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 strip (101c) of the cathode current collector (101a) projects from one side of the assembly (109) and the free edge strip (102c) of the anode current collector (102a) projects 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 member (119) and the other being in direct contact with the second contact sheet metal member (120). It is proposed to process at least one of the edge strips (101c, 102c) which is in direct contact with one of the contact sheet metal members (119, 120) by a forming process so that it has a U-shaped or V-shaped cross section and thus has an elongated depression or indentation (121, 124) on one side and an elongated ridge (122, 123) corresponding to the indentation on the other side.

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, any material capable of absorbing and releasing lithium ions can be used as the electrochemically active component (active material) of a lithium-ion secondary cell. For example, carbon-based particles such as graphitic carbon are used for the negative electrode. The active material for the positive electrode can be, for example, lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), or derivatives thereof. The electrochemically active material is generally contained in the electrode in particulate form.

[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 contain a solution of a lithium salt, such as lithium hexafluorophosphate (LiPF6), in an organic solvent (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 The energy storage element according to the present invention 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 in which they 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 designed and / or positioned relative to one another within the 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 U-shaped or V-shaped cross-section, e.g. as a result of a forming process such as folding or embossing, and therefore has an elongated depression or dent on one side and a corresponding elongated ridge on the other side.

[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. This allows a better connection of the current collector to the contact sheet metal member, which can result in a reduced thermal connection of the electrodes to the housing and a reduced internal resistance of the cell. In addition, the risk of internal short circuits is also reduced, since the U- or V-shaped cross section allows a very clear folding of the edge strips when the contact plate is pressed against them. The uncontrolled compression mentioned at the beginning cannot therefore occur.

[0020] It is particularly preferred that both the edge strips of the anode current collector and the edge strips of the cathode current collector have a U-shaped or V-shaped cross section.

[0021] Of course, the terms "U-shaped" and "V-shaped" in the context of the present invention are not to be interpreted as meaning that the cross section has the shape of a perfect U or V. For example, when the contact plate is mounted, further deformations of one or more edge strips may occur, so that, for example, the cross section of the V-shape is very pointed, i.e. the legs of the V enclose a very small angle, or the U is deformed in the area of ​​its opening.

[0022] Furthermore: the edge strip or strips do not necessarily have a U-shaped or V-shaped cross section in their entirety as a result of the shaping process. Rather, it is preferred that only a portion of the edge strip or strips is subjected to the shaping process. Thus, in this preferred embodiment, the edge strip or strips include at least one portion that is not deformed by the shaping process. This preferably extends along an elongated depression or indentation or along an elongated ridge corresponding to the depression or indentation.

[0023] Cylindrical Design The energy storage element according to the invention can be designed as a cylindrical cell or also as a prismatic one. In the 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.

[0024] 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.

[0025] In this embodiment, the contact sheet metal member preferably rests flat on the two end faces.

[0026] The cylindrical design of the energy storage element according to the invention has some noteworthy advantages. It is known from the prior art that when manufacturing cylindrical windings from electrodes, inaccurate winding of the edges of the electrodes can result in the so-called "telescope effect", which can make the end faces of the windings uneven. This leads to dimensional, mechanical and welding problems. This effect can be avoided by the edge strips formed according to the invention. The edge strips with a U-shaped or V-shaped cross section can provide a guide for winding, which counteracts inaccuracies during winding manufacture.

[0027] 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.

[0028] 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 coupled 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 pole that is not electrically connected to the housing.

[0029] 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.

[0030] 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.

[0031] 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: - Lengths ranging from 0.5m to 25m - Width in the range of 30mm~145mm.

[0032] In this embodiment, the contact sheet metal member preferably has a circular basic shape.

[0033] 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 radial series of adjacent turns in the winding. b. The elongated ridges of the free edge strips of the cathode current collector pointing radially outward or radially inward. c. The ribbon-like positive electrode includes at least one turn, and preferably a plurality of turns, in which an elongated ridge of a free edge strip of a cathode current collector is inserted into an elongated depression or indentation of the free edge strip of the cathode current collector of a radially adjacent turn. 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.

[0034] Preferably, the immediately preceding features a. to c., and particularly preferably also features a. to d., are realized in combination with one another.

[0035] This embodiment is particularly advantageous: Ideally, the continuous metal layer is a closed layer that completely covers the first end face.

[0036] 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.

[0037] 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 one of the end faces, comprises a series of adjacent radial turns in the winding. b. The ridges on the free edge strip of the anode current collector pointing radially outward or radially inward. c. The ribbon-like negative electrode includes at least one turn, and preferably a plurality of turns, in which an elongated ridge of a free edge strip of an anode current collector is inserted into an elongated depression or indentation of the free edge strip of the anode current collector of a radially adjacent turn. d. The free edge strip of the anode current collector forms a continuous metal layer covering at least 80% of the end surface in a direction perpendicular to the second end surface.

[0038] 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.

[0039] 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.

[0040] In a stack, electrodes with opposite polarity are always separated from each other by a separator or solid electrolyte layer.

[0041] 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.

[0042] 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.

[0043] In this embodiment, the contact sheet metal members preferably have a rectangular basic shape.

[0044] 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 an edge strip having a U-shaped or V-shaped cross-section. b. Each anode in the stack features an edge strip having a U-shaped or V-shaped cross-section. 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.

[0045] 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.

[0046] 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 d.: a. The free edge strips of the cathode current collector are arranged parallel to each other. b. The ridges of the free edge strips of adjacent cathode current collectors point in the same direction. c. Adjacent edge strips of the cathode current collector free edge strip are joined to the adjacent cathode current collector free edge strips by inserting their elongated projections into elongated recesses or indentations of the adjacent cathode current collector free edge strips. d. 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.

[0047] Preferably, the immediately preceding features a. to c., and particularly preferably also features a. to d., are realized in combination with one another.

[0048] 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 d.: a. The free edge strips of the anode current collector are arranged parallel to each other. b. The ridges of the free edge strips of adjacent anode current collectors point in the same direction. c. Adjacent edge strips of the anode current collector free edge strip are joined to the adjacent anode current collector free edge strips by inserting their elongated projections into elongated recesses or indentations of the adjacent anode current collector free edge strips. d. 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.

[0049] Preferably, the immediately preceding features a. to c., and particularly preferably also features a. to d., are realized in combination with one another.

[0050] 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.

[0051] Feature a. refers in particular to the described embodiment of the energy storage element according to the invention as a cylindrical cell. In this embodiment, the energy storage element preferably comprises exactly one electrochemical cell.

[0052] 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.

[0053] Essentially all electrode materials known for lithium-ion secondary cells can be used for the electrodes of the energy storage element.

[0054] 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 (Li4Ti5O 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.

[0055] Suitable active materials for the positive electrode include lithium metal oxide compounds and lithium metal phosphate compounds, such as LiCoO2 and LiFePO4. x Mny Co z Lithium nickel manganese cobalt oxide (NMC) having the formula LiMnO2 (where x+y+z is typically 1), lithium manganese spinel (LMO) having the formula LiMn2O4, or lithium manganese spinel (LMO) having the formula LiNi x Co y Al z Lithium nickel cobalt aluminum oxide (NCA) having the formula LiO2 (where x+y+z is generally 1) is also particularly suitable. 1.11 (Ni 0.40 Mn 0.39 Co 0.16 Al 0.05 ) 0.89 Lithium Nickel Manganese Cobalt Aluminum Oxide (NMCA) with O2, 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.

[0056] 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.

[0057] The energy storage element according to the invention preferably comprises an electrolyte, in particular in the case of lithium-ion cells, based on at least one lithium salt, such as lithium hexafluorophosphate (LiPF6), which is present dissolved in an organic solvent, for example a mixture of organic carbonates or cyclic ethers such as THF or nitriles. Other lithium salts that can be used are, for example, lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(oxalato)borate (LiBOB).

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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 conductive salts such as lithium bis(trifluoromethane)sulfonylimide (LiTFSI), lithium hexafluorophosphate (LiPF6), and lithium tetrafluoroborate (LiBF4) can be dissolved therein.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] Preferably, the immediately preceding features a. and b. are realised in combination with each other.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] For example, at least one aperture in the contact sheet metal member may serve to allow the assembly to be impregnated with an electrolyte.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] The second contact sheet metal member is preferably similar, apart from the nature of its material, to the contact sheet metal member present 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] The immediately preceding features a. and b. are particularly preferably realised in combination.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] The method is characterized in particular by the following steps: h. Before the assembly is formed, at least one edge strip is subjected to a molding process so that it has a U-shaped or V-shaped cross-section and therefore has an elongated depression or dent on one side and an elongated ridge corresponding to the dent on the other side.

[0097] In a particularly preferred embodiment, the method is additionally characterized by the following steps: For forming, the edge strip to be formed is guided through a V- or U-shaped gap formed by rollers or a compressor.

[0098] In a further particularly preferred embodiment, the method is additionally characterized by the combination of the following steps a. to e.: a. forming an assembly using a ribbon electrode having a ribbon current collector and a ribbon layer of electrode material; b. forming an assembly using at least one ribbon-shaped separator or at least one ribbon-shaped solid electrolyte layer; c. the assembly is formed into a cylindrical winding shape by spirally winding the electrodes and at least one ribbon-shaped separator or at least one ribbon-shaped solid electrolyte layer around a winding shaft; d. When winding the electrode, a series of adjacent turns is produced; e. When the electrode is wound, the elongated ridges of the edge strips of one turn of the electrode are forced into the elongated depressions or indentations of the adjacent turns.

[0099] A variation of this process is used to manufacture energy storage elements of cylindrical design.

[0100] In another particularly preferred embodiment, the method is additionally characterized by the combination of the following steps a. to f.: a. forming an assembly using polygonal electrodes; b. the assembly is formed in the shape of a prismatic stack in which the cathodes and anodes are stacked together with other cathodes and other anodes; c. Each cathode in the stack features an edge strip having a U-shaped or V-shaped cross-section. d. Each anode in the stack features an edge strip having a U-shaped or V-shaped cross-section. e. When forming the stack, the free edge strips of the cathode current collectors are joined to the free edge strips of adjacent cathode current collectors by inserting their elongated projections into elongated recesses or indentations in the free edge strips of the adjacent cathode current collectors. f. When forming the stack, the free edge strips of the anode current collector are joined to the free edge strips of the adjacent cathode current collector by inserting their elongated projections into elongated recesses or indentations in the free edge strips of the adjacent cathode current collector.

[0101] A variation of this process is used to manufacture energy storage elements of prismatic design. [Brief description of the drawings]

[0102] 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-sectional view through a prior art cell in which the contact plate is pressed against the protruding edge of the current collector. [Diagram 2] Current collector coated on both sides with positive electrode material (top view and cross section) with a free edge strip not coated with electrode material. [Diagram 3] Current collector coated on both sides with negative electrode material (top view and cross section) with a free edge strip not coated with electrode material. [Figure 4] Forming of edge strips with a V-shaped cross section. [Diagram 5] A cross section through several turns of a cylindrical assembly formed by helically winding the cathode and anode. [Figure 6] FIG. 13 is a cross-sectional view of another embodiment of a cylindrical assembly formed by spirally winding a cathode and an anode. [Figure 7] Forming of edge strips with a U-shaped cross section. [Figure 8] 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

[0103] 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.

[0104] 2 shows, firstly, in a plan view from above and secondly, in a cross-sectional view (cross-section along S1), a current collector 101a provided on both sides with a layer of positive electrode material 117. The current collector 101 is preferably an aluminium foil.

[0105] 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.

[0106] 3 shows, firstly, in a plan view from above and secondly, in a cross-sectional view (cross-section along S2), a current collector 102a provided on both sides with a layer of anode material 118. The current collector 101 is preferably a copper foil.

[0107] The strip-shaped current collector 102a includes a main region 102b filled with electrode material 118 and strip-shaped edge strips 102c that do not contain electrode material.

[0108] Figure 4 shows the forming of an edge strip with a V-shaped cross section. The free edge strip 101c of the current collector 101a as shown in Figure 2 is guided longitudinally through a V-shaped gap formed by two rollers R1 and R2. In this process, the edge strip 101c is deformed and given a V-shaped cross section that characterizes the edge strip 101c with an elongated depression or indentation 121 on one side and an elongated ridge 122 corresponding to the indentation 121 on the other side.

[0109] The result of such a process is shown in Figure 5. It shows a cross section through several turns of a cylindrical assembly 109 formed by spirally 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. Both the cathode 101 and the anode 102 have been subjected to a pretreatment according to Figure 4, in the course of which the free edge strips 101c and 102c of the current collectors have been given a V-shaped cross section.

[0110] The assembly 109, formed as a cylindrical winding, has a winding shell with first and second terminal end faces 109a, 109b, a free edge strip 101c of the cathode current collector protruding from the first end face 109a, and a free edge strip 102c of the anode current collector protruding from the second end face 109b.

[0111] 6 shows a cross-sectional view of a further embodiment of a cylindrical assembly formed as a winding formed by helically winding a tape-like cathode and a tape-like anode. The winding has a first end face 109a and a second end face 109b. Here, to improve the overview, only the current collectors 101a and 102a are shown together with their respective free edge strips 101c and 102c. The electrode material and the separators arranged between the electrodes are not shown.

[0112] The free edge strip 101c of the cathode current collector protruding from the end face 109a comprises a radial series of adjacent turns 141-156 in the winding. The free edge strip 102c of the anode current collector protruding from the end face 109b comprises a radial series of adjacent turns 160-174 in the winding. The free edge strips 101c and 102c have been subjected to a pre-treatment according to FIG. 4, in the process of which they have each been given a V-shaped cross section. In the winding itself, the anode and the cathode are arranged slightly offset from each other. In the figure, the elongated ridge 122 of the free edge strip 101c of the cathode current collector points radially inwards, and the elongated ridge 123 of the free edge strip 102c of the anode current collector points radially outwards. Of course, in alternative embodiments, it is conceivable that the elongated ridges 122 and 123 point inward in both cases, or point outward in both cases, or that the elongated ridge 123 points radially inward and the elongated ridge 122 points radially outward.

[0113] The width of edge strips 101c and 102c are sized so that the elongated ridges of the turns are inserted into the elongated depressions or indentations of the radially adjacent turns. On the cathode side, the ridges 122 of each turn (except the innermost and outermost) are inserted into the depressions 121 of the next inner turn. On the anode side of each turn (except the innermost and outermost) the protrusions 123 are inserted into the depressions 124 of the next outermost turn.

[0114] As a result, the free edge strip 101c of the cathode current collector forms a continuous metal layer in a viewing direction perpendicular to the end face 109a, which in this case completely covers the end face 109a. Similarly, on the anode side, the free edge strip 102c of the anode current collector forms a continuous metal layer in a viewing direction perpendicular to the end face 109b, which in this case completely covers the end face 109b.

[0115] The end faces 109a and 109b of the windings are covered by contact sheet metal members 119 and 120. The contact sheet metal member 119 is in direct contact with the edge strip 101c, and the contact sheet metal member 120 is in direct contact with the edge strip 102c. When the contact sheet metal members are applied, the edge strips 101c and 102c may be slightly pressed. Conversely, the edge strips 101c and 102c may exert a spring force on the contact sheet metal members that strengthens the contact with the sheets. Welded connections are particularly preferred between the contact sheet metal members 119 and 120 and the edge strips.

[0116] Figure 7 shows the shaping of an edge strip with a U-shaped cross section. The free edge strip 101c of the cathode 101 as shown in Figure 2 is guided longitudinally through a U-shaped gap formed by two rollers R1 and R2. In this process, the edge strip 101c is deformed and given a U-shaped cross section that characterizes the edge strip 101c with an elongated depression or indentation 121 on one side and an elongated ridge 122 corresponding to the indentation 121 on the other side.

[0117] 8 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.

[0118] 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.

[0119] The free edge strips 101c, 103c, 105c, and 107c of the positive electrode and the free edge strips 102c, 104c, 106c, and 108c of the negative electrode have been subjected to a pretreatment according to Figure 4, in the course of which they have each been given a V-shaped cross section, so that they each have one side with an elongated depression and another side with an elongated ridge.

[0120] 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. They are all arranged parallel to one another and their elongated ridges all point in the same direction. 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. They are also all arranged parallel to one another and their elongated ridges all point in the same direction.

[0121] The free edge strips 101c, 103c, 105c and 107c are connected to each other via their ridges or their depressions or indentations, such that the ridges of edge strip 101c are inserted into the depressions or indentations of edge strip 103c, the ridges of edge strip 103c are inserted into the depressions or indentations of edge strip 105c, and the ridges of edge strip 105c are inserted into the depressions or indentations of edge strip 107c. The situation is the same on the anode side, where the elongated ridges of edge strip 108c are inserted into the elongated depressions or indentations of edge strip 106c, the elongated ridges of edge strip 106c are inserted into the elongated depressions or indentations of edge strip 104c, and the elongated ridges of edge strip 104c are inserted into the elongated depressions or indentations of edge strip 102c. As a result, the free edge strips 101c, 103c, 105c and 107c form a continuous metal layer that almost completely covers the side of the stack when viewed perpendicular to the side from which they protrude. On the anode side, the free edge strips 102c, 104c, 106c and 108c form a continuous metal layer that almost completely covers this side perpendicular to the side of the stack from which they protrude.

Claims

1. a cathode comprising a cathode current collector including a main region filled on both sides with a layer of positive electrode material and a first free edge strip not filled with said positive electrode material, said first free edge strip extending along an edge of said cathode current collector; an anode comprising an anode current collector including a main region filled on both sides with a layer of negative electrode material and a second free edge strip not filled with said negative electrode material, said second free edge strip extending along an edge of said anode current collector; a first contact sheet metal member in direct contact with the cathode current collector and a second contact sheet metal member in direct contact with the anode current collector; An energy storage element comprising: the cathode and the anode are separated by a separator or a solid electrolyte layer, forming a cathode / separator or solid electrolyte layer / anode sequence; each free edge strip of the first free edge strip or the second free edge strip has a U-shaped or V-shaped cross section as a result of the molding process, and therefore has an elongated depression on one side and an elongated ridge corresponding to said depression on the opposite side; Each portion of the elongated ridge is a portion of the elongated depression, the portion of the elongated depression being disposed in a turn of the respective free edge strip radially adjacent the respective portion of the elongated ridge; or a further free edge strip elongated recess of the further electrode; An energy storage element inserted into one of the

2. a cylindrical housing having a circumferential housing shell, a circular bottom, and a lid; the anode and the cathode are ribbon-shaped; at least one ribbon-shaped separator or at least one ribbon-shaped solid electrolyte layer separates the anode and the cathode; the anode, the cathode, and the at least one ribbon-shaped separator or the at least one ribbon-shaped solid electrolyte layer are spirally wound around a winding shaft to form a cylindrical winding assembly; the cylindrical winding assembly includes a first end face, a second end face, and a winding shell; the first free edge strip protruding from the first end face and the second free edge strip protruding from the second end face; the respective portions of the elongated ridges are inserted into the portions of the elongated recesses disposed in the turns of the respective free edge strips radially adjacent to the respective portions of the elongated ridges; 2. The energy storage element of claim 1, wherein the cylindrical winding assembly is axially aligned so that the winding shell abuts the inside of the circumferential housing shell.

3. the cathode and the first free edge strip forming a series of adjacent radial turns in the cylindrical winding assembly; the elongated ridge points radially outward or radially inward; the respective free edge strip being the first free edge strip; the first free edge strip forms a continuous metal layer covering at least 80% of the first edge in a direction perpendicular to the first edge; 3. The energy storage element of claim 2, comprising at least one of:

4. the anode and the second free edge strip forming a series of adjacent radial turns in the cylindrical winding assembly; the elongated ridge points radially outward or radially inward; each said free edge strip being said second free edge strip; the second free edge strip forms a continuous metal layer covering at least 80% of the second edge surface in a direction perpendicular to the second edge surface; 3. The energy storage element of claim 2, comprising at least one of:

5. further comprising one or more further cathodes and one or more further anodes; the cathode and the anode are polygonal; the cathode, the anode, the one or more further cathodes, and the one or more further anodes are stacked together with separators or solid electrolyte layers disposed between adjacent cathode and anode layers to form a prismatic stack; the respective portions of the elongated ridges are inserted into elongated recesses or indentations in a further free edge strip of a further electrode, the further electrode being one of the further cathodes or one of the further anodes; and The energy storage element of claim 1 , wherein the stack is housed within a prismatic housing.

6. the first free edge strip includes the U-shaped or V-shaped cross section; the second free edge strip includes the U-shaped or V-shaped cross section; the first free edge strip protruding from one side of the stack and in direct contact with the first contact sheet metal member; the second free edge strip protruding from another side of the stack and in direct contact with the second contact sheet metal member; 6. The energy storage element of claim 5, comprising at least one of:

7. the further cathodes are arranged parallel to one another and have free edge strips of further cathodes protruding from a first side of the prismatic stack; the free edge strips of said further cathodes include elongated ridges pointing in the same direction; the free edge strips of adjacent cathodes are joined together by inserting their respective elongated ridges into their respective elongated recesses; the free edge strip of the further cathode forms a continuous metal layer completely covering at least 80% of the side surface of the prismatic stack extending in a direction perpendicular to the first side surface of the prismatic stack; 6. The energy storage element of claim 5, comprising at least one of:

8. the further anodes are arranged parallel to one another and have free edge strips of further anodes protruding from a second side of the prismatic stack; the free edge strips of said further anodes include elongated ridges pointing in the same direction; the free edge strips of adjacent anodes are joined together by inserting their respective elongated ridges into their respective elongated recesses; a free edge strip of the further anode forming a continuous metal layer completely covering at least 80% of a side surface of the prismatic stack extending in a direction perpendicular to the second side surface of the prismatic stack; 6. The energy storage element of claim 5, comprising at least one of:

9. the first contact sheet metal member is connected to the first free edge strip by welding, and / or the second contact sheet metal member is connected to the second free edge strip by welding; and 2. The energy storage element of claim 1, wherein the first contact sheet metal member is mechanically connected to the first free edge strip and / or the second contact sheet metal member is mechanically connected to the second free edge strip.

10. 10. A method for manufacturing an energy storage device according to claim 1, said method comprising: subjecting each free edge strip to a forming process to create the U-shaped or V-shaped cross section; The portion of the elongated ridge, the portion of the elongated depression located in the turn of each free edge strip radially adjacent to the respective portion of the elongated ridge; or the elongated recess in the further free edge strip of the further electrode, and A method comprising:

11. 11. The method of claim 10, wherein subjecting each free edge strip to the forming process includes guiding each free edge strip through a V-shaped or U-shaped gap formed by a roller or a compressor.

12. the anode and the cathode are ribbon-shaped; at least one ribbon-shaped separator or at least one ribbon-shaped solid electrolyte layer separates the anode and the cathode; the cylindrical winding assembly is formed by winding the anode, the cathode, and the at least one ribbon-shaped separator or the at least one ribbon-shaped solid electrolyte layer around a winding shaft; When winding the electrode, a series of adjacent turns in the radial direction is produced; and 11. The method of claim 10, wherein, during the turns of the electrode, the respective portions of the elongated ridges are pressed into the portions of the elongated depressions located in the turns of the respective free edge strips radially adjacent to the respective portions of the elongated ridges.

13. one or more further cathodes and one or more further anodes are provided; the cathode, the anode, the one or more further cathodes, and the one or more further anodes are polygonal; the cathode, the anode, the one or more further cathodes, and the one or more further anodes are stacked together with separators or solid electrolyte layers disposed between adjacent cathode and anode layers to form a prismatic stack; each of said further cathodes comprises a free edge strip having a U-shaped or V-shaped cross section, each of said further anodes comprises a free edge strip having a U-shaped or V-shaped cross section, when forming the stack, the free edge strips of the cathode and the further cathode are connected to the free edge strips of adjacent cathodes by inserting respective elongated protrusions into corresponding elongated recesses; and 11. The method of claim 10, wherein when forming the stack, the free edge strips of the anode and the further anode are joined to the free edge strips of adjacent anodes by inserting respective elongated protrusions into corresponding elongated recesses.

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