Energy storage element and manufacturing process

Abstract

An energy storage element (100) is known that comprises a cathode (101) and an anode (102) that are part of an assembly (109) in the following order: cathode (101) / separator or solid electrolyte layer (110) / anode (102) that are separated by a separator or solid electrolyte layer (110). The cathode (101) and anode (102) comprise current collectors (101a and 102a), which have areas (101b and 102b) coated on both sides with electrode material (117 and 118), as well as edge strips (101c and 102c), each of which is not coated with electrode material. The free edge strips (101c) of the cathode current collector (101a) protrude from one side of the assembly (109) and the free edge strips (102c) of the anode current collector (102a) protrude from the other side of the assembly (109), one of the edge strips (101c, 102c) being in direct contact with the first contact sheet metal element (119) and the other one being in direct contact with the second contact sheet metal element (120). It is proposed that at least one of the edge strips (101c, 102c) in direct contact with one of the contact sheet metal elements (119, 120) is folded and / or rolled up so as to have a thickness which corresponds at least to the thickness of the associated cathode (101) or anode (102) in the adjacent main area (101b, 102b) coated on both sides with electrode material (117, 118).

Description

[Technical field]

[0001] The present invention relates to an energy storage element suitable for supplying very high currents, and to a method for manufacturing such an energy storage element. [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 an electrochemical energy storage element is the electrochemical cell. It comprises a positive electrode and a negative electrode separated from each other by a separator. During discharge, electrons are released at the negative electrode as a result of an oxidation process. This results in an electronic current that can be extracted 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 an ionically conductive electrolyte.

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

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

[0005] In principle, all materials capable of absorbing and releasing lithium ions can be used as electrochemically active components (active materials) in lithium-ion secondary cells. For example, carbon-based particles such as graphitic carbon are used for the negative electrode. The active material for the positive electrode is, for example, lithium cobalt oxide (LiCoO 2 ), lithium manganate (LiMn 2 O 4 ), lithium iron phosphate (LiFePO 4 ), or a derivative thereof. The electrochemically active material is generally in particulate form and is contained in the electrode.

[0006] As electrochemically inactive components, composite electrodes generally contain flat and / or strip-shaped current collectors (e.g. metal foils) that serve as carriers for the respective active substances. The current collectors for the negative electrodes (anode current collectors) may be made, for example, of copper or nickel, and the current collectors for the positive electrodes (cathode current collectors) may be made, for example, of aluminum. Furthermore, these electrodes may contain, as electrochemically inactive components, electrode binders (e.g. polyvinylidene fluoride (PVDF) or another polymer, e.g. carboxymethylcellulose), conductivity enhancing additives, and other additives. The electrode binder ensures the mechanical stability of the electrode and in many cases also the adhesion of the active substances to the current collectors.

[0007] As an electrolyte, lithium-ion cells generally use lithium hexafluorophosphate (LiPF 6 ) in organic solvents (e.g., ethers and esters of carbonic acid).

[0008] In manufacturing lithium-ion cells, the composite electrodes are combined with one or more separators to form an assembly. In this process, the electrodes and separators are typically connected under pressure, sometimes by lamination or bonding. The assembly can then be impregnated with an electrolyte to establish basic cell function.

[0009] In many embodiments, the assembly is formed or processed into a winding. Alternatively, the assembly may be a stack of electrodes.

[0010] Applications in the automotive sector, in the case of electric bicycles or other applications with high energy requirements, such as tools, require lithium-ion cells that have the highest possible energy density and are also able to withstand high currents during charging and discharging.

[0011] WO 2017 / 215900 A1 describes a cylindrical round cell in which the assembly is formed from ribbon-like electrodes and is wound. Each electrode has a current collector filled with electrode material. Electrodes with opposite polarity are arranged offset from each other in the assembly, so that the longitudinal edge of the positive current collector protrudes from one side of the winding and the longitudinal edge of the negative current collector protrudes from the other side of the winding. For electrical contact of the current collectors, the cell has a contact plate that rests on the end face of the winding and is connected by welding to the longitudinal edge of the current collector. This allows electrical contact with the current collectors and thus with the associated electrodes over their entire length. This significantly reduces the internal resistance in the described cell. As a result, the generation of high currents can be absorbed much better and also the heat from the winding can be dissipated better.

[0012] A potential problem here is that the edges of the current collector are often compressed in an uncontrolled manner when the contact plate is applied, which can result in random creases. This makes large area, form-fit contact between the edge and the contact plate more difficult. In addition, there is an increased risk of fine circuits or shorts at the edge, for example as a result of damage to the separator located between the electrodes.

[0013] To solve this problem, WO 2020 / 096973 A1 proposes pretreating the edges of the current collector, in particular removing part of the current collector edge so that it has a rectangular shape.

[0014] Targeted pre-deformation of the edges of a current collector is known from US 2018 / 0190962 A1 and JP 2015-149499 A.

[0015] The known solutions have the disadvantage that the pre-treatment of the current collector edges is very complicated. Summary of the Invention [Problem to be solved by the invention]

[0016] In contrast, it was an object of the present invention to provide an energy storage element characterized by an assembly of electrodes and possibly one or more separators which can be contacted more easily by said contact plate. [Means for solving the problem]

[0017] This object is achieved by an energy storage element having the features of independent claim 1. A method having the features of claim 10 also contributes to solving the problem. Preferred embodiments of the invention are defined in the dependent claims.

[0018] Energy storage element according to the present invention An energy storage element according to the invention always has the following characteristics a. to h.: a. it comprises a cathode and an anode, the cathode and the anode being part of an assembly in which they are separated by a separator or a solid electrolyte layer and are in the order cathode / separator or solid electrolyte layer / anode; b. the cathode comprises a cathode current collector and a positive electrode material; c. The cathode current collector is a main region filled on both sides with a layer of positive electrode material; a free edge strip extending along one edge of the cathode current collector and not filled with cathode material; having d. the anode comprises an anode current collector and a negative electrode material; e. The anode current collector is a main region filled on both sides with a layer of anode material; a free edge strip extending along one edge of the anode current collector and not filled with anode material; having f. the cathode and anode are formed and / or positioned relative to one another within an electrode-separator assembly such that a free edge strip of the cathode current collector protrudes from one side of the assembly and a free edge strip of the anode current collector protrudes from another side of the assembly; g. the energy storage element comprises a first contact sheet metal member in direct contact with one of the free edge strips and a second contact sheet metal member in direct contact with the other of the free edge strips; h. At least one of the edge strips in direct contact with one of the contact sheet metal members has a thickness at least corresponding to the thickness of the associated cathode or anode in the adjacent main area coated on both sides with electrode material as a result of the folding and / or rolling-up process.

[0019] The energy storage element according to the invention is therefore particularly characterized by the fact that it has a current collector whose free edge strips have been subjected to a forming process, which allows a better connection of the current collector to the contact sheet metal member and, as a consequence, a reduced thermal connection of the electrodes to the housing and the internal resistance of the cell. In addition, the folded or rolled edge strips of the current collector also reduce the risk of internal short circuits, since uncontrolled compression of the edge strips when the contact plates are pressed against them is made more difficult or prevented.

[0020] Cylindrical Design The energy storage element according to the invention can be designed as a cylindrical cell or as a prismatic cell. In a cylindrical embodiment, it has the following features a. to e.: a. the electrode, the current collector, and the layer of electrode material are in the form of a ribbon; b. it comprises at least one ribbon-shaped separator or at least one ribbon-shaped solid electrolyte layer; c. the assembly is in the form of a cylindrical winding with the electrodes and at least one separator helically wound about a winding shaft, the assembly including first and second terminal end faces and a winding shell, a free edge strip of the cathode current collector protruding from the first end face and a free edge strip of the anode current collector protruding from the second end face; d. It comprises a cylindrical housing, in particular a cylindrical metal housing, with a circumferential housing shell and a circular bottom and lid at the end faces; e. Within the housing, the assembly designed as a winding is aligned axially so that the winding shell abuts against the inside of the circumferential housing shell.

[0021] In this embodiment, the assembly preferably comprises one ribbon-shaped separator or two ribbon-shaped separators, each ribbon-shaped separator having first and second longitudinal edges and two end portions.

[0022] In this embodiment, the contact sheet metal member preferably rests flat on the two end faces.

[0023] In this embodiment, the energy storage element according to the invention is particularly preferably characterized by the following feature a.: a. The metal housing comprises a cup-shaped cylindrical housing portion having a terminal opening, and a lid component that closes the terminal opening in the cup-shaped housing portion.

[0024] Preferably, the lid component has a circumference and is placed in the circular opening of the cup-shaped housing part such that an edge abuts the inside of the cup-shaped housing part along a circumferential contact zone, and the edge of the lid component is connected to the cup-shaped housing part via a circumferential weld line. In this case, the two housing parts preferably have the same polarity, i.e. they are electrically connected to either the positive or negative pole. In this case, the housing also comprises a pole bushing that is used to make electrical contact with the electrode that is not electrically connected to the housing.

[0025] In an alternative embodiment, an electrically insulating seal is fitted to the edge of the lid component, electrically isolating the lid component from the cup-shaped housing portion, in which case the housing is typically sealed by a crimp closure.

[0026] The height of the energy storage elements designed as cylindrical cells is preferably in the range of 50 mm to 150 mm. The diameter of the cylindrical cells is preferably in the range of 15 mm to 60 mm. Cylindrical cells with these form factors are particularly suitable for powering electric drives in automobiles.

[0027] In embodiments in which the cell according to the invention is a cylindrical cell, the anode current collector, cathode current collector, and separator(s) preferably have the following dimensions: -Length in the range of 0.5m~25m -Width in the range of 30mm~145mm.

[0028] In this embodiment, the contact sheet metal member preferably has a circular basic shape.

[0029] In some preferred variants of cylindrical embodiment, the energy storage element according to the invention is characterized by at least one of the following features a. to d.: a. The ribbon-like positive electrode, and therefore also the free edge strip of the cathode current collector protruding from the first end face, comprises a series of adjacent radial turns in the winding. b. Each of the turns includes a portion of the edge strip that has become thickened as a result of the folding and / or rolling process. c. The thickened edge strip portions of adjacent turns are in direct contact with each other. d. The free edge strip of the cathode current collector forms a continuous metal layer covering at least 80% of the end surface perpendicular to the first end surface.

[0030] Preferably, the immediately preceding features a. to c., and particularly preferably also features a. to d., are realized in combination with one another.

[0031] This embodiment is particularly advantageous: Ideally, the continuous metal layer is a closed layer that completely covers the first end face.

[0032] Adjacent turns formed during the manufacture of the winding have different diameters, with the inner turns always being smaller in diameter than the outer turns, or in other words the diameter of the winding increases from turn to turn outward.

[0033] In some further particularly preferred variants of the cylindrical embodiment, the energy storage element according to the invention is characterized by at least one of the following features a. to d.: a. The ribbon-like negative electrode, and therefore also the free edge strip of the anode current collector protruding from the second end face, comprises a series of adjacent radial turns in the winding. b. Each of the turns includes a portion of the edge strip that has become thickened as a result of the folding and / or rolling process. c. The thickened edge strip portions of adjacent turns are in direct contact with each other. d. The free edge strip of the anode current collector forms a continuous metal layer covering at least 80% of the end surface perpendicular to the second end surface.

[0034] Here too, it is preferable that the immediately preceding features a. to c., and particularly preferably features a. to d., are realized in combination with one another.

[0035] Square column design In a prismatic embodiment, the energy storage element according to the invention is characterized by the following features a. to d.: a. The assembly is in the form of a prismatic stack in which cathodes and anodes are stacked together with other cathodes and other anodes. b. The electrodes, current collectors, and layers of electrode material are polygonal, particularly rectangular. c. It comprises at least one ribbon-shaped or polygonal, in particular rectangular, separator or at least one ribbon-shaped or polygonal, in particular rectangular, solid electrolyte. d. The stack is housed within a prismatic housing.

[0036] In a stack, electrodes with opposite polarity are always separated from each other by a separator or solid electrolyte layer.

[0037] The prismatic housing is preferably composed of a cup-shaped housing part with a terminal opening and a lid component. In this embodiment, the base of the cup-shaped housing part and the lid component preferably have a polygonal, particularly preferably rectangular, base. The shape of the terminal opening of the cup-shaped housing part corresponds to the shape of the base and the lid component. In addition, the housing includes several (preferably four) rectangular side parts connecting the base and the lid component to each other.

[0038] The separator layer can be formed by several separators, each of which is arranged between adjacent electrodes. However, it is also possible for ribbon-shaped separators to separate the electrodes of the stack from one another. If there are several separators between the anode and the cathode, these separators also preferably have a polygonal, in particular rectangular, base area.

[0039] In this embodiment, the contact sheet metal members preferably have a rectangular basic shape.

[0040] In some preferred variants of the prismatic embodiment, the energy storage element according to the invention is characterized by at least one of the following features a. to d.: a. Each cathode in the stack features thickened edge strips as a result of the folding and / or rolling process. b. Each anode in the stack features thickened edge strips as a result of the folding and / or rolling process. c. A free edge strip of a cathode current collector of the cathode of the stack protruding from one side of the stack and in direct contact with a first contact sheet metal member. d. A free edge strip of the anode current collector of the anode of the stack protrudes from another side of the stack and makes direct contact with a second contact sheet metal member.

[0041] Preferably, the immediately preceding features a and c, and b and d are realized in combination with one another. Particularly preferably, the immediately preceding features a to d are realized in combination with one another.

[0042] In a further preferred variant of the prismatic embodiment, the energy storage element according to the invention is characterized by at least one of the following features a. to c.: a. The free edge strips of the cathode current collector are arranged parallel to each other. b. Adjacent free edge strips of the cathode current collector are in direct contact with each other. c. The free edge strips of the cathode current collectors form a continuous metal layer that completely covers at least 80% of the side of the stack from which they protrude in the direction perpendicular to that side.

[0043] Preferably, the immediately preceding features a. and b., and particularly preferably even features a. to c., are realized in combination with one another.

[0044] In a further preferred variant of the prismatic embodiment, the energy storage element according to the invention is characterized by at least one of the following features a. to c.: a. The free edge strips of the anode current collector are arranged parallel to each other. b. Adjacent free edge strips of the anode current collector are in direct contact with each other. c. The free edge strips of the anode current collectors form a continuous metal layer that completely covers at least 80% of the side of the stack from which they protrude in the direction perpendicular to that side.

[0045] Preferably, the immediately preceding features a. and b., and particularly preferably even features a. to c., are realized in combination with one another.

[0046] Preferred Electrochemical Embodiments In further particularly preferred embodiments of the invention, the energy storage element according to the invention is characterized by one of the following features: The energy storage element is a lithium ion cell. b. The energy storage element includes a lithium ion cell.

[0047] Feature a. refers in particular to the described embodiment of the energy storage element according to the invention as a cylindrical cell, in which embodiment the energy storage element preferably comprises exactly one electrochemical cell.

[0048] Feature b. refers in particular to the described prismatic embodiment of the energy storage element according to the invention, in which the energy storage element may also comprise two or more electrochemical cells.

[0049] Essentially all electrode materials known for lithium-ion secondary cells can be used for the electrodes of the energy storage element.

[0050] Carbon-based particles, preferably in particulate form, such as graphitic carbon or non-graphitic carbon materials capable of intercalating lithium can be used as the active material of the negative electrode. Alternatively or additionally, lithium titanate (Li 4 Ti 5 O 12 ) or its derivatives can also be included in the negative electrode, preferably in particulate form. In addition, the negative electrode can contain as 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 (e.g. silicon oxide), optionally in combination with a carbon-based active material. Tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. The capacity to absorb lithium, especially in the case of silicon, is many times greater than that of graphite or comparable materials. Thin anodes made of metallic lithium are also possible.

[0051] Suitable active materials for the positive electrode include LiCoO 2 and LiFePO 4 Lithium metal oxide compounds and lithium metal phosphate compounds such as LiNi x Mn y Co z O 2 Lithium nickel manganese cobalt oxide (NMC), having the chemical formula LiMn 2 O 4 Lithium manganese spinel (LMO), or LiNi x Co y Al z O 2 Lithium nickel cobalt aluminum oxide (NCA), having the formula: 1.11 (Ni 0.40 Mn 0.39 Co 0.16 Al 0.05 ) 0.89 O 2Lithium nickel manganese cobalt aluminum oxide (NMCA), or (oder) Li 1+x MO compounds and / or mixtures of the aforementioned materials can also be used. The cathode active material is also preferably used in particulate form.

[0052] In addition, the electrode of the energy storage element according to the present invention preferably contains an electrode binder and / or an additive for improving electrical conductivity. The active material is preferably embedded in the matrix of the electrode binder, and adjacent particles in the matrix are preferably in direct contact with each other. The conductive agent has the function of increasing the electrical conductivity of the electrode. Common electrode binders are based on, for example, polyvinylidene fluoride (PVDF), polyacrylate, or carboxymethyl cellulose. Common conductive agents are carbon black and metal powders.

[0053] The energy storage element according to the invention preferably contains an electrolyte, in particular lithium hexafluorophosphate (LiPF 6 The electrolyte comprises at least one lithium salt based on lithium tetrafluoroborate (LiBF), which is 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 (LiBF 4 ), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(oxalato)borate (LiBOB).

[0054] The nominal capacity of the lithium-ion based energy storage element according to the invention, designed as a cylindrical cell, is preferably up to 90000 mAh. In the case of a 21x70 form factor, the energy storage element in one 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 the case of a 18x65 form factor, the cell in one 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.

[0055] 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 according to the IEC / EN 61951-1 and IEC / EN 60622 standards, information on the nominal capacity of nickel-hydrogen secondary batteries must be based on measurements according to the IEC / EN 61951-2 standard, information on the nominal capacity of lithium secondary batteries must be based on measurements according to the IEC / EN 61960 standard, and information on the nominal capacity of lead-acid batteries must be based on measurements according to the IEC / EN 61056-1 standard. Any information on nominal capacity in the present application is preferably based on these standards.

[0056] Preferred embodiments of the separator and solid electrolyte Preferably, the separator or 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 foil may, for example, consist of polyolefins or polyetherketones. Nonwovens and woven fabrics made of plastic materials or other electrically insulating fabrics may also be used as separators. Separators with a thickness in the range of 5 μm to 50 μm are preferred.

[0057] The separator or separators of the assembly, particularly in prismatic embodiments of the energy storage element, may also be one or more layers of solid electrolyte.

[0058] The solid electrolyte is, for example, 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 may have polyacrylic acid (PAA), polyethylene glycol (PEG), or polymethyl methacrylate (PMMA) as the polymer matrix. Lithium bis(trifluoromethane)sulfonylimide (LiTFSI), lithium hexafluorophosphate (LiPF 6 ), and lithium tetrafluoroborate (LiBF 4 Lithium conductive salts such as ZnO, ZnS, ZnO ...

[0059] Preferred structure of the assembly formed as a winding The ribbon anode, ribbon cathode and ribbon separator are preferably spirally wound in an assembly formed as a winding. To produce the assembly, the ribbon electrodes together with the ribbon separator are fed to a winding device and are preferably wound up spirally around a winding shaft in the winding device. In some embodiments, the electrodes and separator are wound onto a cylindrical or hollow cylindrical winding core for this purpose, which is placed on a winding mandrel and remains in the winding after winding.

[0060] The winding shell may 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.

[0061] Preferred embodiments of the current collector The current collector of the energy storage element has the function of electrically contacting the electrochemically active components contained in the respective electrode materials over as large an area as possible.Preferably, the current collector is made of metal or is metallized at least on the surface.For energy storage elements based on lithium-ion technology, suitable metals for the anode current collector include copper or nickel or other conductive materials, in particular alloys of copper and nickel, or nickel-coated metals.Stainless steel is also an option.For energy storage elements based on lithium-ion technology, aluminum or other conductive materials, including aluminum alloys, are particularly suitable as metals for the cathode current collector.

[0062] Preferably, the anode current collector and / or the cathode current collector, respectively, is 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 cell, a ribbon-shaped metal foil having a thickness in the range of 4 μm to 30 μm.

[0063] However, in addition to foils, other strip-shaped substrates such as metal or metallized nonwovens, or open-pore metal foams, or expanded metals, can also be used as current collectors.

[0064] In the case of the described configuration of the energy storage element as a cylindrical cell, the longitudinal edges of the separators preferably form the end faces of the assembly designed as a winding.

[0065] In the described prismatic configuration of the energy storage element, the edges of the separators preferably form the sides of the stack from which the free edge strips of the current collectors project.

[0066] It is further preferred that any free edge strips of the current collector which protrude beyond the terminal end face of the winding or the side face of the stack do not protrude more than 5500 μm, preferably not more than 4000 μm, from the end face or side face.

[0067] Particularly preferably, the free edge strips of the anode current collectors protrude from the side faces of the stack or the end faces of the windings by no more than 3000 μm, particularly preferably no more than 2000 μm.Particularly preferably, the free edge strips of the cathode current collectors protrude from the side faces of the stack or the end faces of the windings by no more than 4000 μm, particularly preferably no more than 3000 μm.

[0068] Preferred embodiment of connection of first contact sheet metal member to first contact sheet metal member / anode current collector The first contact sheet metal member is preferably electrically connected to the anode current collector, particularly preferably directly to the free edge strip of the anode current collector by welding.

[0069] Additionally or in alternative embodiments, the first contact sheet metal member may be mechanically connected to the free edge strip of the anode current collector, for example by a press connection, or a clamp connection, or a spring connection.

[0070] In a particularly preferred embodiment of the invention, the first contact sheet metal member is characterized by at least one of the following features a. or b.: The contact sheet metal member is made of nickel, copper, titanium, a nickel, copper, or titanium alloy, or stainless steel. b. The contact sheet metal member is made of the same material as the anode current collector.

[0071] Preferably, the immediately preceding features a. and b. are realised in combination with each other.

[0072] The contact sheet metal members are electrically connected to the housing or to contact poles that pass through the housing and are electrically insulated from the housing. The electrical contact can be achieved by welding or mechanical connection. If desired, the electrical connection can also be made through separate electrical conductors.

[0073] In a further particularly preferred embodiment of the invention, the first contact sheet metal member is characterized by at least one of the following features a. to g.: a. The contact sheet metal member 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 member has two opposing flat sides and extends essentially in only one dimension. c. The contact sheet metal member is a circular disk or, preferably, a rectangular plate. d. The contact sheet metal member is sized so that it covers at least 60%, preferably at least 70%, particularly preferably at least 80% of the side or end face on which the free edge strip of the anode current collector connected to it appears. e. The contact sheet metal member has at least one aperture, in particular at least one hole and / or at least one slot. f. the contact sheet metal member has at least one bead which appears as an elongated depression on one flat side of the contact sheet metal member and as an elongated ridge on the opposite flat side, the contact sheet metal member resting with the flat side having the elongated ridge on the free edge strip of the anode current collector. g. The contact sheet metal member is welded to the free edge strip of the anode current collector in the region of the bead, in particular via one or more weld lines arranged within the bead.

[0074] It is particularly preferred that the immediately preceding features a., b. and d. are realized in combination with one another. In a preferred embodiment, features a., b. and d. are realized in combination with one of features c. or e., or with features f. and g. It is particularly preferred that all features a. to g. are realized in combination with one another.

[0075] Covering as much of the end face as possible is important for the thermal management of the grounded energy storage element. The more coverage, the easier it is to contact the first edge of the anode current collector over its entire length. Thus, the heat generated in the assembly can be better dissipated through the contact sheet metal members.

[0076] For example, at least one aperture in the contact sheet metal member may serve to allow the assembly to be impregnated with an electrolyte.

[0077] Preferred embodiment of connection of second contact sheet metal member to second contact sheet metal member / cathode current collector The second contact sheet metal member is preferably electrically connected to the cathode current collector, particularly preferably by welding it is directly connected to the free edge strip of the cathode current collector.

[0078] However, in alternative embodiments, the second contact sheet metal member may also be mechanically connected to the free edge strip of the cathode current collector, for example by a press connection, a spring connection, or a clamp connection.

[0079] In a particularly preferred embodiment of the invention, the energy storage element according to the invention is characterized by the following feature a. a. the second contact sheet metal member is made of aluminum or an aluminum alloy.

[0080] The contact sheet metal members are electrically connected to the housing or to contact poles that pass through the housing and are electrically insulated from the housing. The electrical contact can be achieved by welding or mechanical connection. If desired, the electrical connection can also be made through separate electrical conductors.

[0081] The second contact sheet metal member is preferably similar, apart from its material composition, to the contact sheet metal member on the free edge strip of the anode current collector. It is preferably characterized by at least one of the following features a. to g.: a. the second contact sheet metal member 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 second contact sheet metal member has two opposing flat sides and extends essentially in only one dimension. c. the second contact sheet metal member being a circular disk or, preferably, a rectangular plate. d. The second contact sheet metal member is sized so that it covers at least 60%, preferably at least 70%, particularly preferably at least 80% of the side or end face on which the free edge strip of the cathode current collector appears. e. the second contact sheet metal member has at least one aperture, in particular at least one hole and / or at least one slot. f. a second contact sheet metal member has at least one bead that appears as an elongated depression on one flat side of the contact sheet metal member and as an elongated ridge on the opposite flat side, the contact sheet metal member resting with the flat side having the elongated ridge on the free edge strip of the cathode current collector. g. The second contact metal member is welded to the free edge strip of the cathode current collector in the region of the bead, in particular via one or more weld lines arranged within the bead.

[0082] Here too, it is particularly preferred that the immediately preceding features a., b. and d. are realized in combination with one another. In preferred embodiments, features a., b. and d. are realized in combination with one of features c. or e., or with features f. and g. In particularly preferred embodiments, all features a. to g. are also realized in combination with one another.

[0083] The connection or welding of the free edge strip of the cathode current collector to the second contact sheet metal part is preferably realized in the same way as the connection of the free edge strip of the anode current collector described above, i.e. particularly preferably via a weld in the area of ​​the bead.

[0084] In a preferred embodiment, the second contact sheet metal member is directly welded to the bottom or part of the bottom of the cup-shaped housing part. In a further preferred embodiment, the second contact sheet metal member is connected to the bottom of the cup-shaped housing part via a separate current conductor. In the latter case, the separate current conductor is preferably welded to both the bottom of the cup-shaped housing part and the second contact sheet metal member. The separate current conductor preferably consists of aluminum or an aluminum alloy.

[0085] Preferred embodiments of the housing part 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 following features a. and b.: The cup-shaped housing portion is made of aluminum, stainless steel, or nickel-plated steel. b. The lid components are made of aluminum, stainless steel, or nickel-plated steel.

[0086] The immediately preceding features a. and b. are particularly preferably realised in combination.

[0087] In some embodiments, direct connection of the free edge strip of the cathode current collector to the housing is desirable. To this end, the free edge strip can be welded, for example with a laser, to the bottom of the cup-shaped housing section, which then functions as the second contact plate.

[0088] Conversely, in some embodiments it may be provided that the first contact plate functions as a lid component, i.e. as part of the housing.

[0089] Preferred embodiments of the electrodes In a further particularly preferred embodiment of the invention, the energy storage element according to the invention is characterized by one of the following features a. or b.: a. The energy storage element according to the invention is designed as a cylindrical cell, the electrodes of which have a thickness in the range of 40 μm to 300 μm, preferably in the range of 40 μm to 100 μm. b. The energy storage element according to the present invention is prismatic and the electrodes have a thickness in the range of 40 μm to 1000 μm, preferably >100 μm up to 300 μm.

[0090] Method according to the invention The method according to the invention is used to manufacture the above-mentioned energy storage elements, in particular those having the following characteristics: a. it comprises a cathode and an anode, the cathode and the anode being part of an assembly in which they are separated by a separator or a solid electrolyte layer and are in the order cathode / separator or solid electrolyte layer / anode; b. the cathode comprises a cathode current collector and a positive electrode material; c. The cathode current collector is a main region filled on both sides with a layer of positive electrode material; a free edge strip extending along one edge of the cathode current collector and not filled with cathode material; having d. the anode comprises an anode current collector and a negative electrode material; e. The anode current collector is a main region filled on both sides with a layer of anode material; a free edge strip extending along one edge of the anode current collector and not filled with anode material; having f. the cathode and anode are formed and / or positioned relative to one another within an electrode-separator assembly such that a free edge strip of the cathode current collector protrudes from one side of the assembly and a free edge strip of the anode current collector protrudes from another side of the assembly; g. the energy storage element comprising a first contact sheet metal member in direct contact with one of the free edge strips and a second contact sheet metal member in direct contact with the other of the free edge strips.

[0091] With regard to preferred embodiments of the individual components of the energy storage element to be manufactured, reference is made to the above statements in connection with the description of the energy storage element according to the invention.

[0092] This method is characterized in particular by the following steps: h. Before the assembly is formed, at least one edge strip is subjected to a folding and / or rolling process so that it has a thickness that corresponds at least to the thickness of the associated cathode or anode in the adjacent main area coated on both sides with electrode material.

[0093] In another particularly preferred embodiment, the method is additionally characterized by the combination of the following steps a. to c.: Providing a current collector coated on both sides with electrode material. b. while maintaining at least one folded and / or rolled up edge strip, at least one of the edge strips of the current collector, preferably one edge strip of each current collector, is subjected to a folding and / or rolling process. c. The current collector, coated on both sides with electrode material, including at least one folded and / or rolled up edge strip, is subjected to a calendering process.

[0094] During the calendering step, the respective layers of electrode material are processed in the main area of ​​the current collector by one or more calender rollers, compressing the layers, the thickness of which is reduced in this process. Preferably, during the calendering step, the layers of electrode material and the folded or rolled up edge strips are simultaneously processed using one and the same calender roller.

[0095] At this point, it is useful to mention a further, particularly advantageous aspect of the invention. One of the problems when calendering a layer of electrode material on a current collector is that the pressures that arise during calendering not only reduce the thickness of the layer of electrode material, but also the thickness of the current collector in the main areas covered by the layer. These are stretched in the passing direction as they pass through the calender rollers. In contrast, the current collector in the area from the free edge strips is classically not covered by the calender rollers during calendering. As a result, the length does not change. The stresses that build up in the current collector often lead to a curvature of the electrode produced according to such a process (known as the "camber effect"). This can cause problems, for example, in the production of electrode windings. The simultaneous calendering of the layer of electrode material and the edge strips that are folded or rolled up according to the invention can also lead to a stretching of the current collectors of the free edge strips (since these may have a thickness that exceeds the thickness of the layer of electrode material as a result of the folding and / or rolling up process). As a result, the aforementioned stresses that build up in the current collector may only occur to a lesser extent or not at all.

[0096] In a further particularly preferred embodiment, the method is additionally characterized by at least one of the following features: The folding process includes multiple folds. b. The folding process results in a multi-layer edge strip. c. Targeted structural weakening of the edge strips precedes the folding process.

[0097] It may be preferable to introduce one or more elongated, preferably parallel, beads or other lines of weakness into the free edge strip, which weaken the structure of the current collector and allow a targeted folding of the edge strip along the bead or beads and parallel to the strip-like main area. [Brief description of the drawings]

[0098] Further features and advantages of the invention are evident from the claims and the following description of preferred examples of the invention in conjunction with the drawings. The individual features may be realized individually or in combination with one another. The drawings show, in schematic form, [Figure 1] FIG. 2 is a cross-section through a prior art cell in which the contact plate is pressed against the protruding edge of the current collector. [Diagram 2] Cathode current collector coated on both sides with electrode material (top view and cross section). [Diagram 3] Anode current collector coated on both sides with electrode material (top view and cross section). [Figure 4] FIG. 2 shows an electrode for an energy storage element according to the invention, the edge strip of which has a thickness corresponding to the thickness of the electrode in the main areas coated on both sides with electrode material as a result of the rolling process (cross-section). [Diagram 5] FIG. 2 shows an electrode for an energy storage element according to the invention, the edge strip of which has a thickness corresponding to approximately twice the thickness of the electrode in the main area coated on both sides with electrode material as a result of multiple folding (cross-section). [Figure 6] FIG. 2 shows the fabrication of a preferred embodiment of an electrode for an energy storage element according to the present invention (cross-sectional view). [Figure 7] A cross section through several turns of a cylindrical assembly formed by helically winding the cathode and anode. [Figure 8] 1 is a cross section through several turns of an otherwise cylindrical assembly formed by helically winding the cathode and anode. [Figure 9]2 shows an energy storage element according to the invention, comprising a prismatic assembly and a housing therefor (also in cross section). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0099] 1 shows the result of pressing a contact plate 201 against a protruding edge 202 of a current collector protruding from one side of an assembly 203 consisting of an anode, a cathode and a separator (not shown in the drawing) between them. During pressing, an uncontrolled compression of the current collector edge 202 occurs. This compression results in several random folds, as can be seen particularly clearly in the right-hand region of the edge 202. This makes a large-area form-fit contact between the current collector edge 202 and the contact plate 201 more difficult.

[0100] 2 shows, on the one hand in plan view from above and, on the other hand, in cross section (cross section along S1), a strip-shaped cathode current collector 101a provided with a layer of positive electrode material 117. The current collector 101 is preferably an aluminium foil.

[0101] The strip-shaped current collector 101a includes a main region 101b filled with electrode material 117 and strip-shaped edge strips 101c that do not contain electrode material.

[0102] 3 shows, on the one hand in plan view from above and, on the other hand, in cross section (cross section along S2), a strip-shaped anode current collector 102a provided with a layer of anode material 118. The current collector 101 is preferably a copper foil.

[0103] The strip-shaped current collector 102a includes a strip-shaped main area 102b filled with electrode material 118 and edge strips 102c that are free of electrode material.

[0104] 4 shows an embodiment of a positive electrode 101 for an energy storage element according to the invention, whose edge strips 101c have a thickness D1 as a result of the rolling process, which corresponds to a thickness D2 of the electrode 101 in the main area 101b coated on both sides with electrode material 117. The current collector 101a is preferably an aluminum foil.

[0105] The negative electrode of the energy storage element according to the invention is structurally identical and may differ from the positive electrode shown only in the electrode material and the material of the current collector used.

[0106] 5 shows an embodiment of a positive electrode 101 for an energy storage element according to the invention, whose edge strips 101c have a thickness D1 as a result of multiple folding, which corresponds to about twice the thickness D2 of the electrode 101 in the main area 101b coated on both sides with electrode material 117. The current collector 101a is preferably an aluminum foil.

[0107] The negative electrodes for the energy storage elements according to the invention are structurally identical and may differ from the positive electrodes shown only in the electrode materials used.

[0108] 6 shows the manufacture of a preferred embodiment of a positive electrode 101 for an energy storage element according to the invention. For this, in a first step A, a strip-shaped cathode current collector 101a is provided (shown in cross section), on both sides of which a layer of positive electrode material 117 is applied. The cathode current collector 101a is preferably an aluminium foil.

[0109] The strip-shaped current collector 101a comprises a strip-shaped main area 101b filled with electrode material 117 and a strip-shaped edge strip 101c free of electrode material. Three elongated beads 101d running parallel to one another are rolled into the free edge strip 101c. These weaken the structure of the current collector 101a and allow targeted folding of the edge strip 101c along the beads and parallel to the strip-shaped main area 101b. These foldings lead to the result shown in FIG. B.

[0110] In a further step C, the current collector coated with electrode material 117, indicated at B, is subjected to a calendering step, in which the main area 101b coated with electrode material 117 and the multiply folded edge areas 101c are adjusted to the same thickness D1.

[0111] Negative electrodes for energy storage devices according to the present invention can be fabricated using the same procedure.

[0112] 7 shows a cross section through several turns of a cylindrical assembly 109 formed by helically winding a ribbon-shaped cathode 101 and a ribbon-shaped anode 102. Within the assembly 109, the cathode 101 and the anode 102 are separated from each other by two ribbon-shaped separator or solid electrolyte layers 110 and 111.

[0113] The cylindrical winding of the assembly 109 has a first terminal end face 109a and a second terminal end face 109b. A free edge strip 101c of the cathode current collector projects from the first end face 109a and a free edge strip 102c of the anode current collector projects from the second end face 109b.

[0114] As a result of the multiple folds, the edge strips 101c of the positive electrode 101 have a thickness that corresponds to the thickness of the electrode 101 in the main areas 101b that are coated on both sides with electrode material 117. The current collector 101a is preferably an aluminum foil.

[0115] As a result of the multiple folds, the edge strips 102c of the negative electrode 102 have a thickness that corresponds to the thickness of the electrode 102 in the main areas 102b that are coated on both sides with electrode material 118. The current collector 102a is preferably a copper foil.

[0116] 8 shows a cross section through several turns of a cylindrical assembly 109 formed by helically winding a ribbon-shaped cathode 101 and a ribbon-shaped anode 102. In the assembly 109, the cathode 101 and the anode 102 are separated from each other by two ribbon-shaped separator or solid electrolyte layers 110 and 111. The winding consists of a series of turns of the positive electrode 101 and the negative electrode 102.

[0117] The cylindrical winding of the assembly 109 has a first terminal end face 109a and a second terminal end face 109b. A free edge strip 101c of the cathode current collector projects from the first end face 109a and a free edge strip 102c of the anode current collector projects from the second end face 109b.

[0118] As a result of the winding process, the edge strips 101c of the positive electrode 101 have a thickness that corresponds to twice the thickness of the electrode 101 in the main areas 101b which are coated on both sides with electrode material 117. The current collector 101a is preferably an aluminum foil.

[0119] As a result of the winding process, the edge strips 102c of the negative electrode 102 have a thickness that is twice the thickness of the electrode 102 in the main areas 102b that are coated on both sides with electrode material 118. The current collector 102a is preferably a copper foil.

[0120] The winding is made up of a series of turns of positive electrode 101 and negative electrode 102, each turn of the positive electrode 101 including a portion of an edge strip 101c that has become thicker as a result of the winding process, and each turn of the negative electrode 102 including a portion of an edge strip 102c that has become thicker as a result of the winding process.

[0121] Due to the relatively large thickness of the electrode in the region of edge strips 101c and 102c, the thickened portions of edge strip 102c come into direct contact with each other at adjacent turns.

[0122] Thus, the free edge strips 101c and 102c of the current collectors form a continuous metal layer perpendicular to the end faces 109a and 109b in the line of sight direction, covering most of their respective end faces.

[0123] 9 shows an energy storage element 100 according to the invention. It comprises a prismatic assembly 109 and a prismatic housing 125. The prismatic housing 125 consists of a cup-shaped housing part 128 and a lid component 129. A contact pole 126 connected to the contact sheet metal part 120 by welding is guided through the lid component 129. The contact pole 126 is electrically insulated from the lid component 129 by an insulating element 127. The contact sheet metal part 119 is welded to the bottom of the housing part 128.

[0124] The housing portion contains within it a prismatic stack shaped assembly 109. Positive electrodes 101, 103, 105, and 107 and negative electrodes 102, 104, 106, and 108 are stacked together and separated by separator layers 110, 111, 112, 113, 114, 115, and 116, respectively. Each electrode has a rectangular basic shape.

[0125] The positive electrode free edge strips 101c, 103c, 105c and 107c and the negative electrode free edge strips 102c, 104c, 106c and 108c are formed according to Figure 7. They therefore have an increased thickness as a result of the multiple folds.

[0126] Free edge strips 101c, 103c, 105c, 107c protrude from one side of the prismatic stack and are all in direct contact with contact sheet metal member 119. Free edge strips 102c, 104c, 106c, and 108c protrude from the opposite side of the prismatic stack and are all in direct contact with contact sheet metal member 120.

Claims

1. Features: a. an energy storage element (100) comprising a cathode (101) and an anode (102), said cathode (101) and said anode (102) being part of an assembly (109) in which said cathode (101) and said anode (102) are separated by a separator or solid electrolyte layer (110) and present in the order: cathode (101) / semiconductor or solid electrolyte layer (110) / semiconductor anode (102); b. The cathode (101) comprises a cathode current collector (101a) and a positive electrode material (117); c. The cathode current collector (101a) is a main region (101b) filled on both sides with a layer of said cathode material (117); a free edge strip (101c) extending along the edge of said cathode current collector (101a) and not filled with said positive electrode material (117); and d. The anode (102) comprises an anode current collector (102a) and a negative electrode material (118); e. The anode current collector (102a) a main region (101b) filled on both sides with a layer of said anode material (118); a free edge strip (102c) extending along the edge of the anode current collector (102a) and not filled with the negative electrode material (118); and f. The cathode (101) and the anode (102) are formed and / or positioned relative to one another within the electrode-separator assembly (109) such that the free edge strip (101c) of the cathode current collector (101a) protrudes from one side (109a) of the assembly (109) and the free edge strip (102c) of the anode current collector (102a) protrudes from another side (109b) of the assembly (109); g. the energy storage element comprises a first contact sheet metal member (119) in direct contact with one of the free edge strips (101c, 102c) and a second contact sheet metal member (120) in direct contact with the other of the free edge strips (101c, 102c); and h) an energy storage element (100) wherein at least one of the edge strips (101c, 102c) in direct contact with one of the contact sheet metal members (119, 120) has a thickness, as a result of the folding and / or rolling and calendaring processes, that corresponds at least to the thickness of the associated cathode (101) or anode (102) in the adjacent main area (101b, 102b) coated on both sides with the electrode material (117, 118).

2. Further features include: a. The electrodes (101, 102), the current collectors (101a, 102a), and the layers of electrode material (117, 118) are ribbon-shaped; b. The energy storage element comprises at least one ribbon-shaped separator (110, 111) or at least one ribbon-shaped solid electrolyte layer (110); the assembly (109) is in the form of a cylindrical winding, with the electrodes (101, 102) and the at least one separator (110, 111) spirally wound around a winding shaft, the assembly (109) including first and second terminal end faces (109a, 109b) and a winding shell, the free edge strip (101c) of the cathode current collector (101a) protruding from the first end face (109a) and the free edge strip (102c) of the anode current collector (102a) protruding from the second end face (109b); d) the energy storage element comprises a cylindrical housing with a circumferential housing shell and a circular bottom and lid at the end face; e. Within said housing, said assembly (109) in the form of a winding is axially aligned so that said winding shell abuts the inside of said circumferential housing shell; 10. The energy storage element of claim 1, wherein:

3. Further features include: a. The ribbon-shaped positive electrode (101), and therefore also the free edge strip (101c) of the cathode current collector (101a) protruding from the first end face (109a), comprises a series of adjacent radial turns (160-174) in the winding; b. each of said turns includes a portion of said edge strip (101c) that has thickened as a result of said folding and / or said rolling process; c. In adjacent turns, the portions of the thickened edge strips (101c) are in direct contact with each other; d. The free edge strip (101c) of the cathode current collector (101a) forms a continuous metal layer covering at least 80% of the first end face (109a) in a direction perpendicular to the end face (109a); 3. The energy storage element of claim 2, comprising at least one of:

4. Further features include: a. the ribbon-shaped negative electrode (102), and therefore also the free edge strip (102c) of the anode current collector (102) protruding from the second end face (109b), comprises a series of adjacent radial turns (141-156) in the winding; b. each of said turns includes a portion of said edge strip (102c) that has thickened as a result of said folding and / or said rolling process; c. In adjacent turns, the portions of the thickened edge strips (102c) are in direct contact with each other; d. The free edge strip (102c) of the anode current collector (102a) forms a continuous metal layer covering at least 80% of the second end face (109b) in a direction perpendicular to the end face (109b); 4. The energy storage element according to claim 2, wherein the energy storage element comprises at least one of:

5. Further features include: a. said assembly (109) is in the form of a prismatic stack in which said cathode (101) and said anode (102) are stacked together with further cathodes (103, 105, 107) and further anodes (104, 106, 108); b. the electrodes (101, 102, 103, 104, 105, 106, 107, and 108), the current collectors (101a, 102a, 103a, 104a, 105a, 106a, 107a, and 108a), and the layers of electrode material are polygonal; c) the energy storage element comprises at least one ribbon-shaped or polygonal separator (110, 111, 112, 113, 114, 115, 116) or at least one ribbon-shaped or polygonal solid electrolyte; d. The stack is housed within a prismatic housing (125); 10. The energy storage element of claim 1, wherein:

6. Further features include: a. each of the cathodes (101, 103, 105, 107) of the stack is characterized by thickened edge strips (101c, 103c, 105c, 107c) as a result of the folding and / or rolling and calendering steps; b. each of the anodes (102, 104, 106, 108) of the stack is characterized by thickened edge strips (102c, 104c, 106c, 108c) as a result of the folding and / or rolling and calendering steps; c. the free edge strips (101c, 103c, 105c, 107c) of the cathode current collectors of the cathodes of the stack protrude from one side of the stack and are in direct contact with the first contact sheet metal member (119); d. the free edge strips (102c, 104c, 106c, 108c) of the anode current collectors of the anodes of the stack protrude from another side of the stack and directly contact the second contact sheet metal member (120); 6. The energy storage element of claim 5, comprising at least one of:

7. Further features include: a. the free edge strips (101c, 103c, 105c, 107c) of the cathode current collector are arranged parallel to one another; b. adjacent free edge strips (101c, 103c, 105c, 107c) of the cathode current collector are in direct contact with each other; c) the free edge strips (101c, 103c, 105c, 107c) of the cathode current collector form a continuous metal layer that completely covers at least 80% of the side surface of the stack in a direction perpendicular to the side surface from which the free edge strips (101c, 103c, 105c, 107c) protrude; 7. The energy storage element according to claim 5, wherein the energy storage element comprises at least one of:

8. Further features include: a. the free edge strips (102c, 104c, 106c, 108c) of the anode current collector are arranged parallel to one another; b. adjacent ones of the free edge strips (102c, 104c, 106c, 108c) of the anode current collector are in direct contact with each other; c) the free edge strips (102c, 104c, 106c, 108c) of the anode current collector form a continuous metal layer that completely covers at least 80% of the side surface of the stack in a direction perpendicular to the side surface from which the free edge strips (102c, 104c, 106c, 108c) protrude; 7. The energy storage element according to claim 5, wherein the energy storage element comprises at least one of:

9. Further features include: a) the first contact sheet metal member (119) is connected to the free edge strip (101c) of the cathode current collector (101a) by welding, and / or the second contact sheet metal member (120) is connected to the free edge strip (102c) of the anode current collector (102a) by welding; b. the first contact sheet metal member (119) is mechanically connected to the free edge strip (101c) of the cathode current collector (101a) and / or the second contact sheet metal member (120) is mechanically connected to the free edge strip (102c) of the anode current collector; 10. The energy storage element of claim 1, wherein:

10. Features: a. an energy storage element (100) comprising a cathode (101) and an anode (102), said cathode (101) and said anode (102) being part of an assembly (109) in which said cathode (101) and said anode (102) are separated by a separator or solid electrolyte layer (110) and present in the order: cathode (101) / semiconductor or solid electrolyte layer (110) / semiconductor anode (102); b. The cathode (101) comprises a cathode current collector (101a) and a positive electrode material (117); c. The cathode current collector (101a) is a main region (101b) filled on both sides with a layer of said cathode material (117); a free edge strip (101c) extending along the edge of said cathode current collector (101a) and not filled with said positive electrode material (117); and d. The anode (102) comprises an anode current collector (102a) and a negative electrode material (118); e. The anode current collector (102a) a main region (102b) filled on both sides with a layer of said anode material (118); a free edge strip (102c) extending along the edge of the anode current collector (102a) and not filled with the negative electrode material (118); and f. The cathode (101) and the anode (102) are formed and / or positioned relative to one another within the electrode-separator assembly (109) such that the free edge strip (101c) of the cathode current collector (101a) protrudes from one side (109a) of the assembly (109) and the free edge strip (102c) of the anode current collector (102a) protrudes from another side (109b) of the assembly (109); g. the energy storage element comprises a first contact sheet metal member (119) in direct contact with one of the free edge strips (101c, 102c) and a second contact sheet metal member (120) in direct contact with the other of the free edge strips (101c, 102c); A method for manufacturing the energy storage element (100) comprising: The method comprises the steps of: h) before said assembly (109) is formed, at least one edge strip (101c, 102c) is subjected to a folding and / or rolling and calendering process, as a result of which said at least one edge strip (101c, 102c) has a thickness at least corresponding to the thickness of said associated cathode (101) or anode (102) in said adjacent main region (101b, 102b) coated on both sides with electrode material (117, 118); A method comprising:

11. The following sequence of steps: a. Providing the current collector (101a, 102a) coated on both sides with the electrode material; b. subjecting at least one of said edge strips (101c, 102c) to said folding and / or rolling process to obtain at least one folded and / or rolled edge strip; c. subjecting the current collector (101a, 102a) coated on both sides with the electrode material, including the at least one folded and / or rolled-up edge strip, to the calendering process; The method of claim 10, comprising:

12. Further features include: a. the folding step includes multiple folds; b. the folding step results in a multi-layer edge strip; c. A targeted structural weakening of the edge strip precedes the folding step; 12. The method of claim 10 or 11, comprising at least one of:

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