Energy storage elements and batteries

Abstract

The secondary energy storage element (100) includes a cathode (108) and an anode (105) as electrodes, which are part of an assembly (104), in which (108) and (105) are separated by a separator or solid electrolyte layer (116) in the order of (108) / separator or solid electrolyte layer (116) / (105); (108) is a cathode current collector (109) and positive current (105) comprises an electrode material (110); (105) comprises an anode current collector (106) and a negative electrode material (107); (109) has a main region on which layers of positive electrode material (110) are placed on both sides, and a free edge strip (109b) extending along the edge (109a) of (109) and on which the positive electrode material (110) is not placed, and / or (106) has a main region on which layers of negative electrode material (107) are placed on both sides, (100) has a free edge strip (106b) that extends along the edge (106a) of (106) and on which (107) is not placed; (108) and (105) are formed and / or arranged relative to each other within (104) such that (109b) of (109) protrudes from one side (104b) of (104) and / or (106b) of (106) protrudes from the other side (104a) of (104); the secondary energy storage element includes a first contact metal sheet (112) in direct contact with (106b) and / or a second contact metal sheet (101a) in direct contact with (109b); (105, 108) contains at least one ion from the group consisting of sodium, potassium, calcium, magnesium, and aluminum ions, which are exchanged between (108) and (105) during charging and discharging of (100).

Description

[Technical Field]

[0001] The present invention relates to an energy storage element suitable for supplying extremely high currents, and to a method for manufacturing such an energy storage element. [Background technology]

[0002] Electrochemical energy storage elements can convert stored chemical energy into electrical energy through oxidation-reduction reactions. One of the simplest forms of electrochemical energy storage elements is the electrochemical cell. An electrochemical cell includes a positive electrode and a negative electrode, which are separated from each other, for example, by a separator. During discharge, electrons are released at the negative electrode as a result of the oxidation process. This generates an electron current. This electron current can be drawn out by an external power consumer, with the electrochemical cell acting as an energy source. Simultaneously, an ionic current corresponding to the electrode reaction is generated within the cell. This ionic current crosses the separator and is usually made possible by an ion-conducting electrolyte.

[0003] If the discharge is reversible, that is, if it is possible to recharge the cell by reversing the conversion from chemical energy to electrical energy that occurred during discharge, the cell is called a secondary cell. In secondary batteries, the common terms "anode" for the negative electrode and "cathode" for the positive electrode refer to the discharge function of the electrochemical cell.

[0004] Secondary lithium-ion cells are used today as energy storage elements in many applications because they can supply high currents and are characterized by relatively high energy density. Secondary lithium-ion cells are based on the use of lithium, which can reciprocate between the electrodes of the cell in the form of ions. The negative and positive electrodes of a lithium-ion cell are generally formed by so-called composite electrodes, which contain electrochemically inert components in addition to 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 secondary lithium-ion cell. For the negative electrode, carbon-based particles such as graphite carbon are used, for example. Lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), or their derivatives can be used as the active material for the positive electrode. Electrochemically active materials are generally contained within the electrode in the form of particles.

[0006] As an electrochemically inert component, the composite electrode generally includes a current collector in the shape of a flat and / or ribbon, such as a metal foil, which functions as a carrier for the respective active material. The current collector for the negative electrode (anode current collector) can be made of, for example, copper or nickel, and the current collector for the positive electrode (cathode current collector) can be made of, for example, aluminum. Furthermore, as an electrochemically inert component, the electrode may also include an electrode binder (e.g., polyvinylidene fluoride (PVDF) or other polymers such as carboxymethylcellulose), conductivity-enhancing additives, and other additives. The electrode binder ensures the mechanical stability of the electrode and often ensures the adhesion of the active material to the current collector.

[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., an ether or ester of a carboxylic acid).

[0008] During the manufacturing of lithium-ion cells, composite electrodes are combined with one or more separators to form an assembly. The electrodes and separators are typically combined under pressure, and possibly also by lamination or bonding. The basic function of the cell can be established by impregnating the assembly with an electrolyte.

[0009] In many embodiments, the assembly is formed in the form of a wound body or is fabricated into a wound body. Alternatively, the assembly may be a stack of electrodes.

[0010] Similar to lithium-ion cells, sodium ion cells can be manufactured using the alkali metal sodium in the form of sodium ions, potassium ion cells using the alkali metal potassium in the form of potassium ions, calcium ion cells using the alkaline earth metal calcium in the form of calcium ions, magnesium ion cells using the alkaline earth metal magnesium in the form of magnesium ions, and aluminum ion cells using aluminum in the form of aluminum ions. The structure of composite electrodes and their further processing can generally be adopted in a 1:1 ratio for cells having these alternative cell chemical materials. Thereafter, current collector materials, electrode materials, electrolytes, and separators adapted to each cell chemical material are used.

[0011] Sodium ion cells, in particular, have reached a practically mature stage. Unlike lithium-ion technology, the production of sodium ion cells is not limited by scarce resources. However, sodium ion cells have a lower average energy density than lithium-ion cells.

[0012] Due to their high energy density, lithium-ion cells are particularly suitable as a power source for electric motors in the automotive sector, but they are also suitable for electric motorcycles and other applications requiring high energy, such as power tools. This requires lithium-ion cells optimized to withstand high currents during charging and discharging.

[0013] Traditionally, electrodes are in contact by a winding assembly, particularly via metal strips (tabs), which are connected to a current collector by welding, as shown in Figures 1 and 2 of US2005 / 0277019A1, and protrude from the end face of the winding assembly. This can be detrimental when high currents are generated. Both the tabs and the electrochemically active components of conventional lithium-ion cells have limited high current capacities, particularly in the charging direction and at low temperatures (<10°C). Both electrical and thermal gradients are generated. Mechanically, the winding assembly can be obstructed by the tabs, leading to undesirable pressure conditions.

[0014] Cylindrical lithium-ion cells are known from WO2017 / 215900A1, in which the assembly is formed from ribbon-shaped electrodes and exists in the form of a wound body. Each electrode has a current collector on which the electrode material is mounted. Oppositely polarized electrodes are arranged offset from each other in the assembly such that the longitudinal edge of the current collector of the positive electrode protrudes from one side of the wound body, and the longitudinal edge of the current collector of the negative electrode protrudes from the other side of the wound body. For electrical contact with the current collector, the cell has a contact plate instead of a tab, and the contact plate rests on the end face of the wound body and is connected to the longitudinal edge of the current collector by welding. This allows for electrical contact with the current collector and, therefore, with the associated electrode along its entire length. This significantly reduces the internal resistance in the cell described above. As a result, larger currents can be absorbed better, and heat can be dissipated more efficiently from the wound body.

[0015] Similar cell designs can be seen in EP3916841A1, EP3916828A1, EP3916827A1, EP3916829A1, EP3916870A1, EP3916869A1, EP3916877A1, EP3965196A1, and EP3916868A1.

[0016] Lithium-ion cells have not yet been established in the market as starting batteries for automobiles with combustion engines or for some other specific applications. Lead-acid batteries, in which the electrodes are made of lead or lead dioxide and the electrolyte is dilute sulfuric acid, are still mainly used in these applications. Lead-acid batteries can supply high currents in a short period of time and can exhibit sufficient performance even at low temperatures. In addition, lead-acid batteries can be manufactured relatively inexpensively.

[0017] However, due to environmental reasons, alternatives are urgently needed because lead is extremely toxic. Although there are efficient deposit systems for batteries in many countries, the release of lead during the mining of lead ore and its subsequent processing, as well as during the recycling of lead, can sometimes be difficult to avoid. Summary of the Invention Problems to be Solved by the Invention

[0018] An object of the present invention is to provide an energy storage element that is not inferior to the performance of a lead-acid battery at low temperatures, is less expensive than a lithium-ion cell, can absorb a high current during charging, and can carry a high current during discharging. Means for Solving the Problems

[0019] The object of the present invention is achieved by an energy storage element having the features of independent claim 1. A battery having the features of claim 13 also contributes to the solution of the problems of the present invention. Preferred embodiments of the present invention are defined in the dependent claims.

[0020] Energy storage element according to the present invention The energy storage element according to the present invention has the following features (a) to (g). (a) The secondary energy storage element includes a cathode and an anode as electrodes, which are part of an assembly, and in the assembly, the cathode and the anode are separated by a separator or a solid electrolyte layer in the order of cathode / separator or solid electrolyte layer / anode. (b) The cathode includes a cathode current collector and a positive electrode material, (c) The anode includes an anode current collector and a negative electrode material, (d) The cathode current collector has - a main region with layers of the positive electrode material placed on both sides, and - a free edge strip that extends along the edge of the cathode current collector and on which no positive electrode material is placed or, and / or The anode current collector has - a main region with layers of the negative electrode material placed on both sides, and - a free edge strip that extends along the edge of the anode current collector and on which no negative electrode material is placed and (e) The cathode and the anode are formed and / or arranged relative to each other within the assembly such that the free edge strip of the cathode current collector protrudes from one side of the assembly and / or the free edge strip of the anode current collector protrudes from the other side of the assembly, (f) The secondary energy storage element includes a first contact metal sheet that contacts directly with one free edge strip and / or a second contact metal sheet that contacts directly with the other free edge strip, (g) The electrodes contain at least one kind of ion from the group consisting of sodium ions, potassium ions, calcium ions, magnesium ions, and aluminum ions, and these are exchanged between the cathode and the anode during charging and discharging of the secondary energy storage element.

[0021] Therefore, in its simplest embodiment, the energy storage element according to the present invention is a sodium ion cell, a potassium ion cell, a calcium ion cell, a magnesium ion cell, or an aluminum ion cell. Among these variations, in the present invention, an energy storage element having a sodium ion cell chemistry is particularly preferred.

[0022] When extremely high currents and / or low temperatures are present, it is essential to minimize electrical, thermal, and ionic gradients across all electrochemically active components of the cell. Avoiding ohmic losses plays a critical role. Minimizing gradients as much as possible across the entire assembly, including the electrolyte space, is crucial for service life and current capacity.

[0023] The first and / or second contact metal sheets ensure uniform electrical and thermal connections of the assembly electrodes throughout the entire length of the wound assembly, thus leading to improved performance and increased service life. The contact metal sheets eliminate the need for tabs for electrode contact. Consequently, no mechanical failures that could lead to problems under thermomechanical stress occur within the wound assembly.

[0024] Remarkably, the design of the energy storage element according to the present invention has been found to enable particularly efficient connection of electrodes in assemblies, especially for sodium ion systems (and also for other next-generation lithium systems, such as the aforementioned systems based on sodium, potassium, calcium, magnesium, and aluminum ions). Thus, high-performance sodium ion materials can be charged and discharged at rates up to 100C. In addition, sodium ion systems, in particular, can also be designed to be resistant to deep discharge.

[0025] Energy storage element with wound assembly The energy storage element assembly according to the present invention can be formed as a wound body or a laminate of electrodes. The wound body embodiment has the following features (a) to (e). (a) The electrodes and current collector, as well as the layer made from the electrode material, are in the shape of a ribbon. (b) The secondary energy storage element includes at least one ribbon-shaped separator or at least one ribbon-shaped solid electrolyte layer, (c) The assembly is in the form of a wound body in which electrodes and at least one separator are wound around a winding axis, the assembly includes first and second end faces and a wound body shell, the free edge strip of the cathode current collector protruding from the first end face and / or the free edge strip of the anode current collector protruding from the second end face (d) The secondary energy storage element includes a housing, particularly a metal housing, the housing includes a housing shell or sidewalls, and the housing includes a bottom and a lid on its end faces, (e) Within the housing, the assembly formed as a winding is aligned such that the winding shell leans against the inside of the housing shell or side wall.

[0026] The ribbon-shaped separator forms a separator layer within the assembly.

[0027] In this embodiment, the assembly preferably has one or two ribbon-shaped separators, each of which has a first and a second longitudinal edge and two ends.

[0028] The windings and housing are particularly preferably cylindrical. The housing preferably has a housing shell that extends circumferentially, and a circular bottom and lid. In a cylindrical housing, the assembly formed as a cylindrical winding is preferably aligned axially.

[0029] The electrodes and at least one separator are preferably wound in a spiral pattern around a winding axis.

[0030] Symmetrical and asymmetrical winding contact The coiled assembly can be in contact in both symmetrical and asymmetrical manner.

[0031] Symmetrical contact means the following: - The cathode and anode of the energy storage element are formed and / or arranged within the assembly such that the free edge strip of the cathode current collector protrudes from one end face of the assembly, and the free edge strip of the anode current collector protrudes from the other end face, - The energy storage element includes a first contact metal sheet that is in direct contact with one side of the free edge strip, and a second contact metal sheet that is in direct contact with the other side of the free edge strip. Therefore, the two electrodes are in contact with the two end surfaces of the winding body via a contact metal sheet.

[0032] Asymmetrical contact means the following: - The cathode and anode of the energy storage element are connected to the free-edge strip of the cathode current collector. or Free edge strip of anode current collector Either Only is formed and / or positioned within the assembly such that it protrudes from one of the end faces of the assembly, and - The energy storage element includes only one contact metal sheet that is in direct contact with the free edge strip of the cathode current collector or the free edge strip of the anode current collector protruding from the assembly. In this embodiment, only one electrode is in contact with one of the two end faces of the assembly via a contact metal sheet. Preferably, at least one metal conductor strip (tab) is fixed to the current collector of the other electrode, protruding from the other end face of the assembly.

[0033] In the case of asymmetric contact, the energy storage element according to the present invention has one of the features (a) to (c) below. (a) At least one metal conductor strip is welded to a lid or a metal pole penetrating the lid, while a free-edge strip protruding from one end face is welded to the bottom of the housing or to a metal sheet resting directly on the bottom of the housing (modification A), (b) At least one metal conductor strip is welded to the bottom, while a free edge strip protruding from one end face is welded to the lid or a pole penetrating the lid (modification B), or (c) At least one metal conductor strip is welded to the bottom, while a free edge strip protruding from one end face is welded to a pole penetrating the lid, or to a metal sheet resting on the free edge strip and electrically coupled to the lid or pole (modification C).

[0034] In modification B, the bottom of the housing acts as a contact metal sheet, which is particularly advantageous because, in this embodiment, optimal heat dissipation of the electrodes coupled via the free-edge strip can be achieved.

[0035] It is particularly advantageous if the anode current collector is directly connected to the bottom according to Modification B, while the cathode current collector is connected via a tab. Using a conductive strip on the end face of the winding facing the lid, along with simultaneous connection of the anodes, ideally through the entire longitudinal edge of the current collector, can provide capacitive advantages, which are particularly beneficial in energy-optimized cells. At the same time, favorable effects are obtained from good anode connection, thus resulting in improved performance and service life of the cell according to the present invention. In particular, electrically and thermally uniform connection of the anodes is advantageous for improved fast charging capacity. In this context, it should be noted that sodium ion electrolytes generally have higher conductivity than lithium electrolytes and are therefore advantageous in terms of thick or high-load electrodes, fast charging (>2C), and performance at low temperatures (<0°C).

[0036] A more preferred embodiment of an energy storage element having a wound assembly In an energy storage element having a wound assembly, the contact metal sheet is preferably laid flat on one or two end faces such that the free edge strip is in contact with the contact metal sheet over its entire length. However, in practice, this is often not achievable.

[0037] An energy storage element having a wound assembly according to the present invention is particularly preferably having the feature (a) described below. (a) A metal housing includes a housing portion formed in the shape of a cup-shaped cylinder, the housing portion having end openings, particularly a circular end opening, and a lid that closes the end opening of the cup-shaped housing portion.

[0038] In many preferred embodiments, the lid comprises multiple components. For example, the lid may include a burst membrane and / or have a CID (current interruption device) function.

[0039] The lid is preferably positioned in the circular opening of the cup-shaped housing such that it has a circular perimeter and its edge leans against the inside of the cup-shaped housing along the surrounding contact area, where the edge of the lid is connected to the cup-shaped housing by a surrounding welded seam. In this case, the two housings preferably have the same polarity and are therefore electrically connected to either the positive or negative electrode. In this case, the housing also includes a pole bushing for electrically contacting an electrode that is not electrically connected to the housing.

[0040] In another embodiment, an electrically insulating seal is fixed to the edge of the lid, electrically isolating the lid from the cup-shaped housing. In this case, the housing is typically sealed by a crimp closure.

[0041] The height of the energy storage element, formed as a cylindrical round cell, is preferably in the range of 50 to 150 mm. The diameter of the cylindrical round cell is preferably in the range of 15 to 100 mm.

[0042] In an embodiment of the present invention in which the energy storage element is a cylindrical round cell, the anode current collector, cathode current collector, and separator(s), or solid electrolyte layer, preferably have the following dimensions. - Lengths ranging from 0.3 to 25 meters - Width in the range of 30 to 145 mm In this embodiment, the contact metal sheet has a basic circular shape.

[0043] Prismatic embodiment In the prismatic embodiment, the energy storage element according to the present invention has the features (a) to (c) described below, and is particularly preferably characterized by (a) to (d). (a) The assembly is in the form of a prismatic laminate in which cathodes and anodes are stacked together with further cathodes and anodes, (b) The electrodes and current collectors, and the layers made from the electrode material, are polygonal, particularly rectangular. (c) The secondary energy storage element includes at least one ribbon-shaped or polygonal, particularly rectangular, separator, or at least one ribbon-shaped or polygonal, particularly rectangular, solid electrolyte. (d) A prism-shaped stack is surrounded by a prism-shaped housing. In a laminate, adjacent electrodes with opposite poles are always separated from each other by a separator or solid electrolyte layer.

[0044] A prismatic housing is preferably comprised of a cup-shaped housing portion having an end opening and a lid. In this embodiment, the bottom of the cup-shaped housing portion and the lid preferably have a polygonal, and more preferably rectangular, bottom surface. The shape of the end opening of the cup-shaped housing portion corresponds to the shape of the bottom and the lid. In addition, the housing includes a plurality, particularly four, rectangular side portions, which connect the bottom and the lid to each other.

[0045] The prismatic cell can also be configured as a so-called pouch cell. Instead of a metal housing, a composite film is used, which is formed into the appropriate shape by deep drawing. The current collector is guided outward through an area where the composite film is thermally welded / sealed.

[0046] The separator layer can be formed by multiple separators, each positioned between adjacent electrodes. However, ribbon-shaped separators can also separate the electrodes of the laminate from each other. When there are multiple separators between the anode and cathode, the separators also preferably have polygonal, particularly rectangular, bases.

[0047] In this embodiment, the contact metal sheet preferably has a rectangular shape.

[0048] In some preferred modifications of the prismatic embodiment, the energy storage element according to the present invention has at least one of the features (a) and (b) immediately below. (a) The free edge strip of the cathode current collector of the laminate's cathode protrudes from one side of the laminate and is in direct contact with the first contact metal sheet. (b) The free edge strip of the anode current collector of the anode of the laminate protrudes from the other side of the laminate and is in direct contact with the second contact metal sheet. Preferably, the features of (a) and (b) above are implemented in combination with each other.

[0049] In a more preferred modification of the prismatic embodiment, the energy storage element according to the present invention has at least one of the features (a) and (b) described below. (a) The free edge strips of the cathode current collector are arranged parallel to each other. (b) The free edge strips of the anode current collector are arranged parallel to each other. The features described in (a) and (b) above are preferably realized in combination with each other.

[0050] Preferred electrochemical embodiment and electrolyte In a more particularly preferred embodiment of the present invention, the energy storage element according to the present invention is characterized by one of the features immediately below. (a) The secondary energy storage element is a sodium ion cell. (b) The secondary energy storage element includes a sodium ion cell. (c) The secondary energy storage element includes one of the following electrolytes: - NaClO4 dissolved in at least one organic solvent, particularly PC, or a carbonate mixture from the group consisting of EC / DEC / FEC and PC / FEC. The concentration of NaClO4 in the electrolyte is preferably 0.3 to 5 M, and particularly preferably 0.7 to 1.7 M. In a mixture of EC / DEC / FEC, the three components are contained in the electrolyte in a volume ratio preferably in the range of 1:2 to 2:1, and particularly preferably 1:1:0.5. In the case of a mixture containing EC / DEC, the components are preferably present in the electrolyte in a volume ratio of 1:2 to 2:1. - NaPF6 and / or NaTFSI dissolved in at least one organic solvent, particularly PC, or a carbonate mixture from the group consisting of EC / DEC / FEC, EC / PC, EC / DEC, FEC / EMC and PC / FEC, or an ether mixture such as THF / mTHF. The concentration of NaPF6 and / or NaTFSI in the electrolyte is preferably 0.3 to 5 M, and particularly preferably 0.7 to 1.7 M. In the EC / PC mixture, the two components are preferably present in the electrolyte in a volume ratio of 1:2 to 2:1. In the EC / DEC mixture, the two components are preferably present in the electrolyte in a volume ratio of 1:2 to 2:1. In a mixture of FEC / EMC, the two components are contained in the electrolyte in a volume ratio preferably in the range of 1:2 to 2:1, and particularly preferably in a ratio of 3:7. If necessary, the electrolyte can contain up to 10% FEC. - NaFSI and / or NaTFSI and / or NaTDI dissolved in at least one organic solvent, particularly 1,4-dioxane (DX) and / or 1,3-dioxolane (DOL) and / or dimethyl ether (DME). The concentration of NaFSI and / or NaTFSI and / or NaTDI in the electrolyte is preferably 0.3 to 5 M, and particularly preferably 0.7 to 1.7 M. - NaFSI and / or NaTFSI and / or NaTDI dissolved in at least one organic solvent, particularly dimethyl carbonate (DMC) and / or tris(2,2,2-trifluoroethyl) phosphate (TFP). The concentration of NaFSI and / or NaTFSI and / or NaTDI in the electrolyte is preferably 0.5 to 2.5 M, and particularly preferably 1 to 2 M. In the EC / PC mixture, the components are preferably contained in the electrolyte in a volume ratio of 1:2 to 2:1. The liquid components are contained in the electrolyte in a volume ratio preferably in the range of 1:2 to 2:1. - NaN(SO2F)2 dissolved in at least one organic solvent, particularly 1,4-dioxane (DX) and / or 1,3-dioxolane (DOL) and / or dimethyl ether (DME). The concentration of NaN(SO2F)2 in the electrolyte is preferably 0.3 to 5 M, and particularly preferably 0.7 to 1.7 M. In a DX / DOL mixture, the components are preferably contained in the electrolyte in a volume ratio of 1:2 to 2:1. - NaBF4 dissolved in at least one organic solvent, particularly tetraethylene glycol dimethyl ether (TEGDME) and / or ACN and / or PC and / or GBL. The concentration of NaBF4 in the electrolyte is preferably 0.3 to 5 M, and particularly preferably 0.7 to 1.7 M. Electrolytes containing NaBF4 within TEGDME are particularly suitable for cells having a sodium metal anode (see below).

[0051] It is particularly preferable to combine the features of (a) and (c), as well as (b) and (c), with each other.

[0052] The feature of (a) is particularly relevant to an embodiment of the energy storage element according to the present invention described as a cylindrical round cell. In this embodiment, the energy storage element preferably comprises just one electrochemical cell.

[0053] The feature of (b) is particularly relevant to the prismatic embodiment of the energy storage element according to the present invention described above. In this embodiment, the energy storage element may also include a plurality of electrochemical cells.

[0054] Preferably, the energy storage element according to the present invention, based on sodium ions, further comprises an electrolyte containing at least one of the following solvents and at least one of the following conductive salts.

[0055] The preferred solvents are as follows: - Carbonates: Propylene carbonate (PC), ethylene carbonate-propylene carbonate (EC-PC), propylene carbonate-dimethyl carbonate-ethylmethyl carbonate (PC-DMC-EMC), ethylene carbonate-diethyl carbonate (EC-DEC), ethylene carbonate-dimethyl carbonate (EC-DMC), ethylene carbonate-ethylmethyl carbonate (EC-EMC), ethylene carbonate-dimethyl carbonate-ethylmethyl carbonate (EC-DMC-EMC), ethylene carbonate-dimethyl carbonate-diethyl carbonate (EC-DMC-DEC) - Ethers: Tetrahydrofuran (THF), 2-methyltetrahydrofuran, dimethyl ether (DME), 1,4-dioxane (DX), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), tetraethylene glycol dimethyl ether (TEGDME) - Nitriles: Acetonitrile (ACN), Adiponitrile (AON), γ-Butyrolactone (GBL) Trimethyl phosphate (TMP) and tris(2,2,2-trifluoroethyl) phosphate (TFP) are also possible alternatives.

[0056] The preferred conductive salts are as follows: NaPF6, sodium difluoro(oxalato)borate (NaBOB), NaBF4, sodium bis(fluorosulfonyl)imide (NaFSI), sodium 2-trifluoromethyl-4,5-dicyanoimidazole (NaTDI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), NaAsF6, NaBF4, NaClO4, NaB(C2O4)2, NaP(C6H4O2)3, NaCF3SO3, sodium triflate (NaTf), Et4NBF4

[0057] Similar to solvents, conductive salts can also be used as a mixture of two or more primary salts.

[0058] In a preferred embodiment, additives may also be added to the electrolyte. Examples of preferred additives, particularly stabilizers, are as follows: Fluoroethylene carbonate (FEC), trans-difluoroethylene carbonate (DFEC), ethylene sulfite (ES), vinyl carbonate (VC), bis(2,2,2-trifluoroethyl) ether (BTFE), sodium 2-trifluoromethyl-4,5-dicyanoimidazole (NaTDI), sodium bis(fluorosulfonyl)imide (NaFSI), aluminum chloride (AlCl3), ethylene sulfate (DTD), sodium difluorophosphate (NaPO2F2), sodium difluoro(oxalato)borate (NaODFB), sodium difluorobisoxalatophosphate (NaDFOP), tris(trimethylsilyl) borate (TMSB)

[0059] Instead of the liquid electrolyte having the conductive salt described above, an ionic liquid can also be used, for example, 0.8 mol / l of sodium bis(fluorosulfonyl)imide (Na-TFSI) in 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PMPyrr-TFSI).

[0060] Sodium polymer electrolytes are another alternative, such as polyethylene oxide (PEO), or polymer electrolytes based on polyvinylidene difluoride hexafluoropropylene, such as P(EO)8NaCF3SO3 or hydroxyethylcellulose polyethylene oxide.

[0061] Instead of liquid electrolytes based on organic solvents, OH - NO3 - ,Cl - and SO4 2- Aqueous sodium electrolytes having anions from the group containing the following can also be used for specific purposes, as can aqueous solutions of NaFSI, NaTDI, or NaTFSI.

[0062] Preferred mechanism for electrode material The negative electrode material for the energy storage element according to the present invention, which is based on sodium ions, is preferably at least one of the following materials. - Carbon, especially hard carbon (pure or doped with nitrogen and / or phosphorus), or soft carbon, or graphene-based materials (doped with nitrogen); carbon nanotubes, graphite - Phosphorus or sulfur (exchange anode) - Polyanions: Na2Ti3O7, Na3Ti2(PO4)3, TiP2O7, TiNb2O7, Na-Ti-(PO4)3, Na-V-(PO4)3, Na-M-PO4-P2O7 (where M is V, Ti, Fe, Co, Ni, Mn), or mixtures of 3d transition metals and doping elements such as Al, Cu, Zn. - Na4M3(PO4)2(P2O7) (where M is Na, Zn, Al, Mg, or Ca) - Sn(Na 15 Sn-based or Sb-based materials such as Sn4, Sb(Na3Sb), SnO2, Sb2O3, etc. - Prussian blue: Low sodium type (for aqueous electrolyte systems) - Transition metal oxides: V2O5, MnO2, TiO2, Nb2O5, Fe2O3, Na2Ti3O7, NaCrTiO4, Na4Ti5O 12 - MAXenes (where M is Ti, V, Cr, Mo, or Nb, A is Al, Si, Ga, X is C and / or N, e.g., Ti3C2) - Organics: e.g., sodium terephthalate (Na2C8H2O4)

[0063] An exemplary overview of suitable anode materials can be found in Table 2 on page 19 of the 2019 paper "SODIUM-ION BATTERY ANODES: STATUS AND FUTURE TRENDS" by Zhang et al. (EnergyChem 1, 100012 (2019)).

[0064] Alternatively, a sodium metal anode may be used on the anode side. The metallic sodium is preferably embedded in a porous and electrically conductive matrix structure having good sodium wettability. In this context, minimizing electrical, thermal, and mechanical gradients is extremely important, and these can be achieved in the cells of the present invention by a design characterized by contact on the surface side of the electrode winding body.

[0065] The positive electrode material of the sodium-ion-based energy storage element according to the present invention is preferably at least one of the following materials. - Polyanions: 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 - Prussian blue / white: Prussian blue (PB) is A x Fe[Fe(CN)6] 1-y *In the form of nH2O (where A is an alkali metal, 0 < x < 2, y < 1), Prussian white (Na~2) exists in the forms of Na2Fe[Fe(CN)6], KFe2(CN)6, MnFe(CN)6, Fe2(CN)6. - Layered oxides: NaCoO2, NaFeO2, NaNiO2, NaCrO2, NaVO2, NaTiO2, Na(FeCo)O2, Na(NiFeCo)3O2, Na(NiFeMn)O2, Na(NiFeCoMn)O2, Na(NiMnCo)O2 The above-mentioned positive electrode materials can also be used in combination.

[0066] In addition, the electrodes of the energy storage element according to the present invention preferably contain an electrode binder and / or an additive for improving electrical conductivity. The active material is preferably embedded in the matrix of the electrode binder. The active material is preferably used in the form of particles, 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. Conventional electrode binders are based on, for example, polyvinylidene fluoride (PVDF), (sodium) polyacrylate, styrene-butadiene rubber, (sodium) alginate, carboxymethyl cellulose, or mixtures of various binders. Conventional conductive agents are carbon black, fine graphite, carbon fiber, carbon nanotubes, metal powders.

[0067] The following combinations of materials are particularly preferred for sodium-ion energy storage elements. - Positive electrode: Na3V2(PO4)3 Negative electrode: Hard carbon Electrolyte: Preferably NaPF6 in EC:PC:DMC (45:45:10 vol.%) - Positive electrode: Na 2 / 3 (Ni 1 / 3 Mn 2 / 3 )O2 Negative electrode: Hard carbon - Positive electrode: Na2Fe[Fe(CN)6] Negative electrode: Hard carbon Electrolyte: Preferably NaPF6 in EC:PC

[0068] Ion deposition The function of sodium, potassium, calcium, magnesium, or aluminum ion cells is based on the availability of sufficient mobile ions (e.g., mobile sodium ions in the case of a sodium ion cell) to balance the electrical current drawn by migration between the anode and cathode, or between the negative and positive electrodes. In the context of this application, mobile ions are understood to mean that ions are available for or can be activated for the process of storage and extraction within the electrodes during the discharge and charging processes of the energy storage element according to the present invention. For example, during the discharge and charging process of a sodium ion cell, loss of mobile sodium occurs over time. These losses result in various, generally unavoidable, side reactions. Loss of mobile sodium has already occurred during the first charge and discharge cycle of the sodium ion cell. During this first charge and discharge cycle, a cover layer is generally formed on the surface of the electrochemically active components at the negative electrode. This cover layer is referred to as the solid electrolyte interface (SEI) and generally consists mainly of electrolyte decomposition products and a specific amount of sodium firmly bound to this layer.

[0069] To compensate for these losses, the sodium ion-based energy storage element according to the present invention is characterized in a preferred embodiment by at least one of the features (a) and (b) below. (a) The energy storage element includes a deposit of sodium or sodium-containing material that is not surrounded by a positive electrode and / or a negative electrode, thereby compensating for the loss of moving sodium during operation. (b) The deposit is in contact with the electrolyte of the energy storage element. The features (a) and (b) immediately above are particularly preferable to be realized in combination with each other.

[0070] Particularly suitable sodium-containing materials include, for example, Na3N, Na2C2O4, Na2S, Na2C4O4, Na2C6O6, EDTA-4Na, DPTA-5Na, Na3P, or C 12 This is H9Na (sodium biphenyl). These materials can be added, for example, to electrode active materials. Additional Na sources lead to higher capacity or longer cycle life.

[0071] It is also conceivable that the electrodes could be pre-filled with excess sodium ions.

[0072] The same applies to embodiments of the energy storage element according to the present invention based on potassium, calcium, magnesium, or aluminum ions.

[0073] Preferred Embodiment of Sodium Metal Anode As described above, sodium metal anodes can also be used on the anode side, where metallic sodium is preferably embedded in an electrically conductive matrix structure.

[0074] In further embodiments, the energy storage element according to the present invention is preferably characterized by at least one of the following features: (a) The anode comprises a matrix having depressions and / or pores in which metallic sodium is stored; (b) The matrix is ​​attached to the surface of the anode current collector; (c) The matrix comprises carbon particles and a binder; (d) The matrix comprises a conductive agent and / or a filler; (e) The matrix is ​​the roughened surface of the anode current collector. It is particularly preferable that the features (a) to (d) above, or the features of (a) and (d), be realized in combination with each other.

[0075] The carbon particles, conductive agent, or filler may be, for example, hard carbon, activated carbon, conductive graphite, carbon black, carbon nanotubes, graphene, graphene oxide, or finely dispersed metals such as Ag, Cu, Al, Ni, or Pt. For example, the carbon particles may contain 20-80% by weight of hard carbon, 80-20% by weight of carbon black, and 0-10% by weight of silver, with the silver preferably added in an amount such that the weight percentage of the constituent elements is 100% by weight.

[0076] The binder can be any binder that is also suitable for the manufacture of composite electrodes for lithium-ion batteries. Suitable examples include polyvinylidene fluoride (PVDF), or other polymers such as carboxymethylcellulose or its derivatives.

[0077] The carbon-based matrix may contain doping elements such as boron, oxygen, fluorine, or nitrogen.

[0078] The carbon-based matrix is ​​preferably 500 nm to 250 μm thick.

[0079] The surface of the anode current collector can be roughened, for example, by laser treatment.

[0080] Furthermore, it is preferable that the energy storage element according to the present invention be characterized by at least one of the following features. (a) The anode includes a nucleation layer in which metallic sodium is stored and / or deposited, in particular, instead of a matrix; (b) The nucleation layer is essentially made of at least one material from the group consisting of tin, silver, gold, germanium, carbon, platinum, zinc, aluminum, magnesium, and silicon; (c) The nucleation layer is deposited on the surface of the anode current collector by PVD (physical vapor deposition) or CVD (chemical vapor deposition).

[0081] Nucleation layers made of tin, silver, gold, germanium, and / or carbon facilitate sodium deposition. Carbon, silver, gold, platinum, zinc, aluminum, magnesium, tin, and silicon reduce overpotential.

[0082] The nucleation layer may also contain doping elements such as boron, oxygen, fluorine, or nitrogen.

[0083] The nucleation layer is preferably 100 nm to 50 μm thick.

[0084] The matrix and / or nucleation layer preferably accounts for less than 30% by weight, preferably less than 5% by weight, of the dry weight of the negative electrode.

[0085] To create an electrode with a matrix or nucleation layer, it is best to use an anode current collector that has a matrix or nucleation layer but no metallic sodium. Sodium is best deposited in and / or on the matrix or nucleation layer during the initial charging process. The required sodium is best supplied via the cathode. For example, Na3V2(PO4)3 can be used as the positive electrode material for this purpose. Alternatively, sodium deposition can also be carried out by pre-sodiumification. This treatment prevents dendritic growth. Furthermore, this treatment ensures that no undesirable excess sodium is generated in the electrode.

[0086] To prevent excessive pressure from being built up within the housing of the energy storage element according to the present invention, it may be useful to provide a degassing option during the initial charging process.

[0087] The ratio of the anode capacitance to the cathode capacitance is particularly preferably in the range of 0.7 to 1.2.

[0088] The energy storage element according to the present invention is particularly preferable to have the following characteristics. The nucleation layer and / or matrix is particularly preferably covered by a cover layer. (a) The negative electrode includes a layer sequence of a metallic current collector / matrix or a nucleation layer / cover layer; (b) The matrix or nucleation layer is disposed between the cover layer and the current collector; (c) The cover layer has a thickness in the range of 300 nm to 30 μm; (d) The cover layer is formed from a ceramic material or includes a ceramic material; (e) The ceramic material is preferably aluminum oxide (Al2O3), aluminum hydroxide or aluminum oxyhydroxide (AlOOH), silicon oxide (SiO x , provided that 1 < x ≦ 2), titanium oxide (TiO2), titanium nitride (TiN), titanium aluminum nitride (TiAlN), or titanium carbonitride (TiCN).

[0089] In a further possible preferred embodiment, the cover layer has the chemical formula Na 1+x Zr2Si x P 3-x O 12 (0 < x < 3) and is formed from a superionic conductor or includes such an ionic conductor.

[0090] In a further possible preferred embodiment, the cover layer is formed from a polymer, particularly polysiloxane, polyethylene oxide, perfluoropolyether or polyacrylonitrile, or includes such a polymer.

[0091] When the cover layer includes a ceramic material, in a preferred embodiment, the cover layer further includes a binder. This binder can basically be a binder that is also suitable as a binder for active materials, such as carboxymethyl cellulose for example.

[0092] Preferred Embodiments of Separator and Solid Electrolyte Layer The separator(s) are preferably formed from an electrically insulating plastic film. The separator(s) are preferably permeable to an electrolyte. For this purpose, the plastic film used has, for example, micropores. The film may be, for example, made of polyolefin or polyetherketone. Nonwoven fabrics and textiles made of plastic material, or other electrically insulating flat structures, can also be used as separators. The separator(s) preferably have a thickness in the range of 5 μm to 50 μm.

[0093] Separators made from cellulose-based materials can also be used. These exhibit good wettability and stability at high temperatures.

[0094] In particular, in the prismatic embodiment of the energy storage element, the separator(s) of the assembly may also be one or more layers of solid electrolyte.

[0095] Solid electrolytes can be polymer solid electrolytes based on polymer conductive salt complexes existing in a single phase that contains no liquid components whatsoever. As a polymer matrix, polymer solid electrolytes can include, for example, polyacrylic acid (PAA), polyethylene glycol (PEG), or polymethyl methacrylate (PMMA), particularly polyethylene oxide (PEO). In the case of sodium ion cells, sodium conductive salts such as sodium bis(trifluoromethane)sulfonylimide (NaTFSI), sodium hexafluorophosphate (NaPF6), and sodium tetrafluoroborate (NaBF4) can be present in a dissolved form.

[0096] Ceramic reinforcement of separators Other preferred designs for the separator can be appropriately adapted to individual cases. The energy storage element according to the present invention is preferably further characterized by at least one of the features (a) and (b) immediately below. (a) In the case of an energy storage element having a wound assembly, the side of the assembly from which the free edge strip of the cathode current collector or the free edge strip of the anode current collector protrudes, particularly at the longitudinal edge of the separator, is formed by the edge of the separator. (b) The aforementioned sides of the assembly, particularly the edges or longitudinal edges of the separators forming the end faces, are reinforced with ceramic.

[0097] In a more preferred embodiment, the energy storage element according to the present invention has the following feature (a). (a) The ceramic reinforcement is carried out by at least one particulate ceramic material, in particular at least one particulate ceramic filler material, within the separator.

[0098] Therefore, the separator can preferably be an electrically insulating plastic film embedded with particulate filler material. The plastic film can preferably be impregnated with an electrolyte, for example, because the plastic film has micropores. The film can be made of, for example, polyolefin or polyetherketone. As described above, nonwoven or woven fabrics made from such plastic materials can also be used. These can also be used as appropriate in individual cases.

[0099] The proportion of particulate filler material in the separator is preferably at least 40% by weight, and particularly preferably at least 60% by weight.

[0100] In a more preferred embodiment, the energy storage element according to the present invention has the following feature (a). (a) The ceramic reinforcement is provided by at least one particulate ceramic material that is present as a coating on the surface of the separator(s).

[0101] Therefore, the separator may preferably be a plastic film, nonwoven fabric, woven fabric, or any other electrically insulating sheet material coated with a ceramic material.

[0102] In some embodiments, only one side of a flat structure, particularly a plastic film, is coated with the ceramic material. In further embodiments, the flat structure, particularly a plastic film, is preferably coated on both sides with the ceramic material.

[0103] If necessary, the separator used may also preferably include the same or a different ceramic material as the coating, as well as the ceramic material as the filler.

[0104] In a further possible preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) to (e) described below. (a) At least one ceramic material / filler is or includes an electrical insulating material. (b) At least one ceramic material / filler is or includes at least one material from the group including glass-ceramic materials and glass. (c) At least one ceramic material / filler is, for example, Na5AlO4 * Na4SiO4, NaAlSi2O6, β-Al2O3, or Na3Zr2Si2PO 12 It is a sodium ion conductive ceramic material such as NASICON material, or contains the same. (d) At least one ceramic material / filler is or comprises an oxide material, in particular a metal oxide. (e) Ceramic material or oxide material is aluminum oxide (Al2O3), silicon oxide (SiO2O3) x ), particularly silicon dioxide (SiO2), titanium oxide (TiO2), titanium nitride (TiN), titanium aluminum nitride (TiAlN), or titanium carbonitride (TiCN). It is particularly preferable that the features of (a) to (c) above, or the features of (a), (b), and (d) above, or the features of (a), (b), and (e) above, be realized in combination with each other.

[0105] Among the materials mentioned above, aluminum oxide (Al2O3), aluminum hydroxide (Al(OH)3), aluminum hydroxide oxide (AlOOH), titanium oxide (TiO2), and silicon dioxide (SiO2) are particularly preferred as coating materials.

[0106] In a further possible preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) and (b) described below. (a) The separator(s)(single or multiple) include at least one ceramic material in only a portion of the region. (b) The separator(s)(single or more) have edge strips along the edges forming the first side, particularly along the first end faces, and the separator(s) include at least one ceramic material as a coating and / or particulate filler. The features (a) and (b) immediately above are particularly preferable to be realized in combination with each other.

[0107] It is not necessarily required that the separator contains ceramic material in a uniform distribution or that its entire surface be uniformly coated with ceramic material. Rather, it is preferable that the separator does not have ceramic material in certain regions, such as the main region mentioned above. In this region, the increase in the heat resistance of the separator is not as necessary as the heat resistance at the edges of the separator. Furthermore, the ceramic material can contribute to an undesirable increase in the internal resistance of the energy storage element according to the present invention, particularly in this region.

[0108] However, in many embodiments, the separator is preferably reinforced or coated with a ceramic material over its entire surface, i.e., between the anode and the cathode.

[0109] The front region of the electrode that is not coated with the active material may be coated entirely or partially with a ceramic material to reduce the risk of short circuits.

[0110] Further details on the coating of separators with ceramic materials can be found in WO2021 / 255238A1.

[0111] Preferred embodiment of a current collector The current collector of the electrode of the energy storage element according to the present invention has the function of making electrical contact with the electrochemically active components contained in each electrode material over the largest possible area. Preferably, the current collector is made of metal or at least its surface is metallized.

[0112] In particular, in the case of the energy storage element according to the present invention based on sodium ions, aluminum or aluminum alloys are suitable as metallic materials for both the anode current collector and the cathode current collector. Sodium ion systems having current collectors made of aluminum or aluminum alloy on both the anode and cathode sides have been proven to be particularly resistant to the effects of deep discharge.

[0113] Suitable aluminum alloys for cathode current collectors include, for example, Al alloys of types 1235, 1050, 1060, 1070, 3003, and 5052, Mg3, Mg212 (3000 series), and GM55. AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, Al-CuTiMg, and AlMg are also suitable. The aluminum content of these alloys should preferably be 99.5% or more.

[0114] The anode current collector and / or cathode current collector is preferably a ribbon-shaped metal foil having a thickness in the range of 4 μm to 30 μm.

[0115] However, in addition to metal foil, other ribbon-shaped substrates such as metal nonwoven fabrics or metallized nonwoven fabrics, open-cell metal foam, or expanded metal can also be used as current collectors.

[0116] It is preferable that current collectors be placed on both sides of each electrode material.

[0117] Reinforcement of the edges of the current collector The energy storage element according to the present invention is preferably further characterized by at least one of the features (a) to (c) below. (a) In the free edge strip of the cathode current collector and / or the free edge strip of the anode current collector, the surface of the cathode current collector and / or the surface of the anode current collector are coated with a support material having higher heat resistance than the surface to be coated. (b) The nonmetallic material is a ceramic material, a glass-ceramic material, or glass. (c) The ceramic material is aluminum oxide (Al2O3), aluminum hydroxide (Al(OH)3), aluminum hydroxide oxide (AlOOH), titanium oxide (TiO2), titanium nitride (TiN), titanium aluminum nitride (TiAlN), or titanium carbonitride (TiCN).

[0118] "Heat resistance" means that the support material remains in a solid state even at the temperature at which the coated surface melts. Therefore, the support material has a higher melting point than the coated surface, or sublimes or decomposes only at the temperature at which the coated surface has already melted.

[0119] Preferably, both the free-edge strip of the cathode current collector and the free-edge strip of the anode current collector are coated with a support material. It is particularly preferable to use the same support material in each case.

[0120] The contact metal sheet that is in direct contact with the free edge strip is preferably connected to the edge strip by melting. This can lead to problems such as unintended pressing down or melting of the edge strip of the current collector. The support material counteracts these problems. The support material physically supports the edge strip of the current collector and prevents melting of the edge, especially when both sides of the edge strip are coated with the support material. Furthermore, the support material also prevents short circuits caused by melting of the separator of the assembly described above. The support material electrically insulates the free region covered by the support material. Therefore, in a preferred embodiment, the support material is formed as an electrical insulator.

[0121] Further details regarding suitable support materials can be found in WO2020 / 239512A1.

[0122] In a particularly preferred embodiment, the support material covers not only the edge strip or a portion thereof of the anode current collector, but also the electrode material disposed in the anode current collector within the main region. Thus, the support material layer can also function as a cover layer covering, for example, the matrix or nucleation layer described above. This embodiment is preferred when the support material is one of the ceramic materials described above.

[0123] The support material layer may also include a binder, for example, that binds the ceramic particles of the support material layer together.

[0124] Preferred embodiment of the assembly To prevent direct contact between oppositely polarized electrodes at the axial ends of the winding or laminate, it is preferable to use a separator that is slightly wider than the separated electrodes. Therefore, in an energy storage element having a winding assembly, the assembly terminates at its axial end, in a preferred embodiment, at a projection of the separator forming the end.

[0125] In the prismatic configuration described above, it is preferable that the edges of the separator(s) form the side of the laminate from which the free edge strip of the current collector protrudes.

[0126] It is particularly preferable that the free edge strip of the current collector protruding from the end surface of the winding or the side of the laminate does not protrude by more than 5500 μm, preferably more than 4000 μm, from the end surface of the winding or the side of the laminate.

[0127] It is particularly preferable that the free edge strip of the anode current collector does not protrude more than 3000 μm, and especially more preferably more than 2000 μm, from the end surface of the winding or the side of the laminate. It is particularly preferable that the free edge strip of the cathode current collector does not protrude more than 4000 μm, and especially more preferably more than 3000 μm, from the end surface of the winding or the side of the laminate.

[0128] In a wound assembly, ribbon-shaped anodes, ribbon-shaped cathodes, and ribbon-shaped separators (one or more) are preferably wound in a spiral. To manufacture the assembly, the ribbon-shaped electrodes, preferably together with ribbon-shaped separators, are supplied to a winding device and wound in a spiral around a winding axis inside. In some embodiments, the electrodes and separators (one or more) are wound on a cylindrical or hollow cylindrical winding core for this purpose, the winding core is placed on a winding mandrel and remains in the wound body after winding.

[0129] The wound shell can be formed from, for example, a plastic film or adhesive tape. The wound shell can also be formed from wound bodies of one or more separators.

[0130] Preferred Embodiments of the First and / or Second Contact Metal Sheet The contact metal sheets(s) are preferably connected to each current collector, and the contact metal sheets(s) are in direct contact with each current connector by welding. It is particularly preferable that the contact metal sheets(s) are directly connected to the free edge strip of the anode current collector by welding.

[0131] In a preferred embodiment, the contact metal sheets are made of the same material as the current collectors to which they are connected by welding.

[0132] In a particularly preferred embodiment, the contact metal sheet is made of aluminum or an aluminum alloy, especially in the case of a sodium ion-based energy storage element according to the present invention.

[0133] The same alloy mentioned in connection with the current collector made of aluminum alloy is suitable as the aluminum alloy.

[0134] In other preferred embodiments, the contact metal sheet is made of, for example, nickel, copper, titanium, an alloy of nickel, copper, or titanium, or stainless steel.

[0135] In a more particularly preferred embodiment of the present invention, the first contact metal sheet has at least one of the features (a) to (g) described below. (a) The contact metal sheet has a preferably uniform thickness in the range of 50 μm to 600 μm, preferably in the range of 150 μm to 350 μm. (b) The contact metal sheet has two opposite flat surfaces and extends in essentially only one dimension. (c) The contact metal sheet is a disc or preferably a rectangular plate. (d) The dimensions of the contact metal sheet are determined such that they cover at least 60%, preferably at least 70%, and particularly preferably at least 80% of the side or end face from which the free edge strip of each current collector connected to the contact metal sheet appears. (e) The contact metal sheet has at least one opening, in particular at least one hole and / or at least one groove. (f) The contact metal sheet has at least one bead, which appears as an elongated recess on one flat surface of the contact metal sheet and as an elongated ridge on the opposite flat surface, and the contact metal sheet rests on the free edge strip of each current collector with the flat surface having the elongated ridge. (g) The contact metal sheet is welded to the free edge strip of the current collector in the area of ​​the bead, particularly through one or more weld seams and / or weld points located within the bead. It is particularly preferable that the features (a), (b), and (d) described above be realized in combination with each other. 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 preferable that all features (a) through (g) be realized in combination with each other.

[0136] Covering the end surface as broadly as possible is important for the thermal management of the energy storage element according to the present invention. The larger the cover, the easier it is to make contact with the first edge of the current collector and its entire length. Thus, the heat generated within the assembly can be efficiently dissipated through the contact metal sheet.

[0137] It is particularly advantageous that the contact metal sheet is in direct contact with all the windings of the winding body, that is, with both the innermost and outermost windings of the winding body.

[0138] At least one opening in the contact metal sheet can be useful, for example, to allow the assembly to permeate into the electrolyte.

[0139] Electrical connection of contact metal sheets The contact metal sheet is - Electrically connected to the housing, or - Connected to a connecting pole guided through the housing and electrically isolated from the housing, or - The contact metal sheet is part of the housing, for example, the bottom of a cup-shaped housing portion or a lid for such cup-shaped housing portion.

[0140] Electrical contact to the housing or connecting pole can be achieved, in particular, by welding or physical connection. If necessary, electrical connections can also be made via separate electrical conductors.

[0141] For optimal connection of one or more contact metal sheets to the current collector, it is preferable to subject the side or end surfaces to physical pretreatment. For example, the edge of the current collector protruding from the end surface of the electrode winding can be deformed to create a suitable receiver for the bulge of the contact metal sheet having at least one bead, as described above.

[0142] Preferred embodiment of the housing Regardless of its shape (i.e., prismatic or cylindrical), the housing of the energy storage element according to the present invention is preferably a metal housing. The housing is particularly preferably a cup-shaped housing portion and a lid.

[0143] In a preferred embodiment of the present invention, the energy storage element according to the present invention has at least one of the features (a) and (b) described below. (a) The cup-shaped housing portion is made of aluminum, aluminum alloy, nickel, copper, stainless steel, or nickel-plated steel. (b) The lid shall be made of aluminum, aluminum alloy, nickel, copper, stainless steel, or nickel-plated steel. The features described in (a) and (b) above are particularly preferable when combined.

[0144] In some embodiments, it is desirable to connect the free edge strip of one current collector directly to the housing. For this purpose, the free edge strip of this current collector can be welded, for example, by laser to the bottom of the cup-shaped housing portion. In this case, the bottom serves as a contact plate.

[0145] Conversely, in some embodiments, the contact plate may be provided to function as part of a lid, i.e., a housing.

[0146] In particular, in the case of a sodium ion cell, in a particularly preferred embodiment, both the cup-shaped housing and the lid can be made of aluminum or an aluminum alloy.

[0147] Suitable aluminum alloys for cup-shaped housings include, for example, Al alloys of types 1235, 1050, 1060, 1070, 3003, and 5052, Mg3, Mg212 (3000 series), and GM55. AlSi, AlCuTi, AlMgSi, AlSiMg, AlSiCu, AlCuTiMg, and AlMg are also suitable. The aluminum content of these alloys should preferably be 99.5% or more.

[0148] In some embodiments, the bottom of the cup-shaped housing is fixed by welding; that is, the bottom is manufactured separately and welded to the side wall(s). However, in many cases, the cup-shaped housing is manufactured by deep drawing.

[0149] Preferred nominal capacity of energy storage elements The nominal capacity of the energy storage element according to the present invention is preferably up to 10,000 mAh when designed as a cylindrical round cell. When having a 21 × 70 form factor, the energy storage element in the embodiment as a sodium ion cell preferably has a nominal capacity in the range of 1,000 mAh to 5,000 mAh.

[0150] Insulation of the internal conductor In a particularly preferred embodiment, the energy storage element according to the present invention has the following features (a) to (g). (a) The secondary energy storage element includes an airtight and liquidtight housing, the housing having a metal cup-shaped housing portion with a bottom and a circular opening at the end, and a lid with a circular rim, the lid closing the circular opening at the end; (b) The assembly is axially aligned within the cup-shaped housing, with the first end face facing toward the lid and the second end face facing toward the bottom and optionally in direct contact with the bottom; (c) The secondary energy storage element includes an annular sealing portion made of an electrically insulating material, the annular sealing portion surrounding the circular rim of the lid, electrically insulating the cup-shaped housing portion and the lid from each other; (d) The cup-shaped housing portion includes an inner and outer part, and is continuous in the axial direction, and includes a bottom portion, a central portion, and a closing portion. - The central part is cylindrical, and in the central part, the winding shell of the assembly, which is formed as a wound body, is in contact with the inside of the cup-shaped housing part. - In the closed section, the annular sealing portion is in pressure contact with the inside of the lid and cup-shaped housing portion; (e) The central part and the closing part are separated by a recess, which surrounds the outside of the cup-shaped housing part in a circumferential direction; (f) A contact metal sheet is electrically connected by welding to a free edge strip of the current collector protruding from the first end surface, and preferably electrically connected by welding to the cover; (g) The secondary energy storage element includes at least one insulating element made of an electrical insulating material, the insulating element insulating the contact metal sheet and / or the free edge strip of the current collector protruding from the end face and / or a separate electrical conductor fixed to the contact metal sheet from direct contact with the inside of the cup-shaped housing, particularly in the recessed area.

[0151] This means ensures that the risk of short circuits in the internal contact areas of the cell is reduced. For example, axial forces generated in relation to height calibration no longer cause direct contact between cell components that are generally polarized in the opposite direction. These are prevented by at least one insulating element.

[0152] In a more preferred first evolution of this preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) to (c) below. (a) At least one insulating element is or includes an insulating tape, which is applied to an edge defining the end surface and protects the edge from direct contact with the inside. (b) At least one insulating element is made of plastic and preferably is an annularly molded part having an L-shaped cross-section, the annularly molded part is applied to an edge defining the end surface and protects the edge from direct contact with the inside. (c) The insulating tape or ring-shaped component made of plastic has a thickness in the range of 10 μm to 200 μm. The features of (a) and (c) above, as well as the features of (b) and (c), are preferably realized in combination.

[0153] The insulating tape can be, for example, a Kapton / polyimide adhesive tape.

[0154] The annularly molded plastic part preferably has an L-shaped cross-section and can be manufactured, for example, by injection molding and pressed into the edge to be protected. The annularly molded part may be made of, for example, Teflon® or polyamide.

[0155] In a more preferred second evolution of this preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) to (c) below. (a) At least one contact element is or includes an annular insulating element made of plastic, the annular insulating element leaning in a cup shape in the recessed area, protecting the inside of the housing from direct contact with the contact metal sheet. (b) The annular insulating element is part of the annular sealing portion. (c) The annular insulating element made of plastic has a thickness ranging from 20 μm to 400 μm. The features of (a) and (b) immediately above are preferably realized in combination. The features of (a) to (c) are particularly preferably realized in combination.

[0156] The annular insulating element, like the annular sealing portion, can also be a molded part. The thickness of the insulating element is preferably in the range of 20 μm to 400 μm.

[0157] The cyclic insulating element may consist of, for example, Teflon®, polyamide, polybutylene terephthalate, or a perfluoroalkoxy polymer.

[0158] In a more preferred third evolution of this preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) to (d) below. (a) At least one insulating element is or includes an annular plastic portion, the annular plastic portion surrounding the contact metal sheet and protecting the contact metal sheet from direct contact with the inside of the cup-shaped housing portion in the recessed area. (b) The annular plastic portion is hollow cylindrical, includes a jacket, and is bounded at the end surface by a surrounding edge. (c) The annular plastic portion is hollow cylindrical, includes a jacket, and is bounded at its end surface by a surrounding edge, one of which is formed as an outward-facing annular collar and rests on a contact metal sheet. (d) The annular plastic portion has a thickness ranging from 20 μm to 600 μm. The features of (a) and (b) immediately above are more preferably realized by a combination of features of (a), (b), and (d). The features of (a), (c), and (d) immediately above are more preferably realized by a combination.

[0159] The annular plastic portion can also be a molded part. The thickness of the plastic portion is preferably in the range of 20 μm to 600 μm.

[0160] The plastic parts can be made from, for example, Teflon®, polyamide, polybutylene terephthalate, or perfluoroalkoxy polymers.

[0161] In a further preferred fourth evolution of this preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) and (b) immediately below. (a) At least one insulating element is or includes an electrically insulating plastic coating, the plastic coating surrounding the edge of the contact metal sheet, protecting the edge from direct contact with the inside of the cup-shaped housing portion, particularly in the recessed area. (b) An electrically insulating plastic coating is formed by overmolding the edges of the contact metal sheet. The features of (a) and (b) immediately above are preferably realized in combination.

[0162] In principle, all thermoplastics with electrical insulating properties are suitable for overmolding the edges of contact metal sheets. For example, polyamide is suitable.

[0163] The present invention also includes combinations of the four particularly preferred developments described above. The energy storage element is particularly preferably a combination of two or more of the four features (a) to (d) described below. (a) At least one insulating element includes an annular molded portion made of insulating tape or plastic, the insulating tape or annular molded portion being applied to an edge defining the end surface and protecting the edge from direct contact with the inside. That is, the insulating tape or annular molded portion is according to a particularly preferred first evolution. (b) At least one insulating element includes an annular insulating element, which is pressed in a cup shape in the recessed area to protect the inside of the housing from direct contact with the contact metal sheet. That is, the annular insulating element is according to a particularly preferred second evolution. (c) At least one insulating element includes an annular plastic component, the annular plastic component surrounding the contact metal sheet and protecting the contact metal sheet from direct contact with the inside of the cup-shaped housing portion in the recessed area. That is, the annular plastic component is according to a particularly preferred third evolution. (d) At least one insulating element is or includes an electrically insulating plastic coating, the plastic coating surrounding the edge of the contact metal sheet and protecting the edge from direct contact with the inside of the cup-shaped housing portion, particularly in the recessed area. That is, the plastic coating is according to a particularly preferred fourth evolution.

[0164] The energy storage element according to the present invention is preferably characterized by at least one of the following features (a) or (b). (a) The cup-shaped housing portion has the same maximum outer diameter in the central portion and the closed portion. (b) In the recessed region, the outer diameter of the cup-shaped housing portion is reduced to 4 to 20 times the wall thickness of the cup-shaped housing portion in that region. The features of (a) and (b) immediately above are preferably realized in combination.

[0165] Cell closure using casting compounds In a particularly preferred embodiment, the energy storage element according to the present invention has the following features. (a) The secondary energy storage element includes an airtight and liquidtight housing, the housing having a metal cup-shaped housing portion with a bottom and an end opening, and a lid that closes the end opening; (b) The lid includes a metal lid plate and a connecting pole, the connecting pole being guided through an opening in the lid plate and electrically insulated from the lid plate; (c) The assembly is located within a cup-shaped housing, with one side of the assembly facing the lid and the other side facing the bottom, optionally in direct contact with the bottom; (d) The cathode and anode are formed and / or arranged within the assembly such that the free edge strip of the cathode current collector protrudes from one side of the assembly and the free edge strip of the anode current collector protrudes from the other side of the assembly; (e) The contact metal sheet rests directly on a free edge strip of one of the current collectors protruding from one side of the assembly and is connected by welding; (f) The contact metal sheet is electrically connected to a connecting pole that penetrates an opening in the lid plate, preferably welded directly to the connecting pole, or the connecting pole is part of the contact metal sheet; (g) The connecting pole is electrically insulated from the lid plate by a cured casting compound made from an electrically insulating plastic material.

[0166] This lid design ensures that there is virtually no dead volume between the assembly and the metal lid plate. Any space between the contact metal sheet, connecting poles, and lid plate can be filled with casting compound. A lid having the above features can be manufactured to be very compact.

[0167] Furthermore, an energy storage element having the characteristics of (a) to (g) described above has the advantage of being able to form an electrical contact between the anode and cathode via a lid.

[0168] In a more preferred development of this embodiment, the energy storage element according to the present invention has the following feature (a). (a) The edge strip of the cathode current collector or the edge strip of the anode current collector, which is not in direct contact with the contact metal sheet, is electrically connected to the bottom of the housing, preferably welded directly to the bottom of the housing.

[0169] In many cases, in this embodiment, the cup-shaped housing portion is preferably positively polarized, and the connecting pole is preferably cathode. In these cases, the energy storage element according to the present invention has the feature of (a) immediately below and is optionally combined with at least one of the features of (b) and (c) below. (a) The cup-shaped housing is electrically connected to the cathode. (b) The cup-shaped housing portion is made of aluminum or an aluminum alloy. (c) The lid plate shall be made of aluminum or an aluminum alloy. The features (a) to (c) immediately above are particularly preferable when combined.

[0170] In this embodiment, the housing of the energy storage element is made primarily of aluminum or an aluminum alloy. This offers several advantages. It prevents the formation of localized elements when the outside of the cell comes into contact with moisture. The housing itself can essentially function as an anode on all sides. However, it is particularly preferable that the cell is connected only through a lid, on which the cathode is also located. For this purpose, the current collector can be welded directly to the lid plate, or alternatively, it can be fixed to a separate connecting pole, for example, by welding.

[0171] In other cases, it may be preferable that the cup-shaped housing portion is negatively polarized and the connecting pole is anode. In these cases, the energy storage element according to the present invention has the feature of (a) immediately below and is optionally combined with at least one of the features of (b) and (c) below. (a) The cup-shaped housing is electrically connected to the anode. (b) The cup-shaped housing portion is made of aluminum or an aluminum alloy. (c) The lid plate shall be made of aluminum or an aluminum alloy. The features (a) to (c) immediately above are particularly preferable when combined.

[0172] In a preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) and (b) described below. (a) An annular gap filled with casting compound exists between the lid plate and the contact metal sheet; (b) The annular gap is bounded radially outward by an O-ring shaped insulating disc made of an electrically insulating plastic material.

[0173] In a particularly preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) to (c) described below. (a) The contact metal sheet is made of aluminum or an aluminum alloy. (b) The connecting poles shall be made of aluminum or an aluminum alloy. (c) The contact metal sheet, connecting pole, and cathode current collector are made of the same material.

[0174] In embodiments where the connecting pole is part of the contact metal sheet, the contact metal sheet simultaneously functions as a conductor for the current from the anode current collector or cathode current collector, and as a pole. Thus, there is no need for a separate electrical conductor known in the prior art, which is generally placed between the lid or lid assembly and the contact plate, as described in WO2017 / 215900A1.

[0175] In this embodiment, the contact metal sheet preferably has a flat region which rests directly on a free edge strip of one current collector protruding from one side of the assembly and is connected to that side by welding, and the contact metal sheet has a projection facing away from this side. The projection functions as a connecting pole and is preferably guided through an opening in the cover plate.

[0176] The contact metal sheet has at least one of the features (a) and (b) described below. (a) The protruding metal portion facing away from the first end surface is formed as a cup. (b) The contact metal sheet is a one-piece piece, including any protruding parts. The features of (a) and (b) immediately above are preferably realized in combination.

[0177] A contact metal sheet having a protrusion formed as a cup can be manufactured, for example, by a deep drawing process, in which case it is preferable to form it as a single piece. However, it can also be manufactured, for example, by a manufacturing process involving molding or machining from a metal workpiece, or by 3D printing.

[0178] In a particularly preferred embodiment of the present invention, the energy storage element according to the present invention is characterized by the following features (a) and (b). (a) The bottom of the cup-shaped housing has a primary safety device against internal excess pressure in the form of an opening closed by a metal film; (b) The bottom of the cup-shaped housing portion has a secondary safety device for internal overpressure, in the form of at least one groove on its inside or outside.

[0179] The primary safety device has the function of controlling pressure equalization when an unacceptable excess pressure exceeding a specified threshold occurs. In this case, the membrane ruptures or is blown away by the pressure, and the gas generated inside the housing can escape through an opening at the bottom of the housing.

[0180] The secondary safety device is intended for use in cases where pressure equalization through the primary safety device does not occur quickly or sufficiently. In this case, an outlet opening with a relatively large cross-sectional area is created through which gas generated inside the housing can escape. The bottom of the housing can be torn open along a groove in a weak part of the housing's structure due to excessive pressure.

[0181] The means of such safety devices are already known. The pressure at which the safety device is activated can be precisely controlled by a suitable design of the grooves and membranes.

[0182] The aforementioned safety features are not integrated into the lid, but rather into the bottom of the housing, as in many conventional cells, allowing for an extremely compact lid design. Pre-assembling the lid is not always necessary; instead, the lid can be manufactured during the assembly of the housing.

[0183] In a particularly preferred embodiment, the energy storage element according to the present invention has at least one of the features (a) to (e) described below. (a) The lid plate is welded to the end opening of the cup-shaped housing. (b) The contact metal sheet is connected by welding to the contact metal sheet of the anode current collector or to the free edge strip of the cathode current collector. (c) Free edge strips that do not come into direct contact with the contact metal sheet are placed directly at the bottom of the housing. (d) Free edge strips that do not come into direct contact with the contact metal sheet are welded to the bottom of the housing. (e) At least one groove is located on the inside of the bottom of the housing. The features (a) to (d) immediately above are preferably realized in combination, and the features (a) to (e) immediately above are particularly preferably realized in combination.

[0184] In a further particularly preferred embodiment of the present invention, the energy storage element according to the present invention is characterized by the following (a) feature: (a) The metal film is fixed to the bottom of the cup-shaped housing by welding.

[0185] The bottom of the cup-shaped housing portion may have a flat recess into which the membrane is inserted so as not to protrude. It is preferable that it is connected to the bottom by a circular welded seam guided near the opening of the bottom.

[0186] The membrane thickness can be adjusted to the pressure at which the safety device activates.

[0187] In a preferred embodiment, the energy storage element according to the present invention has at least one of the following features (a) to (g). (a) The bottom of the housing has at least one bead, which appears as an elongated recess on the outside and as an elongated ridge on the inside, and the edge strip of the cathode current collector or anode current collector, which is not in direct contact with the contact metal sheet, is resting inside it. (b) Edge strips of cathode current collectors or anode current collectors that are not in direct contact with the contact metal sheet are electrically connected to the bottom of the housing, preferably welded directly to the bottom of the housing. (c) The bottom of the housing is welded to the free edge strip of the anode current collector or the free edge strip of the cathode current collector in the bead area. (d) The opening is located in the center of the bottom of the housing. (e) At least one bead comprises a plurality of linear beads, in particular three beads, which are arranged in a star shape around the opening. (f) At least one bead includes a plurality of linear sub-regions, the linear sub-regions arranged in a star shape around the opening. (g) At least one bead includes a sub-region running around the opening, and the sub-regions running around the opening connect the star-shaped linear sub-regions to each other. The features of (a) and (b), (c) and (d), and (c), (e), and (f) immediately above are preferably realized in combination. The features of (a) to (g) immediately above are particularly preferably realized in combination.

[0188] It is preferable that one or more weld seams are visible therein as a result of welding in the bead region. It is preferable that the star-shaped bead and the star-shaped linear sub-regions of the groove form an angle of 120° to each other.

[0189] In some embodiments, it has been found advantageous to subject the free-edge strip of the cathode current collector, which rests inside the bottom of the housing, to a pretreatment to improve contact between the bottom of the housing and the current collector. In particular, at least one recess corresponding to at least one bead can be folded into the edge.

[0190] The edges of the current collector may also be pre-treated to form a direction. For example, they may be bent in a specified direction.

[0191] Battery according to the present invention The type of energy storage element according to the present invention is based particularly on sodium ion technology, which not only provides high power density but also fast charging, good performance at low temperatures, and excellent cycle stability. In addition, sodium, for example, is available in virtually unlimited quantities.

[0192] For all these reasons, the energy storage elements according to the present invention, particularly those based on sodium ion technology, are ideally suited for use in starting batteries that can replace, for example, lead-acid batteries in automobiles.

[0193] The present invention as described herein includes the following: - A battery comprising two or more energy storage elements according to the present invention, particularly those based on sodium ion technology, wherein the energy storage elements are connected in series and / or in parallel.

[0194] The battery according to the present invention includes, in particular, a plurality of energy storage elements according to the present invention, wherein the plurality of energy storage elements are connected to one another so as to supply a voltage of 12 volts or 24 volts.

[0195] Typically, the energy storage elements according to the present invention, based on sodium ion technology, supply a nominal voltage in the range of 1.5 volts to 4.8 volts, preferably 2.4 volts to 4 volts. Therefore, a battery according to the present invention having a nominal voltage of 12V includes 3 to 5 energy storage elements according to the present invention connected in series.

[0196] Further features and advantages of the present invention will become apparent from the following description of preferred examples of the invention associated with the claims and drawings. Each feature may be realized individually or in combination with one another. [Brief explanation of the drawing]

[0197] [Figure 1] Figure 1 shows a first embodiment (cross-sectional view) of a sodium ion type energy storage element according to the present invention. [Figure 2] Figure 2 shows a second embodiment of the sodium ion type energy storage element according to the present invention. [Figure 3] Figure 3 shows a third embodiment (cross-sectional view) of the sodium ion type energy storage element according to the present invention. [Figure 4] Figure 4 shows several embodiments (perspective views) of a contact metal sheet suitable for contacting the first longitudinal edge of a current collector protruding from the first end face of a sodium ion type energy storage element according to the present invention. [Figure 5]Figure 5 shows an assembly that is part of a sodium-ion type energy storage element according to the present invention, and its components (top view and perspective view). [Figure 6] Figure 6 shows a further embodiment (perspective view) of a contact metal sheet suitable for contacting the first longitudinal edge of a current collector protruding from the first end face of a sodium-ion type energy storage element according to the present invention. [Figure 7] Figure 7 shows a view from the outside and a longitudinal sectional view of an embodiment of an energy storage element according to the present invention. [Figure 8] Figure 8 is a detailed longitudinal sectional view of the upper and lower end face regions of an embodiment of an energy storage element according to the present invention. [Figure 9] Figures 9A and 9B show a detailed view from diagonally above and a sectional view of a connection pole of a preferred embodiment of an energy storage element according to the present invention. [Figure 10] Figures 10A and 10B show a detailed view from diagonally above and a sectional view of an insulating disk of a preferred embodiment of an energy storage element according to the present invention shown in Figures 7 to 9. [Figure 11] Figures 11A and 11B show a detailed view from diagonally above and a sectional view from diagonally below of a contact metal sheet of a preferred embodiment of an energy storage element according to the present invention shown in Figure 7. [Figure 12] Figure 12 shows the details of the bottom of the housing of a preferred embodiment of an energy storage element according to the present invention shown in Figure 7. [Figure 13] Figures 13A to 13C show an exploded view of various components of a preferred embodiment of an energy storage element according to the present invention shown in Figure 7. [Figure 14] Figures 14A and 14B are detailed views of the upper end face region of a preferred embodiment of an energy storage element according to the present invention, and illustrate a possible manufacturing method of the energy storage element. [Figure 15] Figure 15 shows a preferred embodiment of an energy storage element according to the present invention, and is a view from diagonally above of the bottom of the housing to illustrate the manufacturing method of the energy storage element. [Figure 16]Figures 16A and 16B show alternative embodiments of the contact metal sheet and the connecting pole attached thereto, and are cross-sectional views of a preferred embodiment of the energy storage element according to the present invention. [Figure 17] Figure 17 shows an example of a lid assembly that can be installed as a lid for an energy storage element according to the present invention, for example, as shown in any of Figures 1 to 3. [Modes for carrying out the invention]

[0198] Figure 1 shows an energy storage element 100 according to the present invention, which has a housing that is sealed to air and liquid, the housing comprising a metal cup-shaped housing portion 101 having a circular end opening and a lid 102 having a circular rim 102a, the lid 102 closing the circular opening. The energy storage element further comprises an annular sealing portion 103 made of an electrically insulating material, the annular sealing portion 103 surrounding the circular rim 102a of the lid 102, and electrically insulating the cup-shaped housing portion 101 and the lid 102 from each other.

[0199] The lid is shown only in the form of a disc. However, lid assemblies consisting of multiple parts, such as those shown in Figure 17, are also commonly used as lids.

[0200] The cup-shaped housing portion 101 includes, in axial order, a bottom portion 101a, a central portion 101b, and a closing portion 101c, wherein the central portion 101b is cylindrical, and in the central portion 101b, the wound body shell 104c of the assembly 104, which is formed as a wound body, is in contact with the inside 101d of the cup-shaped housing portion 101, and in the closing portion 101c, the annular sealing portion 103 is in pressure contact with the lid 102 and the inside of the cup-shaped housing portion 101. The central portion 101b and the closing portion 101c are separated by a recess 111, which surrounds the outside 101e of the cup-shaped housing portion 101 in a circumferential direction.

[0201] The assembly 104, which is in the form of a cylindrical wound body, has an anode / separator / cathode in that order, but details are not shown here. Only the longitudinal edge 106a of the anode current collector 106 protruding from the end face 104a of the assembly 104, and the longitudinal edge 109a of the cathode current collector 109 protruding from the end face 104b of the assembly 104 can be seen. The longitudinal edge 109a is directly welded to the bottom 101a of the housing, preferably along its entire length. The longitudinal edge 106a is directly welded to the contact metal sheet 112, preferably along its entire length. The contact metal sheet 112 is then connected to the lid 102 via an electrical conductor 133.

[0202] The energy storage element 100 preferably has a height in the range of 60 mm to 100 mm, and its diameter preferably in the range of 20 mm to 50 mm. The cup-shaped housing portion 101 typically has a wall thickness of the central portion 101b in the range of 0.1 mm to 0.3 mm.

[0203] The energy storage element includes an electrically insulating plastic coating 180 as an insulating element, which surrounds the edge of the contact metal sheet 112 and protects the edge of the contact metal sheet 112 from direct contact with the inside 101d of the cup-shaped housing portion 101, particularly in the region of the recess 111. The electrically insulating plastic coating 180 is formed by overmolding the edge of the contact metal sheet 112. Furthermore, the energy storage element 100 includes an annular plastic portion 170 as an insulating element, which surrounds a separate electrical conductor 133 fixed to the contact metal sheet and protects the electrical conductor 133 from direct contact with the inside 101d of the cup-shaped housing portion 101, particularly in the region of the recess 111.

[0204] As a result, the energy storage element 100 is well protected from short circuits that occur when housing deformation occurs as a result of external physical forces.

[0205] Figure 2 shows an energy storage element 100 according to the present invention having an airtight and liquid-tight sealed housing, the housing including a metal cup-shaped housing portion 101 having a circular end opening, and a lid 102 having a circular rim 102a that closes the circular opening. The energy storage element further includes an annular sealing portion 103 made of an electrically insulating material, the annular sealing portion 103 surrounding the circular rim 102a of the lid 102, electrically insulating the cup-shaped housing portion 101 and the lid 102 from each other.

[0206] The lid is shown only in the form of a disc. However, lid assemblies consisting of multiple parts, such as those shown in Figure 17, are also commonly used as lids.

[0207] The cup-shaped housing portion 101 includes, in axial order, a bottom portion 101a, a central portion 101b, and a closing portion 101c, the central portion 101b being cylindrical, and in the central portion 101b, the wound body shell 104c of the assembly 104, which is formed as a wound body, is in contact with the inside 101d of the cup-shaped housing portion 101 (although for clarity only, the assembly 104 is shown here spaced apart from the inside 101d, in reality it is pressed against the inside 101d, for example as shown in Figure 1), and in the closing portion 101c, the annular sealing portion 103 is in pressure contact with the lid 102 and the inside of the cup-shaped housing portion 101. The central portion 101b and the closing portion 101c are separated by a recess 111, which surrounds the outside 101e of the cup-shaped housing portion 101 in a circumferential direction.

[0208] The assembly 104, in the form of a cylindrical wound body having the anode / separator / cathode in this axial order, is not shown in detail here. Only the longitudinal edge 106a of the anode current collector 106 protruding from the end face 104a of the assembly 104, and the longitudinal edge 109a of the cathode current collector 109 protruding from the end face 104b of the assembly 104 can be seen. The longitudinal edge 109a is directly welded to the bottom 101a of the housing, preferably along its entire length. The contact metal sheet 112 is then connected to the lid 102 via the electrical conductor 133.

[0209] The energy storage element preferably has a height in the range of 60 mm to 100 mm, and its diameter preferably in the range of 20 mm to 50 mm. The cup-shaped housing portion 101 typically has a wall thickness in the range of 0.1 mm to 0.3 mm in the central portion 101b.

[0210] The energy storage element includes an annular molded component made of plastic 150 having an L-shaped cross-section as an insulating element, the annular molded component fencing the end surface 104a and protecting the end surface 104a from direct contact with the inside 101d of the cup-shaped housing portion 101. Furthermore, the energy storage element includes an annular insulating element 160 made of plastic, the annular insulating element 160 leaning against the inside 101d of the cup-shaped housing portion 101 in the region of the recess 111 and protecting the inside 101d from direct contact with the electrical conductor 133. This may also be a portion of the annular sealing portion 103, which may be high enough to cover the recess 111 from the inside.

[0211] As a result, the energy storage element 100 is also well protected from short circuits in the event of deformation of the housing as a result of external physical forces.

[0212] Instead of the annularly shaped part 150 having an L-shaped cross section, the edge defining the end face 104a can also be covered with an insulating tape, for example Kapton tape 150. Ideally, this can be applied to the edge when the wound body is formed and similarly and efficiently protects the edge from direct contact with the inner side 101d.

[0213] FIG. 3 shows an energy storage element 100 according to the invention having a hermetically and liquid-tightly sealed housing, the housing comprising a metallic cup-shaped housing part 101 having an end circular opening and a lid 102 having a circular edge 102a closing the circular opening. The energy storage element further comprises an annular sealing part 103 made of an electrically insulating material, the annular sealing part 103 surrounding the circular edge 102a of the lid 102 and electrically insulating the cup-shaped housing part 101 and the lid 102 from each other.

[0214] The lid is only shown in the form of a disc. However, a lid assembly consisting of a plurality of parts, such as that shown in FIG. 17 for example, is also commonly used as a lid.

[0215] The cup-shaped housing part 101 includes a bottom 101a, a central part 101b, and a closing part 101c in axial order, the central part 101b being cylindrical, in which the winding body shell 104c of the assembly 104 formed as a winding body contacts the inner side 101d of the cup-shaped housing part 101, and in the closing part 101c, the annular sealing part 103 is in pressure contact with the inner sides of the lid 102 and the cup-shaped housing part 101. The central part 101b and the closing part 101c are separated by a recess 111, the recess 111 surrounding the outer side 101e of the cup-shaped housing part 101 in the circumferential direction.

[0216] The assembly 104, in the form of a cylindrical wound body having the anode / separator / cathode in this axial order, is not shown in detail here. Only the longitudinal edge 106a of the anode current collector 106 protruding from the end face 104a of the assembly 104, and the longitudinal edge 109a of the cathode current collector 109 protruding from the end face 104b of the assembly 104 can be seen. The longitudinal edge 109a is directly welded to the contact metal sheet 134, preferably over its entire length. The contact metal sheet 134 is then welded to the bottom 101a. The longitudinal edge 106a is directly welded to the contact metal sheet 112, preferably over its entire length. The contact metal sheet 112 is then connected to the lid 102 via the electrical conductor 133.

[0217] The energy storage element preferably has a height in the range of 60 mm to 100 mm, and its diameter preferably in the range of 20 mm to 50 mm. The cup-shaped housing portion 101 typically has a wall thickness in the range of 0.1 mm to 0.3 mm in the central portion 101b.

[0218] The energy storage element includes an annular plastic portion 170 as an insulating element, which laterally surrounds the electrical conductor 133 and protects the electrical conductor 133 from direct contact with the inner layer 101d of the cup-shaped housing portion 101 in the region of the recess 111. The annular plastic portion 170 is designed to be hollow cylindrical and includes a jacket 171 that stands perpendicular to the contact metal sheet 112. One of its edges is formed as an outward-facing annular collar 171 that rests on the contact metal sheet 112.

[0219] As a result, the energy storage element 100 is also well protected from short circuits in the event of deformation of the housing as a result of external physical forces.

[0220] Figure 4 shows several embodiments of the contact metal sheet 112, which is suitable for contacting the first longitudinal edge 106a of the current collector 106 protruding from the first end surface 104a of the energy storage element 100 according to the present invention.

[0221] Embodiment A shows a circular, essentially flat metal disc having a circumferential edge 112a as a contact metal sheet 112. This is characterized by a central hole 142 and three offset beads 141. Such a component can be used in the energy storage element according to Figures 1-3 for electrical contact of the edge 106a of the anode current collector 106. However, it is also suitable for use as a contact metal plate 134 of the energy storage element according to Figure 3. When such a metal disc is used for contact of the longitudinal edge 106a, a separate electrical conductor 133 shown in Figures 1-3 is generally required to bridge the distance to the contact metal plate 102.

[0222] This is not the case in Embodiment B, where the contact metal sheet 112 includes a first area 112a, which can be placed in close contact with the first longitudinal edge of the current collector protruding from the first end face 104a and extending parallel to the end face 104a. However, the contact metal sheet 112 also includes a second area 112b, which is connected obliquely to the first area 112a, and through the second area 112b, the first area 112a is electrically connected to the lid 102. When using such a contact metal sheet, a separate electrical conductor 133 is not required. The contact metal sheet 112 is further characterized by a hole 142 and two beads 141. The contact metal sheet is preferably welded to the longitudinal edge of each current collector at these beads.

[0223] Embodiments C and D differ from Embodiment B in that area 112a includes three or four strips extending in various directions. Each strip has a bead 141. In addition, each metal sheet portion has two holes 142.

[0224] Figure 5 shows the structure of assembly 104. Assembly 104 includes a ribbon-shaped anode 105 having a ribbon-shaped anode current collector 106, the ribbon-shaped anode current collector 106 having a first longitudinal edge 106a and a second longitudinal edge parallel thereto. The anode current collector 106 is a metal foil made of aluminum. The anode current collector 106 includes a ribbon-shaped main region on which a layer of negative electrode material 107 is placed, and a free edge strip 106b extending along the first longitudinal edge 106a and on which the electrode material 107 is not placed. Furthermore, assembly 104 includes a ribbon-shaped cathode 108 having a ribbon-shaped cathode current collector 109, the ribbon-shaped cathode current collector 109 having a first longitudinal edge 109a and a second longitudinal edge parallel thereto. The cathode current collector is also an aluminum foil. The cathode current collector includes a ribbon-shaped main region on which a layer of positive electrode material 110 is placed, and a free edge strip 109b extending along the first longitudinal edge 109a and on which the electrode material 110 is not placed. Both electrodes are shown separately in their unwound state.

[0225] The anode 105 and cathode 108 are positioned offset from each other within the 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 assembly 104. The offset arrangement is shown in the lower left figure. Two ribbon-shaped separators 116 and 117 are also shown there, separating the electrodes 105 and 108 from each other within the winding.

[0226] The lower right figure shows an assembly 104 in the form of a wound body, which can be used as an energy storage element according to one of Figures 1-4. The edges 106a and 109a of the electrodes protruding from the end faces 104a and 104b are clearly visible. The wound body shell 104c is formed from a plastic film.

[0227] Figure 6 shows a further embodiment of the contact metal sheet 112, which is suitable for contacting the first longitudinal edge 106a of the current collector 106 protruding from the first end surface 104a of the energy storage element 100 according to the present invention.

[0228] Embodiments B to D shown herein differ from the contact metal sheet shown in Embodiments B to D of Figure 4 in that, essentially, area 112b is bent into a U-shape rather than folded into a Z-shape. Such a contact metal sheet can replace the contact metal sheet 112 and electrical conductor 133 of the energy storage element according to Figures 1 to 3.

[0229] Figures 7A-7C show preferred embodiments of the energy storage element according to the present invention, viewed from an oblique angle above (Figure 7A), a longitudinal section (Figure 7B), and a view from an oblique angle below (Figure 7C). The energy storage cell 100 has the shape of a cylindrical round cell. The housing of the energy storage cell 100 is formed by a cup-shaped housing portion 101 and a lid. The lid includes a lid plate 102a having the shape of a perforated plate, and a connecting pole 102b at the center of the lid components.

[0230] As can be seen in the cross-sectional view of Figure 7B, the winding assembly 104 is located inside the energy storage cell 100 and is formed from wound electrode tapes and separator tapes between them.

[0231] Figure 7C shows the bottom side of the energy storage cell 100, which is formed by the bottom 101a of the housing. Three welded embossments in the shape of beads 161 are arranged in a star shape on the bottom 101a of the housing, appearing as recesses on the outside and elongated ridges on the inside. The longitudinal edge of each current collector rests on these beads 161 on the inside, and in the area of ​​these beads, the current collector is preferably welded directly to the bottom of the housing.

[0232] Aluminum is a preferred material for the bottom portion 101a of the housing and the entire cup-shaped housing portion 101.

[0233] In this example, two safety features are incorporated into the bottom 101a of the housing. One is an opening in the center of the bottom 101a of the housing, which is closed by a metal membrane 114. If excessive pressure is generated due to a cell failure, this membrane 114 will rupture or be blown away by the pressure, thereby equalizing the pressure. This allows any gas that may form inside the cell to escape through the opening in the bottom 101a of the housing (primary safety device).

[0234] In addition, further safety features are provided at the bottom 101a of the housing, which are realized by three star-shaped grooves 166. These grooves 166 weaken the structure of the bottom 101a of the housing and thus form predetermined burst points in the event of excessive pressure in the cell (secondary safety device). In this example, the grooves 166 are located inside the bottom 101a of the housing and are therefore shown as break lines in Figure 7C. For example, the grooves 166 can be formed as three scratch lines. The star-shaped arrangement of the scratch lines is further formed by partially circularly connecting the scratch lines or grooves 166. At the corresponding high excessive pressure, the bottom 101a of the housing is torn open along the grooves 166 and the partially circular connections of these grooves so that an outlet opening with a relatively large cross-sectional area is created, through which gas formed inside the housing can escape quickly if necessary.

[0235] Figures 8A and 8B show enlarged views of the end face region of an embodiment of the energy storage cell 100 according to Figure 7. Figure 8A shows details of the end face having a lid 102. The lid 102 includes a lid plate 102a having a central opening and a connecting pole 102b positioned in the center of the lid plate 102a. In this example, the connecting pole 102b can form the cathode, and the surrounding lid plate 102a can form the anode of the energy storage cell 100.

[0236] Below the connecting pole 102b is a contact metal sheet 112, which rests on the free edge strip 106b of the spirally arranged anode current collector of the negative electrode and is welded thereto. The contact metal sheet 112 is electrically connected to the connecting pole 102b, which is formed from two metal components, particularly by welding. The cover plate 102a is electrically insulated from the contact metal sheet 112 by an O-ring shaped insulating disc 177. Furthermore, an electrically insulating molding compound 113 is located in the gap between the connecting pole 102b and the cover plate 102a.

[0237] Figure 8B shows details of the opposite end face of the energy storage cell 100. The free edge strip 109b of the cathode current collector is electrically connected to the bottom 101a of the housing on this end face of the energy storage cell 100, particularly by welding. An electrical connection to a metal cover plate on the opposite end face is established via the jacket of the cup-shaped housing portion 101, so that the positive potential of the cell can also be taken from the upper end face of the energy storage cell 100.

[0238] The preferred safety feature of the cell against overpressure according to the present invention can be seen on the lower end surface of the energy storage cell 100 shown in Figure 8B. The primary safety device is formed by a metal film 114, which closes a central circular opening 155 in the bottom 101a of the housing. The secondary safety device is formed by grooves 166, one of which is partially visible in this figure. The grooves 166 located inside the bottom 101a of the housing represent a defined weakening structure at the bottom of the housing, which allows these structures to open and release gas in the event of relatively high overpressure in the cell.

[0239] A preferred design of the energy storage cell 100 according to the present invention allows for a reduction in the number of components in the upper region of the energy storage cell (Figure 8A), as shown in Figure 8, where the positive and negative terminals of the cell are located. In particular, this design eliminates the need for additional electrical conductors because the connecting pole 102b is a one-piece structure.

[0240] Direct contact of one longitudinal edge of the electrode strip on the bottom side of the housing (partially Figure 8B) also contributes to the particularly compact design of the cell, as there is no dead volume required for the various functions of the cell.

[0241] Direct contact of the longitudinal edges of the electrode strip also achieves improved heat dissipation and reduced internal resistance.

[0242] In addition, this cell design also generally allows for the formation of longer coils, resulting in energy storage cells with higher energy densities.

[0243] The upper end surface of the energy storage cell 100 is designed to be as compact as possible in this configuration. Any gas that may be generated within the cell and lead to a pressure increase is inevitably directed to the lower end region of the cell where safety features for pressure equalization are located. Therefore, as a whole, such a cell has very good safety.

[0244] Figures 9A and 9B show a detailed view (Figure 9A) and a cross-sectional view (Figure 9B) of the connecting pole 102b from an oblique angle above, as seen in Figures 7 and 8. The connecting pole 102b can consist of two metal components. The upper region (top of the pole) 1020 does not necessarily have to be made of the same material as the lower region (bottom of the pole) 1021. The upper region 1020 has a chamfered circumferentially extending upper edge. As seen in the cross-sectional view in Figure 4B, the lower region 1021 has an outer circumferentially extending welded shoulder 1021a and a central pin 1021b projecting downward. The pin 1021b conveniently engages with a recess given corresponding to the center of the contact metal sheet 112, thus ensuring a good fit of the connecting pole 102b.

[0245] Figures 10A and 10B show a complete view (Figure 10A) and a cross-sectional view (Figure 10B) of the O-ring shaped insulating disc 177, viewed from an oblique angle above. The insulating disc 177 preferably serves to electrically insulate the positively polarized lid plate 102a from the reversely polarized components of the energy storage cell 100. In addition, the insulating disc 177 also provides an airtight and liquidtight seal for the housing.

[0246] In the preferred example of the insulating disc 177 shown herein, the insulating disc is made from two different materials. The outer region 177a of the insulating disc 177 is preferably made of a particularly strong plastic material such as PBT (polybutylene terephthalate). The inner region 177b is preferably made of a slightly more flexible and, in particular, heat-resistant plastic such as PET (polyethylene terephthalate). Thus, the outer region 177a ensures mechanical safety in particular. The inner region 177b provides flexibility and is particularly resistant to the high temperature of the casting compound 13 during the assembly of the energy storage cell.

[0247] The inner circumference of the O-ring shaped insulating disc 177 has particular advantages in being thickened in the circumferential direction, thereby supporting the stability of the components in the end region of the energy storage cell on which the insulating disc 177 is placed.

[0248] When the energy storage cell is assembled, inserting the insulating disc 177 into the cell's cover area first provides a temporary seal to the cell until the subsequently introduced sealant 113 hardens to completely seal the cell. Furthermore, the specific shape of the insulating disc 177 allows for axial support of the winding assembly 104, for example, during cell inspection. If the cell is deformed laterally, the shape of the insulating disc 177 also provides space for any deformation of the contact metal sheet 112. Finally, the shape of the insulating disc 177 allows for a reduction in the volume of the casting compound 113 and the amount of any bubbles trapped during casting when the energy storage cell is assembled.

[0249] As a possible alternative to such insulating discs, insulating sealing beads comparable to silicone beads can be applied. This also ensures a secure seal. However, insulating discs 177, particularly those in the embodiments illustrated herein, offer the various advantages described above.

[0250] Figures 11A and 11B show a preferred embodiment of the contact metal sheet 112, which is provided to contact the free edge of the current collector of each electrode in the upper region of the energy storage cell. Figure 11A shows a top view of the disc-shaped contact metal sheet 112. Figure 11B shows a cross-section of the contact metal sheet 112 viewed from below, i.e., the side of the contact metal sheet that faces the assembly 104 inside the energy storage cell.

[0251] Similar to the bead 161 on the bottom 101a of the housing, the contact metal sheet 112 also has three star-shaped beads 112d, which appear as indentations on the outside (Figure 11A) and as elongated ridges on the inside (Figure 11B). The beads 112d are, for example, embossed and have a depth of, for example, 0.25 mm. When the cell is assembled, the beads 112d come into contact with each of the longitudinal edges of the electrode strip of the assembly to which it is connected. The contact metal sheet 112 is preferably welded to each of the longitudinal edges of the electrode strip via the beads 112d.

[0252] There is a recess 112e in the center of the contact metal sheet 112. The recess 112e serves to receive the connecting pole 102b, thereby engaging the central pin 1021b of the connecting pole 102b with the recess 112e. This allows the connecting pole 102b to be easily positioned and fixed on the contact metal sheet 112 so that it can be attached by welding without any problems.

[0253] Furthermore, in a particularly preferred embodiment of the contact metal sheet 112 shown herein, additional star-shaped narrow indentations 112f are provided, located on the inward-facing side of the two sides of the contact metal sheet 112. In this example, a total of nine of these indentations 112f are provided as narrow grooves arranged in a star pattern. For example, the grooves may have a depth of 0.1 mm. The indentations 112f help to improve the distribution of electrolytes within the cell.

[0254] Furthermore, in this preferred embodiment, the contact metal sheet 112 has an embossed circumferential edge 112g, the edge 112g is positioned as a predetermined bending point, particularly with the burr facing downwards. This predetermined bending point facilitates the assembly of the energy storage cell housing.

[0255] In a preferred embodiment, the contact metal sheet 112 is made of aluminum, for example, an aluminum sheet having a material thickness of 0.3 mm.

[0256] Figure 12 shows a detailed view of the bottom 101a of the housing of an energy storage cell having inwardly projecting star-shaped beads 161, which are formed as weld embossing, particularly for contact with the winding assembly. The star-shaped arrangement of the three beads 161 has rotational symmetry, which is particularly advantageous for mounting the cell.

[0257] The central opening 155 at the bottom 101a of the housing is covered by a metal film 114, which serves as a first safety device for the cell in case of excessive pressure. In particular, the opening 155 is intended to be used first to fill the cell with electrolyte during the manufacturing of the cell. After that, the opening 155 is closed with the metal film 114.

[0258] It is preferable that a circumferential recess 1010b surrounding the central opening 155 is provided so that the metal film 114 for closing the central opening 155 can be accurately received.

[0259] Furthermore, in this embodiment, the three star-shaped weakening structures are provided in the form of grooves 166 that open inward, and the grooves 166 are connected to each other by semicircular connecting lines 1010c. These weakening structures 166,1010c serve as a secondary safety measure against internal excess pressure. As an alternative to attaching the weakening structures to the bottom of the housing from the inside, such weakening structures, such as scratch lines, can also be attached from the outside.

[0260] One or more labeling areas 1010a can also be provided on the outside of the bottom 101a of the housing, which can be used to attach various written information.

[0261] Figures 13A-C show exploded views of various components of a preferred embodiment of an energy storage cell according to the present invention. Figure 13A shows the components of the housing, which includes a housing cup 101, connecting poles 102b, an O-ring shaped insulating disc 177, a lid plate 102 having a central recess into which the connecting poles 102b engage, and a casting compound 113. Below the housing cup 101, the closure of the energy storage cell is shown in the form of a metal film 114, which is attached after the assembled cell is filled with the electrolyte shown schematically here.

[0262] Figure 13B shows an electrode-separator winding assembly 104 and a contact metal sheet 112 attached thereto. The assembly 104 can be manufactured by a method known to itself, specifically by winding the electrode tape and separator on a winding machine. To complete the winding shape, the outermost winding of the winding body can be bent inward by, for example, 30° to 45° using a conical pressure component, to stabilize the winding shape. Next, an adhesive tape 118 (Figure 13C), preferably made of polypropylene, is applied to the outer surface of the winding body, providing stabilization and, if necessary, electrical insulation of the cell. After stabilization of the winding assembly 104, a disc-shaped contact metal sheet 112 made of aluminum can be loosely placed, for example, on the upper end surface of the winding body and secured with a particularly stable adhesive tape 119, for example, made of polyimide. For this purpose, a 50 μm thick tape made of Kapton® can be used, for example.

[0263] Next, the assembly 104 with the contact metal sheet 112 attached can be inserted into the cup-shaped housing portion 101. After aligning the beads on the bottom of the housing and the contact metal sheet, and if necessary with the help of a camera, the arrangement can be pressed together with a suitable crimping tool and laser-welded from above and below to bring the longitudinal edges of the electrode strip into contact with each bead simultaneously or continuously. Next, the connecting pole 102b is placed on the contact metal sheet 112 and welded over it.

[0264] Figures 14A and 14B illustrate the details of the manufacturing of the cell lid assembly. Figure 14A shows a detailed view of the welding of the connecting pole 102b to the contact metal sheet 112, therein the laser can be operated obliquely or vertically, particularly in the area of ​​the welding shoulder 1021a extending circumferentially from the connecting pole 102b. Figure 14B shows how the insulating disc 177 can be inserted and compressed to an appropriate height before the lid plate 102a is placed horizontally on the cup-shaped housing portion (not shown) and welded to the cup-shaped housing portion (not shown) obliquely, vertically, or horizontally. The connecting pole 102b can be compressed to an appropriate height relative to the cell shoulder formed by the upper side of the lid plate 102a, if necessary. The distance given for this purpose can be, for example, 1 mm between the upper side of the connecting pole 102b and the upper side of the lid plate 102a. The gap between the lid plate 102a and the connecting pole 102b is filled with casting compound 113 to seal this portion of the energy storage cell, making it airtight and liquid-tight.

[0265] Next, the energy storage cell can be transferred to an oven to cure the casting compound 113 and evaporate any remaining moisture from the winding assembly.

[0266] Figure 15 shows the final filling of the electrolyte 115, which is filled from the bottom side (top in this figure) of the energy storage cell 100 through the opening 101b at the bottom 101a of the housing. Finally, the metal film 114 is applied as a closure for the opening at the bottom 101a of the housing, or for the closure of the central opening 155. For this purpose, for example, a vertical laser beam can be used.

[0267] Figure 16 shows alternative options for mounting the lid assembly. Figure 16A shows a cross-sectional view of the contact metal sheet 112 and the connecting pole 102b attached to it, viewed from a diagonal downward angle. Figure 16B shows a longitudinal cross-sectional view of the upper end face region of the cell.

[0268] In this alternative manufacturing process, the connecting pole 102b is pre-welded to the contact metal sheet 112. For this purpose, friction welding or friction stir welding can be used.

[0269] In the design of the contact metal sheet 112 in this embodiment, the star-shaped bead 112d of the contact metal sheet 112 can be shortened as needed, because the bead 112d is covered by the connecting pole 102b during welding of the subsequent electrode-separator assembly. Thus, overall, there is slightly less welding surface available to bring each longitudinal edge of the electrode strip into contact with the contact metal sheet 112. However, this design can provide advantages to the assembly.

[0270] Since the connecting pole 102b can be easily attached directly to the contact metal sheet 112 on the outside of the housing cup assembly, a central recess in the contact metal sheet and a corresponding pin on the connecting pole 102b can be omitted.

[0271] Further assembly of the energy storage cell having the connecting pole 102b is, in principle, no different from the manufacturing method for the energy storage cell 100 described above, as the connecting pole 102b is already welded directly to the contact metal sheet 112.

[0272] Figure 17 shows an example of a lid assembly 202 that can be installed as a lid on an energy storage element according to the present invention, as shown in Figures 1, 2, or 3.

[0273] The lid assembly 202 includes a metal disc 213 having a metal film 214, which bulges outward or ruptures when excessive pressure is generated inside the housing. The metal disc 213 with the metal film 214 is in direct electrical contact with a metal pole cup 217, which seals the lid assembly 202 to the outside. The metal disc 213 with the metal film 214 is also in electrical contact with an inner metal contact disc 215, but this electrical contact is only made through the metal film 214. Otherwise, the metal disc 213 and the contact disc 215 are electrically insulated from each other by an annular insulator 216. If the film 214 bulges outward as a result of excessive pressure that can act directly on the film through the opening 215a, the electrical contact between the metal disc 213 and the contact disc 215 is broken. At high pressures, the film may rupture. The conductor 113 of the cell shown in Figures 1-3 can be welded to the contact disc 213.

Claims

1. A secondary energy storage element (100) having the following characteristics: (a) The secondary energy storage element includes a cathode (108) and an anode (105) as electrodes, which are part of an assembly (104), in which the cathode (108) and anode (105) are separated by a separator or solid electrolyte layer (116) in the order of cathode (108) / separator or solid electrolyte layer (116) / anode (105), (b) The cathode (108) includes a cathode current collector (109) and a positive electrode material (110), (c) The anode (105) includes an anode current collector (106) and a negative electrode material (107), (d) The cathode current collector (109) - Main region on which layers of positive electrode material (110) are placed on both sides, - A free edge strip (109b) extending along the edge (109a) of the cathode current collector (109) and on which the positive electrode material (110) is not placed. Having, and / or The anode current collector (106) - Main region on which layers of negative electrode material (107) are placed on both sides, - A free edge strip (106b) extending along the edge (106a) of the anode current collector (106) and on which the negative electrode material (107) is not placed. It has, (e) The cathode (108) and anode (105) are formed and / or arranged in the assembly (104) relative to each other such that the free edge strip (109b) of the cathode current collector (109) protrudes from one side (104b) of the assembly (104) and / or the free edge strip (106b) of the anode current collector (106) protrudes from the other side (104a) of the assembly (104), (f) The secondary energy storage element includes a first contact metal sheet (112) that is in direct contact with one free edge strip (106b), and / or a second contact metal sheet (101a) that is in direct contact with the other free edge strip (109b), (g) The electrodes (105, 108) contain at least one ion from the group consisting of sodium ions, potassium ions, calcium ions, magnesium ions, and aluminum ions, which are exchanged between the cathode (108) and anode (105) during charging and discharging of the secondary energy storage element (100).

2. The secondary energy storage element according to claim 1, having the following additional features: (a) The layers made from electrodes (105, 108) and current collectors (106, 109), and electrode material (107, 110) are ribbon-shaped, (b) The secondary energy storage element includes at least one ribbon-shaped separator (116) or at least one ribbon-shaped solid electrolyte layer, (c) The assembly (104) is in the form of a wound body in which electrodes (105, 108) and at least one separator (116) are wound around a winding axis, and the assembly (104) includes first and second end faces (104a, 104b) and a wound body shell (104c), wherein the free edge strip (109b) of the cathode current collector (109) protrudes from the first end face (104b) and / or the free edge strip (106b) of the anode current collector (106) protrudes from the second end face (104a), (d) The secondary energy storage element includes a housing, particularly a metal housing, the housing includes a housing shell or sidewalls, and the housing includes a bottom (101a) and a lid (102) on its end faces, (e) Within the housing, the assembly (104) formed as a wound body is aligned such that the wound body shell (104c) leans against the inside (101d) of the housing shell or side wall.

3. The secondary energy storage element according to claim 1, having the following additional features: (a) The assembly (104) is in the form of a prismatic laminate in which cathodes (108) and anodes (105) are stacked together with further cathodes (108) and anodes (105), (b) The electrodes (105, 108) and current collectors (106, 109), as well as the layers made from the electrode material, are polygonal, particularly rectangular. (c) The secondary energy storage element includes at least one ribbon-shaped or polygonal, particularly rectangular, separator (116), or at least one ribbon-shaped or polygonal, particularly rectangular, solid electrolyte, (d) A prismatic stack is surrounded by a prismatic housing.

4. A secondary energy storage element according to any one of claims 1 to 3, having at least one of the following additional features: (a) The secondary energy storage element (100) is a sodium ion cell; (b) The secondary energy storage element (100) includes a sodium ion cell; (c) The secondary energy storage element (100) includes one of the following electrolytes; - NaClO dissolved in at least one organic solvent, particularly PC, or a carbonate mixture from the group consisting of EC / DEC / FEC and PC / FEC ４ ; - NaPF dissolved in at least one organic solvent, particularly PC, or a carbonate mixture from the group consisting of EC / DEC / FEC, EC / PC, EC / DEC, FEC / EMC and PC / FEC, or an ether mixture such as THF / mTHF ６ and / or NaTFSI; - NaFSI and / or NaTFSI and / or NaTDI dissolved in at least one organic solvent, particularly 1,4-dioxane (DX) and / or 1,3-dioxolane (DOL) and / or dimethyl ether (DME); - NaFSI and / or NaTFSI and / or NaTDI dissolved in at least one organic solvent, particularly dimethyl carbonate (DMC) and / or tris(2,2,2-trifluoroethyl) phosphate (TFP); - NaN(SO4) dissolved in at least one organic solvent, particularly 1,4-dioxane (DX) and / or 1,3-dioxolane (DOL) and / or dimethyl ether (DME). ２ F) ２ ; - NaBF dissolved in at least one organic solvent, particularly tetraethylene glycol dimethyl ether (TEGDME) and / or ACN and / or PC and / or GBL. ４ .

5. A secondary energy storage element according to any one of claims 1 to 4, having at least one of the following additional features: (a) The anode comprises a matrix having depressions and / or pores, in which metallic sodium is stored; (b) The matrix is ​​attached to the surface of the anode current collector; (c) The matrix comprises carbon particles and a binder; (d) The matrix comprises a conductive agent and / or filler; (e) The matrix is ​​the roughened surface of the anode current collector.

6. A secondary energy storage element according to any one of claims 1 to 4, having the following additional features: (a) The anode contains a nucleation layer in which metallic sodium is stored and / or deposited; (b) The nucleation layer is essentially made of at least one material from the group consisting of tin, silver, gold, germanium, carbon, platinum, zinc, aluminum, magnesium, and silicon; (c) The nucleation layer is deposited on the surface of the anode current collector by PVD (physical vapor deposition) or CVD (chemical vapor deposition).

7. The secondary energy storage element according to claim 6, having at least one of the following additional features: (a) The negative electrode includes a layer sequence of metal current collector / matrix or nucleation layer / cover layer; (b) The nucleation layer is positioned between the cover layer and the current collector; (c) The cover layer has a thickness in the range of 300 nm to 30 μm; (d) The cover layer is formed from or contains a ceramic material; (e) The cover layer contains aluminum oxide (Al ２ O ３ ), aluminum hydroxide or aluminum oxyhydroxide (AlOOH), silicon oxide (SiO ｘ , provided that 1 < x ≦ 2), titanium oxide (TiO ２ ), titanium nitride (TiN), titanium aluminum nitride (TiAlN), or titanium carbonitride (TiCN), or is formed from any of them.

8. A secondary energy storage element according to any one of claims 2, 4 to 7, having at least one of the following additional features: (a) The secondary energy storage element includes an airtight and liquidtight housing, the housing having a metal cup-shaped housing portion (101) with a bottom (101a) and a circular opening at the end, and a lid (102) having a circular rim (102a), the lid (102) closing the circular opening at the end; (b) The assembly (104) is arranged axially within the cup-shaped housing, with the first end surface (104a) facing toward the lid (102) and the second end surface (104b) facing toward the bottom (101a) and optionally in direct contact with the bottom (101a); (c) The secondary energy storage element includes an annular sealing portion (103) made of an electrically insulating material, the annular sealing portion (103) surrounding the circular rim (102a) of the lid (102), electrically insulating the cup-shaped housing portion (101) and the lid (102) from each other; (d) The cup-shaped housing portion (101) includes an inner portion (101d) and an outer portion (101e), and is continuous in the axial direction, and includes a bottom portion (101a), a central portion (101b), and a closing portion (101c), - The central part (101b) is cylindrical, and the central part (101b) is formed as a wound shell of the assembly (104). (104c) is in contact with the inside (101d) of the cup-shaped housing portion (101), - In the closed portion (101c), the annular sealing portion (103) is in pressure contact with the inside of the lid (102) and the cup-shaped housing portion (101); (e) The central portion (101b) and the closing portion (101c) are separated by a recess (111), and the recess (111) surrounds the outside (101e) of the cup-shaped housing portion (101) in a circumferential direction; (f) The contact metal sheet (112) is electrically connected by welding to the free edge strip (106b) of the current collector protruding from the first end surface (104a), and is preferably electrically connected by welding to the cover (102); (g) The secondary energy storage element includes at least one insulating element (150; 160; 170; 180) made of an electrical insulating material, the insulating element (150; 160; 170; 180) insulating the contact metal sheet (112) and / or the free edge strips (106b, 109b) of the current collectors (106, 109) protruding from the end face (104a), and / or a separate electrical conductor (133) fixed to the contact metal sheet (112), particularly in the region of the recess (111), from direct contact with the inside (101d) of the cup-shaped housing portion (101).

9. A secondary energy storage element according to any one of claims 1 to 7, having at least one of the following additional features: (a) The secondary energy storage element includes an airtight and liquidtight housing, the housing having a metal cup-shaped housing portion (101) with a bottom (101a) and an end opening, and a lid (102) that closes the end opening; (b) The lid (102) includes a metal lid plate (102a) and a connecting pole (102b), the connecting pole (102b) being guided through an opening in the lid plate (102a) and electrically insulated from the lid plate (102); (c) The assembly (104) is positioned within the cup-shaped housing portion (101), with one side (104a) of the assembly (104) facing the lid (102) and the other side (104b) of the assembly (104) facing the bottom portion (101a) and optionally in direct contact with the bottom portion (101a); (d) The cathode (108) and anode (105) are formed and / or arranged within the assembly (104) such that the free edge strip (109b) of the cathode current collector (109) protrudes from one side (104b) of the assembly (104) and the free edge strip (106b) of the anode current collector (106) protrudes from the other side (104a) of the assembly (104); (e) The contact metal sheet (112) rests directly on a free edge strip of one of the current collectors protruding from one side of the assembly (104), and is connected by welding; (f) The contact metal sheet (112) is electrically connected to a connecting pole (102b) that penetrates an opening in the lid plate (102a), preferably by being directly welded to the connecting pole (102b), or the connecting pole (102b) is part of the contact metal sheet (112); (g) The connecting pole (102b) is electrically insulated from the lid plate (102) by a cured casting compound (113) made from an electrically insulating plastic material.

10. The secondary energy storage element according to claim 9, having the following additional features: (a) The edge strip of the cathode current collector (109) or the edge strip of the anode current collector (106) that is not in direct contact with the contact metal sheet (112) is electrically connected to the bottom of the housing (101a), preferably welded directly to the bottom of the housing (101a).

11. A secondary energy storage element according to claim 9 or 10, having at least one of the following additional features: (a) An annular gap is present between the lid plate (102) and the contact metal sheet (112), filled with a hardened casting compound (113); (b) The annular gap is bounded radially outward by an O-ring shaped insulating disc (177) made of an electrically insulating plastic material.

12. A secondary energy storage element according to any one of claims 9 to 11, having the following additional features: (a) The bottom (101a) of the cup-shaped housing portion (101) has a primary safety device against internal excess pressure in the form of an opening (155) closed by a metal film (114); (b) The bottom (101a) of the cup-shaped housing portion (101) has a secondary safety device for internal excess pressure in the form of at least one groove (166) on its inside or outside.

13. A battery comprising at least two secondary energy storage elements according to any one of claims 1 to 12, connected in parallel and / or in series.

14. The battery according to claim 13, characterized in that the battery has a nominal voltage of 12V or 24V.

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