Energy storage element, cap assembly and method of manufacture

Abstract

An energy storage element (100) includes an electrode-membrane assembly (104) having an anode (105) / membrane (156) / cathode (108) arranged in sequence, having a first end face (104a) and a second end face (104b). It further comprises a contact sheet metal member (112) resting on a longitudinal edge (106a, 109a) of the current collector (106, 109) of one of the electrodes, covering one of the end faces (104a, 104b) and connected to the longitudinal edge. The electrode-diaphragm assembly (104) is arranged in an interior space of a gas-tight and liquid-tight closed housing comprising a metal housing cup (101) with a terminal circular opening and a lid (102) with a circular edge (102a) closing the circular opening. The cover (102) is preferably formed as a cover assembly, comprising a metal disc (113) having a rounded edge, where the metal disc (113) has an inner side defining an interior space. It is proposed that the contact sheet metal component (112) comprises a distance compensation region (112d) which is connected to the inner side of the metal disc (113) in a connection region (112e). Alternatively, a distance compensation sheet metal member (177) may be provided, which is welded to the contact sheet metal member (112), where the distance compensation sheet metal member (177) comprises a distance compensation region (177a) connected to the inner side of the metal disc (113) in a connection region (177b). The connection between the distance compensation region (177a) and the inner side of the metal disc (113) may be formed after the housing has been closed.

Description

Technical Field

[0001] The invention described relates to an energy storage element, a cover assembly, and a method of manufacturing. Background Technology

[0002] Electrochemical energy storage devices can convert stored chemical energy into electrical energy through redox reactions. The simplest form of an electrochemical energy storage device is an electrochemical cell. An electrochemical cell includes a positive electrode and a negative electrode, with a separator positioned between them. During discharge, electrons are released at the negative electrode due to oxidation. This generates an electron current that can be drawn from an external power-consuming device, which the electrochemical cell then serves as its energy source. Simultaneously, an ionic current corresponding to the electrode reactions appears within the cell. This ionic current passes through the separator and is realized through an ion-conducting electrolyte. Therefore, the separator prevents direct contact between the electrodes. However, it simultaneously enables charge balance between the electrodes.

[0003] If the discharge is reversible, meaning that the conversion of chemical energy to electrical energy during discharge can be reversed and the cell can be recharged, then the cell is called a secondary cell. In a secondary cell, the negative electrode is usually designated as the anode and the positive electrode as the cathode; this refers to the discharge capability of the electrochemical cell.

[0004] Today, rechargeable lithium-ion battery cells are used as energy storage devices in many applications because they can provide high current and have relatively high energy density. Rechargeable lithium-ion battery cells are based on the use of lithium, which can migrate back and forth between the electrodes of the battery cell in the form of ions. The negative and positive electrodes of a lithium-ion battery cell are typically formed by so-called composite electrodes, which include both electrochemically active components and electrochemically inactive components.

[0005] In principle, any material capable of absorbing and re-releasing lithium ions can be used as the electrochemically active component (active material) for a secondary lithium-ion battery cell. For the negative electrode, carbon-based particles (such as graphite carbon) are used for this purpose. Active materials for the positive electrode can include lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), or their derivatives. Electrochemically active materials are typically contained in the electrode in particulate form.

[0006] As an electrochemically inactive component, composite electrodes typically include flat and / or strip-shaped current collectors (e.g., metal foils) that serve as a carrier for the corresponding active material. The current collector is typically coated with a thin layer of the corresponding active material. The current collector for the negative electrode (anode current collector) can be made of, for example, copper or nickel, while the current collector for the positive electrode (cathode current collector) can be made of, for example, aluminum.

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

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

[0009] During the manufacture of lithium-ion battery cells, composite electrodes are typically combined with one or more separators to form an electrode-separator assembly. The electrodes and separators are usually (but not necessarily) bonded together under pressure, or they can be bonded together by lamination or adhesive bonding. The basic functionality of the battery cell can then be established by utilizing an electrolyte-impregnated assembly.

[0010] In many embodiments, the electrode-diaphragm assembly is formed or processed into a wound piece. In a first case, for example, strip-shaped positive and negative electrodes and at least one strip-shaped diaphragm are fed separately into a winding machine and wound into a wound piece in a helical sequence of positive electrode / diaphragm / negative electrode. In a second case, strip-shaped positive and negative electrodes and at least one strip-shaped diaphragm are first joined to form the electrode-diaphragm assembly, for example, by applying the aforementioned pressure. In a further step, the assembly is then wound.

[0011] For applications in the automotive industry, for e-bikes, or for other applications with high energy demands (such as in power tools), there is a need for lithium-ion battery cells with the highest possible energy density, which can also be charged and discharged at high currents.

[0012] Battery cells used in the aforementioned applications are typically formed as cylindrical cells, for example, with dimensions of 21 × 70 (diameter * height, in mm). This type of cell always includes an electrode-separator assembly in the form of a wound section. Modern lithium-ion battery cells of this size can achieve energy densities up to 270 Wh / kg.

[0013] The electrical contact of the electrodes in energy storage elements presents challenges. For example, in a circular battery cell with dimensions of 21 × 70, the electrodes of the winding must be electrically connected to the electrode posts of the corresponding housing.

[0014] The classic method used here is the so-called "tab design". One end of a strip of metal ("tab") is soldered to an electrode, and the other end is connected to a functional part of a CID (current interruption device) integrated into a multi-piece cover, for example, into a metal housing. An example of this is described in US 7432010 B2.

[0015] The function of the CID is known to technicians; in the event of a failure, the CID ensures that the current flow in the energy storage element is interrupted. Another safety feature is the so-called PRV (Pressure Relief Valve). This opens when a predetermined pressure limit is exceeded, preventing the accumulation of dangerous overpressure in the energy storage element.

[0016] The tab design has several drawbacks. One problem is that, because the tab can only be welded to the inside of the cover before the casing is sealed, it must be relatively long. Furthermore, the tab must be folded at least once when the casing is closed, which is often difficult to achieve in production. Additionally, folded tabs occupy space within the casing that is no longer available for electrochemically active materials, and the tab itself is a bottleneck in terms of current flow into and out of the casing, as well as heat dissipation. When an electrochemical cell is operating, heat is generated in the electrodes, and this heat must be dissipated. This is challenging when only the tab can serve as a thermal bridge.

[0017] In recent years, work on lithium-ion battery cells has increased, with the use of a so-called "tabless design" for electrode contact. This design completely eliminates the use of tabs. Instead, the electrode-separator assembly is manufactured in the form of a wound, where the electrodes have metal current collectors with uncoated longitudinal edges protruding from the wound at the end faces. Metal contact sheet components can be welded to these longitudinal edges, as described, for example, in WO 2017 / 215900 A1. This allows the current collectors, and thus the associated electrodes, to make electrical contact over their entire length. This significantly reduces the internal resistance within the battery cell. Consequently, large currents can be absorbed more effectively, and heat can also be dissipated more effectively from the wound.

[0018] However, the "tabless design" in the known variants does not solve all existing problems. For example, an electrical connection between the cover and the contact metal plate component to be contacted is still required. A suitable electrical conductor must be as long as the aforementioned tab because it must be soldered to the cover before the housing is closed. Therefore, when the housing is closed, the conductor must fold like a tab, thus creating a dead zone volume within the housing. Summary of the Invention

[0019] The object of this invention is to provide an energy storage element characterized by high energy density. Simultaneously, the provided energy storage element should meet the highest safety standards.

[0020] This objective is achieved by an energy storage element having the features of claim 1. The cover assembly according to claim 8 is also the subject of this invention. The method belonging to this invention is the subject of claim 9. Preferred embodiments of the invention are found in dependent claims 2 to 7.

[0021] The energy storage element (100) according to the present invention is characterized by the following features: a. The energy storage element includes an electrode-diaphragm assembly having an anode / diaphragm / cathode arranged in sequence.

[0022] b. The electrode-diaphragm assembly is in the form of a cylindrical wound having a first end face and a second end face and a wound housing therebetween.

[0023] c. The anode of the electrode-diaphragm assembly includes an anode current collector having a first longitudinal edge and a second longitudinal edge parallel to the first longitudinal edge, a main region loaded with a layer of negative electrode material, and a free edge strip extending along its first longitudinal edge and not loaded with negative electrode material.

[0024] d. The cathode of the electrode-diaphragm assembly includes a cathode current collector having a first longitudinal edge and a second longitudinal edge parallel to the first longitudinal edge, a main region loaded with a layer of positive electrode material, and a free edge strip extending along its first longitudinal edge and not loaded with positive electrode material.

[0025] e. The anode and cathode are arranged within the electrode-diaphragm assembly in such a manner that the first longitudinal edge of the anode current collector protrudes from the first end face, and the first longitudinal edge of the cathode current collector protrudes from the second end face of the electrode-diaphragm assembly.

[0026] f. The energy storage element includes a contact metal sheet member that rests on a first longitudinal edge of an anode current collector and covers a first end face, or the contact metal sheet member rests on a first longitudinal edge of a cathode current collector and covers a second end face, and is particularly connected to the latter by a material locking connection, particularly preferably by welding, bonding or brazing.

[0027] g. The energy storage element includes a hermetically and liquidally sealed housing, the hermetically and liquidally sealed housing including a metal housing cup with a circular opening at the end and a cover with a circular edge that closes the circular opening and encloses an internal space in which an electrode-diaphragm assembly is arranged.

[0028] h. The cover includes a metal disc with a circular edge, wherein the metal disc has an inner side that defines an internal space.

[0029] The energy storage element (100) according to the present invention is characterized in particular by, i. The contact metal sheet component includes a distance compensation region connected to the inside of the metal disk in the connection region, or the distance compensation metal sheet component is welded to the contact metal sheet component, wherein the distance compensation metal sheet component includes a distance compensation region connected to the inside of the metal disk in the connection region.

[0030] The connection between the distance compensation area of ​​the contact metal sheet component or distance compensation metal sheet component on one side and the inner side of the metal disk on the other side is preferably formed by material locking connection, especially by welding, bonding or brazing.

[0031] In some embodiments, the distance compensation area and the metal disc can also be connected to each other via shape-locking connections (e.g., riveting connections).

[0032] As explained below, the design according to the invention eliminates the need for electrical connections between the cover and the contact sheet components using long electrical conductors. The function of the conductor is performed by distance-compensating sheet components or contact sheet components with distance-compensating regions. These components bridge the gap between the cover and the electrode-diaphragm assembly within the housing. Furthermore, the welded connection to the cover can only be formed after the housing has been closed, which offers significant advantages in terms of optimal utilization of the available housing volume.

[0033] The connection between the distance compensation area and the inner side of the metal disc in the connection area is preferably achieved by welding. The metal disc and the contact metal sheet component or the distance compensation metal sheet component are preferably fused together in the connection area.

[0034] Bonding can be achieved by using an adhesive with conductive properties to connect the distance compensation area and the inside of the metal disk. Such adhesives are known, for example, from printed circuit board technology.

[0035] Soft solder joints are formed by melting the solder and allowing it to solidify when it comes into contact with one of the distance compensation area and the inside of the metal disk.

[0036] Riveted connections can be achieved, for example, by means of blind rivets that are pushed through holes in the distance compensation area and in the metal disc.

[0037] In a preferred embodiment, the cover has at least one of the following features a to e: a. The cover is a cover assembly that, in addition to the metal disk, includes an electrode cap that is in electrical contact with the metal disk.

[0038] b. The electrode caps are placed directly on the metal plate.

[0039] c. The electrode cap and metal disk enclose the intermediate space.

[0040] d. The metal disc includes a connection area in which a connection is formed with a connection area of ​​a distance compensation area of ​​a contact metal sheet member or a distance compensation metal sheet member.

[0041] e. The electrode cap includes at least one perforation through which the connection area of ​​the metal disc can be accessed from the outside of the housing, particularly by means of a laser.

[0042] Combining the features a through e immediately preceding them is particularly preferred. In a further preferred embodiment, at least features a and c through e are combined.

[0043] In the design of the cap as a cover assembly, perforations in the electrode cap ensure external access to the connection area. This allows for laser welding.

[0044] If the above-mentioned adhesive or soldering is used instead of welding, the corresponding perforation is not absolutely necessary.

[0045] In an embodiment of the energy storage element according to the invention, wherein the contact metal sheet member performs a distance compensation function between the cover and the electrode-diaphragm assembly, and the energy storage element according to the invention is preferably characterized by at least one of the following features a to c.

[0046] a. The contact metal sheet component includes a contact area, particularly a disc-shaped contact area, to which the longitudinal edge of the anode current collector is connected, particularly welded, to the contact area.

[0047] b. The contact area surrounds the distance compensation area.

[0048] c. The distance compensation area extends from the plane of the contact area to the metal disk.

[0049] Preferably, features a. and b. immediately preceding the preceding text are implemented in combination. Particularly preferably, features a. to c. immediately preceding the preceding text are implemented in combination.

[0050] In a preferred embodiment, the contact metal sheet member thus includes a contact area and a distance compensation area extending from the plane of the contact area to the metal disk. The distance compensation area includes a connecting area in which the contact metal sheet member connects to the inner side of the metal disk. Preferably, the connecting area is therefore axially spaced from the plane of the contact area. Furthermore, the contact metal sheet member therefore preferably includes two areas (the contact area and the connecting area) in different planes.

[0051] The contact area of ​​the contact sheet member can be formed as an annular disk. In other embodiments, the contact area can have separate contact segments. These segments are arranged around and / or connected to each other via the distance compensation region. For example, the connection area and the contact area of ​​the contact sheet member can be connected to each other via a web. For example, the contact segments can also be annular segments. In a preferred embodiment, the distance compensation region is formed as a spring that presses downward against the electrode-diaphragm assembly and upward against the cover. In a preferred embodiment, for this purpose, the connection area and the contact area can be elastically connected to each other, for example, via the aforementioned web. In a tensioned state, the distance compensation region can be axially compressed, such that the distance between the connection area and the contact area of ​​the contact sheet member decreases. In this case, the aforementioned web can be under compressive stress.

[0052] In an embodiment of the energy storage element according to the invention, wherein the distance compensation sheet member performs the distance compensation function between the cover and the electrode-diaphragm assembly, and the energy storage element according to the invention is preferably characterized by at least one of the following features a to c.

[0053] a. The distance compensation sheet component includes a contact area, particularly an annular disc-shaped contact area, which is connected to the contact sheet component, especially by welding.

[0054] b. The contact area is arranged around the distance compensation area; in a preferred embodiment, the contact area surrounds the distance compensation area.

[0055] c. The distance compensation area extends from the plane of the contact area to the metal disk.

[0056] Preferably, features a. and b. immediately preceding the preceding text are implemented in combination. Particularly preferably, features a. to c. immediately preceding the preceding text are implemented in combination.

[0057] In a preferred embodiment, the distance compensation sheet component thus includes a contact area and a distance compensation area extending from the plane of the contact area to the metal disk. The distance compensation area includes a connecting area in which the distance compensation sheet component connects to the inner side of the metal disk. Preferably, the connecting area is therefore axially spaced from the plane of the contact area. Furthermore, the distance compensation sheet component therefore preferably includes two areas (the contact area and the connecting area) in different planes.

[0058] Besides the annular disc shape, the contact area of ​​the distance compensation sheet member can also have other designs. For example, the contact area can be annular and have a polygonal outer circumference, i.e., an outer edge with six or eight corners. In other embodiments, such as in the case of a contact sheet member, the contact area can have individual contact segments arranged around and / or connected to each other via the distance compensation area.

[0059] Here, the connection area and contact area of ​​the distance compensation metal sheet component can also be connected to each other via the web.

[0060] In a preferred embodiment, the connecting region and the contact region can be connected to each other, for example, via the aforementioned web in a spring-loaded manner. When the distance compensation sheet member is tensioned, it can be axially compressed, thereby reducing the distance between the connecting region and the contact region. In this case, the aforementioned web can be under compressive stress.

[0061] It should be noted that, in principle, the metal disc of the cover can also perform the task of compensating for the distance between the cover and the contact metal sheet member. For this purpose, the metal disc needs to include a distance compensation region, which is connected to the contact metal sheet member in the connection area by welding or adhesive. This distance compensation region then extends axially, preferably to the contact metal sheet member, which rests on a first longitudinal edge of the anode current collector and covers a first end face, or rests on a first longitudinal edge of the cathode current collector and covers a second end face, and is connected to the respective longitudinal edge, for example, by welding. In a preferred embodiment, the contact metal sheet member can be designed to be, for example, flat or substantially flat.

[0062] Preferably, several safety functions are integrated into the cover of the energy storage element according to the invention: a. The metal disc of the cover is formed as a PRV (pressure relief valve) and includes elongated, weakened grooves for this purpose.

[0063] b. In the connecting region, the metal disk is characterized by a material thickness that is lower than the material thickness of the region surrounding the connecting region.

[0064] Features a and b, which are immediately preceding in the text, are particularly preferred when implemented in combination. However, they can also be implemented independently of each other.

[0065] Feature b, which follows above, relates to the CID function of the cover, and will be explained below with reference to the accompanying drawings relating to the invention.

[0066] In any case, it should be noted that the energy storage element according to the invention is preferably an energy storage element having both PRV and CID functions.

[0067] Regarding the mechanical stability and the aforementioned safety functions of the energy storage element according to the present invention, the following preferred features are also important: a. The housing includes a seal made of plastic material that surrounds the edge of the lid and is disposed between the lid and the housing cup.

[0068] b. The energy storage element includes a support ring made of plastic material, which is arranged, in particular, between a metal disk and a distance compensation sheet member or between a metal disk and a contact sheet member.

[0069] c. The support ring rests on the contact area of ​​the contact metal sheet component or the contact area of ​​the distance compensation metal sheet component.

[0070] d. The support ring is part of the seal.

[0071] Features a to c that immediately follow above are particularly preferred, and in some particularly preferred embodiments, features a to d are also implemented in combination.

[0072] In a particularly preferred embodiment, the energy storage element is further characterized by the following features a. and b.: a. The shell cup comprises, in axial order, a bottom, a central section, and a closed section, wherein, - The central section is formed in a cylindrical shape, and within this central section, the wound shell of the electrode-diaphragm assembly, designed as a wound element, contacts the inner side of the housing cup, and - In the enclosed section, the annular seal presses into contact with the edge of the cap and the inside of the housing cup, and b. The shell cup has an opening edge defining a circular opening in the closed section, the opening edge being radially inwardly curved on the edge of the cap surrounded by a seal, and the cap including the seal is secured in a form-locking manner in the circular opening of the shell cup.

[0073] The electrode-diaphragm assembly is preferably in direct contact with the inner side of the housing cup. Particularly preferred is that the electrode-diaphragm assembly directly abuts against the inner side of the housing cup. However, in some embodiments, it may be proposed to electrically insulate the inner side, for example, by means of a membrane. In this case, the electrode-diaphragm assembly is connected to the inner wall via the membrane.

[0074] The bottom of the shell cup is preferably round. The shell cup is usually formed by deep drawing. However, the cup can also be formed by welding the bottom to the tubular half.

[0075] The energy storage element according to the invention is preferably formed as a cylindrical round battery cell. Its height is preferably in the range of 50 mm to 150 mm. Its diameter is preferably in the range of 15 mm to 60 mm. A cylindrical round battery cell with these dimensions is suitable, for example, for supplying electrical power to an electric drive device in a motor vehicle.

[0076] Examples of lithium-ion energy storage devices In a particularly preferred embodiment of the invention, the energy storage element according to the invention is based on lithium-ion technology.

[0077] Basically, all electrode materials known for secondary lithium-ion battery cells can be used for the electrodes of the energy storage element.

[0078] In the negative electrode, carbon-based particles (such as graphite carbon or non-graphite carbon materials) capable of embedding lithium (preferably also in particulate form) can be used as the active material. Alternatively or additionally, lithium titanate (Li4Ti5O 12 ) or its derivatives can be included in the negative electrode, preferably also in particulate form. Additionally, the negative electrode can include at least one material from the group including: silicon, aluminum, tin, antimony, or compounds or alloys of these materials that can reversibly store and release lithium (such as silicon oxide (especially SiO x , where 0 < x < 2), optionally in combination with a carbon-based active material). Tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. The lithium absorption capacity is many times that of graphite or similar materials, especially in the case of silicon. Mixtures of silicon-based and carbon-based storage materials are often used. A thin anode made of metallic lithium is also suitable.

[0079] For the positive electrode, active materials such as lithium metal oxide compounds and lithium metal phosphate compounds (such as LiCoO2 and LiFePO4) are suitable. Lithium nickel x Mn y Co z O2 (where x + y + z is usually 1) lithium nickel manganese cobalt oxide (NMC), lithium manganese spinel (LMO) with the chemical formula LiMn2O4, or lithium nickel x Co y Al z O2 (where x + y + z is usually 1) lithium nickel cobalt aluminum oxide (NCA). Its derivatives can be used, such as lithium nickel manganese cobalt aluminum oxide (NMCA) with the chemical formula Li 1.11 (Ni 0.40 Mn 0.39 Co 0.16 Al 0.05 ) 0.89 O2 or Li 1+xMO compounds, and / or mixtures of the aforementioned materials. The cathode active material is also preferably used in particulate form.

[0080] Furthermore, the electrodes of the energy storage element preferably include electrode binders and / or additives to improve conductivity. The active material is preferably embedded in the matrix of the electrode binder, wherein adjacent particles in the matrix are preferably in direct contact with each other. Conductive agents have the function of increasing the conductivity of the electrodes. Conventional electrode binders are based on, for example, polyvinylidene fluoride (PVDF), lithium polyacrylate, styrene-butadiene rubber, or carboxymethyl cellulose, or mixtures of different binders. Conventional conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes, and metal powders.

[0081] The energy storage element preferably includes an electrolyte, and in the case of a lithium-ion battery cell, particularly an electrolyte based on at least one lithium salt (such as lithium hexafluorophosphate (LiPF6)) dissolved in an organic solvent (e.g., organic carbonates or mixtures of cyclic ethers or nitriles such as THF). Other lithium salts that can be used include lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(oxalic acid)borate (LiBOB).

[0082] The nominal capacity of the lithium-ion-based energy storage element is preferably up to 15,000 mAh, and the energy storage element is formed as a cylindrical spherical battery cell. In the case of a 21 × 70 size specification, the spherical battery cell in the lithium-ion battery cell embodiment preferably has a nominal capacity in the range of 1,500 mAh to 7,000 mAh, particularly preferably in the range of 3,000 mAh to 5,500 mAh. In the case of a 18 × 65 size specification, the spherical battery cell in the lithium-ion battery cell embodiment preferably has a nominal capacity in the range of 1,000 mAh to 5,000 mAh, particularly preferably in the range of 2,000 mAh to 4,000 mAh.

[0083] In the European Union, strict regulations govern manufacturer information regarding the nominal capacity of secondary batteries. For example, information on the nominal capacity of secondary nickel-cadmium batteries must be based on measurements performed according to IEC / EN 61951-1 and IEC / EN 60622 standards; information on the nominal capacity of secondary nickel-metal hydride batteries must be based on measurements performed according to IEC / EN 61951-2 standard; information on the nominal capacity of secondary lithium batteries must be based on measurements performed according to IEC / EN 61960 standard; and information on the nominal capacity of secondary lead-acid batteries must be based on measurements performed according to IEC / EN 61056-1 standard. Any information regarding nominal capacity in this application is also preferably based on these standards.

[0084] Examples based on sodium ions In other embodiments, the energy storage element may also be a sodium-ion battery cell, a potassium-ion battery cell, a calcium-ion battery cell, a magnesium-ion battery cell, or an aluminum-ion battery cell. Among these variations, energy storage elements having the chemical properties of sodium-ion battery cells are particularly preferred.

[0085] Preferably, the sodium ion-based energy storage element includes an electrolyte comprising at least one of the following solvents and at least one of the following conductive salts: Organic carbonates, ethers, nitriles, and mixtures thereof are particularly suitable as solvents. Preferred examples are: - Carbonates: Propylene carbonate (PC), ethylene carbonate-propylene carbonate (EC-PC), propylene carbonate-dimethyl carbonate-ethyl methyl carbonate (PC-DMC-EMC), ethylene carbonate-diethyl carbonate (EC-DEC), ethylene carbonate-dimethyl carbonate (EC-DMC), ethylene carbonate-ethyl methyl carbonate (EC-EMC), ethylene carbonate-dimethyl carbonate-ethyl methyl carbonate (EC-DMC-EMC), ethylene carbonate-dimethyl carbonate-diethyl carbonate (EC-DMC-DEC) - Ethers: Tetrahydrofuran (THF), 2-Methyltetrahydrofuran, Dimethyl ether (OME), 1,4-Dioxane (DX), 1,3-Dioxolane (DOL), Diethylene glycol dimethyl ether (DEGDME), Tetraethylene glycol dimethyl ether (TEGDME) - Nitriles: Acetonitrile (ACN), Adiponitrile (AON), Gamma-butyrolactone (GBL) Trimethyl phosphate (TMP) and tri(2,2,2-trifluoroethyl) phosphate (TFP) can also be considered.

[0086] The preferred guiding salt is: NaPF6, sodium difluoro(oxalate)borate (NaBOB), NaBF4, sodium bis(fluorosulfonyl)imide (NaFSI), sodium 2-trifluoromethyl-4,5-dicyanimidazolium (NaTDI), sodium bis(trifluoromethylsulfonyl)imide (NaTFSI), NaAsF6, NaClO4, NaB(C2O4)2, NaP(C6H4O2)3; NaCF3SO3, sodium trifluoromethanesulfonate (NaTf), and Et4NBF4.

[0087] In a preferred embodiment, an additive may be added to the electrolyte. Examples of preferred additives, particularly for stabilization, are as follows: Fluorinated vinyl carbonate (FEC), trans-fluoroethylene carbonate (DFEC), vinyl sulfite (ES), vinyl carbonate (VC), bis(2,2,2-trifluoroethyl) ether (BTFE), sodium 2-trifluoromethyl-4,5-dicyanimidazolium (NaTDI), sodium bis(fluorosulfonyl)imide (NaFSI), aluminum chloride (AlCl3), vinyl sulfate (DTD), sodium difluorophosphate (NaPO2F2), sodium difluoro(oxalate)borate (NaODFB), sodium difluorodioxalate phosphate (NaDFOP), and tri(trimethylsilyl)borate (TMSB).

[0088] The negative electrode material of a sodium ion-based energy storage element is preferably at least one of the following materials: - Carbon, particularly hard carbon (pure or with nitrogen and / or phosphorus doping) or soft carbon or graphene-based materials (with N doping); carbon nanotubes, graphite - Phosphorus or sulfur (conversion anode) - Polyanionic compounds: Na₂Ti₃O₇, Na₃Ti₂(PO₄)₃, TiP₂O₇, TiNb₂O₇, Na-Ti-(PO₄)₃, Na-V-(PO₄)₃ - Prussian blue: a sodium-poor variant (for systems with aqueous electrolytes) - Transition metal oxides: V₂O₅, MnO₂, TiO₂, Nb₂O₅, Fe₂O₃, Na₂Ti₃O₇, NaCrTiO₄, Na₄Ti₅O 12 - MXene, where M = Ti, V, Cr, Mo or Nb and A = Al, Si and Ga, and X = C and / or N, such as Ti3C2 - Organic compounds: for example, sodium terephthalate (Na2C8H2O4) Alternatively, a Na metal anode can be used on the anode side.

[0089] The positive electrode material of a sodium ion-based energy storage device is at least one of the following materials: - Polyanionic: NaFePO4 (triphylite type), Na2Fe(P2O7), Na4Fe3(PO4)2(P2O7), Na2FePO4F, Na / Na2[Fe 1 / 2 Mn 1 / 2 ]PO4F, Na3V2(PO4)2F3, Na3V2(PO4)3, Na4(CoMnNi)3(PO4)2P2O7, NaCoPO4, Na2CoPO4F - Silicates: Na₂MnSiO₄, Na₂FeSiO₄ - Layered oxides: NaCoO2, NaFeO2, NaNiO2, NaCrO2, NaVO2, NaTiO2, Na(FeCo)O2, Na(NiFeCo)3O2, Na(NiFeMn)O2, and Na(NiFeCoMn)O2, Na(NiMnCo)O2 Furthermore, the electrodes of the energy storage element according to the invention preferably comprise electrode binders and / or additives to improve conductivity. The active material is preferably embedded in the matrix of the electrode binder, whereby the active material is preferably used in particulate form, and adjacent particles in the matrix are preferably in direct contact with each other. The conductive agent has the function of improving the conductivity of the electrode. Conventional electrode binders are based on, for example, polyvinylidene fluoride (PVDF), sodium polyacrylate, styrene-butadiene rubber, sodium alginate, or carboxymethyl cellulose, or mixtures of different binders. Conventional conductive agents are carbon black, fine graphite, carbon fibers, carbon nanotubes, and metal powders.

[0090] In sodium-ion-based energy storage devices, it is particularly preferred that both the anode current collector and the cathode current collector are made of aluminum or aluminum alloy. The housing, contact plates, and any other current conductors within the housing may also be made of aluminum or aluminum alloy.

[0091] Preferred design of the housing The energy storage element according to the invention is particularly preferred if it has at least one of the following features a to c: a. The central section and the closed section are separated by a recessed section that extends in a ring shape around the outer side of the shell cup.

[0092] b. The shell cup has the same maximum outer diameter in the central section and the closed section.

[0093] c. In the recessed region, the outer diameter of the shell cup is preferably reduced by 4 to 20 times the wall thickness of the shell cup in that region.

[0094] Preferably, at least the preceding features a. and b. are implemented in combination. Particularly preferred is that all three preceding features a. to c. are implemented in combination.

[0095] Preferably, the annular seal is compressed within the closed section. It is preferably pressed radially against the circular edge of the cap.

[0096] Suitable contact metal sheet components and distance compensation metal sheet components The contact metal sheet component suitable for the present invention is preferably characterized by the following features a to f: a. The contact metal sheet component includes a contact area, particularly a disc-shaped contact area, in which a connection is formed with the longitudinal edge of the anode current collector or the longitudinal edge of the cathode current collector.

[0097] b. The contact metal sheet component includes a distance compensation area that rises from the plane of the contact area.

[0098] c. The contact area is formed as a disk and preferably extends substantially in a plane.

[0099] d. The contact area surrounds the distance compensation area.

[0100] e. The distance compensation region includes a central connecting region, the bottom side of which points toward the plane of the contact region, and the top side which faces away from the plane of the contact region.

[0101] f. The top side is flat.

[0102] Particularly preferably, the contact area annularly surrounds the distance compensation area. For example, it can be formed in the shape of an annular disk.

[0103] The distance compensation metal sheet component suitable for the present invention is preferably characterized by the following features a. to f.: a. The distance compensation metal sheet component includes a contact area, particularly an annular contact area, in which a connection is formed with the longitudinal edge of the anode current collector or the longitudinal edge of the cathode current collector.

[0104] b. The distance compensation sheet component includes a distance compensation area that rises from the plane of the contact area.

[0105] c. The contact area is formed as a disk and preferably extends substantially in a plane.

[0106] d. The contact area surrounds the distance compensation area.

[0107] e. The distance compensation region includes a central connecting region, the bottom side of which points toward the plane of the contact region, and the top side which faces away from the plane of the contact region.

[0108] f. The top side is flat.

[0109] Particularly preferred is that the contact area surrounds the distance compensation area in a ring shape. In particular, the distance compensation area is formed as a ring disk.

[0110] Cover assembly according to the present invention The cover assembly according to the invention is characterized by the following features a. to e.: a. The cover assembly includes a metal disc and an electrode cap that are in electrical and direct mechanical contact with each other.

[0111] b. The electrode caps are placed directly on the metal plate.

[0112] c. The electrode cap and metal disk enclose the intermediate space.

[0113] d. The electrode cap includes at least one perforation through which the laser can reach the connection area from outside the housing, and in particular, the laser can reach the connection area from outside the housing.

[0114] e. The cover assembly includes a seal fitted onto its edge.

[0115] Preferred embodiments of contact metal sheet components and distance compensation metal sheet components In principle, the contact metal sheet component can be electrically connected to the anode current collector or the cathode current collector.

[0116] In a particularly preferred embodiment of the invention, the contact metal sheet member electrically connected to the anode current collector is characterized by at least one of the following features a. and b.: a. The contact metal sheet component is made of nickel, or copper, or titanium, or nickel alloy, or copper alloy, or titanium alloy, or stainless steel (e.g., type 1.4303 or type 1.4404 or type SUS304), or nickel-plated copper.

[0117] b. The contact metal sheet component is made of the same material as the anode current collector.

[0118] In another particularly preferred embodiment of the invention, the contact metal sheet member electrically connected to the cathode current collector is characterized by at least one of the following features a. and b.: a. The contact metal sheet component is made of aluminum or an aluminum alloy.

[0119] b. The contact metal sheet component is made of the same material as the cathode current collector.

[0120] The distance compensation metal sheet component is made of the same material as the contact metal sheet component and is welded to the contact metal sheet component.

[0121] The contact metal plate component connected to the anode current collector and / or electrically connected to the cathode current collector is characterized in particular by at least one of the following features a. and b.: a. The contact metal sheet component preferably has a uniform thickness in the range of 50 μm to 600 μm, and more preferably in the range of 150 μm to 350 μm.

[0122] b. The size of the contact metal sheet member is determined such that it covers at least 40%, preferably at least 70%, and particularly preferably at least 80% of the first end face or the second end face.

[0123] It is particularly preferred that features a. and b., which are immediately preceding above, are implemented in combination with each other.

[0124] The distance compensation metal sheet component is preferably made of a metal sheet with a thickness in the range of 50 μm to 1 mm.

[0125] Extensive coverage of the end face is important for thermal management of the energy storage element according to the invention. A larger coverage area makes it more likely to contact the longest possible segment of the first longitudinal edge of the corresponding current collector. Therefore, heat generated in the electrode-diaphragm assembly can be efficiently dissipated via the contact metal sheet members.

[0126] In some embodiments, it has been shown to be advantageous to pretreat the longitudinal edges of the current collector before attaching it to the contact metal sheet component.

[0127] The longitudinal edges of the current collector can also be oriented by means of pretreatment. For example, they can be bent in a defined direction. Alternatively, the longitudinal edges of the current collector can also be deformed in a non-oriented manner, for example, due to pressure contact with the contact metal sheet member.

[0128] Optimal design of current collector and diaphragm The anode current collector, cathode current collector, and one or more separators of the battery cell according to the present invention preferably have the following dimensions: - Length in the range of 0.5 m to 25 m - Width in the range of 40 mm to 145 mm An electrode-diaphragm assembly formed as a wound piece has a strip anode, a strip cathode, and one or more strip diaphragms preferably wound in a helical shape. To manufacture the electrode-diaphragm assembly, the strip electrode and the strip diaphragm(s) are typically fed into a winding apparatus and preferably wound helically around a winding axis. Bonding of the electrode and diaphragm or contact at elevated temperatures is generally unnecessary. In some embodiments, the electrode and one or more diaphragms are wound onto a cylindrical or hollow cylindrical winding core, which rests on a winding mandrel and remains in the wound piece after winding.

[0129] The housing of the wound component can be formed, for example, from a plastic film or tape. The housing of the wound component can also be formed from one or more diaphragm wound components.

[0130] The current collector of the energy storage element according to the invention has the function of electrically contacting the electrochemically active components contained in the corresponding electrode material over the largest possible area. Preferably, the current collector is made of metal, or at least metallized on its surface.

[0131] In the case of energy storage elements formed as lithium-ion battery cells according to the present invention, metals (such as copper or nickel) or other conductive materials, particularly copper and nickel alloys or nickel-coated metals, are suitable for the anode current collector. Materials of type EN CW-004A or EN CW-008A with a copper content of at least 99.9% can be used as copper alloys. Alloys of the NiFe, NiCu, CuNi, NiCr, and NiCrFe types are particularly suitable as nickel alloys. Stainless steel is also suitable in principle, for example, type 1.4303, 1.4404, or SUS304 stainless steel.

[0132] In the case of energy storage elements formed as lithium-ion battery cells according to the present invention, aluminum or other conductive materials (including aluminum alloys) are particularly suitable as metals for cathode current collectors.

[0133] Suitable aluminum alloys for cathode current collectors include, for example, Al alloys of types 1235, 1050, 1060, 1070, 3003, 5052, Mg3, Mg212 (series 3000), and GM55. AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg, and AlMg are also suitable. The aluminum content of these alloys is preferably above 99.5%.

[0134] The anode current collector and / or cathode current collector are preferably strip metal foils with a thickness in the range of 4 μm to 30 μm.

[0135] Besides foil, other strip-shaped substrates (such as metal or metallized nonwovens or open-cell metal foams or porous metals) can also be used as current collectors.

[0136] The current collector is preferably coated with corresponding electrode materials on both sides.

[0137] Preferably, the longitudinal edges of one or more diaphragms form the end face of an electrode-diaphragm assembly, which is formed as a wound element.

[0138] Possible designs for seals Preferably, the energy storage element according to the invention is characterized by at least one of the following features a. and b.: a. The seal is made of a plastic material having a melting point of >200°C, preferably >300°C, particularly preferably >300°C and <350°C.

[0139] b. The plastic material is polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), or polybutylene terephthalate (PBT).

[0140] Preferably, features a. and b. that immediately follow above are implemented in combination.

[0141] According to the method of the present invention.

[0142] The method according to the present invention can be used to manufacture energy storage devices as described above, and is characterized by the following steps: a. Set up a metal shell cup with a circular end opening.

[0143] b. An electrode-diaphragm assembly having anodes / diaphragms / cathodes arranged in sequence, the electrode-diaphragm assembly having a first end face and a second end face.

[0144] c. Apply the contact metal sheet component to one of the end faces.

[0145] d. If necessary, the distance compensation sheet component may be welded to the contact sheet component or fixed to the contact sheet component by forming a material locking or shape locking connection, particularly an adhesive connection, a brazing connection, or a riveting connection.

[0146] e. Insert the electrode-diaphragm assembly into the housing cup.

[0147] f. Seal the circular opening of the shell cup with a lid.

[0148] g. Establishing a connection, particularly a welded connection, between the cover and the contact metal sheet component or between the cover and the distance compensation metal sheet component.

[0149] All components used in this method have been described. Please refer to the corresponding explanations.

[0150] Step c. is preferably performed before step e. However, the contact metal member can also be applied to one of its end faces (the end face facing the opening) after the electrode-diaphragm assembly has been inserted into the housing cup. In both cases, it is preferable to form a connection between the longitudinal edge of the current collector protruding from that end face and the contact metal member after application. For example, welding can be performed using a laser to form a material-locked connection.

[0151] In many cases, after the electrode-diaphragm assembly has been inserted, one of the end faces of the electrode-diaphragm assembly rests directly on the bottom of the housing cup. Typically, it is necessary to connect the current collector edge protruding from this end face to the bottom of the housing. This can be accomplished, for example, by welding through the bottom of the housing using a laser. In other possible embodiments, a suitable contact metal member is applied to this end face prior to step e, such that after insertion, only this contact metal member needs to contact the housing cup or the bottom of the housing cup, for example, via a weld joint. The weld joint between the contact metal member and the bottom can be created, for example, by resistance welding. For this purpose, a welding electrode can be guided through an axial cavity in the winding, and a second welding electrode can be pressed against the bottom from the outside.

[0152] Step d. is necessary if the contact metal sheet component itself does not include a distance compensation area. Step d. can also be performed before or after step e. (i.e., inserting the electrode-diaphragm assembly into the housing cup).

[0153] The circular opening of the housing cup can be closed using a conventional sealing method with a cap. Flange sealing is particularly preferred. In this process, the edge of the housing cup is bent radially inward while the seal is compressed in the manner described above.

[0154] Before or after sealing the housing, a suitable electrolyte-impregnated electrode-diaphragm assembly can be used. In the second variant, the electrolyte must be metered through a suitable orifice in the housing, which is then sealed.

[0155] One of the core aspects of this invention is the creation of a connection, preferably a material-locking connection, and particularly a welded connection, between the cover and the contact metal sheet member or between the cover and the distance-compensating metal sheet member after the housing has been closed. This step eliminates the need for the long protrusion mentioned at the beginning.

[0156] The welded connection between the cover and the contact metal sheet member, or between the cover and the distance compensation metal sheet member, can be made specifically by means of laser welding. For this purpose, a laser beam can be guided through at least one perforation in the aforementioned electrode cap to the connection area of ​​the metal disc of the cover, as has already been described, with the central connection area of ​​the distance compensation metal sheet member or the distance compensation area of ​​the contact metal sheet member resting on the inner side of this connection area.

[0157] In some embodiments, it is particularly preferred to guide two or more welding electrodes through the at least one perforation, these welding electrodes being pressed against the connection area of ​​the metal disc of the cover at a distance from each other. When a voltage is applied between the welding electrodes, the current flowing between the electrodes can flow through the metal disc and cause welding to the distance compensation sheet member or the contact sheet member on its inner side.

[0158] If the aforementioned adhesive or soldering is used instead of welding, step g of the method according to the invention is omitted. Alternatively, in these cases, it is preferable to apply a conductive adhesive or solder to the connection area of ​​the contact metal sheet member or the distance compensation metal sheet member. In a subsequent step, the connection area of ​​the cover or the metal disc of the cap is then pressed onto the connection area of ​​the contact metal sheet member or the distance compensation metal sheet member, or onto the adhesive or liquefied solder applied thereon. This also allows for the establishment of a reliable electrical connection.

[0159] After the battery cell is sealed, a calibration procedure is preferably performed, in which the height of the energy storage element is calibrated. During sealing and calibration, considerable axial forces can act on the housing and the components arranged therein. These can be compensated for by the aforementioned support rings and distance compensation sheet members or contact sheet members. Attached Figure Description

[0160] Further features and advantages of the invention will be apparent from the claims and from the following description of preferred embodiments of the invention taken in conjunction with the accompanying drawings. The features shown may be implemented individually or in combination with other features.

[0161] The attached diagram schematically shows - Figure 1 A cross-sectional view of a first embodiment of an energy storage element according to the present invention is shown, the energy storage element having a cover assembly according to the present invention and a distance compensation sheet member according to the present invention; - Figure 2 A cross-sectional view of a second embodiment of the energy storage element according to the present invention is shown; - Figure 3 A cross-sectional view of a third embodiment of an energy storage element according to the present invention is shown; - Figure 4 A partial cross-sectional view of a first embodiment of an energy storage element according to the present invention is shown; - Figure 5 A preferred embodiment of the cover assembly according to the present invention is shown; - Figure 6 A preferred embodiment of a distance compensation sheet component suitable for an energy storage element according to the present invention is shown; - Figure 7 A preferred embodiment of a contact metal sheet component suitable for an energy storage element according to the present invention is shown; - Figure 8 An electrode-diaphragm assembly and its components, which may be part of an energy storage element according to the present invention, are shown. - Figure 9 A view (cross-sectional view) of the bottom region of the energy storage element according to the present invention is shown; - Figure 10A cross-sectional view of a fourth embodiment of the energy storage element according to the present invention is shown. Detailed Implementation

[0162] Figure 1 The energy storage element 100 shown includes an electrode-diaphragm assembly 104 in the form of a cylindrical wound member having two end faces and a wound member housing between them. A first longitudinal edge 106a of an anode current collector 106 protrudes from an end face 104a. It is not loaded with electrode material and is welded to a contact sheet member 112, which rests on the longitudinal edge 106a and covers the first end face 104a.

[0163] Additionally, the energy storage element 100 includes a hermetically and liquidally sealed housing. This sealed housing comprises a metal housing cup 101 with a circular opening at its end and a cap assembly 102 with a circular edge 102a that closes the circular opening. The cap assembly 102 is formed according to the invention. It includes a metal disk 113 and an electrode cap 117. The bottom side 113b of the metal disk defines the internal space 140 of the housing. The electrode cap rests directly on the metal disk 113 and is in electrical contact with the metal disk, enclosing the intermediate space.

[0164] A distance compensation sheet component 177 is welded to a contact sheet component 112 and includes a distance compensation region 177a, which is connected to a connection region 177b by welding to the inner side 113b of a metal disc 113, which rests directly on the connection region 177b. The distance compensation sheet component 177 is formed according to the invention. The connection region 177b is limited by an annular groove 178. Additionally, the distance compensation sheet component 177 includes an annular contact region 177c. This is welded to the contact sheet component 112 and surrounds the distance compensation region 177a, which extends from the plane of the contact region 177c to the metal disc 113. The metal disc 113 includes a connection region 113a at its center, in which a weld to the connection region 177b is formed. It is formed as a PRV (pressure relief valve) and includes a circular, elongated weakening groove 199 for this purpose.

[0165] The electrode cap 117 includes several perforations, including a hole 117a through which the laser can reach the connection area 113a from the outside of the housing.

[0166] The housing also includes a plastic seal 103 that surrounds the edge 102a of the cover assembly 102 and electrically insulates the metal parts of the cover assembly 102 from the housing cup 101. The plastic seal also helps to seal the housing.

[0167] The energy storage element 100 further includes a support ring 189 that is clamped between the metal disk 113 and the distance compensation sheet member 177. The support ring 189 rests on the contact area 177c of the distance compensation sheet member 177 and presses against the metal disk 113 from below. In this case, the support ring 189 is part of the seal 103.

[0168] The embodiment of the energy storage element 100 according to the present invention shown has various advantages: - The cap assembly 102 according to the invention consists of only three parts: (from outside to inside) electrode cap 117, metal disc 113, and seal 103. Classic cap assemblies with comparable functionality typically include at least four parts. In contrast, the design of cap assembly 102 is simplified.

[0169] - The distance compensation metal sheet component 177 replaces the "protrusion" mentioned at the beginning.

[0170] The resulting simplified structure allows for a welded connection between the distance-compensating sheet member 177 and the metal disk 113 only after the housing has been closed. All that is required is the hole 117a in the electrode cap 117, as shown. Welding can be performed externally using a laser.

[0171] - The energy storage element 100 has two safety functions: a pressure relief valve (PRV) and the aforementioned critical ID (CID). The PRV is implemented by a groove 199. If the pressure inside the housing exceeds a predetermined limit, the metal disc 113 tears along the groove 199.

[0172] - The circular groove in the distance compensation region 177a ensures CID functionality. When the pressure inside the housing increases, the metal disc 113 bulges outward. Due to the welded connection between the metal disc 113 and the distance compensation region 177a, the bulging metal disc applies tension to the distance compensation region 177a. If this force is strong enough, the connection region 177b tears apart from the distance compensation region 177a along the groove 178. This interrupts the direct contact and electrical connection between the metal disc 113 and the distance compensation region 177a, thus leaving a hole in the upper portion of the distance compensation region 177a.

[0173] Another important aspect is the risk that the aforementioned tension could lift the entire distance compensation sheet component 177 along with the metal disc 113, potentially causing CID failure. To avoid this, the seal may include a support ring 189. If the metal disc 113 protrudes outward, the support ring holds the distance compensation sheet component 177 in place and ensures CID functionality.

[0174] Figure 2 The energy storage element 100 shown is Figure 1The only difference in the energy storage element shown is that the support ring 189 is not formed as part of the seal 103.

[0175] Figure 3 The energy storage element 100 shown is Figure 1 The energy storage element shown differs in that the support ring 189 is not formed as part of the seal 103. Another difference is that the edge 177d of the contact area 177c is curved upward at 90°.

[0176] Figure 4 yes Figure 1 The figure shows a partial cross-sectional view of an embodiment of the energy storage element according to the present invention.

[0177] Figure 5 The cover assembly 102 shown includes an electrode cap 117, a metal disc 113, an annular seal 103, and a support ring 116. The metal disc 113 is in direct contact with the electrode cap 117. The annular seal 103 is fitted onto the circular edge of the cover assembly 102. The edge of the cover assembly is further formed by the edge of the metal disc 113, which is folded into a U-shape around the edge of the electrode cap 117.

[0178] The electrode cap 117 has a central hole 117a as a through hole. The center of the metal disk 113 is located below this hole. At the center of the metal disk 113 is a connection region 113a, which is characterized by having a lower material thickness relative to the surrounding region.

[0179] The cover assembly is shown as being in an unassembled state.

[0180] Figure 6 A distance compensation sheet member 177, which can be used in the context of this invention, is shown. It includes an annular contact region 177c, which can be welded to a contact sheet member 112. The contact region 177c surrounds a distance compensation region 177a, which rises from the plane of the contact region 177c. The distance compensation region 177a further includes a circular connecting region 177b and three webs 177g, the circular connecting region being defined by a circular recess 178 and having a flat surface, the three webs connecting the contact region 177c to the connecting region 177b. Three openings 177f are arranged between the webs, these openings being intended for electrolyte passage and for pressure equalization. A recess 177e serves the same purpose.

[0181] Figure 7A contact sheet member 112 is shown that can be used in the context of this invention. This contact sheet member includes a disc-shaped contact region 112c, which is intended to be welded to a longitudinal edge 106a of an anode current collector 106 or a longitudinal edge 109a of a cathode current collector 109. Preferably, the contact region 112c extends substantially in a plane. The contact region 112c surrounds a distance compensation region 112d, which rises from the plane of the contact region 112c. The distance compensation region 112d further includes a circular connecting region 112e and three webs 112f, the circular connecting region having a flat surface, the three webs connecting the contact region 112c to the connecting region 112e.

[0182] The contact area 112c has three weld beads 166 arranged in a star shape. Welding to one of the longitudinal edges can be performed in the area of ​​these weld beads 166.

[0183] Distance compensation in energy storage elements (such as Figures 1 to 4 In energy storage elements (as shown), this is often necessary because individual components (such as the electrode-separator assembly 104) cannot always be manufactured to exactly the same dimensions, for example, at exactly the same height. Instead, process-related variations occur, and these variations must be compensated for. The contact metal sheet member 112 shown enables tolerance compensation in the axial direction within the battery cell, while contacting the electrode-separator assembly or the longitudinal edge protruding from the assembly at the end face. In the illustrated embodiment, the distance compensation region 112d can act as a spring that presses downward against the electrode-separator assembly and upward against the cover. This spring effect can have a particularly compensating effect during the aforementioned calibration.

[0184] Figure 8 The diagram illustrates the structure of an electrode-diaphragm assembly 104, which can be part of an energy storage element according to the present invention. Assembly 104 includes a strip anode 105 having a strip anode current collector 106 having a first longitudinal edge 106a and a second longitudinal edge parallel thereto. The anode current collector 106 is a foil made of copper or nickel. The anode current collector includes a strip-shaped main region loaded with a layer of negative electrode material 107, and free edge strips 106b extending along its first longitudinal edge 106a without electrode material 107 loaded. Additionally, assembly 104 includes a strip cathode 108 having a strip-shaped cathode current collector 109 having a first longitudinal edge 109a and a second longitudinal edge parallel thereto. The cathode current collector 109 is an aluminum foil. The cathode current collector includes a strip-shaped main region loaded with a layer of positive electrode material 110, and free edge strips 109b extending along its first longitudinal edge 109a without electrode material 110 loaded. The two electrodes are shown separately in their unwound state.

[0185] The anode 105 and cathode 108 are offset from each other within the electrode-diaphragm assembly 104, such that the first longitudinal edge 106a of the anode current collector 106 protrudes from the first end face 104a, and the first longitudinal edge 109a of the cathode current collector 109 protrudes from the second end face 104b of the electrode-diaphragm assembly 104. The offset arrangement is shown in the lower left figure. Two strip-shaped diaphragms 156 and 157 are also shown there, which separate the electrodes 105 and 108 from each other within the winding.

[0186] The lower right illustration shows an electrode-diaphragm assembly 104 in a wound form, as this electrode-diaphragm assembly can be used according to... Figures 1 to 4 In one of the energy storage elements. The electrode edges 106a and 109a protruding from the end faces 104a and 104b are clearly visible. The winding housing 104c is formed of a plastic film.

[0187] Figure 9 The bottom region of a preferred embodiment of the energy storage element 100 according to the invention is shown. An electrode-diaphragm assembly 104 is arranged in a housing cup 101. A contact sheet member 132 rests on the bottom 101a of the housing cup. The bottom side of the contact sheet member is preferably connected to the bottom 101a by welding. Welding can be achieved by means of a laser passing through the bottom 101a. Alternatively, for example, at least one welding electrode may also be guided through an axial cavity 150 at the center of the electrode-diaphragm assembly 104. A counter electrode may also be pressed against the outside of the bottom 101a. The top side of the contact sheet member 132 is in direct contact with the longitudinal edge 109a of the cathode current collector. Preferably, the longitudinal edge 109a and the contact sheet member 132 are also connected to each other by welding.

[0188] Contact sheet component 132 is shown separately. Like contact sheet component 112, this contact sheet component has weld beads to improve contact with the longitudinal edge 109a. Slit-shaped perforations are used for degassing and for better electrolyte distribution.

[0189] Figure 10 The embodiments of the energy storage element according to the present invention shown are... Figures 1 to 4 The energy storage element shown differs in that the contact metal sheet member 112 includes a distance compensation region 112d, which is connected to the inside of the metal disk 113 in the connection region 112e. Therefore, the embodiment shown here does not include a distance compensation metal sheet member welded to the contact metal sheet member. The contact metal sheet member itself performs the function of the distance compensation metal sheet member. This has significant advantages. The electrical contact of the electrode-diaphragm assembly is achieved from the electrode cap via only two metal parts (i.e., the metal disk 113 and the contact metal sheet member 112), which can be used as a contact post for bridging the voltage of the energy storage element.

[0190] The contact metal sheet member 112 rests on the upper end face of the electrode-diaphragm assembly 104, which is formed as a wound member, and is ideally connected by welding to a current collector protruding from this end face. The contact metal sheet member 112 is used in conjunction with... Figure 7 The contact metal sheet component shown is formed in the same or similar manner. The contact area 112c surrounds the distance compensation area 112d, which protrudes upward in a dome shape from the plane of the contact area 112c and extends to the metal disk 113 or the connection area 113a of the metal disk 113. The distance compensation area 112d includes the connection area 112e therein. Therefore, the contact metal sheet component preferably includes two areas (contact area 112c and connection area 112e) in different planes, which are axially spaced from each other.

[0191] The metal disk 113 and the contact metal sheet component 112 are welded together in connection areas 112e and 113a. Similar to the case of energy storage elements, grooves 199 and 178 ensure PRV and CID functionality. The CID function is supported by a support ring 189. This support ring rests on the contact area 112c and is positioned between the contact area and the edge region of the metal disk 113. When the center of the metal disk 113 bulges upward due to pressure, the contact area 112c is secured to the end face of the winding 104 by the support ring and cannot be lifted. This ensures that when sufficient pressure is applied, the connection area 112e can break, thereby interrupting the flow of current.

[0192] It is worth noting that the battery cell shown has a housing cup 101, which increases in thickness within the enclosed section. Below the transition section 101e, the housing cup is formed to be thinner than above. This is because, depending on the enclosing technology, in some cases, higher mechanical strength is required in the enclosed section than in the central section. This allows for material savings in the housing material.

[0193] It is also worth mentioning that it is advantageous if at least the metal disc 113, and possibly the contact metal sheet member 112, has holes in its respective connection areas through which pressure equalization can occur between the interior of the housing and the housing environment. This can be helpful when welding connections are made between the connection areas. The one or more holes can be closed after the welding connection has been made or during the formation of the welding connection.

Claims

1. An energy storage element (100), said energy storage element having the following characteristics: a. The energy storage element includes an electrode-diaphragm assembly (104) having an anode (105) / diaphragm (156) / cathode (108) arranged in sequence. b. The electrode-diaphragm assembly (104) is in the form of a cylindrical wound member having a first end face (104a) and a second end face (104b) and a wound member housing (104c) therebetween. c. The anode (105) of the electrode-diaphragm assembly (104) includes an anode current collector (106) having a first longitudinal edge (106a) and a second longitudinal edge parallel to the first longitudinal edge, a main region loaded with a negative electrode material layer (107), and a free edge strip extending along its first longitudinal edge (106a) without the negative electrode material loaded. d. The cathode (108) of the electrode-diaphragm assembly (104) includes a cathode current collector (109) having a first longitudinal edge (109a) and a second longitudinal edge parallel to the first longitudinal edge, a main region loaded with a positive electrode material layer (110), and a free edge strip extending along its first longitudinal edge (109a) without being loaded with the positive electrode material. e. The anode (105) and the cathode (108) are arranged within the electrode-diaphragm assembly (104) in such a manner that the first longitudinal edge (106a) of the anode current collector (106) protrudes from the first end face (104a), and the first longitudinal edge (109a) of the cathode current collector (109) protrudes from the second end face (104b) of the electrode-diaphragm assembly (104). f. The energy storage element includes a contact metal sheet member (112) that rests on the first longitudinal edge (106a) of the anode current collector (106) and covers the first end face (104a), or the contact metal sheet member rests on the first longitudinal edge (109a) of the cathode current collector (109) and covers the second end face (104b), and is connected to the second end face. g. The energy storage element includes a gas-tight and liquid-tight sealed housing, comprising a metal housing cup (101) with a circular opening at the end and a cap (102) with a circular edge (102a), the cap closing the circular opening and enclosing an internal space, wherein the electrode-diaphragm assembly (104) is arranged in the internal space. h. The cover (102) includes a metal disc (113) with a circular edge, wherein, The metal disk (113) has an inner side that defines the internal space. Its features are, i. The contact metal sheet member (112) includes a distance compensation region (112d) connected to the inner side of the metal disk (113) in the connection region (112e), or the distance compensation metal sheet member (177) is welded to the contact metal sheet member (112), the distance compensation metal sheet member (177) including a distance compensation region (177a) connected to the inner side of the metal disk (113).

2. The energy storage element (100) according to claim 1, having at least one of the following additional features: a. The cover (102) is a cover assembly, which, in addition to the metal disk (113), also includes an electrode cap (117) that is in electrical contact with the metal disk (113). b. The electrode cap (117) rests directly on the metal disk (113). c. The electrode cap (117) and the metal disk (113) enclose the intermediate space. d. The metal disk (113) includes a connection region (113a) in which a connection is formed with the connection region (112e) or the connection region (177b). e. The electrode cap (117) includes at least one perforation (117a) through which the connection area (113a) can be accessed from outside the housing, and in particular, the laser can access the connection area from outside the housing.

3. The energy storage element (100) according to claim 1 or claim 2, having at least one of the following additional features: a. The contact metal sheet component (112) includes a contact area (112c), particularly a disc-shaped contact area, wherein the longitudinal edge (106a) of the anode current collector (106) or the longitudinal edge (109a) of the cathode current collector (109) is welded or connected to the contact area via a material locking connection or a shape locking connection. b. The contact area (112c) surrounds the distance compensation area (112d), which extends from the plane of the contact area (112c) to the metal disk (113).

4. The energy storage element (100) according to claim 1 or claim 2, having at least one of the following additional features: a. The distance compensation metal sheet component (177) includes a contact area (177c), particularly an annular disc-shaped contact area (177c), which is connected to the contact metal sheet component (112) by welding or by means of alternative material locking connection or shape locking connection. b. The contact area (177c) surrounds the distance compensation area (177a), which extends from the plane of the contact area (177c) to the metal disk (113).

5. The energy storage element (100) according to any one of the preceding claims has at least one of the following additional features: a. The metal disc (113) is formed as a PRV (pressure relief valve) and includes elongated weakening grooves (199) for this purpose. b. In the connection region (113a), the metal disk (113) is characterized in that the material thickness is lower than the material thickness in the region surrounding the connection region (113a).

6. The energy storage element (100) according to any one of the preceding claims has at least one of the following additional features: a. The housing includes a seal (103) made of plastic material, the seal surrounding the edge (102a) of the cover (102) and disposed between the cover (102) and the housing cup (101). b. The energy storage element includes a support ring (189) made of plastic material, which is arranged, in particular, between the metal disk (113) and the distance compensation metal sheet member (177) or between the metal disk (113) and the contact metal sheet member (112). c. The support ring (189) rests on the contact area (112c) of the contact metal sheet member (112) or on the contact area (177c) of the interval compensation metal sheet member (177). d. The support ring (189) is part of the seal (103).

7. The energy storage element (100) according to at least one of the preceding claims has at least one of the following additional features: a. The shell cup (101) comprises, in axial order, a bottom (101a), a central section (101b), and a closed section (101c), wherein, - The central section (101b) is cylindrical in shape, and within the central section (101b), the winding shell (104c) of the electrode-diaphragm assembly (104), designed as a winding, contacts the inner side of the housing cup (101), and - In the closed section (101c), the annular seal (103) presses into contact with the edge of the cover (102) and the inner side of the housing cup (101), and b. The housing cup (101) has an opening edge (101d) in the closed section (101c) that defines the circular opening, the opening edge being radially inwardly curved on the edge of the cover (102) surrounded by the seal (103), and the opening edge securing the cover (102) including the seal (103) in the circular opening of the housing cup (101) in a shape-locking manner.

8. A cover assembly (102) having the following features: a. The cover assembly includes a metal disc (113) and an electrode cap (117) that are in electrical contact with each other and in direct mechanical contact with each other. b. The electrode cap (117) rests directly on the metal disk (113). c. The electrode cap (117) and the metal disk (113) enclose the intermediate space. d. The electrode cap (117) includes at least one perforation (117a) through which the connection area (113a) can be accessed from outside the housing, and in particular, the laser can access the connection area from outside the housing. e. The cover assembly includes a seal (103) fitted onto its edge.

9. A method for manufacturing an energy storage element (100) according to any one of claims 1 to 7, comprising the following steps: a. Provide a metal shell cup (101) with a circular opening at the end. b. Provide an electrode-diaphragm assembly (104) having an anode (105) / diaphragm (156) / cathode (108) arranged in sequence, the electrode-diaphragm assembly having a first end face (104a) and a second end face (104b). c. Apply the contact metal sheet component (112) to one of the end faces. d. If necessary, the distance compensation sheet component (177) may be welded to the contact sheet component or secured to the contact sheet component by forming an alternative material locking connection or shape locking connection. e. Insert the electrode-diaphragm assembly (104) into the housing cup (101), f. The circular opening of the shell cup (101) is closed by means of the lid (102). g. Establishing a connection, particularly a welded connection, between the cover (102) and the contact metal sheet member (112) or between the cover (102) and the distance compensation metal sheet member (177).

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