SO2-based electrolyte for rechargeable battery cells and rechargeable battery cells

Abstract

A rechargeable battery cell (2, 20, 40) having an SO2-based electrolyte and the electrolyte, the electrolyte comprising at least one conductive salt having the formula (I), where M is a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements and aluminum, x is an integer from 1 to 3, and R 1 , R 2 , R 3 and R 4 are independently halogen atoms, hydroxy groups, chemical groups -OR 5 and the substituent R 1 , R 2 , R 3 and R 4 and R 1 , R 2 , R 3 and R 4 There are four halogen atoms and four chemical groups -OR 5 , particularly an alkoxy group, and the substituent R 5 is C1~C 10 Alkyl, C2-C 10 Alkenyl, C2-C 10 Alkynyl, C3-C 10 Cycloalkyl, C6-C 14 Aryl and C5-C 14 heteroaryl; and Z is aluminum or boron. [Formula 1] JPEG2024504479000015.jpg39168

Description

[Technical field]

[0001] The present invention relates to an SO2-based electrolyte for a rechargeable battery cell and to a rechargeable battery cell. [Background technology]

[0002] Rechargeable battery cells are very important in many technical fields. In many cases, they are used in applications where only small rechargeable battery cells with relatively low currents are needed, such as for example the operation of mobile phones. However, there is also a demand for larger rechargeable battery cells for high energy applications, and for electric drive of vehicles, it is especially important to store large amounts of energy in the form of battery cells.

[0003] An important requirement for this type of rechargeable battery cell is a high energy density. This means that the rechargeable battery cell must contain as much electrical energy per unit of weight and volume as possible. For this purpose, lithium has proven to be particularly advantageous as an active metal. The active metal of a rechargeable battery cell is a metal whose ions in the electrolyte migrate to the negative or positive electrode during charging and discharging of the cell and there take part in electrochemical processes. The electrochemical processes directly or indirectly lead to the release of electrons to or the acceptance of electrons from an external circuit. Rechargeable battery cells containing lithium as an active metal are also called lithium-ion batteries. It is possible to increase the energy density of the lithium-ion battery either by increasing the specific capacity of the electrodes or by increasing the cell voltage.

[0004] Both the positive and negative electrodes of a lithium-ion battery are formed as insertion electrodes. The term "insertion electrode" in the sense of the present invention is understood to be an electrode having a crystalline structure in which ions of the active material can be stored or released during operation of the lithium-ion battery. This means that electrode processes can occur not only on the surface of the electrode but also within the crystalline structure. Both electrodes are therefore formed very thin, usually with a thickness of less than 100 μm. During charging of the lithium-ion battery, ions of the active metal are released from the positive electrode and stored in the negative electrode. During discharging of the lithium-ion battery, the reverse process takes place.

[0005] The electrolyte is also an important functional element for a rechargeable battery cell. The electrolyte usually comprises a solvent or a mixture of solvents and at least one conductive salt. For example, a solid electrolyte or an ionic solution does not comprise a solvent and only comprises the conductive salt. The electrolyte is in contact with the positive and negative electrodes of the battery cell. At least one ion (anion or cation) of the conductive salt is mobile in the electrolyte so that the charge transport between the electrodes, which is necessary for the functioning of the rechargeable battery cell, can be carried out by ionic conduction. The electrolyte is electrochemically decomposed oxidatively above a certain upper cell voltage limit of the rechargeable battery cell. This process often leads to irreversible destruction of the electrolyte components and thus to the failure of the rechargeable battery cell. Reductive processes can also destroy the electrolyte below a certain lower cell voltage limit. To avoid this process, the positive and negative electrodes are selected such that the cell voltage is lower or higher than the decomposition voltage of the electrolyte. The electrolyte thus determines the voltage window (in English: voltage window) within which the rechargeable battery cell can be operated reversibly, ie repeatedly charged or discharged.

[0006] Lithium ion batteries known from the prior art contain an electrolyte consisting of an organic solvent or solvent mixture and a conductive salt dissolved therein. The conductive salt is a lithium salt, such as lithium hexafluorophosphate (LiPF6). The solvent mixture may contain, for example, ethylene carbonate (EC). The electrolyte LP57, with the composition 1M LiPF6 in EC:EMC 3:7, is an example of such an electrolyte. By using the organic solvent or solvent mixture, this type of lithium ion battery is also called organic lithium ion battery. Besides lithium hexafluorophosphate (LiPF6), which is frequently used as a conductive salt in the prior art, other conductive salts for organic lithium ion batteries are described. For example, in JP 4306858 (hereinafter referred to as [V1]), conductive salts in the form of tetraalkoxy salts or tetraaryloxyborate salts, which may be fluorinated or partially fluorinated, are described. JP 2001-143750 A (hereinafter referred to as [V2]) describes fluorinated or partially fluorinated tetraalkoxyborates and tetraalkoxyaluminates as conductive salts. The conductive salts described in both documents [V1] and [V2] are dissolved in an organic solvent or solvent mixture and used in organic lithium-ion batteries. In many organic lithium-ion batteries, the negative electrode consists of a carbon coating applied onto a conductor element made of copper. The conductor element forms the required electronic conductive connection between the carbon coating and the external circuit. The positive electrode consists of lithium cobalt oxide (LiCoO2) applied onto a conductor element made of aluminum.

[0007] It has long been known that unintentional overcharging of organic lithium-ion batteries leads to irreversible decomposition of electrolyte components. In this case, oxidative decomposition of the organic solvent and / or the conductive salt occurs at the surface of the positive electrode. The reaction heat formed during the decomposition and the gaseous products generated during this process are the cause of the subsequent so-called "thermal runaway" and thus the destruction of the organic lithium-ion battery. Most charging protocols for organic lithium-ion batteries use the cell voltage as an indicator of the end of charge. Thermal runaway accidents are particularly likely to occur when using multi-cell battery packs in which several organic lithium-ion batteries of different capacities are connected in series.

[0008] Organic lithium-ion batteries therefore have problems with regard to their own stability and operational safety in long-term use. Safety risks also arise in particular from the flammability of the organic solvent or solvent mixture. If an organic lithium-ion battery were to catch fire or even explode, the organic solvent of the electrolyte would form flammable materials. A further drawback of organic lithium-ion batteries is that the hydrolysis products that arise in the event of possible residual amounts of water being present are very aggressive to the cell components of the rechargeable battery cells. The aforementioned problems with regard to stability and operational safety in long-term use are particularly acute in the development of organic lithium-ion batteries that, on the one hand, have very good electrical energy and performance data, and, on the other hand, have a very high operational safety and service life, in particular a high number of available charge-discharge cycles.

[0009] A development known from the prior art therefore provides for the use of sulfur dioxide (SO2)-based electrolytes in rechargeable battery cells instead of organic electrolytes. Rechargeable battery cells containing SO2-based electrolytes have a particularly high ionic conductivity. The term "SO2-based electrolyte" is understood to mean an electrolyte which not only contains SO2 in low concentrations as an additive, but in which the ionic mobility of the conductive salts contained in the electrolyte and which effect the charge transport is at least partially, mostly or completely ensured by SO2. SO2 thus acts as a solvent for said conductive salts. Said conductive salts can form liquid solvate complexes with gaseous SO2, in which the SO2 is bound and the vapor pressure is significantly reduced compared to pure SO2. An electrolyte with a lower vapor pressure is produced. This type of SO2-based electrolyte has the advantage over the aforementioned organic electrolytes that it is non-flammable. It is thus possible to eliminate safety risks resulting from the flammability of the electrolyte.

[0010] For example, European Patent Specification No. 1201004 (hereinafter referred to as [V3]) shows an SO2-based electrolyte with the composition LiAlCl4*SO2 in combination with a positive electrode made of LiCoO2. [V3] proposes the use of an additional salt to avoid decomposition reactions, such as the undesired production of chlorine (Cl2) from lithium tetrachloroaluminate (LiAlCl4), during overcharging of rechargeable battery cells above a potential of 4.1 to 4.2 volts.

[0011] EP 2534719 (hereinafter referred to as [V4]) also discloses an SO2-based electrolyte with, inter alia, LiAlCl4 as conductive salt, which forms a complex with SO2, for example with the formula LiAlCl4*1.5 mol SO2 or LiAlCl4*6 mol SO2. Lithium iron phosphate (LiFePO4) is used as the positive electrode. LiFePO4 has a lower charging potential (3.7 V) compared to LiCoO2 (4.2 V). Unwanted overcharging reactions are not an issue in the rechargeable battery cell, since the potential of 4.1 volts, which is harmful to the electrolyte, is not reached.

[0012] A particular drawback of the SO2-based electrolyte is that the hydrolysis products produced in the presence of possible traces of residual water can react with the cell components of the rechargeable battery cell, leading to the formation of undesirable by-products. Therefore, when manufacturing such rechargeable battery cells using SO2-based electrolytes, care must be taken to minimize the amount of residual water in the electrolyte and cell components.

[0013] A further problem with SO2-based electrolytes is the insolubility of many conductive salts, especially those known in organic lithium-ion batteries, in SO2. Measurements have shown that SO2 is a poor solvent for many conductive salts, such as, for example, lithium fluoride (LiF), lithium bromide (LiBr), lithium sulfate (Li2SO4), lithium hexafluoroarsenate (LiAsF6), lithium tetrafluoroborate (LiBF4), lithium trilithium hexafluoroaluminate (Li3AlF6), lithium hexafluoroantimonate (LiSbF6), lithium bis(trifluoromethanesulfonyl)imide (LiTFSL), lithium metaborate (LiBO2), lithium aluminate (LiAl02), lithium triflate (LiCF3SO3) and lithium chlorosulfonate (LiSO3Cl). The solubility of the conductive salts in SO2 is about 10 -2 From 10 -4 mol / L (see Table 1). It can be assumed that at these low concentrations there is at best low conductivity, insufficient for useful operation of a rechargeable battery cell.

[0014] [Table 1] [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Patent No. 4306858 [Patent Document 2] JP 2001-143750 A [Patent Document 3] European Patent No. 1201004 [Patent Document 4] European Patent No. 2534719 Summary of the Invention [Problem to be solved by the invention]

[0016] In order to further improve the application and properties of SO2-based electrolytes and rechargeable battery cells containing said electrolytes, the present invention is based on the task of proposing an SO2-based electrolyte which, in comparison with the electrolytes known from the prior art, is: - It has a wide electrochemical window so that oxidative electrolyte decomposition does not occur at the positive electrode. - forming a stable surface layer on the negative electrode, where the surface capacity should be low and no further reductive electrolytic decomposition of the negative electrode occurs during subsequent operation; - Offers the possibility to operate rechargeable battery cells with high voltage cathodes due to a wide electrochemical window, - have good solubility of conductive salts and are therefore good ionic conductors and electronic insulators, thus facilitating ionic transport and minimizing self-discharge; - be inert to other components in the rechargeable battery cell, such as the separator, electrode materials and cell housing materials; - Robust against electrical, mechanical or thermal abuse; - It has higher stability against residual water in the cell components of the rechargeable battery cell.

[0017] Electrolytes of this kind are intended to be applicable in particular in rechargeable battery cells which simultaneously have good energy and performance data, high operational stability and service life, in particular a high number of available charge / discharge cycles, without the electrolyte being decomposed during operation of the rechargeable battery cell.

[0018] On the other hand, the object of the present invention is to propose a rechargeable battery cell which contains an SO2-based electrolyte and which, in comparison with rechargeable battery cells known from the prior art, has: - Improved electrical performance data, especially high energy density, - Improved overcharge and deep discharge capabilities, - Lower self-discharge, - Longer service life, especially high number of available charge / discharge cycles; - Lower overall weight, - Higher operating safety even under adverse environmental conditions for the vehicle, as well as - Lower manufacturing costs. [Means for solving the problem]

[0019] The problem is solved by an SO2-based electrolyte having the features of claim 1 and a rechargeable battery cell having the features of claim 15. Advantageous embodiments of the electrolyte according to the invention are defined in claims 2 to 14. Claims 16 to 25 describe advantageous developments of the rechargeable battery cell according to the invention.

[0020] The SO2-based electrolyte for a rechargeable battery cell according to the present invention comprises at least one SO2-based electrolyte having the formula (I): First comprising a conductive salt, [ka] M is a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements and aluminium; - x is an integer from 1 to 3; - Substituent R 1 and R 2 are independently halogen atoms, hydroxy groups, chemical groups -OR 5 Oh Biki is selected from the group formed by the rate ligands, - Substituent R 3 is a hydroxy group, a chemical group -OR 5 Oh Bikiis selected from the group formed by the rate ligands, - Substituent R 4 is a halogen atom, a hydroxyl group and Biki is selected from the group formed by the rate ligands, The chelating ligand is the substituent R 1 、R 2 、R 3 and R 4 is formed by at least two of the following and coordinated to Z; - Substituent R 5 is C1~C 10 Alkyl, C2-C 10 Alkenyl, C2-C 10 Alkynyl, C3-C 10 Cycloalkyl, C6-C 14 Aryl and C5-C 14 heteroaryl, and further - Z is aluminum or boron.

[0021] Therefore, the substituent R 1 , R 2 , R 3 and R 4 are, independently of each other, halogen atoms, hydroxyl groups (-OH) and chemical groups -OR 5 wherein the substituent R 1 , R 2 , R 3 and R 4 It has four halogen atoms and four chemical groups -OR 5 In the sense of the present invention, the term "substituent R 1 , R 2 , R 3 and R 4 The term "chelating ligand coordinated to Z formed by at least two of the substituents R 1 , R 2 , R 3 and R 4It is understood that at least two of the substituents may be bridged together, such bridgement of two substituents resulting in the formation of a bidentate chelating ligand. For example, the chelating ligand may be of the formula -OR 5 The chelating ligand -OR may be bidentate. 5 In order to form -O-, the first substituent R 1 is preferably OR 5 group, the second substituent R 2 may preferably be a hydroxy group, and the substituents are connected to each other by forming a chemical bond in their bridged state to form the above formula -OR 5 Such chelating ligands can have the following structural formula, for example:

[0022] [ka]

[0023] The chelating ligand is coordinated to the central atom Z after formation of the chelate complex. 5 In the case of -O-, both oxygen atoms are coordinated to the central atom Z. Synthetically, this type of chelate complex can be prepared according to Example 1 described below. The term "chelate complex" refers to a complex compound in which a multidentate ligand (having more than one free electron pair) occupies at least two coordination sites (binding sites) of the central atom. The substituent R 1 , R 2 , R 3 and R 4 It is also possible to make the chelating ligand multidentate if three or four of the are bridged to one another.

[0024] The SO2-based electrolyte of the present invention does not only contain SO2 as an additive in low concentrations, but also in a concentration in which the ionic mobility of the first conductive salt contained in the electrolyte and carrying out the charge transport is at least partially, mostly or completely ensured by SO2. The first conductive salt is dissolved in the electrolyte and has very good solubility in the electrolyte. The conductive salt can form a liquid solvate complex with gaseous SO2, in which SO2 is bound. In this case, the vapor pressure of the liquid solvate complex is significantly reduced compared to pure SO2, resulting in an electrolyte with a lower vapor pressure. However, it is also within the scope of the present invention that no vapor pressure reduction may occur during the preparation of the electrolyte according to the present invention, depending on the chemical structure of the first conductive salt according to formula (I). In the latter case, it is preferable to work at low temperature or under pressure during the preparation of the electrolyte according to the present invention. The electrolyte may also contain a plurality of conductive salts according to formula (I), which differ from each other in their chemical structure.

[0025] In the sense of the present invention, "C1-C 10 The term "alkyl" comprises linear or branched saturated hydrocarbon groups having from 1 to 10 carbon atoms, including, in particular, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, 2,2-dimethylpropyl, n-hexyl, isohexyl, 2-ethylhexyl, n-heptyl, isoheptyl, n-octyl, isooctyl, n-nonyl, n-decyl, and the like.

[0026] In the sense of the present invention, "C2-C 10 The term "alkenyl" comprises unsaturated linear or branched hydrocarbon radicals having 2 to 10 carbon atoms, said hydrocarbon radical having at least one C-C double bond, including, in particular, ethenyl, 1-propenyl, 2-propenyl, 1-n-butenyl, 2-n-butenyl, isobutenyl, 1-pentenyl, 1-hexenyl, 1-heptenyl, 1-octenyl, 1-nonenyl, 1-decenyl, and the like.

[0027] In the sense of the present invention, "C2-C 10 The term "alkynyl" comprises unsaturated linear or branched hydrocarbon radicals having from 2 to 10 carbon atoms, said hydrocarbon radical having at least one C-C triple bond, including, in particular, ethynyl, 1-propynyl, 2-propynyl, 1-n-butynyl, 2-n-butynyl, isobutynyl, 1-pentynyl, 1-hexynyl, 1-heptynyl, 1-octynyl, 1-nonynyl, 1-decynyl, and the like.

[0028] In the sense of the present invention, "C3-C 10 The term "cycloalkyl" comprises cyclic saturated hydrocarbon groups having from 3 to 10 carbon atoms, including in particular cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclohexyl, cyclononyl and cyclodecanyl.

[0029] In the sense of the present invention, "C6-C 14 The term "aryl" comprises aromatic hydrocarbon groups having 6 to 14 cyclic carbon atoms. This includes, in particular, phenyl (CH), naphthyl (CH), ... 10 H7 group) and anthracyl (C 14 H9 group) is applicable.

[0030] In the sense of the present invention, "C5-C 14 The term "heteroaryl" includes aromatic hydrocarbon groups having from 5 to 14 cyclic hydrocarbon atoms, at least one of which is substituted or replaced by a nitrogen, oxygen or sulfur atom, including, among others, pyrrolyl, furanyl, thiophenyl, pyridinyl, pyranyl, thiopyranyl, and the like.

[0031] This type of electrolyte has the advantage that, compared to electrolytes known from the prior art, the first conductive salt contained in the electrolyte has a higher oxidation stability, so that there is practically no decomposition at higher cell voltages. The electrolyte preferably exhibits oxidation stability up to a potential of at least 4.0 volts, more preferably up to a potential of at least 4.2 volts, more preferably up to a potential of at least 4.4 volts, more preferably up to a potential of at least 4.6 volts, more preferably up to a potential of at least 4.8 volts, and particularly preferably up to a potential of at least 5.0 volts. Thus, when such an electrolyte is used in a rechargeable battery cell, there is no or very little electrolyte decomposition within the working potential of both electrodes of the rechargeable battery cell. This results in a significantly longer service life of the electrolyte compared to electrolytes known from the prior art. Furthermore, such an electrolyte has low temperature stability. In the case of traces of water remaining in the electrolyte (in the ppm range), the electrolyte or the first conductive salt together with the water form hydrolysis products that are significantly less aggressive to cell components compared to the SO2-based electrolytes known from the prior art. The absence of water in the electrolyte compared to the SO2-based electrolytes known from the prior art therefore plays a less important role in the case of the LiAlCl4 conductive salt. The advantages of the electrolyte according to the invention outweigh the disadvantages resulting from the significantly larger anion size of the first conductive salt according to formula (I) compared to the conductive salts known from the prior art, which leads to a lower conductivity of the first conductive salt according to formula (I) compared to that of LiAlCl4.

[0032] Another aspect of the present invention relates to a rechargeable battery cell comprising the electrolyte according to the present invention as described above or according to the preferred embodiments of the electrolyte according to the present invention, further comprising an active metal, at least one positive electrode, at least one negative electrode and a housing.

[0033] electrolyte Advantageous developments of the electrolyte according to the invention are described below:

[0034] In a first advantageous embodiment of the electrolyte according to the invention, the substituent R 5 is selected from the group formed by: - C1-C6 alkyl, preferably C2-C4 alkyl, particularly preferably 2-propyl, methyl and ethyl alkyl groups; alkenyl radicals from C2 to C6 alkenyl, preferably C2 to C4 alkenyl, particularly preferably ethenyl and propenyl, - C2-C6 alkynyl, preferably C2-C4 alkynyl, - C3-C6 cycloalkyl, - Phenyl, and - C5-C7 heteroaryl.

[0035] In this advantageous embodiment of the electrolyte according to the invention, the term "C1-C6 alkyl" comprises linear or branched saturated hydrocarbon radicals having 1 to 6 hydrocarbon groups, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, 2,2-dimethylpropyl, n-hexyl and isohexyl. Of these, C2-C4 alkyl is preferred. Particularly preferred are the C2-C4 alkyls 2-propyl, methyl and ethyl.

[0036] In this advantageous embodiment of the electrolyte according to the invention, the term "C2-C6 alkenyl" comprises an unsaturated linear or branched hydrocarbon radical having 2 to 6 carbon atoms, said hydrocarbon radical having at least one C-C double bond. This applies in particular to ethenyl, 1-propenyl, 2-propenyl, 1-n-butenyl, 2-n-butenyl, isobutenyl, 1-pentenyl, 1-hexenyl, with C2-C4 alkenyl being preferred. Particularly preferred are ethenyl and 1-propenyl.

[0037] In this advantageous embodiment of the electrolyte according to the invention, the term "C2-C6 alkynyl" comprises an unsaturated linear or branched hydrocarbon radical having 2 to 6 carbon atoms, said hydrocarbon radical having at least one C-C triple bond. This applies in particular to ethynyl, 1-propynyl, 2-propynyl, 1-n-butynyl, 2-n-butynyl, isobutynyl, 1-pentynyl, 1-hexynyl. Of these, C2-C4 alkynyl is preferred.

[0038] In this advantageous embodiment of the electrolyte according to the invention, the term "C3-C6 cycloalkyl" comprises cyclic saturated hydrocarbon groups having 3 to 6 carbon atoms, including in particular cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

[0039] In this advantageous embodiment of the electrolyte according to the invention, the term "C5-C7 heteroaryl" comprises phenyl and naphthyl.

[0040] In order to improve the solubility of the first conductive salt in an SO2-based electrolyte, the substituent R 5 at least one individual atom or one atomic group of is replaced by a halogen atom, in particular a fluorine atom, or one of said chemical groups, said chemical group being selected from the group formed by C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, phenyl, benzyl and fully to partially halogenated, in particular fully to partially fluorinated C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, phenyl and benzyl. Said chemical groups C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, phenyl and benzyl have similar properties or chemical structure as the aforementioned hydrocarbon groups.

[0041] Substituent R 1 , R 2 , R 3 and R 4As long as one to three of them are hydroxyl groups (-OH), the hydrogen elements (H) of said one to three hydroxyl groups can also be replaced by chemical groups selected from the group formed by C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, phenyl, benzyl and fully to partially halogenated, in particular fully to partially fluorinated, C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, phenyl and benzyl. The said chemical groups C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, phenyl and benzyl have the same properties or chemical structure as the aforementioned hydrocarbon groups.

[0042] The substituent R 5 At least one of the atomic groups is preferably a CF3 group or an OSO2CF3 group, which makes it possible to obtain extremely high solubility of the first conductive salt in the SO2-based electrolyte.

[0043] In another advantageous development of the electrolyte according to the invention, the first conductive salt is selected from the group formed by:

[0044] [ka]

[0045] In order to adapt the conductivity and / or other properties of the electrolyte to the desired values, in another advantageous embodiment the electrolyte comprises at least one second conductive salt different from the first conductive salt according to formula (I), which means that besides the first conductive salt, the electrolyte may comprise one or more second conductive salts which differ from the first conductive salt not only in their chemical composition but also in their chemical structure.

[0046] In a preferred embodiment of the electrolyte according to the invention, the second conductive salt has the formula (II) has.

[0047] [ka]

[0048] In formula (II), M is a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table and aluminum. x is an integer from 1 to 3. The substituent R 6 , R 7 , R 8 and R 9 are C1 to C 10 Alkyl, C2-C 10 Alkenyl, C2-C 10 Alkynyl, C3-C 10 Cycloalkyl, C6-C 14 Aryl and C5-C 14 The central atom Z is aluminum or boron. In order to improve the solubility of the second conductive salt according to formula (II) in SO2-based electrolytes, in another advantageous embodiment of the rechargeable battery cell, the substituent R 6 , R 7 , R 8 and R 9 is substituted by at least one halogen atom and / or at least one chemical group, said chemical group being selected from the group formed by C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, phenyl and benzyl. Substitution in this context means that the substituent R 6 , R 7 , R 8 and R 9 is substituted with said halogen atoms and / or said chemical groups. 10 Alkyl, C2-C 10 Alkenyl, C2-C 10 Alkynyl, C3-C 10 Cycloalkyl, C6-C 14 Aryl and C5-C 14 The heteroaryl has the same properties or chemical structure as the first conductive salt having a hydrocarbon group represented by the above formula (I). 6 , R7 , R 8 and R 9 At least one of the groups is a CF3 group or an OSO2CF3 group, so that it is possible to obtain a very high solubility of the second conductive salt according to formula (II) in the SO2-based electrolyte.

[0049] In another advantageous embodiment of the electrolyte according to the invention, the second conductive salt is an alkali metal compound, in particular a lithium compound, selected from the group formed by aluminates, halides, oxalates, borates, phosphates, arsenates and gallates. The second conductive salt is preferably a lithium tetrahaloaluminate, in particular LiAlCl4.

[0050] In yet another preferred embodiment, the electrolyte comprises at least one additive. The additives in question are vinylene carbonate and its derivatives, vinyl ethylene carbonate and its derivatives, methyl ethylene carbonate and its derivatives, lithium (bisoxalato)borate, lithium difluoro(oxalato)borate, lithium tetrafluoro(oxalato)phosphate, lithium oxalate, 2-vinylpyridine, 4-vinylpyridine, cyclic exomethylene carbonate, sulfones, cyclic and acyclic sulfonates, acyclic sulfites, cyclic and acyclic sulfinate esters, Organic esters, inorganic acids , acyclic and cyclic alkanes (wherein the acyclic and cyclic alkanes have a boiling point of at least 36° C. at 1 bar), aromatic compounds, halogenated cyclic and acyclic sulfonylimides, halogenated cyclic and acyclic phosphates, halogenated cyclic and acyclic phosphines, halogenated cyclic and acyclic phosphites, halogenated cyclic and acyclic phosphazenes, halogenated cyclic and acyclic silylamines, halogenated cyclic and acyclic halogenated esters, halogenated cyclic and acyclic amides, halogenated cyclic and acyclic anhydrides and halogenated organic heterocycles.

[0051] In another preferred embodiment, the electrolyte has the following composition, by weight of the total electrolyte composition: (i) 5 to 99.4 wt. % sulfur dioxide; (ii) 0.6 to 95 wt % of the first conductive salt; (iii) 0 to 25 wt % of said second conductive salt, and (iv) 0 to 10 wt % of said additive.

[0052] As mentioned above, the electrolyte can contain not only one of the first conductive salts and one of the second conductive salts according to formula (I), but also a plurality of first conductive salts and a plurality of second conductive salts, respectively according to formula (I). In the latter case, the above-mentioned ratio includes a plurality of first conductive salts and a plurality of second conductive salts. The concentration of the substance amount of the first conductive salt is in the range of 0.05 mol / l to 10 mol / l, preferably 0.1 mol / l to 6 mol / l and particularly preferably 0.2 mol / l to 3.5 mol / l with respect to the total volume of the electrolyte.

[0053] In another preferred embodiment of the rechargeable battery cell according to the invention, the electrolyte comprises at least 0.1 mole of SO2 per mole of conductive salt, preferably at least 1 mole of SO2, more preferably at least 5 moles of SO2, even more preferably at least 10 moles of SO2 and particularly preferably at least 20 moles of SO2. The electrolyte can also comprise a very high molar ratio of SO2, with a preferred upper limit of 2600 moles of SO2 per mole of conductive salt, with upper limits of 1500, 1000, 500 and 100 moles of SO2 per mole of conductive salt being preferred in that order. The term "per mole of conductive salt" refers to all conductive salts contained in the electrolyte. SO2-based electrolytes with this type of concentration ratio between SO2 and the conductive salt have the advantage that they are capable of dissolving a larger amount of conductive salt than electrolytes known from the prior art, for example based on organic solvent mixtures. Within the scope of the present invention, it has surprisingly been found that electrolytes with a relatively small conductive salt concentration are advantageous, in particular with regard to their stability over multiple charge / discharge cycles of the rechargeable battery cell, despite the associated increase in vapor pressure. The SO2 concentration in the electrolyte affects the conductivity of the electrolyte. Thus, by selecting the SO2 concentration, it is possible to adapt the conductivity of the electrolyte to the intended use of the rechargeable battery cell operated by the electrolyte.

[0054] The total weight of SO2 and the first conductive salt can be greater than 50 weight percent (wt%) of the weight of the electrolyte, preferably greater than 60 wt%, more preferably greater than 70 wt%, more preferably greater than 80 wt%, more preferably greater than 85 wt%, more preferably greater than 90 wt%, more preferably greater than 95 wt%, or more preferably greater than 99 wt%.

[0055] The electrolyte may contain at least 5 wt% SO2 with respect to the total amount of electrolyte contained in the rechargeable battery cell, with more preferred values ​​being 20 wt% SO2, 40 wt% SO2 and 60 wt% SO2. The electrolyte may contain up to 95 wt% SO2, with maximum values ​​of 80 wt% SO2 and 90 wt% SO2 being preferred in that order.

[0056] It is within the scope of the present invention that the proportion of at least one organic solvent in the electrolyte is low or absent. The proportion of organic solvent in the electrolyte, for example in the form of a solvent or a mixture of organic solvents, may be at most 50 wt% of the weight of the electrolyte. Particularly preferred are smaller proportions, such as at most 40 wt%, at most 30 wt%, at most 20 wt%, at most 15 wt%, at most 10 wt%, at most 5 wt% or at most 1 wt% of the weight of the electrolyte. It is further preferred that the electrolyte is free of organic solvents. With a low or no proportion of organic solvents, the electrolyte has little or no flammability. This improves the operational safety of rechargeable battery cells operated with this type of SO2-based electrolyte. It is particularly preferred that the SO2-based electrolyte is substantially free of organic solvents.

[0057] active metal Advantageous developments of the rechargeable battery cell according to the invention with respect to the active metals are described below:

[0058] In a first advantageous development of the rechargeable battery cell, the active metal is: - an alkali metal, in particular lithium or sodium, - alkaline earth metals, especially calcium, - metals of group 12 of the periodic table, in particular zinc, or - Aluminum.

[0059] negative electrode Advantageous developments of the rechargeable battery cell according to the invention with respect to the negative electrode are described below:

[0060] In another advantageous development of the rechargeable battery cell, the negative electrode is an insertion electrode. The insertion electrode comprises an insertion material as active material, in which ions of the active metal can be stored during charging of the rechargeable battery cell and released from the insertion material during discharging of the rechargeable battery cell. This means that electrode processes can be carried out not only on the surface of the negative electrode but also inside the negative electrode. For example, when using lithium-based conductive salts, lithium ions can be stored in the insertion material during charging of the rechargeable battery cell and released from the insertion material during discharging of the rechargeable battery cell. The negative electrode preferably comprises carbon, in particular modified graphite, as active or insertion material. However, it is also within the scope of the invention that the carbon is in the form of natural graphite (flaky promoter or round), synthetic graphite (mesophase graphite), graphitized mesocarbon microbeads (MCMB), carbon-coated graphite or amorphous carbon.

[0061] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode is, for example, lithium titanate (e.g. Li4Ti5O 12 ) or the like.

[0062] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode comprises an active negative electrode material which forms an alloy with lithium, for example metals and metal alloys which store lithium (e.g. Si, Ge, Sn, SnCo). x C y , SnSi x etc.) and oxides of metals and metal alloys that store lithium (e.g., SnO x , SiO x Or oxide glasses of Sn, Si, etc.

[0063] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode comprises a converted negative electrode active material, for example manganese oxide (MnO x), iron oxide (FeO x ), cobalt oxide (CoO x ), nickel oxide (NiO x ), copper oxide (CuO x ), metal hydrides in the form of magnesium hydride (MgH2), titanium hydride (TiH2), aluminum hydride (AlH3), and ternary hydrides based on boron, aluminum, and magnesium.

[0064] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode comprises a metal, in particular metallic lithium.

[0065] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode is porous, with a porosity of preferably at most 50%, more preferably at most 45%, more preferably at most 40%, more preferably at most 35%, more preferably at most 30%, more preferably at most 20% and particularly preferably at most 10%. The porosity refers to the void volume relative to the total volume of the negative electrode, the void volume being formed by so-called pores or voids. The porosity results in an increase in the internal surface of the negative electrode. Furthermore, the porosity reduces the density of the negative electrode and thus also its weight. The individual pores of the negative electrode can preferably be completely filled by the electrolyte during operation.

[0066] In another advantageous development of the battery cell according to the invention, the negative electrode has a conductor element. This means that the negative electrode also contains a conductor element in addition to the active material or the intercalation material. The conductor element is used to enable the required electronically conductive connection of the active material of the negative electrode. To this end, the conductor element is in contact with the active material participating in the electrode reaction of the negative electrode. The conductor element can be formed planar in the form of a thin metal sheet or thin metal foil. The thin metal foil preferably has a perforated or mesh-like structure. The active material of the negative electrode is preferably applied to the surface of the thin metal sheet or thin metal foil. Planar conductor elements of this kind have a thickness in the range of 5 μm to 50 μm. The thickness of the planar conductor element is preferably in the range of 10 μm to 30 μm. When planar conductor elements are used, the total thickness of the negative electrode can be at least 20 μm, preferably at least 40 μm and particularly preferably at least 60 μm. The maximum thickness is at most 200 μm, preferably at most 150 μm and particularly preferably at most 100 μm. The area-specific capacitance of the negative electrode is preferably at least 0.5 mAh / cm when planar conductor elements are used. 2 and furthermore the following values ​​in this order are preferred: 1 mAh / cm 2 , 3mAh / cm 2 , 5mAh / cm 2 , 10mAh / cm 2 .

[0067] It is also possible to form the conductor element three-dimensionally in the form of a porous metal structure, in particular a metal foam. The term "three-dimensional porous metal structure" refers to any metallic structure that extends not only over the length and width of the planar electrode, such as the thin metal sheet or metal foil, but also over the thickness dimension of the electrode. The three-dimensional porous metal structure is porous so that the active material of the negative electrode can be incorporated into the pores of the metal structure. The amount of the active material incorporated or applied refers to the loading of the negative electrode. When the conductor element is three-dimensionally formed in the form of a porous metal structure, in particular a metal foam, the negative electrode preferably has a thickness of at least 0.2 mm, preferably at least 0.3 mm, more preferably at least 0.4 mm, more preferably at least 0.5 mm and particularly preferably at least 0.6 mm. The thickness of the electrode in this case is significantly greater than that of the negative electrodes used in organic lithium-ion batteries. In another advantageous embodiment, when using a metal foam shape, in particular a three-dimensional conductor element formed in the shape of a metal foam, the area-specific capacity of the negative electrode is preferably at least 2.5 mAh / cm 2 and the following values ​​are more preferred in this order: 2 , 10mAh / cm 2 , 15mAh / cm 2 , 20mAh / cm 2 , 25mAh / cm 2 , 30mAh / cm 2 When the conductor element is formed in the form of a three-dimensional porous metal structure, in particular in the form of a metal foam, the amount of active material of the negative electrode, i.e. the filling of the electrode with respect to its surface, is at least 10 mg / cm 2 , preferably at least 20 mg / cm 2 , and more preferably at least 40 mg / cm 2 , and more preferably at least 60 mg / cm 2 , and more preferably at least 80 mg / cm 2 and particularly preferably at least 100 mg / cm 2This loading of the negative electrode has a positive effect not only on the charging process but also on the discharging process of the rechargeable battery cell.

[0068] In another advantageous development of the battery cell according to the invention, the negative electrode comprises at least one binder, which is a fluorinated binder, in particular polyvinylidene fluoride and / or a terpolymer formed from tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride. However, it may also be a binder consisting of a polymer of monomeric structural units of conjugated carboxylic acids or of the alkali metal, alkaline earth metal or ammonium salts of said conjugated carboxylic acids or a combination thereof. It may also be a polymer based on monomeric styrene and butadiene structural units. It may also be a binder from the carboxymethylcellulose group. The binder is preferably present in the negative electrode in a concentration of at most 20 wt%, more preferably at most 15 wt%, more preferably at most 10 wt%, more preferably at most 7 wt%, more preferably at most 5 wt% and particularly preferably at most 2 wt%, relative to the total weight of the negative electrode.

[0069] positive electrode Advantageous developments of the rechargeable battery cell according to the invention with respect to the positive electrode are described below:

[0070] In another advantageous development of the battery cell according to the invention, the positive electrode comprises at least one intercalation compound as active material. The term "intercalation compound" in the sense of the present invention is to be understood as a subcategory of the aforementioned intercalation materials. The intercalation compound functions as a host matrix with interconnected voids into which the ions of the active metal can diffuse and accumulate during the discharge process of the rechargeable battery cell. Little or no structural changes of the host matrix occur in the course of the accumulation of the ions of the active metal. The intercalation compound is Li x M' y M”z O a The composition is M' is at least one metal selected from the group formed by the elements Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, M″ is at least one element selected from the group formed by the elements of groups 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 and 16 of the Periodic Table of the Elements, - x and y are independent numbers greater than 0, - z is a number equal to or greater than 0, and - a is a number greater than 0.

[0071] The indices y and z represent the sum of the metals and elements represented by M' or M", respectively. For example, if M' comprises two metals M'1 and M'2, then the index y is y=y1+y2, where y1 and y2 represent the indices of the metals M'1 and M'2. The indices x, y, z and a must be selected such that the charge in the composition is neutral.

[0072] Formula Li x M' y M” z In another advantageous development of the rechargeable battery cell according to the invention, the compound Li x M' y M” z In the embodiment, M′ is iron and M″ is phosphorus. In this case, the intercalation compound is lithium iron phosphate (LiFePO4). In another advantageous development of the rechargeable battery cell according to the invention, the compound Li x M' y M” z In this case, the intercalation compound is lithium cobalt manganese oxide (LiCoMnO4). By using LiCoMnO4, it is possible to manufacture high-voltage electrodes for so-called high-energy cells, whose cell potential exceeds 5 volts. LiCoMnO4 is a compound containing Mn 3+ It is preferred that the formula is not included.

[0073] In another advantageous development of the rechargeable battery cell according to the invention, M' consists of the metals nickel and manganese and M" is cobalt. In this case, the metals of the formula Li x Ni y1 Mn y2 Co z O2(NMC) compound. An example of such an intercalation compound made of lithium nickel manganese cobalt oxide is LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2(NMC111), LiNi 0.6 Mn 0.2 Co2O2(NMC622) and LiNi 0.8 Mn 0.1 Co 0.1 O2(NMC811).

[0074] The high voltage electrode may be cycled in the rechargeable battery cell according to the invention to an upper potential of at least 4.0 volts, more preferably to an upper potential of 4.2 volts, more preferably to an upper potential of 4.4 volts, more preferably to an upper potential of 4.6 volts, more preferably to an upper potential of 4.8 volts and particularly preferably to an upper potential of 5.0 volts.

[0075] In another advantageous development of the rechargeable battery cell according to the invention, the positive electrode comprises at least one metal compound selected from the group formed by metal oxides, metal halides and metal phosphates, the metal of which is preferably a transition metal of atomic numbers 22 to 28 of the periodic table of the elements, in particular cobalt, nickel, manganese or iron.

[0076] In another advantageous development of the battery cell according to the invention, the positive electrode has a conductor element, which means that in addition to the active material, the positive electrode also comprises a conductor element, which is used to enable the required electronically conductive connection of the active material of the positive electrode, for which the conductor element is in contact with the active material participating in the electrode reaction of the positive electrode.

[0077] The conductor element may be formed planar in the form of a thin metal sheet or a thin metal foil. The thin metal foil preferably has a perforated or mesh structure. The active material of the positive electrode is preferably applied to the surface of the thin metal sheet or the thin metal foil. Planar conductor elements of this kind have a thickness in the range of 5 μm to 50 μm. A thickness of the planar conductor elements in the range of 10 μm to 30 μm is preferred. When planar conductor elements are used, the total thickness of the positive electrode may be at least 20 μm, preferably at least 40 μm and particularly preferably at least 60 μm. The maximum thickness is at most 200 μm, preferably at most 150 μm and particularly preferably at most 100 μm. The area-specific capacitance of the positive electrode is preferably at least 0.5 mAh / cm when planar conductor elements are used. 2 and furthermore the following values ​​in this order are preferred: 1 mAh / cm 2 , 3mAh / cm 2 , 5mAh / cm 2 , 10mAh / cm 2 .

[0078] It is also possible to form the conductor elements of the positive electrode three-dimensionally in the form of a porous metal structure, in particular in the form of a metal foam. The three-dimensional porous metal structure is porous so that the active material of the positive electrode can be incorporated into the pores of the metal structure. The amount of the incorporated or applied active material refers to the loading of the positive electrode. When the conductor elements are formed three-dimensionally in the form of a porous metal structure, in particular in the form of a metal foam, the positive electrode preferably has a thickness of at least 0.2 mm, preferably at least 0.3 mm, more preferably at least 0.4 mm, more preferably at least 0.5 mm and particularly preferably at least 0.6 mm. In another advantageous embodiment, the area-specific capacity of the positive electrode when using three-dimensional conductor elements in the form of a metal foam, in particular in the form of a metal foam, is preferably at least 2.5 mAh / cm. 2 and the following values ​​are more preferred in this order:2 , 10mAh / cm 2 , 15mAh / cm 2 , 20mAh / cm 2 , 25mAh / cm 2 , 30mAh / cm 2 When the conductor element is formed in the form of a three-dimensional porous metal structure, in particular in the form of a metal foam, the amount of active material of the positive electrode, i.e. the filling of the electrode with respect to its surface, is at least 10 mg / cm 2 , preferably at least 20 mg / cm 2 , and more preferably at least 40 mg / cm 2 , and more preferably at least 60 mg / cm 2 , and more preferably at least 80 mg / cm 2 and particularly preferably at least 100 mg / cm 2 This loading of the positive electrode has a positive effect not only on the charging process but also on the discharging process of the rechargeable battery cell.

[0079] In another advantageous development of the battery cell according to the invention, the positive electrode comprises at least one binder, which is a fluorinated binder, in particular polyvinylidene fluoride and / or a terpolymer formed by tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride. However, it can also be a binder consisting of a polymer consisting of monomeric structural units of conjugated carboxylic acids or of alkali metal, alkaline earth metal or ammonium salts of said conjugated carboxylic acids or a combination thereof. It can also be a polymer based on monomeric styrene and butadiene structural units. It can also be a binder consisting of a binder from the carboxymethylcellulose group. The binder is preferably present in the positive electrode in a concentration of at most 20 wt%, more preferably at most 15 wt%, more preferably at most 10 wt%, more preferably at most 7 wt%, more preferably at most 5 wt% and particularly preferably at most 2 wt%, relative to the total weight of the positive electrode.

[0080] Rechargeable battery cell structure Advantageous developments of the rechargeable battery cell according to the invention are explained below with respect to its structure:

[0081] In order to further improve the function of the rechargeable battery cell, in another advantageous development of the rechargeable battery cell according to the invention, the rechargeable battery cell has a number of negative electrodes and a number of positive electrodes arranged in a housing in an alternating stack, the positive electrodes and the negative electrodes being preferably electrically separated from each other by respective separators.

[0082] However, the rechargeable battery cell may also be formed as a coil cell, in which the electrodes are formed as thin layers wound with a separator material. The separator, on the one hand, spatially and electrically separates the positive and negative electrodes, and on the other hand, is permeable, inter alia, to the ions of the active metal. This creates a large electrochemically effective surface, which allows a correspondingly high current yield. The separator can be formed using nonwovens, membranes, wovens, knits, organic materials, inorganic materials or combinations thereof. Organic separators can consist, for example, of unsubstituted polyolefins (e.g. polypropylene or polyethylene), fully to partially halogenated polyolefins (e.g. partially to fully fluorinated, in particular PVDF, ETFE, PTFE), polyesters, polyamides or polysulfones. Separators comprising a combination of organic and inorganic materials are, for example, woven glass fiber materials, in which the glass fibers are provided with a suitable polymer coating. The coating is a fluorine-containing polymer, such as polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), perfluoroethylene propylene (FEP), THV (a terpolymer of tetrafluoroethylene, hexafluoroethylene, and vinylidene fluoride), perfluoroalkoxy polymer (PFA), aminosilane, polypropylene, or polyethylene (PE). The separator can also be folded in the housing of the rechargeable battery cell, for example in a so-called "Z-fold" shape. In the case of the Z-fold, the strip-shaped separator is folded in a Z shape so as to pass through the electrodes or around the electrodes. The separator can also be formed as a separator paper.

[0083] It is also within the scope of the present invention that the separator may be formed as a coating, and each positive electrode or each negative electrode may be covered by the coating, which may be formed using a nonwoven fabric, a membrane, a woven fabric, a knitted fabric, an organic material, an inorganic material, or a combination thereof.

[0084] The coating of the positive electrode ensures uniform ion migration and distribution in the rechargeable battery cell. The more uniform the ion distribution, especially in the negative electrode, the greater the possible loading of active material in the negative electrode and, therefore, the greater the usable capacity of the rechargeable battery cell. At the same time, the risk of non-uniform loading and the resulting precipitation of the active metal is avoided. This advantage is particularly evident when the positive electrode of the rechargeable battery cell is covered by the coating.

[0085] The surface dimensions of the electrode and the coating are preferably coordinated with one another such that the outer dimensions of the coating on the electrode and the outer dimensions of the uncoated electrode match in at least one dimension.

[0086] The surface area of ​​the coating may preferably be larger than the surface area of ​​the electrode, in which case the coating extends beyond the boundaries of the electrode, so that two layers of the coating covering both sides of the electrode may be connected to each other at the edge of the positive electrode by an edge connection.

[0087] In a further advantageous embodiment of the rechargeable battery cell according to the invention, the negative electrode has a coating whereas the positive electrode has no coating.

[0088] Further advantageous properties of the present invention are described and explained in detail below with the aid of figures, examples and experiments. [Brief description of the drawings]

[0089] [Figure 1] 1 is a cross-sectional view of a first example embodiment of a rechargeable battery cell according to the present invention; [Diagram 2] FIG. 2 is a detailed view of an electron microscope photograph of the three-dimensional pore structure of the metal foam according to the first embodiment of FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view of a second example embodiment of a rechargeable battery cell according to the present invention. [Figure 4] FIG. 4 is a diagram showing details of the second embodiment of FIG. 3. [Diagram 5] FIG. 11 is an exploded view of a third example embodiment of a rechargeable battery cell according to the present invention. [Figure 6] FIG. 1 shows the charge / discharge potential course (in [V]) as a function of the charge fraction of a half-cell filled with electrolyte X1. [Figure 7] FIG. 1 shows the charge / discharge potential course (in [V]) as a function of charge fraction for an experimental complete cell filled with electrolyte X1. [Figure 8] FIG. 2 shows the potential (in [V]) during charging in two experimental complete cells filled with 9% / 91% electrolyte and with the reference electrolyte as a function of capacity relative to the theoretical capacity of the negative electrode during the formation of the surface layer on the negative electrode. [Figure 9] FIG. 1 shows the discharge capacity as a function of cycle number in two experimental complete cells filled with 9% / 91% electrolyte and reference electrolyte. [Figure 10] FIG. 1 shows the potential (in [V]) during charging in two experimental complete cells filled with 30% / 70% electrolyte and with the reference electrolyte as a function of capacity relative to the theoretical capacity of the negative electrode during the formation of the surface layer on the negative electrode. [Figure 11] FIG. 1 shows the discharge capacity as a function of cycle number for two experimental complete cells filled with 30% / 70% electrolyte and reference electrolyte. [Figure 12] FIG. 2 shows the conductivity (units [mS / cm]) of the electrolyte X1 according to the invention depending on the concentration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0090] FIG. 1 shows a cross-sectional view of a first embodiment of a rechargeable battery cell 2 according to the invention. The rechargeable battery cell 2 is formed as a prismatic cell and has, inter alia, a housing 1. The housing 1 encloses an electrode unit 3, which comprises three positive electrodes 4 and four negative electrodes 5. The positive electrodes 4 and the negative electrodes 5 are arranged in an alternating stack in the electrode unit 3. However, the housing 1 can also accommodate more positive electrodes 4 and / or negative electrodes 5. In general, it is preferred that the number of negative electrodes 5 exceeds the number of positive electrodes 4 by one. The outer end face of the electrode stack is thus formed by the electrode surface of the negative electrode 5. The electrodes 4, 5 are connected via electrode connections 6, 7 to corresponding connection contacts 9, 10 of the rechargeable battery cell 2. The rechargeable battery cell 2 is filled with an SO2-based electrolyte, with the electrolyte penetrating as completely as possible into all pores or cavities of the electrodes 4, 5, in particular on the inside. The electrolyte is not shown in FIG. 1. In this embodiment, the positive electrode 4 comprises an intercalation compound as active material. The intercalation compound is LiCoMnO4.

[0091] In this embodiment, the electrodes 4, 5 are formed as planar layers, i.e. layers with a small thickness in relation to their surface area. They are separated from each other by a separator 11. The housing 1 of the rechargeable battery cell 2 is formed in a substantially cubic shape, the electrodes 4, 5 and the walls of the housing 1, shown in cross-section, extend perpendicular to the drawing plane and are formed substantially straight and flat. The rechargeable battery cell 2 may, however, also be formed as a coil cell, in which the electrodes are formed as thin layers wound with a separator material. The separator 11, on the one hand, spatially and electrically separates the positive electrode 4 and the negative electrode 5, and on the other hand, is permeable, inter alia, to the ions of the active metal. This forms a large electrochemically effective surface, which allows a correspondingly high current yield.

[0092] Furthermore, the electrodes 4, 5 have a conductor element, not shown in FIG. 1, used to enable the required electronically conductive connection of the active material of the respective electrode. The conductor element is in contact with the active material (not shown in FIG. 1) participating in the electrode reaction of the respective electrode 4, 5. The conductor element is formed in the form of a porous metal foam. The metal foam extends over the thickness dimension of the electrodes 4, 5. The active material of the positive electrode 4 and the negative electrode 5 is respectively incorporated into the pores of the metal foam, so that the active material fills the pores of the metal foam uniformly over the total thickness of the metal structure. To improve the mechanical strength, the positive electrode 4 contains a binder. The binder is a fluoropolymer. The negative electrode 5 contains carbon as the active material in a form suitable for accepting lithium ions as an intercalation material. The structure of the negative electrode 5 is similar to that of the positive electrode 4.

[0093] Figure 2 illustrates an electron micrograph of the three-dimensional pore structure of the metal foam 18 of the first example embodiment in Figure 1. Based on the scale shown, it can be seen that the average diameter of the pores P is greater than 100 μm, i.e., relatively large.

[0094] FIG. 3 shows a cross-sectional view of a second embodiment of a rechargeable battery cell 20 according to the invention. This second embodiment differs from the first embodiment shown in FIG. 1 in that the electrode unit comprises one positive electrode 23 and two negative electrodes 22. The electrodes 22, 23 are separated from each other by a separator 21 and are surrounded by a housing 28. The positive electrode 23 comprises a conductor element 26 in the form of a planar metal foil on which the active material 24 of the positive electrode 23 is applied on both sides. The negative electrode 22 also comprises a conductor element 27 in the form of a planar metal foil on which the active material 25 of the negative electrode 22 is applied on both sides. Alternatively, it is also possible to coat only one side of the planar conductor element of the edge electrode, i.e. the electrode that closes the electrode stack, with active material. The uncoated side faces the wall of the housing 28. The electrodes 22 , 23 are connected via electrode connections 29 , 30 to corresponding connection contacts 31 , 32 of the rechargeable battery cell 20 .

[0095] Figure 4 illustrates the planar metal foil used as conductor elements 26, 27 of the positive electrode 4 and the negative electrode 5, respectively, in the second embodiment of Figure 3. The metal foil has a perforated or mesh-like structure with a thickness of 20 μm.

[0096] Fig. 5 shows an exploded view of a third embodiment of a rechargeable battery cell 40 according to the invention. This embodiment differs from the previous two embodiments in that the positive electrode 44 is covered by a coating 13 acting as a separator. The surface area of ​​the coating 13 is larger than that of the positive electrode 44, the boundary 14 of which is drawn in Fig. 5 by a dashed line. The two layers 15, 16 of the coating 13, which cover both sides of the positive electrode 44, are connected to each other by an edge connection 17 at the periphery of the positive electrode 44. Both negative electrodes 45 are uncoated. The electrodes 44 and 45 can be contacted via the electrode connections 46 and 47.

[0097] [Example 1] Preparation of reference electrolyte For the experiments described below, a reference electrolyte based on SO2 was prepared. For this purpose, the following compound 1 was prepared as a conductive salt according to formula (II) according to the preparation method described in the following document [V5]: [V5]I. Krossing, Chem. Eur. J. 2001, 7, 490

[0098] Compound 1 is a member of the polyfluoroalkoxyaluminate family and reacts with LiAlH4 and the corresponding alcohol R-OH(R 1 =R 2 =R 3 =R 4 ) and prepared according to the following reaction scheme:

[0099] [ka]

[0100] This formed compound 1, which has the molecular or structural formula shown below:

[0101] [ka]

[0102] To prepare a reference electrolyte, the compound 1 was dissolved in SO2. The concentration of the conductive salt in the reference electrolyte was 0.6 mol / L.

[0103] Example 2: Preparation of an embodiment of an electrolyte according to the present invention Conductive salts according to formula (I) containing chelating ligands were prepared starting from the corresponding diols H-R-OH according to the preparation method described in document [V6]: [V6]Wu Xu et al., Electrochem. Solid-State Lett. 2000, 3, 366-368. The following chemical equation illustrates, for example, the preparation of compound X1:

[0104] [ka]

[0105] For purification, the compound X1 was first recrystallized, which removed residual free form from the conductive salt.

[0106] Conductive salts according to formula (I), in which three alkoxy groups and one fluoride group are coordinated to a central atom, can be prepared according to the preparation method described in document [V7]: [V7]A. Martens et al., Chem. Sci., 2018, 9, 7058-7068

[0107] The following compounds X2 were used in the experiments:

[0108] [ka] To prepare conducting salts according to formula (I) with at least one alkoxy group and at least one hydroxy group coordinated to the central atom, a tetraalkoxy compound is treated with a stoichiometric amount of a donor solvent, thus for example reacting Li[Al(OC(CF3)3)4] with water to give the following compounds X3 and X4:

[0109] [ka]

[0110] The compounds X1, X2, X3 and X4 were dissolved in SO2 to prepare the electrolytes X1, X2, X3 and X4. The preparation was carried out at low temperature or under pressure according to the method steps 1 to 4 listed below: 1) Each of the compounds X1, X2, X3 and X4 is placed in a pressure flask equipped with a riser pipe. 2) Emptying the pressure flask; 3) Liquid SO2 is injected, and 4) Repeat steps 2 and 3 until the target amount of SO2 has been added.

[0111] Example 3: Preparation of a complete experimental cell The experimental complete cells used in the experiments described below are rechargeable battery cells with two negative electrodes and one positive electrode, each separated by a separator. The positive electrode had an active material, a conductivity enhancer, a binder and a conductor element consisting of nickel or aluminum. The active material of the positive electrode is stated in the respective experiment. The negative electrode also contained graphite as active material, a binder and a conductor element consisting of nickel or copper. If stated in the experiment, the negative electrode may further have a conductive additive. In particular, the purpose of the experiments is to demonstrate the functionality of various electrolytes in a battery cell according to the invention. The experimental complete cells were filled with the electrolyte required for the experiment, i.e. the reference electrolyte or the electrolytes X1, X2, X3 and X4 according to the invention. For the experiments, several identical experimental complete cells were produced, i.e. two to four. The results shown in each experiment are then the average of the measurements obtained on each identical experimental complete cell.

[0112] [Example 4] Measurements in a complete experimental cell Surface capacity: The capacity consumed in the first cycle to form a surface layer on the negative electrode is an important criterion for the quality of the battery cell. The surface layer is formed on the negative electrode during the first charge of the experimental full cell. The surface layer formation consumes lithium ions irreversibly (surface capacity), which reduces the cyclable capacity available for the experimental full cell in subsequent cycles. The surface capacity (unit [%]) relative to the theoretical value used to form the surface layer on the negative electrode is calculated by the following formula:

[0113] Surface capacity [% of theoretical value] = (Q lad (xmAh)-Q ent (ymAh) / Q NEL

[0114] Q lad is the charge amount (unit [mAh]) specified in each experiment, Q ent Q is the charge (unit: mAh) obtained during the subsequent discharge of the experimental complete cell. NEL is the theoretical capacity of the negative electrode used. For example, in the case of graphite, the theoretical capacity is calculated based on a value of 372 mAh / g.

[0115] Discharge capacity: In the measurement of an experimental complete cell, for example, the discharge capacity is determined by the number of cycles. For this purpose, the experimental complete cell is charged to a predetermined upper potential limit at a predetermined charging current. The corresponding upper potential limit is held until the charging current drops to a certain value. Then, discharging is performed at a predetermined discharging current until a predetermined discharging potential is reached. This charging method is called I / U charging. The process is repeated for the desired number of cycles.

[0116] The upper limit potential or the discharge capacity and the respective charge and discharge current are described in the experiments. The value to which the charge current should be reduced is also described in the experiments.

[0117] The term "upper potential limit" is used synonymously with the terms "charging potential", "charging voltage", "end-of-charge voltage" and "upper potential limit", which indicate the voltage / potential that a cell or battery must reach when being charged by a battery charging device.

[0118] Charging of the battery is preferably carried out at a current rate of C / 2 and at a temperature of 22°C.

[0119] The term "discharge potential" is used synonymously with the term "bottom cell voltage," which refers to the voltage / potential that a cell or battery must reach when it is discharged by a battery charging device.

[0120] Discharging of the battery is preferably carried out at a current rate of C / 2 and at a temperature of 22°C.

[0121] The discharge capacity is determined by the discharge current and the time until the criteria for terminating discharge are met. The associated figures show the average discharge capacity as a function of the cycle number. The average discharge capacity is often normalized to 100% of the starting capacity and expressed as a percentage of the nominal capacity.

[0122] [Experiment 1] Behavior of the negative electrode in a half cell with electrolyte X1 The experiments were carried out in a half-cell with metallic lithium as the return and reference electrodes. The working electrode was a graphite electrode. The half-cell was filled with electrolyte X1.

[0123] The half-cell was charged to a potential of 0.03 V and discharged to a potential of 0.5 V at a charge / discharge rate of 0.02 C. Figure 6 shows the charge and discharge curve potentials of the half-cell for the second cycle. The solid curve corresponds to the charge curve potential, and the dashed curve corresponds to the discharge curve potential.

[0124] The charge / discharge curves show typical behavior for a battery, thus demonstrating the basic functionality of the electrolyte X1 in a half cell.

[0125] [Experiment 2] Behavior of the experimental complete cell with electrolyte X1 The electrolyte X1 was investigated in this experiment in an experimental complete cell, the construction of which corresponded to that described in example 3. The negative electrode had graphite as active material, and for the positive electrode nickel manganese cobalt oxide (NMC622) was used as active material.

[0126] To determine the discharge capacity, the experimental complete cell was charged to a potential of 4.6 volts and discharged to a potential of 2.5 volts at a charge / discharge current of 100 mA.

[0127] 7 shows the potential profile during charging and discharging of an experimental complete cell in the second cycle, which shows typical behavior for a battery, thus demonstrating the basic functionality of the electrolyte X1 in a battery cell.

[0128] [Experiment 3] Behavior of experimental complete cells containing mixtures of 9 wt% of electrolytes X2, X3 and X4 and 91 wt% of the reference electrolyte To investigate the electrolytes X2, X3 and X4, mixtures of said electrolytes were prepared. 9 wt% of said mixtures were mixed with 91 wt% of the reference electrolyte. The electrolyte thus obtained is called "electrolyte 9% / 91%". Various experiments were carried out with said electrolyte 9% / 91%. On the one hand, the surface capacity of said electrolytes was determined. On the other hand, the discharge capacity in said electrolytes was determined. For comparison, both experiments were also carried out with the reference electrolyte.

[0129] For this experiment, the reference electrolyte and the electrolyte 9% / 91%, respectively, were investigated in experimental complete cells. The construction corresponded to that described in Example 3. The negative electrode had graphite as active material, and for the positive electrode nickel manganese cobalt oxide (NMC622) was used as the electrode active material.

[0130] FIG. 8 shows the potential (in [V]) of a rechargeable battery cell during charging as a function of capacity with respect to the theoretical capacity of the negative electrode, with the dotted line showing the results for the reference electrolyte and the solid line showing the results for the electrolyte 9% / 91% according to the invention. Each of the two illustrated curves shows the results of one representative individual cell. The experimental complete cell was first charged at a current of 15 mA until it reached a capacity of 125 mAh. It was then discharged at a current of 15 mA until it reached a potential of 2.5 volts. The surface capacity was determined from the capacity behavior in the first cycle.

[0131] The capacity loss is 6.64% for the 9% / 91% electrolyte and 5.62% for the reference electrolyte. The capacity for surface layer formation is slightly higher for the electrolyte according to the invention than for the reference electrolyte. The capacity loss value in the range of 6.6% is a good result.

[0132] To determine the discharge capacity (see Example 4), both experimental complete cells were charged to a potential of 4.4 volts at a current of 100 mA after determining the surface capacity, and then discharged to a potential of 2.5 volts at a current of 100 mA.

[0133] Figure 9 shows the percentage of discharge capacity [% of nominal capacity] of an experimental full cell over 100 cycles as a function of cycle number, with the dotted line showing the results for the reference electrolyte and the solid line showing the results for the electrolyte 9% / 91% according to the invention. During the measurement of the experimental full cell with the electrolyte 9% / 91%, a disturbance occurred in the measurements from cycle 4 to cycle 34, so that the values ​​in this range are slightly lower. From cycle 35 onwards, the disturbance disappeared. The course of the discharge capacity of both experimental full cells is very flat. The electrolyte 9% / 91% is very suitable for the operation of a battery cell.

[0134] [Experiment 4] Behavior of experimental complete cells containing mixtures of 30 wt% of electrolytes X2, X3 and X4 and 70 wt% of the reference electrolyte To further investigate the electrolytes X2, X3 and X4, a mixture of said electrolytes was prepared. This time 30 wt% of said mixture was mixed with 70 wt% of the reference electrolyte. The electrolyte thus obtained is called "electrolyte 30% / 70%". The same experiment was carried out with said electrolyte 30% / 70% as with the electrolyte 9% / 91% described in experiment 3. The measurement parameters are found in experiment 3. On the one hand, the surface capacity of said electrolyte was determined. On the other hand, the discharge capacity on said electrolyte was determined. For comparison, both experiments were also carried out with the reference electrolyte.

[0135] Figure 10 shows the potential (in [V]) of an experimental complete cell as a function of capacity with respect to the theoretical capacity of the negative electrode during charging of the cell, with the dotted line showing the results for the reference electrolyte and the solid line showing the results for the electrolyte 30% / 70% according to the invention. The capacity loss is 5.63% for the electrolyte 30% / 70% and 6.09% for the reference electrolyte. The capacity for surface layer formation is slightly lower for the electrolyte according to the invention than for the reference electrolyte. The capacity loss values ​​in the range of 5.6% are excellent results.

[0136] Figure 11 shows the percentage of discharge capacity [% of nominal capacity] of experimental full cells over 200 cycles as a function of cycle number, with the dotted line showing the results for the reference electrolyte and the solid line showing the results for the 30% / 70% electrolyte according to the invention. Both experimental full cells show a very flat course of discharge capacity, with the curve for the 30% / 70% electrolyte being a little more stable. The 30% / 70% electrolyte is excellently suited for operation in a battery cell.

[0137] [Experiment 5] Measurement of the conductivity of electrolyte X1 For conductivity measurement, the electrolyte X1 was prepared with the compound X1 in various concentrations. The conductivity of the electrolyte was measured for each concentration of the compound using a conductance measurement method, in which a four-electrode sensor was held in contact with the solution after tempering and the measurement range was 0.02 to 500 mS / cm.

[0138] 12 illustrates the conductivity of the electrolyte X1 according to the invention depending on the concentration of compound X1. The maximum conductivity is seen to be about 11.3 mS / cm when said compound X1 has a concentration of 0.6 mol / L.

Claims

1. SO for rechargeable battery cells ２ A cation-based electrolyte having the formula (I) 【Chemistry 1】 at least one first conductive salt having the formula: M is a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements and aluminum; x is an integer from 1 to 3; substituent R １ and R ２ are selected independently of one another from the group formed by halogen atoms, hydroxy groups, chemical groups -OR5 and chelating ligands, substituent R ３ is a hydroxy group, a chemical group -OR ５ and a chelating ligand, substituent R ４ is selected from the group formed by halogen atoms, hydroxy groups and chelating ligands, the chelating ligand is formed by at least two of the substituents R 1 , R 2 , R 3 and R 4 and is coordinated to Z; substituent R ５ is C １ ~C １０ Alkyl, C ２ ~C １０ Alkenyl, C ２ ~C １０ Alkynyl, C ３ ~C １０ Cycloalkyl, C ６ ~C １４ Aryl and C ５ ~C １４ Heteroaryl, An electrolyte wherein Z is aluminum or boron.

2. The substituent R ５ Electrolyte according to claim 1, characterized in that is selected from the group formed by: C １ ~C ６ Alkyl, C ２ ~C ６ Alkenyl, C ２ ~C ６ Alkynyl, C ３ ~C ６ Cycloalkyl, Phenyl, and C ５ ~C ７ Heteroaryl.

3. The substituent R ５ At least one individual atom or group of atoms of is replaced by a halogen atom or a chemical group, said chemical group being C １ ~C ４ Alkyl, C ２ ~C ４ Alkenyl, C ２ ~C ４ Alkynyl, phenyl, benzyl and fully to partially halogenated C １ ~C ４ Alkyl, C ２ ~C ４ Alkenyl, C ２ ~C ４ Electrolyte according to claim 1 or 2, characterized in that it is selected from the group formed by alkynyl, phenyl and benzyl.

4. The electrolyte described in claim 3, characterized in that at least one individual atom or one atomic group of the substituent R 5 is substituted by a fluorine atom or a chemical group selected from the group formed by fully to partially fluorinated C 1 -C 4 alkyl, C 2 -C 4 alkenyl, C 2 -C 4 alkynyl, phenyl and benzyl.

5. The substituent R ５ At least one atomic group of ３ Group or OSO ２ CF ３ The electrolyte according to any one of claims 1 to 4, characterized in that it is a group.

6. The chelating ligand has the formula -O-R ５ 6. The electrolyte according to claim 1, which is formed so as to be bidentate or polydentate by -O-.

7. Electrolyte according to any one of claims 1 to 6, characterized in that the first conductive salt is selected from the group formed by: 【Chemistry 2】

8. 8. An electrolyte according to any one of the preceding claims, characterized in that it comprises at least one second conductive salt different from the first conductive salt according to formula (I).

9. The second conductive salt has the formula (II): 【Chemistry 3】 having M is a metal selected from the group formed by alkali metals, alkaline earth metals, metals of group 12 of the periodic table of the elements and aluminum; x is an integer from 1 to 3; substituent R ６ , R ７ , R ８ and R ９ are independently C １ ~C １０ Alkyl, C ２ ~C １０ Alkenyl, C ２ ~C １０ Alkynyl, C ３ ~C １０ Cycloalkyl, C ６ ~C １４ Aryl and C ５ ~C １４ Heteroaryl, 9. The electrolyte of claim 8, wherein Z is aluminum or boron.

10. 9. The electrolyte of claim 8, wherein the second conductive salt is an alkali metal compound selected from the group formed by aluminates, halides, oxalates, borates, phosphates, arsenates and gallates.

11. Electrolyte according to any one of the preceding claims, characterized in that it comprises at least one additive.

12. The additives include vinylene carbonate and its derivatives, vinyl ethylene carbonate and its derivatives, methyl ethylene carbonate and its derivatives, lithium (bisoxalato)borate, lithium difluoro(oxalato)borate, lithium tetrafluoro(oxalato)phosphate, lithium oxalate, 2-vinylpyridine, 4-vinylpyridine, cyclic exomethylene carbonate, sulfones, cyclic and acyclic sulfonates, acyclic sulfites, cyclic and acyclic sulfinic acid esters, organic esters, inorganic acids, acyclic and cyclic alkanes (including the acyclic and cyclic alkanes), 12. The electrolyte according to claim 11, characterized in that the halogenated cyclic and acyclic sulfonyl imides, halogenated cyclic and acyclic phosphate esters, halogenated cyclic and acyclic phosphines, halogenated cyclic and acyclic phosphites, halogenated cyclic and acyclic phosphazenes, halogenated cyclic and acyclic silylamines, halogenated cyclic and acyclic halogenated esters, halogenated cyclic and acyclic amides, halogenated cyclic and acyclic anhydrides and halogenated organic heterocycles.

13. 13. The electrolyte of claim 1, characterized in that the electrolyte has the following composition with respect to the total weight of the electrolyte composition: (i) from 5 to 99.4 wt. % of sulfur dioxide, (ii) from 0.6 to 95 wt. % of the first conductive salt, (iii) from 0 to 25 wt. % of a second conductive salt, and (iv) from 0 to 10 wt. % of an additive.

14. Electrolyte according to any one of claims 1 to 13, characterized in that the concentration of the quantity of substance of the first conductive salt is in the range of 0.05 mol / l to 10 mol / l with respect to the total volume of the electrolyte.

15. The electrolyte contains at least 0.1 mole of SO per mole of conductive salt. ２ Electrolyte according to any one of claims 1 to 14, characterized in that it comprises

16. A rechargeable battery cell (2, 20, 40) comprising an electrolyte according to at least one of the claims 1 to 15, an active metal, at least one positive electrode (4, 23, 44), at least one negative electrode (5, 22, 45) and a housing (1, 28).

17. The active metal is Alkali metals, Alkaline earth metals, a metal from group 12 of the periodic table, or 17. A rechargeable battery cell (2, 20, 40) according to claim 16, characterized in that it is made of aluminium.

18. 18. Rechargeable battery cell (2, 20, 40) according to claim 16 or 17, characterized in that the negative electrode (5, 22, 45) is an insertion electrode containing carbon as active material.

19. The positive electrode (4, 23, 44) contains Li as an active material. ｘ M' ｙ M” ｚ O ａ At least one intercalation compound having a composition M' is at least one metal selected from the group formed by the elements Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn; M″ is at least one element selected from the group formed by the elements of groups 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 and 16 of the Periodic Table of the Elements, x and y are each independently a number greater than 0; z is a number equal to or greater than 0; A rechargeable battery cell (2, 20, 40) according to any one of claims 16 to 18, characterized in that a is a number greater than 0.

20. The intercalation compound is Li ｘ M' ｙ M” ｚ O ａ 20. The rechargeable battery cell (2, 20, 40) according to claim 19, characterized in that it has the composition: where M' is iron and M" is phosphorus.

21. The intercalation compound is Li ｘ M' ｙ M” ｚ O ａ 20. The rechargeable battery cell (2, 20, 40) according to claim 19, characterized in that it has the composition: where M' is manganese and M" is cobalt.

22. The intercalation compound is Li ｘ M' ｙ M” ｚ O ａ 22. The rechargeable battery cell (2, 20, 40) according to claim 19 or 21, characterized in that M' comprises nickel and manganese and M" is cobalt.

23. 23. The rechargeable battery cell (2, 20, 40) according to any one of claims 16 to 22, characterized in that the positive electrode (4, 23, 44) comprises at least one metal compound selected from the group formed by metal oxides, metal halides and metal phosphates.

24. The positive electrode (4, 23, 44) and / or the negative electrode (5, 22, 45) are Planar in the form of metal sheet or foil, or Rechargeable battery cell (2, 20, 40) according to any one of claims 16 to 23, characterized in that it comprises conductor elements (26, 27) which are three-dimensionally formed in the form of a porous metal structure.

25. The positive electrode (4, 23, 44) and / or the negative electrode (5, 22, 45) are / is preferably formed of at least one binder, a fluorinated binder, or a binder comprising a polymer of monomeric structural units of conjugated carboxylic acids or the alkali metal, alkaline earth metal or ammonium salts of said conjugated carboxylic acids, or a combination thereof; or The binder comprises a polymer based on monomeric styrene and butadiene structural units or a binder from the carboxymethyl cellulose group, Rechargeable battery cell (2, 20, 40) according to any one of claims 16 to 24, characterized in that the binder is present in a concentration of at most 20 wt% with respect to the total weight of the positive electrode or the negative electrode.

26. The rechargeable battery cell (2, 20, 40) according to any one of claims 16 to 25, comprising a plurality of positive electrodes (4, 23, 44) and a plurality of negative electrodes (5, 22, 45) arranged in an alternating stack within the housing (1), the positive electrodes (4, 23, 44) and the negative electrodes (5, 22, 45) being electrically isolated from each other by separators (11, 21), respectively.

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