Electrochemical energy storage element with contact sheet

Abstract

An electrochemical energy storage element having a contact sheet metal member and a method of manufacturing the same. The invention relates to an electrochemical energy storage element (100) having a housing. An electrode-separator assembly (104) is disposed within the housing. The electrode-separator assembly (104) includes a side portion (104a, 104b) defined by one circumferential edge or a plurality of edges. A contact sheet metal member (110) is arranged on a side (104a, 104b) of the electrode-separator assembly (104), which contact sheet metal member is connected to the electrode-separator assembly in the region of the side by welding. The energy storage element (100) is further characterized in that the contact sheet metal member (110) comprises at least one portion (120) which is curved in the direction of the electrode-separator assembly (104), in particular on the edge defining the side or one of the edges defining the side.

Description

Technical Field

[0001] The invention relates to an electrochemical energy storage element having at least one contact sheet metal component which rests on an end face of an electrode-separator assembly of the energy storage element, and to a method for producing such an electrochemical energy storage element. Background Art

[0002] Electrochemical energy storage elements can convert stored chemical energy into electrical energy by redox reactions. Electrochemical energy storage elements generally include at least one energy storage cell having a positive electrode and a negative electrode, which are separated from each other by a separator. During discharge, electrons are released at the negative electrode due to the oxidation process. This results in an external consumer being able to draw an electron current, for which the at least one electrochemical energy storage cell serves as an energy supplier. At the same time, an ion current corresponding to the electrode reaction occurs in the battery. This ion current passes through the separator and is made possible by the ion-conducting electrolyte.

[0003] If the discharge is reversible (i.e. it is possible to convert chemical energy back into electrical energy during discharge and thus recharge the battery), this is referred to as a secondary battery. In secondary batteries, the common designation of the negative electrode as anode and the positive electrode as cathode refers to the discharge function of the electrochemical cell.

[0004] Lithium-ion batteries are used today in many applications, as these batteries can deliver high currents and are characterized by a relatively high energy density. Lithium-ion batteries are based on the use of lithium, which can migrate back and forth between the electrodes of the battery in the form of ions.

[0005] The negative electrode and the positive electrode in the energy storage element are often formed by so-called composite electrodes, which include electrochemically inactive components as well as electrochemically active components. Composite electrodes are usually combined with one or more separators to form an electrode-separator assembly. The basic function of the battery can be established by impregnating the assembly with an electrolyte. Alternatively, a solid electrolyte can be used instead of a separator impregnated with an electrolyte.

[0006] In many embodiments of the energy storage element, the electrode-separator assembly is formed in the form of a winding or is processed into a winding. The electrode-separator assembly generally includes the following sequence: positive electrode / separator / negative electrode. The assembly is often produced as a so-called bibattery with the following possible sequence: negative electrode / separator / positive electrode / separator / negative electrode or positive electrode / separator / negative electrode / separator / positive electrode. In other embodiments, the electrode-separator assembly is formed by stacked electrodes and has a separator or solid electrolyte layer in between.

[0007] Energy storage elements comprising an electrode-separator assembly in the form of a wound body often have a cylindrical design. A distinction is made between cylindrical round batteries and button cells. Cylindrical round batteries are usually characterized by the fact that their height is greater than their diameter. Button cells, on the other hand, have a height that is less than their diameter.

[0008] Some button cells are available in very small designs. They are suitable, for example, for powering small electronic devices such as watches, hearing aids, wireless headphones or the like. Their maximum diameter is typically <3 cm.

[0009] Typical dimensions for cylindrical round cells are, for example, 21 x 70 (diameter x height in mm). For example, modern lithium-ion cells with these dimensions can achieve an energy density of 270 Wh / kg.

[0010] The housing of the energy storage element of the electrode-separator assembly with stacked electrodes is usually a prismatic housing and is characterized by a polygonal base, in particular a rectangular base. The stack usually includes electrodes with the same polygon, which are placed on top of each other in such a way that the electrode-separator assembly is also prismatic. Such a prismatic assembly can perfectly fill the inner space of the prismatic housing. Usually, all electrodes with the same polarity are connected to a common current conductor, which electrically connects these electrodes to the metal housing part of the prismatic housing or is connected to the pole drawn out of the housing through the corresponding orifice.

[0011] WO 2017 / 215900 A1 describes an energy storage battery in which the electrodes are strip-shaped and the electrode-separator assembly is in the form of a winding. The electrodes each have a current collector loaded with electrode material. The electrodes of opposite polarity are arranged in an electrode-separator assembly in a manner offset from each other, so that the longitudinal edge of the current collector of the positive electrode protrudes from the winding on one side and the longitudinal edge of the current collector of the negative electrode protrudes from the winding on the opposite side. In order to make electrical contact with the current collector, the battery has at least one contact metal sheet member, which is placed on one of the longitudinal edges and on an end face of the electrode-separator assembly. The contact metal sheet member is connected to the longitudinal edge by welding. This makes it possible to electrically contact the current collector over its entire length and therefore also contact the associated electrode. This significantly reduces the internal resistance in the described battery. As a result, the occurrence of large currents can be better absorbed.

[0012] The housing of an electrochemical energy storage element is often made of metal parts. For example, the housing can be formed by a cup-shaped metal housing part and a metal cover part. In these cases, the energy storage element can be manufactured in such a way that the electrode-separator assembly in the form of the described winding or stack is inserted into the cup-shaped housing part, after which the housing is closed with the help of the cover part (for example, welded thereon). These processes for manufacturing energy storage elements are usually implemented in an automated manner as part of an industrial manufacturing process.

[0013] In order to achieve the highest possible energy density of the energy storage element to be produced, attempts are usually made to incorporate as much electrochemically active material as possible into the energy storage element. Therefore, attempts are made to maximize the housing volume available for the electrode-separator assembly by inserting the largest possible assembly into the housing. This can cause problems, for example, when inserting a cylindrical winding into a cup-shaped housing part. If the electrode-separator assembly presses too hard against the interior of the housing during insertion, the insertion can fail or cause damage.

[0014] This problem is further exacerbated by contact sheet metal components welded to the electrode-separator assembly, as described in WO 2017 / 215900A1. This applies in particular if the contact sheet metal components are not positioned exactly on the respective end face of the electrode-separator assembly but protrude beyond the edge of the end face. In industrial manufacturing processes, an exact central arrangement of such contact sheet metal components is not always easy, since the circumference of the electrode-separator assembly is subject to production-related fluctuations, so that this alone can cause problems when placing and welding the contact sheet metal components on the end faces.

[0015] In addition, if the contact metal sheet member is not positioned exactly, the electrode-separator assembly cannot be welded to the contact metal sheet member optimally or over the entire available area of ​​the corresponding end face. For example, if the contact metal sheet member is not positioned optimally, the outer winding of the cylindrical electrode-separator assembly may not be in contact with the contact metal sheet member. This increases the internal resistance of the affected energy storage element.

[0016] Various procedures are known to solve the known problems associated with inserting an electrode-separator assembly into a housing. For example, US10505222B2 proposes compressing the electrode-separator assembly before inserting it into the housing. EP4053955A1 relates to a method for manufacturing an energy storage element, in which a metal housing part is heated before inserting the electrode-separator assembly. This causes the housing part to expand, making it easier to insert the electrode-separator assembly into the housing part. However, the smaller the housing part, the smaller the heating effect.

[0017] However, these approaches do not address the problems described above with respect to contact sheet metal members placed on the end faces of the electrode-separator assemblies. Summary of the invention

[0018] Against this background, the invention sets itself the task of facilitating the exact placement of the contact sheet metal component on the end face of the electrode-separator assembly. In addition, the insertion of the electrode-separator assembly into the housing of the energy storage element is to be facilitated.

[0019] This object is achieved by an electrochemical energy storage element having the features of claim 1. Advantageous embodiments of the energy storage element will be apparent from the dependent claims. The object is further solved by a method for producing an energy storage element according to claim 13. Advantageous embodiments of the production method will also be apparent from the dependent claims.

[0020] The electrochemical energy storage element according to the invention is characterized by the following features:

[0021] a. The electrochemical energy storage element includes a shell.

[0022] b. The electrode-separator assembly is arranged inside the shell.

[0023] c. The electrode-separator assembly includes a side portion defined by a circumferential edge or edges.

[0024] d. The contact sheet metal member rests on a side of the electrode-separator assembly which is bounded by a circumferential edge or edges, the contact sheet metal member being connected to the electrode-separator assembly in the region of this side by welding.

[0025] According to the present invention, the energy storage element is further characterized by the following features:

[0026] e. The contact metal sheet member comprises at least one portion which is bent in the direction of the electrode-separator assembly, in particular on the edge delimiting the side portion or on an edge delimiting the side portion.

[0027] Particularly preferably, the at least part that is bent in the direction of the electrode-separator assembly, in particular on the edge defining the side, is at least one extension or, alternatively, a protruding area in the marking, which extends from a main part of the contact metal sheet member arranged on the side.

[0028] Particularly preferably, the bent extension or the bent protruding area encloses a bending angle with the main part of the contact metal sheet member, which bending angle is in the range from 60° to 120°. Bending angles in the range from 80° to 100° are preferred, in particular angles in the range of 90°±5 or exactly 90° are preferred.

[0029] Preferably, the energy storage element according to the invention is characterized by at least one of the following features:

[0030] a. The electrode-separator assembly comprises at least one anode, at least one cathode and at least one separator in the order of anode / separator / cathode.

[0031] b. The electrode-separator assembly comprises at least one anode, at least one cathode and at least one solid electrolyte layer in the order of anode / solid electrolyte / cathode.

[0032] c. The housing in which the electrode-separator assembly is arranged is a gas-tight and liquid-tight sealed housing.

[0033] d. The electrode-separator assembly is electrically connected to a portion of the housing or an electrical pole that passes through the housing via a contact metal sheet member.

[0034] The energy storage element can have a prismatic housing or a cylindrical housing. In the case of a prismatic housing, the electrode-separator assembly preferably also has a prismatic shape. In the case of a cylindrical housing, the electrode-separator assembly preferably has a cylindrical shape.

[0035] Therefore, in a preferred embodiment, the energy storage element according to the invention is characterized by at least one of the following features:

[0036] a. The electrode-separator assembly is formed by a spirally wound electrode strip and at least one separator strip located therebetween, and the electrode-separator assembly has a first end face and a second end face and a winding shell located therebetween, one of the end faces being a side of the electrode-separator assembly defined by a circumferential edge.

[0037] b. The electrode strip is formed by a strip-shaped current collector coated with electrode material.

[0038] c. At least one of the strip-shaped electrode current collectors has a longitudinal edge not coated with electrode material, and the electrode strip is arranged in the electrode-separator assembly so that the longitudinal edge not coated with electrode material protrudes from the end surface of the electrode-separator assembly on which the contact metal sheet member is arranged.

[0039] d. The contact metal sheet members are welded to the longitudinal edges protruding from the end faces.

[0040] Preferably, the above features a. to d. are realized in combination with one another.

[0041] In this embodiment, the energy storage element preferably includes a cylindrical housing and a cylindrical electrode-separator assembly.

[0042] In a typical case, the spirally wound electrode tape and the at least one separator tape preferably have the following dimensions:

[0043] - lengths ranging from 0.5m to 25m,

[0044] - Widths in the range from 40 mm to 145 mm.

[0045] In order to produce a wound electrode-separator assembly consisting of an electrode strip and at least one strip-shaped separator, the strip-shaped electrode and the at least one separator are usually fed to a winding device, where they are preferably wound helically around a winding axis. It is usually not necessary for the electrode and separator to be bonded or to be in contact at high temperatures. In some embodiments, the electrode and the at least one separator are wound onto a cylindrical or hollow cylindrical winding core, which is located on a winding mandrel and remains wound after winding.

[0046] For example, the wrapping shell may be formed from a plastic film or adhesive tape. The wrapping shell may also be formed from one or more separator wrappings.

[0047] In a further preferred embodiment, the energy storage element according to the invention is characterized by at least one of the following features:

[0048] a. The electrode-separator assembly is formed of stacked electrodes with a separator or solid electrolyte layer arranged between the stacked electrodes.

[0049] b. The electrodes are formed by current collectors coated with electrode materials.

[0050] c. The current collectors of the positive electrode and / or the negative electrode each have a current collector edge that is not coated with electrode material, and these electrodes are arranged in a stack so that all current collector edges of the positive electrode or the negative electrode that are not coated with electrode material protrude from one side of the electrode-separator assembly, which is the side of the electrode-separator assembly on which the contact metal sheet member is placed.

[0051] d. The contact metal sheet member is welded to the edge of the current collector protruding from this side.

[0052] Preferably, the above features a. to d. are realized in combination with one another.

[0053] In this exemplary embodiment, the energy storage element preferably has a prismatic housing and a prismatic electrode-separator assembly.

[0054] In a prismatic electrode-separator assembly, the current collector edges of the positive and negative electrodes may also protrude from more than one side of the electrode-separator assembly. For example, it may be provided that the positive electrodes having a rectangular base shape each have two uncoated current collector edges protruding from two adjacent sides of the electrode-separator assembly. In this case, the contact metal sheet members may, for example, be L-shaped and be arranged on the two sides from which the uncoated longitudinal edges protrude.

[0055] In the case of a prismatic shape, the electrode-separator assembly preferably comprises a plurality of electrodes having a rectangular base shape. On the other hand, if the electrode-separator assembly has a cylindrical shape, it preferably consists of a spirally wound strip electrode and the at least one strip separator. Like the electrodes, the separator is preferably impregnated with a suitable electrolyte.

[0056] Furthermore, the electrode-separator assembly may also be formed as a flat coil with a helically wound ribbon electrode and have a substantially prismatic shape.

[0057] The electrode is preferably a composite electrode comprising an electrochemically active component and an electrochemically inactive component, which components have already been mentioned in the introduction.

[0058] The current collector of the energy storage element according to the invention has the function of electrically contacting the electrochemically active components contained in the corresponding electrode material over the largest possible area. Preferably, the current collector consists of metal or is at least metallized on the surface.

[0059] In the case of energy storage elements designed as lithium-ion batteries, 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 the EN CW-004A or EN CW-008A type with a copper content of at least 99.9% can be used as copper alloys. Alloys of the NiFe, NiCu, CuNi, NiCr and NiCrFe types are particularly suitable as nickel alloys. Alloys of the NiFe, NiCu, CuNi, NiCr and NiCrFe types are particularly suitable as nickel alloys. Stainless steels, for example of the 1.4303 or 1.4404 type or SUS304 type can also be considered.

[0060] In the case of energy storage elements designed as lithium-ion batteries, aluminum or other electrically conductive materials (including aluminum alloys) are particularly suitable as metals for the cathode current collector.

[0061] Suitable aluminum alloys for cathode current collectors are, for example, Al alloys of the 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55 types. AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg and AlMg are also suitable. The aluminum content of these alloys is preferably higher than 99.5%.

[0062] Preferably, the anode current collector and / or the cathode current collector are each a metal foil having a thickness ranging from 4 μm to 30 μm.

[0063] However, besides foils, other substrates such as metal or metallized nonwovens or open-cell metal foams or expanded metals can also be used as current collectors.

[0064] The current collector is preferably loaded on both sides with the corresponding electrode material.

[0065] The separator of the energy storage element according to the invention is preferably formed by an electrically insulating plastic film. The plastic film preferably has pores so that the liquid electrolyte can penetrate it. For example, the plastic film can consist of polyolefin or polyetherketone. However, nonwoven fabrics and fabrics made of plastic materials or other electrically insulating fabrics can also be used as separators.

[0066] A separator having a thickness ranging from 5 μm to 50 μm is preferred.

[0067] In particular, in the case of a prismatic electrode-separator assembly, the above-mentioned solid electrolyte layer can also be used instead of a separator. The solid electrolyte has an inherent ionic conductivity and does not need to be impregnated with a liquid electrolyte. The solid electrolyte can, for example, be a polymer solid electrolyte based on a polymer conductive salt complex, which exists in a single phase without any liquid component. The polymer solid electrolyte can have polyacrylic acid (PAA), polyethylene glycol (PEG) or polymethyl methacrylate (PMMA) as a polymer matrix. It can include lithium conductive salts such as lithium bis-(trifluoromethane) sulfonyl imide (LiTFSI), lithium hexafluorophosphate (LIPF6) and lithium tetrafluoroborate (LIBF4).

[0068] Preferably, the longitudinal edges of one or more separators or the longitudinal edges of the layer of solid electrolyte form one or more sides of the electrode-separator assembly, and (in the case of a cylindrical electrode-separator assembly) the longitudinal edges not coated with electrode material or (in the case of a prismatic electrode-separator assembly of a stacked electrode) all the collector edges of the positive electrode or negative electrode not coated with electrode material protrude from the one or more sides.

[0069] With regard to electrochemistry, the energy storage element according to the invention is not limited to a specific type. In a particularly preferred embodiment, the energy storage element is or comprises a lithium-ion battery, since such batteries can provide a particularly high energy density at a relatively low weight.

[0070] In other embodiments, the energy storage element is a sodium ion battery or includes a sodium ion battery, a potassium ion battery, a calcium ion battery, a magnesium ion battery or an aluminum ion battery. Among these variants, energy storage elements with sodium ion battery chemistry are particularly preferred.

[0071] As is well known, lithium-ion batteries are based on the use of lithium, which can migrate back and forth between electrodes of an energy storage element in the form of ions.

[0072] In the context of the present invention, all materials that can absorb and release lithium ions can be considered as electrochemically active ingredients (active materials) for lithium-ion batteries. For example, carbon-based particles (such as graphite carbon) are used for negative electrodes. The active material for the positive electrode can be, for example, lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4) or its derivatives. The electrochemically active material is usually contained in the electrode in the form of particles.

[0073] The active material is usually the main component of the layer applied to the current collector. The current collector is an electrochemically inactive component of the energy storage element. Metal foil is particularly suitable as a current collector. For example, the current collector of the negative electrode of a lithium-ion battery (anode current collector) can be made of copper or nickel, and, for example, the current collector of the positive electrode (cathode current collector) can be made of aluminum. In addition, the electrode can include an electrode binder (e.g., polyvinylidene fluoride (PVDF) or another polymer, such as carboxymethyl cellulose), an additive to increase conductivity, and other additives as electrochemically inactive ingredients. The electrode binder ensures the mechanical stability of the layer on the current collector, and often also ensures the adhesion of the layer to the current collector. Common additives that enhance conductivity are carbon black, fine graphite, carbon fiber, carbon nanotubes, and metal powders.

[0074] Solutions of lithium salts such as lithium hexafluorophosphate (LiPF6) in organic solvents such as ethers and esters of carbonic acid are particularly suitable as electrolytes for lithium-ion batteries.

[0075] Sodium-ion batteries are known to be based on the use of sodium, which can migrate back and forth in the form of ions between the electrodes of the energy storage element.

[0076] In the context of the present invention, the following materials may be regarded, for example, as electrochemically active components (active materials) of sodium-ion batteries on the anode side:

[0077] - Carbon, in particular hard carbon (pure or doped with nitrogen and / or phosphorus) or soft carbon or graphene-based materials (e.g. doped with nitrogen); carbon nanotubes, graphite

[0078] - Polyanions, such as Na2Ti3O7, Na3Ti2(PO4)3, TiP2O7, TiNb2O7, Na-Ti-(PO4)3, Na-V-(PO4)3

[0079] - Transition metal oxides: V2O5, MnO2, TiO2, Nb2O5, Fe2O3, Na2Ti3O7, NaCrTiO4, Na4Ti5O 12

[0080] On the cathode side, for example, the following materials can be considered:

[0081] -Polyanions: NaFePO4 (lithium iron phosphate type), Na2Fe(P2O7), Na4Fe3(PO4)2(P2O7), Na2FePO4F, Na / Na2[Fe 1 / 2 Mn 1 / 2 ]PO4F, Na3V2(PO4)2F3, Na3V2(PO4)3, Na4(CoMnNi)3(PO4)2P2O7, NaCoPO4, Na2CoPO4F

[0082] -Silicate: Na2MnSiO4, Na2FeSiO4

[0083] -Layered oxides: NaCoO2, NaFeO2, NaNiO2, NaCrO2, NaVO2, NaTiO2, Na(FeCo)O2, Na(NiFeCo)3O2, Na(NiFeMn)O2, Na(NiFeCoMn)O2, Na(NiMnCo)O2

[0084] In addition, the sodium ion-based energy storage element electrode according to the present invention preferably further comprises the above-mentioned electrode binder and / or an additive for improving conductivity or other additives.

[0085] In sodium-ion energy storage cells, both the anode current collector and the cathode current collector are preferably composed of aluminum or an aluminum alloy.

[0086] An energy storage element based on sodium-ion technology preferably has an electrolyte which comprises at least one solvent and at least one conductive salt.

[0087] Organic carbonates, ethers, nitriles and mixtures thereof are particularly suitable as solvents.

[0088] Preferred lead salts are NaPF6, sodium difluoro(oxalato)borate (NaBOB), NaBF4, sodium bis(fluorosulfonyl)imide (NaFSI), sodium 2-trifluoromethyl-4,5-dicyanoimidazole (NaTDI), sodium bis(trifluoromethylsulfonyl)imide (NaTFSI), NaAsF6, NaBF4, NaClO4, NaB(C2O4)2, NaP(C6H4O2)3; NaCF3SO3, sodium trifluoromethanesulfonate (NaTf) and Et4NBF4.

[0089] In a preferred embodiment, additives may be added to the electrolyte of the sodium ion battery. Examples of preferred additives (particularly for stabilization) are the following: fluoroethylene carbonate (FEC), trans-difluoroethylene carbonate (DFEC), ethylene sulfite (ES), ethylene carbonate (VC), bis(2,2,2-trifluoroethyl) ether (BTFE), 2-trifluoromethyl-4,5-dicyanoimidazole sodium (NaTDI), sodium bis(fluorosulfonyl)imide (NaFSI), aluminum chloride (AICI3), vinyl sulfate (DTD), sodium difluorophosphate (NaPO2F2), sodium difluoro(oxalate)borate (NaODFB), sodium difluorobis(oxalate)phosphate (NaDFOP), and tris(trimethylsilyl)borate (TMSB).

[0090] In a preferred embodiment, the energy storage element according to the invention is characterized by at least one of the following features:

[0091] a. The bent portion of the contact metal sheet member, in particular an extension or a protruding area protruding from the main part of the contact metal sheet member, is located in the area of ​​the outer circumference of the contact metal sheet member, in particular the outer circumference of the main part of the contact metal sheet member.

[0092] b. The contact metal sheet member comprises at least two, preferably 2 to 100, particularly preferably three or four parts, extensions or protruding areas, which are bent in the direction of the electrode-separator assembly, particularly at the edge of the side on which the contact metal sheet member rests.

[0093] The particular advantage of the energy storage element according to the present invention is firstly that one or more curved portions can significantly facilitate the accurate placement and (if appropriate) centering of the contact metal sheet member on the end face of the electrode-separator assembly. This is particularly applicable in the case where the contact metal sheet member has two or particularly preferably three or more curved portions. These curved portions can force correct placement and ensure that incorrect placement is avoided. Even if the contact metal sheet member may not be correctly placed on the end face of the electrode-separator assembly at first, it can be aligned on the end face of the electrode-separator assembly by means of an extension or a protruding area so that it is arranged flat and centered on the end face of the electrode-separator assembly. This allows compensation for production-related fluctuations in the size and shape of the end face, so that no difficulties will arise during the subsequent processing of the electrode-separator assembly provided with the contact metal sheet member. For example, the exact positioning of the contact metal sheet member placed on the end face simplifies the subsequent insertion of the electrode-separator assembly into the cup-shaped housing portion. This makes it possible to maximize the diameter or generally the size of the electrode-separator assembly, so that the energy density of the energy storage element according to the present invention can be improved compared with conventional energy storage elements.

[0094] It is also conceivable that the at least one extension or protruding region is bent in more than one step. For example, it is possible to subject the extension or protruding region to a first bending process (pre-bending) (which for example results in a bending at a bending angle of 30° to 55° in the direction of the electrode-separator assembly) and in a further step to a second bending process (which for example results in a bending at a bending angle of 60° to 120° in the direction of the electrode-separator assembly).

[0095] In a preferred embodiment, the pre-bending is performed before placing the contact metal sheet member on the end face of the electrode-separator assembly, and the further bending is performed after placing the contact metal sheet member on the end face of the electrode-separator assembly. For example, when the electrode-separator assembly is inserted into the above-mentioned cup-shaped housing part, the further bending can be performed by corresponding contact with the interior of the cup-shaped housing part during insertion.

[0096] It is possible that the contact metal sheet member has two extensions or protruding areas, wherein the bending process produces different bending results. For example, one extension or protruding area can be bent at a greater bending angle than the other extension or protruding area. This can occur, for example, in the case where the contact metal sheet member is not exactly centered on one end face of the electrode-separator assembly. When the electrode-separator assembly is inserted into the housing part, one extension can then bend to a greater extent than the other extension.

[0097] The measures according to the invention can also improve the scrap rate when producing a welded joint between an electrode-separator assembly and a contact sheet metal component.

[0098] The particular advantages of the measures according to the invention are particularly useful for energy storage elements with cylindrical electrode-separator assemblies and cylindrical housings, since centering the contact sheet metal components on the end faces of cylindrical electrode-separator assemblies creates particular difficulties in the production process. However, the advantages of the measures according to the invention can also be used for energy storage elements with prismatic housings and prismatic electrode-separator assemblies.

[0099] In a particularly preferred embodiment of the energy storage element according to the invention, the contact sheet metal member is designed according to at least one of the following additional features:

[0100] a. The contact sheet metal member has the main portion from which the extension or protruding area protrudes, or the extensions or protruding areas protrude from the main portion.

[0101] b. The main portion has at least one circular or one straight outer edge, from which one or more extensions or protruding areas protrude.

[0102] c. The maximum extension length of the main portion of the contact metal sheet member is smaller than the maximum extension length of the side of the electrode-separator assembly on which the contact metal sheet member is arranged.

[0103] The shape and dimensions of the main part of the contact metal sheet member are appropriately adapted to the shape and dimensions of the side of the electrode-separator assembly on which the contact metal sheet member is arranged, since the contact metal sheet member should, over its entire length (if possible), contact the edge of the current collector protruding from this side. In the case of an electrode-separator assembly in the form of a cylindrical winding, in a preferred embodiment the contact metal sheet member has, for example, a disc-shaped main part with a circular outer edge, so that it corresponds to the shape of the end face to be covered. If the electrode-separator assembly is a prismatic winding or comprises, for example, a prismatic electrode stack and the side to be covered by the main part has a polygonal base, it is preferred that the contact metal sheet member has a polygonal main part.

[0104] Particularly preferably, the outer edge of the main part is a circumferential edge, particularly preferably a circumferential edge in the case of a cylindrical wound body.

[0105] The maximum extension of the main portion of the contact metal sheet member is defined as the maximum possible distance between two points on the outer edge of the main portion.

[0106] The maximum extension of the side of the electrode-separator assembly on which the contact metal sheet member is arranged is defined as the maximum possible distance between two points on one or more edges defining the side.

[0107] With regard to the at least one bent portion of the contact metal sheet member, in a particularly preferred embodiment of the energy storage element according to the invention, it is characterized by at least one of the following additional features:

[0108] a. The at least one curved portion has a rectangular shape or a strip shape;

[0109] b. said at least one curved portion having a triangular shape;

[0110] c. The at least one curved portion has a semicircular contour or comprises a rounded end, in particular an end having a semicircular contour.

[0111] d. The contact sheet metal member comprises several bent portions, between which recesses, in particular notched recesses, are provided.

[0112] e. The contact metal sheet member includes several bent portions, and notches are provided between the bent portions.

[0113] f. The contact metal sheet member includes a plurality of bent portions protruding from the at least one outer edge of the main portion at regular intervals.

[0114] The curved portion may have various shapes and configurations. A rectangular shape or a triangular shape according to the above-mentioned features a. or b. is particularly preferred.

[0115] If there are several curved portions, these are preferably distributed at equal intervals over the entire outer edge of the main portion. These curved portions may also be next to each other. If these curved portions are directly adjacent to each other, notched recesses or embossed recesses may be provided between them according to features d. or e. above.

[0116] Preferably, the at least one bent portion, preferably at least two bent portions, consists of the same material as the main portion. In theory, it would be possible to manufacture these portions separately and to fix them to the main portion. However, it is much simpler to manufacture the contact metal sheet member in one piece (including the extension or the protrusion), for example as a stamped part. The stamping die is then preferably designed so that the contact metal sheet member can be stamped from the sheet material (including the extension) in a single operation. Thereafter, the bending is preferably carried out, which will be mentioned in more detail below.

[0117] With regard to the at least one extension or protruding area, the energy storage element according to the invention is preferably characterized by the following additional features:

[0118] a. The at least one extension or protruding area protrudes from the outer edge of the main portion by at least 0.1 mm and not more than 1 mm.

[0119] Particularly preferably, the at least one extension or protruding area protrudes from the outer edge of the main part by at least 0.1 mm and at most 0.5 mm.

[0120] The preferred values ​​given preferably refer to a state of the contacting sheet metal member in which the at least one extension or protruding region has not yet been bent.

[0121] With regard to the above-mentioned advantages of the measures according to the invention, even a very short length of the extension or protrusion of the contact metal sheet member (i.e. in particular a length in the region of less than 1 mm) is sufficient. In some preferred embodiments, the length of the extension can be selected so that, after bending, the extension or protruding region only contacts the uncoated longitudinal edge of one or more current collectors to which the contact metal sheet member is welded. However, it is also possible to select the length so that the extension or protruding region extends into the region of the current collector coated with electrode material.

[0122] Preferably, the maximum projection of the at least one extension or protruding area from the outer edge of the main portion is smaller than the minimum distance of the main portion from the end face from which the one or more longitudinal edges protrude.

[0123] In a preferred embodiment of the energy storage element according to the invention, the contact metal sheet member is characterized by the following additional features:

[0124] a. The contact metal sheet member has a preferably uniform thickness in the range from 50 μm to 600 μm, in particular in the range from 100 μm to 500 μm, preferably 200 μm or 300 μm.

[0125] A contact metal sheet member having a thickness of 200 μm is particularly suitable for contacting an anode or negative electrode, and a contact metal sheet member having a thickness of 300 μm is particularly suitable for contacting a cathode or positive electrode.

[0126] In a particularly preferred embodiment of the energy storage element according to the invention, the contact sheet metal member is characterized by the following additional features:

[0127] a. The contact metal sheet member has at least one weld bead, which is formed as an elongated recess on one flat side of the contact metal sheet member and as an elongated protrusion on the opposite flat side, wherein the contact metal sheet member faces the electrode-separator assembly with the flat side carrying the elongated protrusion.

[0128] Furthermore, in a preferred embodiment, the energy storage element according to the invention can be characterized by at least one of the following additional features:

[0129] a. The contact metal sheet member is welded to the electrode-separator assembly in the region of at least one weld bead.

[0130] b. The weld is linear.

[0131] c. The weld is formed by two or more parallel welds per weld bead.

[0132] Preferably, the abovementioned features a. and b. and particularly preferably the abovementioned features a. to c. are realized in combination with one another.

[0133] Welding the contact metal sheet member to the electrode-separator assembly in the region of the at least one weld bead can further increase the stability of the weld and in general the weld contact to the electrode.

[0134] Preferably, the contact metal sheet member has two or three or more welding beads.

[0135] It may be provided that the beads do not include a central region of the contact metal sheet member. In a preferred embodiment, an aperture may be provided in this central region of the contact metal sheet member, for example in the form of a circular hole. This aperture in the contact metal sheet member may be used for filling with electrolyte liquid.

[0136] In some embodiments, it has proven to be advantageous to subject the longitudinal edges of the respective current collector protruding from the end face of the electrode-separator assembly to a pretreatment before placing the contact metal sheet member on top. In particular, at least one depression can be folded into the longitudinal edge, which corresponds to the at least one weld bead or elongated protuberance on the flat side of the contact metal sheet member facing the electrode-separator assembly.

[0137] The longitudinal edge of the current collector may also have been subjected to directional shaping by pre-treatment. For example, it may be bent in a defined direction.

[0138] In a particularly preferred embodiment of the energy storage element according to the invention, the contact sheet metal member is characterized by the following additional features:

[0139] a. The contact metal sheet member has at least one extension or protruding area adjacent to the area of ​​the weld bead.

[0140] This embodiment has the advantage that the extension or protruding region can be bent in a particularly simple manner. Since the weld bead forms a channel-shaped depression on the flat side of the contact metal sheet component facing away from the electrode-separator assembly, the adjacent extension or protruding region is also at a lower level than other regions of the contact metal sheet component. This provides a target bending line for bending the extension or protruding region, making bending easier.

[0141] Preferably, the contact metal sheet member has at least one extension or protruding area configured as an extension to the weld bead.

[0142] The contact metal sheet member can be electrically connected to the anode current collector or cathode current collector of the energy storage element. As explained in WO 2017 / 215900A1, the use of the contact metal sheet member has the following advantages: the electrodes are in contact with the contact metal sheet member along their respective longitudinal edges. This can generally reduce the internal resistance of the energy storage element, so that it can better withstand the occurrence of larger currents compared to classic energy storage elements.

[0143] In particular in lithium-ion batteries, the contact metal sheet member provided for electrical connection to the anode current collector of the electrode-separator assembly may be characterized by at least one of the following features:

[0144] a. The contact metal sheet member consists of nickel or copper or titanium or a nickel or copper or titanium alloy or stainless steel (eg 1.4303 or 1.4404 type or SUS304 type) or nickel-plated copper.

[0145] b. The contact metal sheet member and the anode current collector are composed of the same material.

[0146] In particular in lithium-ion batteries, the contact metal sheet member provided for electrical contact with the cathode current collector of the electrode-separator assembly may be characterized by at least one of the following features:

[0147] a. The contact metal sheet member is composed of aluminum or an aluminum alloy.

[0148] b. The contact metal sheet member and the cathode current collector are composed of the same material.

[0149] Suitable aluminum alloys for contacting the sheet metal members include Al alloys of the 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55 types. AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg and AlMg are also suitable. The aluminum content of these alloys is preferably above 99.5%.

[0150] Furthermore, the contact metal sheet member may be characterized by at least one of the following features:

[0151] a. The contact metal sheet member has two opposing flat sides and extends substantially in only one dimension.

[0152] b. The contact metal sheet member is a disc or a polygonal plate.

[0153] c. The contact metal sheet member is dimensioned so that it covers at least 40%, preferably at least 50%, preferably at least 60%, preferably at least 70%, particularly preferably at least 80% of the end face of the electrode-separator assembly on which it is arranged.

[0154] Preferably, the abovementioned features a. and b., or a. and c., or b. and c., or particularly preferably immediately abovementioned features a. to c. are realized in combination with one another.

[0155] Covering the end face of the electrode-separator assembly with the contact metal sheet component over the largest possible area is advantageous for thermal management of the energy storage element according to the invention. The greater the coverage, the easier it is to contact the longest possible section of the corresponding electrode. As a result, the heat generated in the electrode-separator assembly can be dissipated particularly well to the housing via the contact metal sheet component.

[0156] The housing is preferably formed by a cup-shaped metal housing part and a cover part, which is at least partially composed of metal. For example, the cup-shaped housing part can be formed in a deep drawing process. However, it is also possible to produce the cup-shaped housing part by welding the bottom to the tubular housing part. The two housing parts can be connected via a seal, which has an electrically insulating property and electrically insulates the two housing parts from each other. It is also possible to connect the two housing parts by welding. In this case, preferably, the metal pole insulated from the housing is led out through an orifice in the housing.

[0157] The electrical and thermal contact of the electrode with the housing or with one of the housing parts is made via the contact sheet metal member. The contact sheet metal member itself can be electrically connected to the housing part or the metal pole, for example via current conductors or direct welding.

[0158] The housing part can consist of aluminum, an aluminum alloy or a steel sheet (e.g., a nickel-plated steel sheet). Suitable aluminum alloys for the cup-shaped metal housing part are, for example, Al alloys of the 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (3000 series) and GM55 types. AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg and AlMg are also suitable. The aluminum content of these alloys is preferably greater than 99.5%.

[0159] The invention further comprises a method for producing the described electrochemical energy storage element, the method comprising the following method steps:

[0160] a. Providing an electrode-separator assembly (104) having at least one side defined by a circumferential edge or edges.

[0161] b. Placing a contact metal sheet member (110) on this side of the electrode-separator assembly, the contact metal sheet member having at least one extension or protruding area (120).

[0162] c. Bending the at least one extension or protruding area (120) in the direction of the electrode-separator assembly, in particular on one or more edges delimiting the side.

[0163] d. Connecting the contact metal sheet member (130) to the electrode-separator assembly by welding in the region of the end face before or after the bending of the at least one extension or protruding region (120).

[0164] e. Providing a housing of the energy storage element with a cup-shaped housing part (101) having an opening and a cover part (102).

[0165] f. Inserting the electrode-separator assembly (104) with the contact metal sheet member (110) into the cup-shaped housing portion (101).

[0166] g. Close the opening of the cup-shaped housing part (101) with the cover part (102).

[0167] h. Before and / or after closing the opening of the cup-shaped housing portion with the cover portion, the electrodes of the electrode-separator assembly (104) are brought into electrical contact with the housing portions and / or the pole liner.

[0168] The functional parts used in the method have all been explained in relation to the energy storage element according to the invention. Reference is hereby made to the corresponding explanations.

[0169] In the method for manufacturing an energy storage element according to the present invention, the contact metal sheet member in step a. is preferably first placed on the side of the electrode-separator assembly so that at least one extension or protruding area of ​​the contact metal sheet member protrudes beyond one or more edges defining the side. In a further step, at least one extension or protruding area is bent in the direction of the electrode-separator assembly so that the contact metal sheet member is clamped around the side of the electrode-separator assembly on which the contact metal sheet member is arranged with at least one bent extension or protruding area. Ideally, at least one extension or protruding area is bent in such a way that it is at an angle of 90° to the main part of the contact metal sheet member. Compared with conventional methods, it is significantly easier to insert an electrode-separator assembly with such a contact metal sheet member into a cup-shaped housing part.

[0170] Clamping also has the advantage that the outer edge of the current collector can no longer be squeezed past the contact sheet metal component.

[0171] Before or after bending, the contact metal sheet member may be welded to one or more current collector edges protruding from the side of the electrode-separator assembly on which the contact metal sheet member rests.

[0172] As an alternative to the above-mentioned step c. (according to which the at least one extension or protruding area is bent in the direction of the electrode-separator assembly), it is also possible to bend the at least one extension or protruding area before the contact metal sheet member is placed on the end face of the electrode-separator assembly.

[0173] Closing the cup-shaped housing part with the cover part according to the above-mentioned step g. can be carried out in a manner known per se, for example by welding, in particular laser welding, or possibly by crimping or gluing.

[0174] Before or after closing the opening of the cup-shaped housing part with the cover part, the electrolyte can be added to the electrode-separator assembly. For this purpose, for example, an opening can be provided in the bottom of the cup-shaped housing part, through which the electrolyte is introduced into the interior of the housing. The activation opening can then be closed again with a gasket or the like or, for example, by gluing or welding.

[0175] In a particularly preferred embodiment of the method according to the invention, the electrode-separator assembly with the contact metal sheet member is inserted into the cup-shaped housing part so far that the contact metal sheet member is in direct contact with its bottom. The cup-shaped housing part is often electrically connected to the anode and therefore has a negative polarity. The contact metal sheet member with the curved extension serves as an insertion aid, making assembly easier. In a subsequent step, the bottom and the contact metal sheet member can be connected by welding.

[0176] It may also be advantageous to use a contact metal sheet member on the cathode side.

[0177] Due to the improved positioning and fixation of the contact metal sheet component on the corresponding end face of the electrode-separator assembly, it is possible to guide the welding part (for example, the laser line) to the outer area of ​​the corresponding end face of the electrode-separator assembly, so that the outer layer of the electrode-separator assembly can also be better connected. BRIEF DESCRIPTION OF THE DRAWINGS

[0178] Further features and advantages of the present invention will become apparent from the following description of preferred examples taken in conjunction with the accompanying drawings.

[0179] In the accompanying drawings:

[0180] Figure 1 is a schematically represented longitudinal section through a preferred embodiment of an energy storage element according to the invention;

[0181] Figure 2 are views of two preferred embodiments of the contact metal sheet member according to the invention (sub-figures A and B);

[0182] Figure 3 are views of two further preferred embodiments of the contact sheet metal member according to the invention (sub-figures A and B);

[0183] Figure 4 is a schematic cross-sectional view illustrating the connection of a contact metal sheet member to an electrode-separator assembly according to the present invention; and

[0184] Figure 5 It can be installed, for example, in Figure 1 The electrode-separator assembly and its components in the energy storage element shown in FIG. DETAILED DESCRIPTION

[0185] exist Figure 1 In the embodiment of the energy storage element according to the invention shown in , the energy storage element 100 comprises a housing, which is substantially formed by a cup-shaped housing part 101 and a cover part 102. In the upper part of this embodiment, the cup-shaped housing part 101 has a circular opening, which is closed by the cover part 102. An electrically insulating seal 103 is provided between the opening edge of the cup-shaped housing part 101 and the cover part 102, which electrically insulates the housing parts 101 and 102 from each other and seals the housing.

[0186] Inside the housing is a wound electrode-separator assembly 104, which is a cylindrical winding of a spirally wound strip electrode and at least one strip separator. The electrodes are composite electrodes, each of which is formed by a strip current collector coated with electrode material. The electrode-separator assembly 104 has an upper end face facing the cover portion 102 and a lower end face facing the bottom of the housing portion 101. The free longitudinal edge 106a or 109a of the current collector included in the electrode, which is not coated with electrode material, protrudes from each of these end faces. For example, the free longitudinal edge 106a of the anode current collector may protrude from the lower end face of the electrode-separator assembly, and the free longitudinal edge 109a of the cathode current collector may protrude from the upper end face of the electrode-separator assembly. The illustration does not show multiple layers of electrode material and separator strips arranged between the electrodes.

[0187] In the present embodiment, the contact metal sheet member 110 is provided on each of the two end surfaces of the electrode separator assembly 104. In other embodiments, for example, the contact metal sheet member may be provided only on the upper end surface or only on the lower end surface.

[0188] The contact metal sheet members 110 are each electrically connected to the free longitudinal edge 106a or 109a of the current collector protruding from the respective end face. The free longitudinal edge 106a or 109a of the current collector is in direct contact with the respective contact metal sheet member 110 over its entire length and is connected to it by welding.

[0189] The contact metal sheet member 110 welded to the free edge 106a of the anode current collector rests directly on the bottom of the cup-shaped housing portion 101 and is assembled to the bottom by welding. The contact metal sheet member 110 welded to the free edge 109a of the cathode current collector is in electrical contact with the cover portion 102 via an electrical conductor 117. Preferably, the electrical conductor 117 is connected to both the cover portion 102 and the bottom of the cup-shaped housing portion 101 by welding.

[0190] Since the cover part 102 is electrically insulated from the cup-shaped housing part 101 by the insulating seal 103 , the cup-shaped housing part 101 forms the negative pole of the energy storage element 100 and the cover part 102 forms the positive pole of the energy storage element.

[0191] The illustrated design of the energy storage element 100 can be transferred in an analogous manner to a battery having a prismatic housing and, for example, a flat wound or stacked electrode-separator assembly.

[0192] The energy storage element 100 according to the present invention differs from conventional energy storage elements provided with contact plates or contact metal sheet members in the design of the contact metal sheet members 110. According to the present invention, these contact metal sheet members are provided with a plurality of extensions 120, each of which is bent in the direction of the electrode-separator assembly 104, so that the contact metal sheet members 120 surround the two end faces of the electrode-separator assembly 104 on which these contact metal sheet members are placed with these bent extensions. In the embodiment shown, both contact metal sheet members 110 include bent extensions 120.

[0193] The bending of the extension 120 is performed during the manufacturing process of the energy storage element 100. Preferably, the extension 120 is pressed onto the corresponding end face of the electrode-separator assembly after the contact metal sheet member 110 has been placed on the electrode-separator assembly 104. The bending can be performed before or after the contact metal sheet member 110 is welded to the longitudinal edges 106a and 109a of the current collector.

[0194] Figure 2 Two exemplary embodiments of a contact metal sheet member 110 according to the invention are shown in sub-figures A and B. Both embodiments have a main portion 155 delimited by a circular outer edge 111 from which an extension 120 protrudes. Such a contact metal sheet member 110 is suitable, for example, for placement in Figure 1 On the end surface of the electrode-separator assembly shown in .

[0195] In these examples, the extensions 120 are each arranged along the entire outer edge 111 of the contact metal sheet member 110. In the example according to sub-figure A, recesses with notches are provided between adjacent extensions 120. In the example according to sub-figure B, notches are provided between the individual extensions 120.

[0196] The contact sheet metal member 110 is a stamped part.

[0197] The contact metal sheet members 110 each have three welding beads 130 arranged in a star shape. On the flat side of the contact metal sheet member 110 provided for contacting the electrode-separator assembly, the welding beads 130 each appear as a ridge. On the side of the contact metal sheet member 110 facing away from the electrode-separator assembly, the welding beads 130 each appear as an elongated depression. For example, the welding beads 130 can be produced by an embossing process.

[0198] Preferably, the contact metal sheet member 110 is welded to the respective free longitudinal edge of the current collector in the region of the weld bead 130 , for example by means of one, two or more parallel weld seams 131 within the weld bead 130 .

[0199] Figure 3 Two further particularly preferred embodiments of the contact metal sheet member 110 according to the invention are shown in sub-figures A and B. In sub-figure A, the contact metal sheet member 110 is shown with three extensions 120, each of which is an extension of one of three star-shaped arranged welding beads 130. The embodiment of the contact metal sheet member 110 shown in sub-figure B is similar, but in this example four welding beads 130 are provided, each of which encloses an angle of 90° with another welding bead.

[0200] Configuring the extension 120 as an extension of the weld bead 130 has proven to be particularly advantageous in practice. The extension is at a lower level than the rest of the contact metal sheet member 120. This can facilitate bending of the extension 120.

[0201] according to Figure 3 The embodiment of the contact sheet metal component 110 of the partial view B is particularly preferred, because with this embodiment a particularly exact placement of the contact sheet metal component 110 on the corresponding end face of the electrode-separator assembly can be achieved.

[0202] Figure 3 The embodiments of the contact metal sheet member 110 shown in sub-figures A and B of each have a central aperture 140 in the form of a hole. This aperture 140 can be used to impregnate the electrode-separator assembly with electrolyte after the contact metal sheet member 110 has been attached and welded.

[0203] Figure 4 A cross section through a contact metal sheet member 110 according to the invention is shown, wherein Figure 3 Comparatively, the (not yet bent) extension 120 is formed as an extension of the weld bead 130. The extension 120 is located at a lower level than the remaining portion of the contact metal sheet member 110 outside the weld bead 130.

[0204] Further, an electrode-separator assembly 104 is shown, on one end face of which a contact metal sheet member 110 is placed. Preferably, after the contact metal sheet member 110 has been placed on the end face of the electrode-separator assembly 104, the extensions 120 are bent downwards so that they are oriented in the direction of the electrode-separator assembly 104. The bent extensions 120 clamp around the edge region of the respective end. On the one hand, this ensures the exact positioning of the contact metal sheet member 110 on the end face. On the other hand, this facilitates the insertion of the electrode-separator assembly 104 with the contact metal sheet member 110 into the cup-shaped or tubular housing part. The contact metal sheet member 110 acts as an insertion aid.

[0205] Figure 5 The structure of an electrode-separator assembly 104 is illustrated, which can be a component of an energy storage element according to the present invention. Assembly 104 includes a strip anode 105 having a strip anode current collector 106, which has a first longitudinal edge 106a and a second longitudinal edge parallel to it. Anode current collector 106 is a foil made of copper or nickel. The anode current collector includes: a strip-shaped main area, which is loaded with a layer of negative electrode material 107; and a free edge strip 106b, which extends along the first longitudinal edge 106a of the anode current collector and is not loaded with electrode material 107. Further, assembly 104 includes a strip cathode 108 having a strip cathode current collector 109, which has a first longitudinal edge 109a and a second longitudinal edge parallel to it. Cathode current collector 109 is aluminum foil. The cathode current collector comprises a strip-shaped main region loaded with a layer of positive electrode material 110 and a free edge strip 109b extending along a first longitudinal edge 109a of the cathode current collector and not loaded with electrode material 110. Both electrodes are shown separately in an unwound state.

[0206] The anode 105 and the cathode 108 are arranged in an offset manner with respect to each other in the electrode-separator assembly 104, so that the first longitudinal 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 longitudinal edge 109a of the cathode current collector 109 protrudes from the second terminal end face 104b of the electrode-separator assembly. The offset arrangement can be seen in the illustration at the lower left. Two strip separators 156 and 157 are also shown there, which separate the electrodes 105 and 108 in the winding.

[0207] In the lower right inset, the electrode-separator assembly 104 is shown in a wound form as it can be used according to Figure 1 The electrode edges 106a and 109a protruding from the end faces 104a and 104b are clearly visible. The winding shell 104c is formed of a plastic film.

Claims

1. An electrochemical energy storage element (100) having the following characteristics: a. The electrochemical energy storage element comprises a housing; b. The electrode-separator assembly (104) is arranged inside the housing; c. The electrode-separator assembly (104) includes a side portion defined by a circumferential edge or edges; and d. a contact metal sheet member (110) is arranged on the side of the electrode-separator assembly (104), the contact metal sheet member being connected to the electrode-separator assembly (104) in the region of the side by welding; It is characterized in that e. The contact metal sheet member (110) comprises at least one portion (120) which is bent in the direction of the electrode-separator assembly (104), in particular on the edge defining the side or one of the edges defining the side.

2. The electrochemical energy storage element according to claim 1, having the following additional features: a. The at least one portion of the contact metal sheet member (110) is at least one extension or protruding area protruding from the main portion of the contact metal sheet member arranged on the end surface, and the at least one portion is bent in the direction of the electrode-separator assembly (104), in particular, bent on the edge defining the end surface.

3. The electrochemical energy storage element according to any one of claims 1 or 2, having at least one of the following additional features: a. the electrode-separator assembly (104) is formed by spirally wound electrode strips and at least one separator strip located between the electrode strips, and the electrode-separator assembly has a first end face and a second end face and a winding shell located between the first end face and the second end face, one of the end faces being a side of the electrode-separator assembly defined by the circumferential edge and on which the contact metal sheet member (110) is arranged; b. The electrode belt is formed by a belt-shaped current collector coated with an electrode material; c. at least one of the strip-shaped current collectors has a longitudinal edge (106a, 106) not coated with electrode material, the electrode strip being arranged in the electrode-separator assembly (104) such that the longitudinal edge not coated with electrode material protrudes from the end face of the electrode-separator assembly on which the contact metal sheet member (110) is arranged; d. The contact sheet metal member (110) is welded to the longitudinal edge protruding from the end face.

4. The electrochemical energy storage element according to any one of claims 1 or 2, having at least one of the following additional features: a. The electrode-separator assembly (104) is formed by stacked electrodes, with a separator or a solid electrolyte layer arranged between the stacked electrodes; b. The electrode is formed by a current collector coated with an electrode material; c. The current collectors of the positive electrode and / or the negative electrode each have a current collector edge that is not coated with electrode material, wherein, The electrodes are arranged in a stack so that all edges of the current collector of the positive electrode or the negative electrode that are not coated with electrode material protrude from a side of the electrode-separator assembly, which is the side of the electrode-separator assembly on which the contact metal sheet member (110) is arranged; d. The contact metal sheet member (110) is welded to the edge of the current collector protruding from the side.

5. The electrochemical energy storage element according to any one of the preceding claims, having at least one of the following additional features: a. the at least one bent portion (120) of the contact metal sheet member (110) is located in the area of ​​the periphery of the contact metal sheet member (110), in particular in the area of ​​the periphery of the main part of the contact metal sheet member (110); b. The contact metal sheet member (110) comprises at least two, preferably 2 to 100, particularly preferably three or four parts, extensions or protruding areas, which are bent in the direction of the electrode-separator assembly (104), particularly bent on the edge of the side on which the contact metal sheet member (110) is arranged.

6. The electrochemical energy storage element according to claim 5, comprising at least one of the following additional features: a. The contact metal sheet member has the main portion, one extension portion or one protruding area protruding from the main portion, or a plurality of extension portions or a plurality of protruding areas protruding from the main portion; b. The main portion has at least one circular or one straight outer edge, and one or more extensions or one or more protruding areas protrude from the at least one circular or one straight outer edge; c. The maximum extension length of the main portion of the contact metal sheet member is smaller than the maximum extension length of the side portion of the electrode-separator assembly on which the contact metal sheet member is arranged.

7. The electrochemical energy storage element according to any one of the preceding claims, comprising at least one of the following additional features: a. The at least one curved portion (120) has a rectangular shape or a strip shape; b. The at least one curved portion (120) has a triangular shape; c. The at least one curved portion (120) has a semicircular profile or includes a circular end, preferably an end having a semicircular profile; d. The contact metal sheet member comprises a plurality of bent portions (120), and recesses, in particular recesses with notches, are provided between the plurality of bent portions; e. The contact metal sheet member comprises a plurality of bent portions (120), and recesses are provided between the plurality of bent portions; f. The contact metal sheet member includes a plurality of bent portions (120) protruding from the at least one outer edge of the main portion at regular intervals.

8. The electrochemical energy storage element according to any one of the preceding claims, having the following additional features: a. The at least one extension or protruding area (120) protrudes from the outer edge of the main portion by at least 0.1 mm and at most 1 mm.

9. The electrochemical energy storage element according to any one of the preceding claims, having the following additional features: a. The thickness of the contact metal sheet member (110) is in the range from 50 μm to 600 μm, in particular in the range from 100 μm to 500 μm, preferably 200 μm or 300 μm.

10. The electrochemical energy storage element according to any one of the preceding claims, having the following additional features: a. The contact metal sheet member (110) has at least one weld bead (130), which is formed as an elongated recess on one flat side of the contact metal sheet member and as an elongated protrusion on the opposite flat side, and the contact metal sheet member faces the electrode-separator assembly (104) with the flat side carrying the elongated protrusion.

11. The electrochemical energy storage element according to any one of the preceding claims, having at least one of the following additional features: a. The contact metal sheet member (110) is welded to the electrode-separator assembly in the region of the at least one weld bead (130); b. The weld is linear; c. The welding portion is formed by two parallel welding seams (131) of each welding bead (130).

12. The electrochemical energy storage element according to any one of the preceding claims, having the following additional features: a. The contact metal sheet member has at least one extension (120) or protruding area adjacent to the area of ​​the weld bead (130).

13. A method for manufacturing an electrochemical energy storage element (100) according to any one of claims 1 to 12, the method comprising the following steps: a. Providing an electrode-separator assembly (104) having at least one side defined by a circumferential edge or edges; b. placing a contact metal sheet member (110) on the side of the electrode-separator assembly, the contact metal sheet member having at least one extension or protruding area (120); c. bending the at least one extension or protruding area (120) in the direction of the electrode-separator assembly, in particular on the edge or edges defining the side; d. connecting the contact sheet metal member (130) to the electrode-separator assembly by welding in the region of the end face before or after the bending of the at least one extension or protruding region (120); e. providing a cup-shaped housing portion (101) and a cover portion (102) having an opening for the housing of the energy storage element; f. inserting the electrode-separator assembly (104) having the contact metal sheet member (110) into the cup-shaped housing portion (101); g. Closing the opening of the cup-shaped housing portion (101) with the cover portion (102); h. Before and / or after closing the opening of the cup-shaped housing portion with the cover portion, bringing the electrodes of the electrode-separator assembly (104) into electrical contact with the housing portions and / or pole bushings.

14. The method according to claim 13, comprising the following additional method steps: a. Adding electrolyte to the electrode-separator assembly (104) before or after closing the opening of the cup-shaped housing portion (101) with the cover portion (102).

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