the present invention, in which the cup-shaped housing part is positively polarized and the connection pole is a negative connection pole, the contact sheet metal part electrically connected to the negative connection pole is characterized by at least one of the immediately following features a. to c. a. The contact sheet metal parts consist of nickel, or copper, or titanium, or a nickel, copper, or titanium alloy, or stainless steel, for example of type 1.4303 or 1.4404 or type SUS304, or nickel-plated copper. b. The contact sheet metal portion is made of the same material as the negative connecting pole or the lower pole portion of the negative connecting pole. c. The contact sheet metal is made of the same material as the anode current collector.

[0101] It is preferable that the immediately preceding features a. and b., and particularly preferably features a. to c., are realized in combination with one another.

[0102] In a particularly preferred embodiment of the present invention, in which the cup-shaped housing part is negatively polarized and the connection pole is a positive connection pole, the contact sheet metal part electrically connected to the positive connection pole is characterized by at least one of the immediately following features a. to c. a. The contact sheet metal portion is made of aluminum or an aluminum alloy. b. The contact sheet metal portion is made of the same material as the positive terminal. c. The contact sheet metal portion is made of the same material as the cathode current collector.

[0103] It is particularly preferred that the immediately preceding features a. and b., preferably also features a. to c., are realised in combination with one another.

[0104] If the contact sheet metal part is made of the same material as the positive terminal and / or the cathode current collector, these parts can be welded together without any problems.

[0105] Suitable aluminum alloys for the contact sheet metal parts include Al alloys of types 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55. Also suitable are AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg and AlMg. The aluminum content of these alloys is preferably greater than 99.5%.

[0106] In a possible preferred further development of the invention, the contact sheet metal part is characterized by at least one of the immediately following features a. to f. a. The contact sheet has a preferably uniform thickness in the range of 50 μm to 600 μm, preferably in the range of 150 μm to 350 μm. b. The contact sheet metal portion has two opposing flat sides and extends essentially in only one dimension. c. The contact sheet metal part is a disk or a polygonal plate. d. The contact sheet metal part is dimensioned so that it covers at least 40%, preferably at least 60%, particularly preferably at least 80% of the end face of the current collector on which it rests, from which the edge of the current collector protrudes. e. the contact sheet metal portion has at least one bead that appears as an elongated recess on one flat side of the contact sheet metal portion and as an elongated ridge on the opposing flat side, the contact sheet metal portion resting on the first edge of the anode current collector or the first edge of the cathode current collector with the flat side carrying the elongated ridge. f. A contact sheet metal portion is welded to the first edge of the anode current collector or the first edge of the cathode current collector in the area of ​​the bead.

[0107] It is particularly preferred that the immediately preceding features a. to c., particularly preferably the immediately preceding features a. to d., are realized in combination with one another. In a preferred embodiment, features a. to d. are realized in combination with features e. and f.

[0108] Covering as many of the end faces as possible is important for the thermal management of the energy storage element according to the invention. The greater the coverage, the easier it is to contact the first edge of each current collector over its entire length. The heat formed in the electrode-separator assembly can therefore be better dissipated through the contact sheet metal parts.

[0109] In some embodiments, it has proven advantageous to subject the edge of the respective current collector, on which the contact sheet metal part is to be placed, before the contact sheet metal part is placed, to a pretreatment similar to the pretreatment of the current collector which is to be placed on the housing bottom. In particular, at least one recess can now be folded into the edge, which corresponds to at least one bead or elongated ridge on the flat side of the contact sheet metal part facing the first terminal end face.

[0110] The edge of the current collector may also be directionally shaped by pretreatment, for example it may be bent in a defined direction.

[0111] In some particularly preferred embodiments, the contact sheet metal part is pressed into the end face of the winding. In this case, at least one bead is not necessary. In these cases, the contact sheet metal part is preferably polygonal or strip-shaped and preferably covers at least 50%, particularly preferably at least 80%, of the end face into which it is pressed.

[0112] Membrane at the bottom of the housing (primary protection device) In a further particularly preferred embodiment of the invention, the energy storage element according to the invention is characterized by the following feature a. a. The metal membrane is fixed to the bottom of the cup-shaped housing portion by welding.

[0113] The bottom of the cup-shaped housing part may have a shallow recess into which the membrane is inserted so that it does not protrude. Preferably, it is connected to the bottom via a circular weld seam that extends around the periphery of the aperture in the bottom.

[0114] The thickness of the membrane can be adjusted to suit the pressure at which the protector is triggered.

[0115] Preferred housing design In a further particularly preferred embodiment of the invention, the energy storage element according to the invention is characterized by at least one of the immediately following features a. to c. a. The bottom of the cup-shaped housing portion has a thickness in the range of 200 μm to 2000 μm. b. The sidewall of the cup-shaped housing portion has a thickness in the range of 150 μm to 2000 μm. c. The lid part, particularly the lid plate of the lid part, has a thickness in the range of 200 μm to 2000 μm. The immediately preceding features a to c are particularly preferably realized in combination.

[0116] Method according to the invention The method according to the invention is used to manufacture an energy storage element according to the invention and is characterized by the following steps a. to e. a. providing a metal cup-shaped housing portion including a housing bottom, a peripheral sidewall, and a terminal opening; b. providing an electrode-separator assembly, the electrode-separator assembly comprising: a cathode having a cathode current collector having a first edge and a second edge parallel thereto; - an anode having an anode current collector with a first edge and a second edge parallel thereto; a first flat terminal end surface and a second flat terminal end surface; Including, - the anode current collector includes a main area loaded with a layer of negative electrode material and a free edge strip extending along a first edge thereof and not loaded with electrode material; - the cathode current collector includes a main area loaded with a layer of positive electrode material and a free edge strip extending along a first edge thereof and not loaded with electrode material; - disposing the anode and cathode within the electrode-separator assembly such that a first edge of the anode current collector protrudes from a first terminal end face of the electrode-separator assembly and a first edge of the cathode current collector protrudes from a second terminal end face; c. inserting the electrode-separator assembly into the housing cup such that a first edge of the anode current collector or a first edge of the cathode current collector rests on the housing bottom; d. forming a welded connection between the first edge resting on the housing bottom and the housing bottom; e. At the housing bottom of the cup-shaped housing portion, - a primary protection device against internal overpressure in the form of an aperture closed by a metal membrane; - a secondary protection device against internal overpressure in the form of at least one groove on its inside or outside; The step where Includes.

[0117] The components used in the method have all been described in relation to the energy storage element according to the invention, to which reference is now made to the corresponding description.

[0118] As already explained above, it is preferred that either the first edge of the anode current collector or the first edge of the cathode current collector sits directly on the housing bottom. Furthermore, it is preferred that the edge that rests on the housing bottom is connected to the housing bottom by welding.

[0119] The weld joint in step d. is preferably made by welding from the outside, in particular by laser welding.

[0120] In a preferred embodiment, the method comprises immediately following steps a. and b.: a. a contact sheet metal part is positioned on a first edge of the anode current collector or a first edge of the cathode current collector that is not placed on the housing bottom, and is connected to this edge by welding; b. The connecting pole is fixed to the contact sheet metal part. Includes at least one of the following.

[0121] Preferably, the method according to the invention comprises both steps a. and b.

[0122] Both steps a. and b. can be performed before or after inserting the electrode-separator assembly into the housing cup. The connecting pole is also fixed to the contact sheet metal part by welding.

[0123] Particularly preferably, the method according to the invention comprises the following two steps a. and b.: a. a cover plate having an aperture for a connection electrode is inserted into a terminal opening of a cup-shaped housing portion; b. filling any remaining gaps between the cover plate and the contact sheet metal with a potting compound which, when hardened, electrically insulates the cover plate from the connection terminals and the contact sheet metal. Includes.

[0124] These steps form the housing for the energy storage element and simultaneously seal its top side. A cover plate is preferably welded to the cup-shaped housing part before step b. This measure, combined with the application of a potting compound in step b., ensures a liquid-tight and gas-tight closure of the housing.

[0125] In a particularly preferred embodiment, the above-mentioned O-ring-shaped insulating washer made from an electrically insulating plastic material is placed on the contact sheet metal part before the cover plate is inserted, which limits the gap to be filled with the potting compound radially outward.

[0126] The electrode-separator assembly can be impregnated with a suitable electrolyte through an aperture in the housing bottom of the metallic cup-shaped housing portion, which can then be closed by a metal membrane.

[0127] Further features and advantages of the invention are apparent from the following description of preferred embodiments of the invention in conjunction with the claims and the drawings. The individual features can be realized individually or in combination with one another. [Brief description of the drawings]

[0128] [Figure 1] FIG. 2 is a schematic diagram of electrode ribbons and their arrangement to illustrate the structure of the electrode-separator assembly of the energy storage cell according to the present invention. [Figure 2A-C] 1 shows an energy storage cell according to the invention from the outside and in longitudinal section; [Figure 3A-B] 2 is a detailed view in longitudinal section of the upper and lower end face regions of an energy storage cell according to the invention; [Figure 4A-B] 3A and 3B are detailed views in a perspective view from above and in a cross-sectional view of a connecting pole for an energy storage cell according to the invention; [Figure 5A-B] FIG. 2 is a detailed view in a top perspective view and in a cross-sectional view of an insulating disk for an energy storage cell according to the invention. [Figure 6A-B] 1A and 1B are detailed views in perspective from above and in cross-sectional perspective from below of a contact sheet metal part for an energy storage cell according to the invention; [Figure 7] FIG. 2 is a detailed view of the bottom of the housing of the energy storage cell according to the present invention. [Figure 8A-C] FIG. 2 is an exploded view of the various parts of an energy storage cell according to the present invention. [Figure 9A-B] 2A-2C are detailed views from the top face region of an energy storage cell according to the invention illustrating the manufacturing process for the energy storage cell; [Figure 10]1 is a top-diagonal view of the bottom of the housing of an energy storage cell according to the present invention illustrating the manufacturing process for the energy storage cell; FIG. [Figure 11A-B] FIG. 2 is a cross-sectional view of an alternative embodiment of a contact sheet metal part with an attached connecting pole and its installation in an energy storage cell according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0129] The ribbon-shaped electrode-separator assembly shown in Figures 1A-D comprises a ribbon-shaped anode 105 (Figure 1A) 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 preferably a foil made of copper or nickel. It comprises a strip-shaped main area loaded with a layer of anode material 107 and a free edge strip 106b extending along its first longitudinal edge 106a and not loaded with electrode material 107. Furthermore, the electrode-separator assembly comprises a ribbon-shaped cathode 108 (Figure 1B) 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 preferably an aluminum foil. It comprises a strip-shaped main area loaded with a layer of positive electrode material 110 and a free edge strip 109b extending along its first longitudinal edge 109a and not loaded with electrode material 110. In Figures 1A and B both electrodes are shown individually in an unwound state.

[0130] The anode 105 and the cathode 108 are arranged offset from each other in the electrode-separator assembly such that the first longitudinal edge 106a of the anode current collector 106 protrudes from the first terminal end face 104a and the first longitudinal edge 109a of the cathode current collector 109 protrudes from the second terminal end face 104b of the electrode-separator assembly 104. The offset arrangement is shown in FIG. 1C. Two ribbon-like separators 116 and 117 are also shown there, which separate the electrodes 105 and 108 from each other in the winding. In FIG. 1D, the electrode-separator assembly is shown in a wound form so that it can be used in an energy storage element according to the invention. The electrode edges 106a, 109a protruding from the end faces 104a, 104b are clearly visible. The outer wound shell 104c is formed by a plastic film.

[0131] Figures 2A-C show an energy storage cell according to the invention in a perspective view from above (Figure 2A), in a longitudinal section (Figure 2B) and in a perspective view from below (Figure 2C). The energy storage cell 100 has the shape of a cylindrical circular cell. The housing of the energy storage cell 100 is formed by a cup-shaped housing part 101 and a lid part. The lid part comprises a lid plate 102a having the shape of a perforated plate and a connecting pole 102b in the middle of the lid part.

[0132] As can be seen in the cross-sectional view of FIG. 2B, a wound electrode-separator assembly 104 formed from wound electrode ribbons with a separator ribbon therebetween is located inside the energy storage cell 100.

[0133] 2C shows the bottom side of the energy storage cell 100, which is formed by the housing bottom 101a, where three star-shaped weld embossments are arranged in the form of beads 101d, which appear on the outside as recesses and on the inside as elongated ridges. The longitudinal edges of the respective current collectors rest on the inside of these beads 101d, and the current collectors are preferably welded directly to the housing bottom in the region of these beads.

[0134] The material of the housing bottom 101a and the entire cup-shaped housing portion 101 is preferably aluminum.

[0135] According to the invention, two safety features are integrated in the housing bottom 101a. First, there is an aperture in the center of the housing bottom 101a, which is closed by a metal membrane 114. This membrane 114 provides pressure equalization in case of overpressure caused by a cell failure, in which case the membrane is blown open or blown away by the pressure. In this way, any gas that may have formed in the cell can escape through the aperture in the housing bottom 101a (primary protection device).

[0136] In addition, the housing bottom 101a is provided with a further safety feature, which is realized by three grooves 101c arranged in a star shape. These grooves 101c represent weak points in the structure of the housing bottom 101a and therefore form a predetermined breaking point in case of an overpressure occurring inside the cell (secondary protection device). In this example, the grooves are located on the inside of the housing bottom 101a and are therefore shown in dashed lines in FIG. 2C. In particular, the grooves 101c can be realized as three score lines. The star-shaped arrangement of the score lines is further formed by a semicircular connection of the score lines or grooves 101c. At a corresponding high overpressure, the housing bottom 101a tears open along the grooves 101c and the semicircular connection of these grooves, so that an outlet opening with a relatively large cross section is formed, through which any gas formed inside the housing can be quickly evacuated.

[0137] Figures 3A,B show an enlarged view of an end face region of an energy storage cell 100 according to the invention. Figure 3A shows a detail of the end face with a lid part 102. The lid part 102 comprises a lid plate 102a with a central aperture and a connecting pole 102b arranged in the center of the lid plate 102a. In this example, the connecting pole 102b forms the negative pole of the energy storage cell 100, while the surrounding lid plate 102a forms the positive pole.

[0138] Beneath the connecting pole 102b there is a contact sheet metal part 111, which sits on and is welded to the free edge strip 106b of the spirally arranged anode current collector of the negative pole. The contact sheet metal part 111 is electrically connected, in particular by welding, to the connecting terminal 102b formed from two metal parts. The cover plate 102a is electrically insulated from the contact sheet metal part 111 by an O-ring-shaped insulating disk 112. Furthermore, an electrically insulating potting compound 113 is located in the gap between the connecting pole 102b and the cover plate 102a.

[0139] 3B shows a detail of the opposite end face of the energy storage cell 100 contained in the housing bottom 101a. The free edge strip 109b of the cathode current collector is electrically connected, in particular welded, directly to the housing bottom 101a at this end face of the energy storage cell 100. At the opposite end face, it is electrically contacted through the shell of the cup-shaped housing part 101 with the metallic cover plate 102a, so that the positive potential of the cell can also be taken out at the top face of the energy storage cell 100.

[0140] On the lower end face of the energy storage cell 100 shown in Fig. 3B, the safety features of the cell against overpressure according to the invention can be seen. The primary protection is formed by a metal membrane 114 closing a central circular aperture 101b in the housing bottom 101a. The secondary protection is formed by grooves 101c, whereby one of three star-shaped grooves 101c can be seen in cross section in this figure. The grooves 101c, located on the inside of the housing bottom 101a, represent defined weakened structures of the housing bottom, so that in case of a relatively high overpressure occurring in the cell, these structures can open and gas can escape.

[0141] The preferred design of the energy storage cell 100 according to the invention, shown with reference to Figure 3, allows a reduction in the number of components in the upper region of the energy storage cell (Figure 3A), the negative and positive terminals of the cell being arranged in this upper region. In particular, this design allows the elimination of the need for an additional arrester, due to the integral design of the connection pole 102b.

[0142] The direct contact of one longitudinal edge of the electrode band on the side of the bottom of the housing (part of the illustration, FIG. 3B) also serves to make the cell particularly compact, so that no dead volumes are required for the various functions of the cell.

[0143] Direct contact between the longitudinal edges of the electrode ribbons also improves heat dissipation and reduces internal resistance.

[0144] In addition, the cell design generally also allows for the formation of longer windings and therefore greater energy density in the resulting energy storage cell.

[0145] The upper surface of the energy storage cell 100 is maximally compact with this design. If gases are generated inside the cell that lead to a rise in pressure, these gases are necessarily directed to the lower area of ​​the cell, where the safety features for pressure equalization are located. Overall, such a cell therefore has a very good level of safety.

[0146] 4A,B show a detailed view of the connecting pole 102b in a perspective view from above (FIG. 4A) and in a cross-sectional view (FIG. 4B). In this preferred embodiment, the connecting pole 102b is composed of two metal parts. The upper region (upper pole part) 1020 is preferably made of aluminum, and the lower region (lower pole part) 1021 is preferably made of copper. The upper region 1020 has a chamfered circumferential upper edge. As can be seen in the cross-sectional view of FIG. 4B, the lower region 1021 has a peripheral weld shoulder 1021a and a central downwardly protruding pin 1021b. The pin 1021b properly engages with a correspondingly provided recess in the center of the contact sheet metal part 111, thus ensuring a good fit of the connecting pole 102b.

[0147] Such a connecting pole 102b may be formed, for example, from a bimetal strip having aluminum and copper. For example, a blank is stamped out of the bimetal for this purpose. The upper region 1020 with the chamfered edges and the lower region 1021 with the central pin 2021b and the peripheral weld shoulder 1021a may be formed by cold forming.

[0148] Copper is particularly suitable for the lower region 1021 of the connecting pole 102b, in particular if the connecting pole 102b is intended to contact the anode current collector via the contact sheet metal part 111. This material is also particularly suitable for the connecting pole, since the anode current collector usually also consists of copper. In this case, the contact sheet metal part 111 preferably also consists of copper.

[0149] Forming the top 1020 of the connecting pole 102b from aluminum has the particular advantage that in this case the entire housing of the energy storage cell can be formed from aluminum, since the cup-shaped housing part 101 also generally consists of aluminum. The cathode current collector, which can be in electrical contact with the housing bottom part 101a, also often consists of aluminum. If the energy storage cell 100 is constructed with reverse polarity as required, it is of course also possible to select the metal material for the housing and / or the connecting pole differently.

[0150] 5A and 5B show an overall view (FIG. 5A) and a cross-sectional view (FIG. 5B) of the O-ring-shaped insulating disk 112. On the one hand, the insulating disk 112 preferably has the function of electrically insulating the cover plate 102a having the positive polarity from the components of the energy storage cell 100 having the negative polarity. In addition, the insulating disk 112 also achieves a liquid-tight and gas-tight closure of the housing.

[0151] In the preferred example of the insulating washer 112 shown here, the insulating washer is made from two different materials: the outer area 112a of the insulating disk 112 is preferably made from a particularly strong plastic material, for example PBT (polybutylene terephthalate); the inner area 112b is preferably made in particular from a somewhat more flexible, particularly heat-resistant plastic material, for example PET (polyethylene terephthalate). The outer area 112a therefore ensures a particular mechanical stability; the inner area 112b ensures flexibility and is particularly resistant to the high-temperature potting compound 13 applied during the assembly of the energy storage cell.

[0152] Particularly advantageously, the inner circumference of the O-ring-like insulating disk 112 has a circumferential thickening, which further supports the stability of the components in the end face region of the mounted energy storage cell. When assembling the energy storage cell, a temporary sealing of the cell is first achieved by inserting the insulating washer 112 in the lid region of the cell until the subsequently applied potting compound 113 hardens and completely seals the cell. Furthermore, due to its special shape, the insulating disk 112 allows for axial support of the electrode-separator assembly 104 in a rolled shape, for example during testing of the cell. If the cell is deformed laterally, the shape of the insulating disk 112 also provides space for any deformation of the contact sheet metal parts 111 that may occur. Finally, the shape of the insulating disk 112 makes it possible to reduce the volume of the potting compound 113 and the amount of air bubbles that may be trapped during potting when the energy storage cell is assembled.

[0153] As a possible alternative to such an insulating washer, an insulating sealing bulge, for example similar to a silicone bulge, can be applied, which also ensures a tight seal, but the insulating washer 112, especially in the embodiment shown here, offers various advantages in comparison, which are mentioned below.

[0154] Figures 6A,B show a preferred embodiment of a contact sheet metal part 111 provided for contacting the free edge of the current collector of the respective electrode in the range from the upper region of the energy storage cell. Figure 6A shows a plan view of the disk-shaped contact sheet metal part 111. Figure 6B shows a cross section of the contact sheet metal part 111 seen from below, i.e. on the side of the contact sheet metal part facing the electrode-separator assembly inside the energy storage cell.

[0155] Similar to the beads 101d of the housing bottom 101a, the contact sheet metal part 111 also has three star-shaped beads 111d, which appear as recesses on the outside (FIG. 6A) and as elongated ridges on the inside (FIG. 6B). The beads 111d can be, for example, embossed and can have a depth of, for example, 0.25 mm. In the assembled cell, the beads 111d contact the respective longitudinal edges of the electrode strips of the electrode-separator assembly through which they are in contact. The contact sheet metal part 111 is preferably welded to the respective longitudinal edges of the electrode strips through the beads 111d.

[0156] The recess 111e is located in the center of the contact sheet metal part 111. The recess 111e serves to receive the connecting pole 102b in that the central pin 1021b of the connecting pole 102b engages in the recess 111e. In this way, the connecting pole 102b can be easily positioned and fixed on the contact sheet metal part 111 so that the connecting pole 102b can be welded without any problems.

[0157] Furthermore, in a particularly preferred embodiment of the contact sheet metal part 111 shown here, further star-shaped narrow recesses 111f are provided located on the inward-facing side of the contact sheet metal part 111. In this exemplary embodiment, a total of nine of these recesses 111f are provided as narrow grooves arranged in a star shape. The grooves may have a depth of, for example, 0.1 mm. The channels of the recesses 111f serve to improve the distribution of the electrolyte inside the cell.

[0158] Furthermore, in this preferred embodiment, the contact sheet metal portion 111 has an embossed peripheral edge 111g, which is specifically positioned with a ridge downwards as a predetermined buckling point, which facilitates the assembly of the housing of the energy storage cell.

[0159] In a preferred embodiment, the contact sheet metal part 111 is made from sheet copper, for example with a material thickness of 0.3 mm. Copper is particularly advantageous when the contact sheet metal part contacts the longitudinal edge of the anode current collector, which end is preferably also formed from copper.

[0160] 7 shows a detailed view of the housing bottom 101a of the energy storage cell with star-shaped inwardly protruding beads 101d, which are designed as welding embossments for contacting the electrode-separator assembly in particular in the form of a wound electrode. The star-shaped arrangement with three beads 101d is particularly advantageous for mounting the cell due to its rotational symmetry.

[0161] A central aperture 101b in the housing bottom 101a is covered by a metal film 114 and serves as a primary protection device for the cell in the event of overpressure. In particular, aperture 101b is intended to be used initially to fill the cell with electrolyte during manufacture of the cell, before aperture 101b is closed with metal film 114.

[0162] A peripheral recess 1010b is preferably provided surrounding the central aperture 101b to precisely fit and receive the metal membrane 114 to close the central aperture 101b.

[0163] Moreover, in this embodiment, three star-shaped weakening structures are provided in the form of inwardly open grooves 101c, which are interconnected by semicircular connecting lines 1010c. These weakening structures 101c and 1010c act as secondary protection devices against internal overpressure. Instead of attaching the weakening structures to the housing bottom from the inside, such weakening structures, e.g. score lines, can also be attached from the outside.

[0164] One or more labeling fields 1010a may further be provided on the outside of the housing bottom 101a, which may be used to affix various textual information.

[0165] 8-10 below show various details related to the fabrication of an energy storage cell according to the present invention.

[0166] Figures 8A-C show exploded views of the various parts of an energy storage cell according to the invention. Figure 8A shows the parts of the housing, which include the housing cup 101, the connecting pole 102b, the O-ring shaped insulating washer 112, the cover plate 102 with a central recess into which the connecting pole 102b engages and the potting compound 113. A closure for the energy storage cell in the form of a metal film 114 is shown below the housing cup 101, which closure is attached after the assembled cell has been filled with an electrolyte 115, shown here only diagrammatically.

[0167] FIG. 8B shows the electrode-separator assembly 104 in a wound shape and the contact sheet metal part 111 attached thereto. The electrode-separator assembly 104 in a wound shape can be produced by winding the electrode ribbon and the separator in a manner known per se, in particular on a winding machine. To complete the wound shape, the outermost winding turn can be bent inwards, for example by 30°-45°, preferably by means of a conical pressure piece, so that the wound shape is stable. An adhesive tape 118 (FIG. 8C), for example made of polypropylene, is then preferably applied to the outer circumferential surface of the winding, which, in addition to its stabilizing function, can also have an electrical insulating function in the cell. After this stabilization of the electrode-separator assembly 104 in a wound shape, the disk-shaped contact sheet metal part 111, for example made of copper, can be placed loosely on the upper end surface of the winding and fixed in place with a particularly stable adhesive tape 119, for example made of polyimide. For example, a tape made of Kapton® with a thickness of 50 μm can be used for this purpose.

[0168] The electrode-separator assembly 104 with the contact sheet metal portion 111 attached is then inserted into the cup-shaped housing portion 101. After aligning the beads in the housing bottom and the contact sheet metal portion, using a camera if necessary, the arrangement can be pressed with a suitable press tool and laser welded simultaneously or sequentially from above and below to bring the longitudinal edges of the electrode ribbons into contact with their respective beads. The connecting pole 102b can then be placed on the contact sheet metal portion 111 and welded.

[0169] 9A, B show a detail of the manufacture of the lid assembly of the cell. FIG. 9A shows a detailed view of the welding of the connecting pole 102b on the contact sheet metal part 111, whereby the laser can be applied obliquely or vertically, especially in the area of ​​the circumferential weld shoulder 1021a of the connecting pole 102b. FIG. 9B shows how the insulating disk 112 can be inserted and pressed to the correct height before the cover plate 102a is placed and welded vertically or horizontally from an angle to the cup-shaped housing part, not shown here. Here, the connecting pole 102b can be pressed to the correct height against the cell shoulder formed by the upper side of the cover plate 102a, if necessary. The distance provided for this can be, for example, 1 mm between the upper side of the connecting pole 102b and the upper side of the cover plate 102a. The gap between the cover plate 102a and the connecting pole 102b is filled with a potting compound 113 in order to seal this part of the energy storage cell gas-tight and liquid-tight.

[0170] The energy storage cell can then be placed in an oven to cure the potting compound 113 and heat up any residual moisture in the rolled electrode-separator assembly.

[0171] 10 shows the final filling with electrolyte 115, which is filled from the bottom side (top in this figure) of the energy storage cell 100 through the aperture 101b in the housing bottom 101a. Finally, a metal film 114 is applied as a closure to the opening in the housing bottom 101a or to the central aperture 101b. For this purpose, for example a vertical laser beam can be used.

[0172] Figure 11 shows an alternative way of attaching the lid assembly: Figure 11A shows in cross section from below the contact sheet metal part 111 with the connecting terminals 102b attached, and Figure 11B shows the upper end face area of ​​the cell in longitudinal section.

[0173] In this alternative manufacturing process, the connecting pole 102b is pre-welded to the contact sheet metal part 111. Friction welding or friction stir welding can be used for this.

[0174] If the contact sheet metal part 111 is designed in this embodiment, the star-shaped bead 111d of the contact sheet metal part 111 can be shortened if necessary, since it is covered by the connecting pole 102b during the subsequent welding of the electrode-separator assembly. Overall, therefore, slightly less welding area is available for contacting the longitudinal edge of each electrode strip with the contact sheet metal part 111. However, this configuration can provide advantages for assembly.

[0175] Since it may be easier to attach the connecting pole 102b directly to the contact sheet metal part 111 outside the housing cup assembly, the central recess in the contact sheet metal part and the corresponding pin on the connecting pole 102b may be omitted if desired.

[0176] The further assembly of the energy storage cell with the connecting pole 102 b already welded directly onto the contact plate 111 does not differ in principle from the manufacturing process described above for the energy storage cell 100 .

[0177] Various aspects of the present invention The individual elements of the energy storage element according to the invention described in detail here can in principle be realized independently of one another as separate aspects of the invention.

[0178] According to a first aspect, the invention relates to an energy storage element having an electrode-separator assembly and a metal housing cup. The electrodes of the electrode-separator assembly are preferably in direct electrical contact with a contact sheet metal part on one end face of the energy storage element and with a housing bottom on the other end face of the energy storage element via one of their longitudinal edges. This energy storage element is characterized by a primary protection device as described in detail and a secondary protection device at the housing bottom.

[0179] According to a further aspect, the invention comprises an energy storage element having an electrode-separator assembly and a metal housing cup. The electrodes of the electrode-separator assembly are preferably in direct electrical contact with the contact sheet metal part on one end face of the energy storage element and with the housing bottom on the other end face of the energy storage element in each case via one of their longitudinal edges. This energy storage element is further characterized by the fact that a cover part is provided in a compact design with a metallic cover plate and a connecting pole. Preferably, the connecting pole forms the negative pole of the element and the cover plate forms the positive pole. The connecting pole is preferably formed by two metal parts assembled together as a bimetal. This connecting pole is preferably realized according to the design described with reference to FIG. 4.

[0180] According to a further aspect, the invention comprises an energy storage element having an electrode-separator assembly and a metal housing cup. The electrodes of the electrode-separator assembly are preferably in direct electrical contact with the contact sheet metal part on one end face of the energy storage element and with the housing bottom on the other end face of the energy storage element in each case via one of their longitudinal edges. This energy storage element is further characterized by the fact that an O-ring-shaped insulating washer is provided to seal the connecting pole against the other parts of the element having the opposite polarity. Preferably, this insulating disk is formed from two plastic parts. In particular, the insulating washer is characterized by the features according to the embodiment described with reference to FIG. 5.

[0181] According to a further aspect, the invention comprises an energy storage element having an electrode-separator assembly and a metal housing cup. The electrodes of the electrode-separator assembly are preferably in electrical contact, via one of their longitudinal edges, with the contact sheet metal part on one end face of the energy storage element and with the housing bottom on the other end face of the energy storage element. This energy storage element is further characterized by the fact that the contact sheet metal part has no apertures. Additionally or alternatively, in a preferred embodiment, the contact sheet metal part has a central recess that serves to position a connecting pole attached to this contact sheet metal part. Alternatively or additionally, the contact sheet metal part comprises at least one channel-like recess, which is directed towards the interior of the energy storage element comprising it and is provided for an optimized electrolyte distribution within the element. In a preferred manner, this contact sheet metal part is characterized by the features described in more detail with reference to FIG. 6.

[0182] According to a further aspect, the invention comprises an energy storage element having an electrode-separator assembly and a metal housing cup. The electrodes of the electrode-separator assembly are preferably in direct electrical contact with the contact sheet metal part on one end face of the energy storage element and with the housing bottom on the other end face of the energy storage element in each case via one of their longitudinal edges. This energy storage element is further characterized by the fact that a potting compound is provided to seal the polarities of the elements guided outwards relative to each other and is introduced during assembly of the cell into the gap located between the connecting poles of the element and the inner edge of the cover plate having a central aperture. The connecting poles engage with the central aperture of the cover plate. The connecting poles form one polarity and the surrounding cover plate forms the opposite polarity of the element. In a preferred embodiment of this aspect of the invention, the element is characterized by the features described with reference to Figures 3 and 9 and, optionally alternatively, with reference to Figure 11.

[0183] Such potting for sealing and electrically insulating the energy storage element is particularly advantageous in combination with a compact design in the region from the lid assembly of the element. In this connection, contact sheet metal parts without apertures, for example according to the embodiment shown in Figure 3 with a central recess or according to the embodiment shown in Figure 11 lacking a central recess, are also particularly advantageous.

Claims

1. An energy storage element (100), comprising: a. the energy storage element (100) includes an air-tight and liquid-tight housing and an electrode-separator assembly (104) disposed therein; b. the housing includes a metal cup-shaped housing portion (101) including a housing bottom (101a), a peripheral sidewall, and a terminal opening; c) the housing includes a cover part (102) that closes the terminal opening of the cup-shaped housing part (101); d. The cover part (102) includes a metallic cover plate (102a) and a connection terminal (102b) guided through an aperture in the cover plate (102) and electrically insulated from the cover plate (102); e. the electrode-separator assembly (104) includes a first flat terminal end surface (104a) and a second flat terminal end surface (104b); f. the electrode-separator assembly (104) comprises an anode (105) having an anode current collector (106) having a first edge (106a) and a second edge parallel thereto; g. said anode current collector (106) includes a main area loaded with a layer of anode material (107) and a free edge strip (106b) extending along a first edge (106a) thereof that is not loaded with said cathode material (107); h. the electrode-separator assembly (104) includes a cathode (108) having a cathode current collector (109) with a first edge (109a) and a second edge parallel thereto; i. said cathode current collector (109) comprises a main area loaded with a layer of cathode material (110) and a free edge strip (109b) extending along a first edge (109a) thereof that is not loaded with said electrode material (110); j. the anode (105) and the cathode (108) are disposed within the electrode-separator assembly (104) such that the first edge (106a) of the anode current collector (106) protrudes from the first terminal end face (104a) of the electrode-separator assembly (104) and the first edge (109a) of the cathode current collector (109) protrudes from the second terminal end face (104b); k. the energy storage element includes a contact sheet metal portion (111) seated directly on the first edge (106a) of the anode current collector (106) or directly on the first edge (109a) of the cathode current collector (109); l. the contact sheet metal portion (111) is electrically connected to a connecting pole (102b) leading through the aperture in the cover plate (102a); m. the first edge (109a, 106a) of the cathode current collector (109) or the anode current collector (106) that is not in direct contact with the contact sheet metal portion (111) is electrically connected to the housing bottom (101a); n. the housing bottom (101a) of the cup-shaped housing part (101) has a primary protection against internal overpressure in the form of an aperture (101b) closed by a metal membrane (114); o. the housing bottom (101a) of the cup-shaped housing part (101) has a secondary protection against internal overpressure in the form of at least one groove (101c) on its inside or outside; An energy storage element (100).

2. Additional features include: a. the cup-shaped housing portion (101) is electrically connected to the cathode; b. the contact sheet metal portion (111) rests on the first edge (106a) of the anode current collector (106) and is connected thereto by welding; c. the cup-shaped housing portion (101) is made of aluminum or an aluminum alloy; d. The cover plate (102a) is made of aluminum or an aluminum alloy; e. The contact sheet metal part (111) is in direct contact with the connecting pole (102b) guided through the aperture in the cover plate (102a) and is connected thereto, preferably by welding. The energy storage element according to claim 1 , comprising at least one of:

3. Additional features include: a. the cup-shaped housing portion (101) is electrically connected to the anode; b. the contact sheet metal portion (111) rests on the first edge (109a) of the cathode current collector (109) and is connected thereto by welding; c. the cup-shaped housing portion (101) is made of copper or nickel or a copper or nickel alloy or steel or nickel-plated steel; d. the cover plate (102a) is made of copper or nickel or a copper or nickel alloy or steel or nickel-plated steel; e. The contact sheet metal part (111) is in direct contact with the connecting pole (102b) guided through the aperture in the cover plate (102a) and is connected thereto, preferably by welding. The energy storage element according to claim 1 , comprising at least one of:

4. Additional features include: a. the housing bottom (101a) has at least one bead (101d) which appears on its outside as an elongated recess and on its inside as an elongated ridge, the first edge (106a) of the anode current collector (106) or the first edge (109a) of the cathode current collector (109) resting on said inside, b. the housing bottom (101a) is welded to the first edge (106a) of the anode current collector (106) or to the first edge (109a) of the cathode current collector (109) in the region of the bead (101d); c. said aperture (101b) is positioned in the center of said housing bottom (101a); d. said at least one bead (101d) comprises several linear beads, in particular three beads, arranged in a star-shaped configuration around said aperture (101b); e. said at least one groove (101c) includes several linear partial sections arranged in a star-shaped configuration around said aperture (101b); f. said at least one groove (101c) includes a partial section (1010c) extending around said aperture (101b) connecting said linear partial sections arranged in a star shape; The energy storage element according to any one of claims 1 to 3, comprising at least one of the following:

5. Additional features include: a. the connecting pole (102b) is seated directly on the contact sheet metal part (111) and connected thereto by welding; b. the connection terminal (102b) is electrically insulated from the cover plate (102) by a hardened potting compound (113) made of an electrically insulating plastic material; c. there is an annular gap between said cover plate (102) and said contact sheet metal portion (111) which is filled with said potting compound (113); d. said annular gap is bounded radially outwardly by an O-ring-shaped insulating washer (112) made of an electrically insulating plastic material; The energy storage element according to any one of claims 1 to 4, comprising at least one of the following:

6. Additional features include: a. the connecting pole (102b) is seated directly on the contact sheet metal part (111) and connected thereto by welding; b. the contact sheet metal portion (111) is made of nickel, copper, titanium, or a nickel, copper, or titanium alloy, or stainless steel; c. the connecting pole (102b) is a bimetal connecting pole and includes a pole lower part (1021) made of nickel, copper, titanium, nickel, copper, titanium alloy, or stainless steel, and a pole upper part (1020) made of aluminum or aluminum alloy; d. the lower portion (1021) of the pole is welded to the contact sheet metal portion (111); e. the lower part (1021) of the pole, the contact sheet metal part (111) and the anode current collector (106) are made of the same material; The energy storage element according to any one of claims 1 to 5, comprising at least one of the following:

7. Additional features include: a. the connecting pole (102b) is seated directly on the contact sheet metal part (111) and connected thereto by welding; b. the contact sheet metal portion (111) is made of aluminum or an aluminum alloy; c. The connecting electrode (102b) is made of aluminum or an aluminum alloy; d. The contact sheet metal portion (111), the connecting electrode (102b), and the cathode current collector (109) are made of the same material. The energy storage element according to any one of claims 3 to 6, comprising at least one of the following:

8. Additional features include: a. said contact sheet metal part (111) has a preferably uniform thickness in the range of 50 μm to 600 μm, preferably in the range of 150 μm to 350 μm; b. said contact sheet metal portion (111) has two opposing flat sides and extends essentially in only one dimension; c. the contact sheet metal portion (111) is a disk or a polygonal plate; d) the contact sheet metal part (111) is dimensioned such that it covers at least 40% of the end face from which the edge (106a, 109a) of the current collector (106, 109) on which it rests, preferably at least 60%, particularly preferably at least 80% of the end face (104a, 104b); e. the contact sheet metal part (111) has at least one bead (111d) which appears as an elongated recess on one flat side of the contact sheet metal part (111) and as an elongated ridge on the opposite flat side, the contact sheet metal part (111) resting on the first edge (106a) of the anode current collector (106) or on the first edge (109a) of the cathode current collector (109) with the flat side bearing the elongated ridge; f. the contact sheet metal part (111) is welded to the first edge (106a) of the anode current collector (106) or to the first edge (109a) of the cathode current collector (109) in the region of the bead (111d); The energy storage element according to any one of claims 1 to 7, comprising at least one of the following:

9. Additional features include: a. The metal film (114) is fixed to the bottom (101a) of the cup-shaped housing part (101) by welding. The energy storage element according to any one of claims 1 to 8, comprising:

10. A method for producing an energy storage element according to any one of claims 1 to 9, comprising the steps of: a. providing a metallic cup-shaped housing portion (101) including a housing bottom (101a), a peripheral sidewall, and a terminal opening; b. providing an electrode-separator assembly (104), said electrode-separator assembly (104) comprising: a cathode (108) having a cathode current collector (109) with a first edge (109a) and a second edge parallel thereto; an anode (105) having an anode current collector (106) with a first edge (106a) and a second edge parallel thereto; a first flat terminal end face (104a) and a second flat terminal end face (104b); Including, said anode current collector (106) comprises a main area loaded with a layer of anode material (107) and a free edge strip (106b) extending along a first edge (106a) thereof and not loaded with said electrode material (107); said cathode current collector (109) comprises a main area loaded with a layer of positive electrode material (110) and a free edge strip (109b) extending along a first edge (109a) thereof and not loaded with said electrode material (110); - placing said anode (105) and said cathode (108) in said electrode-separator assembly (104) such that said first edge (106a) of said anode current collector (106) projects from said first terminal end face (104a) of said electrode-separator assembly (104) and said first edge (109a) of said cathode current collector (109) projects from said second terminal end face (104b); c. inserting the electrode-separator assembly (104) into the housing cup (101) such that the first edge (106a, 109a) of the anode current collector (106) or the first edge (109a) of the cathode current collector (109) rests on the housing bottom (101a); d. creating a welded connection between said first edge (106a, 109a) resting on said housing bottom (101a) and said housing bottom; e. At the housing bottom (101a) of the cup-shaped housing portion (101), a primary protection device against internal overpressure in the form of an aperture (101b) closed by a metal membrane (114), a secondary protection device against internal overpressure in the form of at least one groove (101c) on its inside or outside; The step where The method includes:

11. Additional steps below: a. a contact sheet metal part (111) is positioned on the first edge (106a) of the anode current collector (106) or the first edge (109a) of the cathode current collector (109) that is not resting on the housing bottom (101a) and is connected to the edges (106a, 109a) by welding; b. The connecting pole (102b) is fixed to the contact sheet metal part (111). The method for manufacturing the energy storage element according to claim 10, comprising at least one of the steps of:

12. Additional steps below: a. a cover plate (102a) having an aperture for the connection terminal (102b) is inserted into the terminal opening of the cup-shaped housing part (101); b. filling any remaining gap between the cover plate (102a) and the contact sheet metal part (111) with a potting compound (113) which, when hardened, electrically insulates the cover plate (102a) from the connection terminals (102b) and the contact sheet metal part (111); A method for manufacturing the energy storage element of claim 11, comprising:

Images