Rechargeable Battery Cell

Abstract

The present invention relates to a compound of formula (I)M a B m X n wherein M is a metal selected from the group consisting of alkali metals, alkaline earth metals, metals of Group 12 of the Periodic Table of the Elements, and aluminum, B is the element boron of the Periodic Table of the Elements, X is a halogen, and a, m, and n are integers. The present invention further relates to a rechargeable battery cell (2, 20, 40) comprising an SO2-based electrolyte having at least a first conductive salt according to formula (I), an active metal, at least one positive electrode (4, 23, 44), at least one negative electrode (5, 22, 45), and a housing (1, 28).

Description

[Technical Field]

[0001] The present invention , Mitsuru This relates to rechargeable battery cells.

[0002] Rechargeable battery cells are very important in many technical fields. In many cases, rechargeable electric cells are used in applications where only small rechargeable battery cells are needed, with a relatively low current, such as for the operation of a mobile phone. However, there is also a demand for larger rechargeable battery cells for high-energy applications, and large amounts of energy storage in the form of battery cells is particularly important for electric vehicle drives.

[0003] A key requirement for these types of rechargeable battery cells 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 reason, lithium has proven to be particularly advantageous as an active metal. The active metal of a rechargeable battery cell refers to a metal whose ions in the electrolyte migrate to the negative or positive electrode during charging and discharging of the battery cell, where they participate in electrochemical processes. These 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. The energy density of such lithium-ion batteries can be increased either by increasing the specific capacity of the electrodes or by increasing the battery 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 mean an electrode having a crystalline structure in which ions of the active metal 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. 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 discharge of the lithium-ion battery, the reverse process takes place.

[0005] The electrolyte is a key functional element of all rechargeable battery cells. The electrolyte typically contains a solvent or solvent mixture and at least one conductive salt. For example, solid electrolytes or ionic solutions contain no solvent and only a 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, allowing ionic conduction to transport charge between the electrodes, which is necessary for the function of the rechargeable battery cell. The electrolyte undergoes oxidative electrochemical decomposition above a predetermined upper cell voltage limit of the rechargeable battery cell. This process often leads to irreversible destruction of the electrolyte components and ultimately to failure of the rechargeable battery cell. Reductive processes can also destroy the electrolyte below a predetermined lower cell voltage limit. To avoid this process, the positive and negative electrodes are selected so that the cell voltage is less than or greater than the decomposition voltage of the electrolyte. The electrolyte thus determines the voltage window within which the rechargeable battery cell can be reversibly operated.

[0006] Lithium-ion batteries known from the prior art include an electrolyte consisting of an organic solvent or solvent mixture and a conductive salt dissolved therein. The conductive salt is, for example, a lithium salt such as lithium hexafluorophosphate (LiPF6). The solvent mixture can include, for example, ethylene carbonate. By using such an organic solvent or solvent mixture, this type of lithium-ion battery is also called an organic lithium-ion battery. The negative electrode of the organic lithium-ion battery consists of a carbon coating applied to a copper conductor element. The conductor element forms the necessary electronic conductive connection between the carbon coating and the external circuit. The positive electrode consists of lithium cobalt oxide (LiCoO2) applied to an aluminum conductor element. Both electrodes are extremely thin, typically having a thickness of less than 100 μm.

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

[0008] Therefore, organic lithium-ion batteries have problems with their stability and operational safety during long-term use. Safety risks also arise, particularly due to the flammability of organic solvents or solvent mixtures. If an organic lithium-ion battery catches fire or explodes, the organic solvent in the electrolyte can form flammable materials. To avoid such safety risks, additional measures must be implemented. These measures include, inter alia, highly precise control of the charge and discharge processes of the organic lithium-ion battery and optimization of the battery structure. Furthermore, the organic lithium-ion battery contains components that melt during an unintended temperature rise, which can fill the organic lithium-ion battery with molten plastic. This prevents further uncontrollable temperature rises. However, these measures increase the manufacturing cost and increase the volume and weight of the organic lithium-ion battery. Furthermore, these measures reduce the energy density of the organic lithium-ion battery.

[0009] Another drawback of organic lithium-ion batteries is that the hydrolysis products that may result from the possible presence of residual water are highly corrosive to the cell components of the rechargeable battery cell. For example, LiPF6, a conductive salt often used in organic cells, reacts with traces of water to produce highly reactive and corrosive hydrogen fluoride (HF). Therefore, when manufacturing this type of rechargeable battery cell using an organic electrolyte, care must be taken to minimize the residual moisture contained in the electrolyte and the cell components. Therefore, manufacturing is often carried out in costly dry rooms with extremely low humidity. The aforementioned issues regarding stability and operational safety over long periods of use are particularly serious 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 very high operational reliability and service life, particularly with a large number of usable charge / discharge cycles.

[0010] Thus, a further development known from the prior art involves replacing organic electrolytes in rechargeable battery cells with sulfur dioxide (SO2). base The use of electrolytes is being considered. base Rechargeable battery cells containing electrolytes have particularly high ionic conductivity. base The term "electrolyte" is understood to mean an electrolyte containing not only low concentrations of SO2 as an additive, but also an electrolyte in which the ionic mobility of the conductive salt that performs the charge transport is ensured at least partially, mostly, or completely by SO2. Thus, SO2 functions as a solvent for the conductive salt. The conductive salt can form liquid solvate complexes with gaseous SO2, in which SO2 is combined and has a significantly reduced vapor pressure compared to pure SO2. An electrolyte with a lower vapor pressure is produced. This type of SO2 base The electrolyte has the advantage of being non-flammable compared to the organic electrolytes mentioned above, thereby eliminating safety risks caused by the flammability of the electrolyte.

[0011] For example, EP1201004 B1 (hereinafter referred to as [V1]) describes a SO2 cathode having the composition LiAlCl4*SO2 in combination with a positive electrode made of LiCoO2. base The electrolyte is shown. To avoid destructive decomposition reactions, such as the undesired formation of chlorine (Cl2) from lithium tetrachloroaluminate (LiAlCl4), when rechargeable battery cells are overcharged at potentials of 4.1 to 4.2 volts, EP1201004 B1 proposes the use of an additional salt.

[0012] EP2534719 B1 (hereinafter referred to as [V2]) also discloses a SO2 containing LiAlCl4 as a conductive salt. baseAn electrolyte is disclosed in which LiAlCl4 forms a complex with SO2 having 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). The rechargeable battery cell does not encounter the problem of unintended overcharge reactions because it does not reach the potential of 4.1 volts, which is harmful to the electrolyte. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] European Patent No. 1201004 [Patent Document 2] European Patent No. 2534719 Summary of the Invention [Problem to be solved by the invention]

[0014] SO2 base In order to further improve the application and properties of the electrolyte and the rechargeable battery cells containing said electrolyte, the present invention provides, on the one hand, a solution containing SO2 as follows, in comparison with the electrolytes known from the prior art: base The objective is to propose an electrolyte that: - has a wide electrochemical window so that no oxidative electrolyte decomposition occurs at the positive electrode; - forms a stable surface layer on the negative electrode, the surface capacity of which should be low and no further reductive electrolytic decomposition occurs at said negative electrode during subsequent operation; - offers the possibility of operating rechargeable battery cells with high voltage cathodes due to its wide electrochemical window; - is a good ionic conductor and electronic insulator due to its good solubility of conductive salts, thus facilitating ion transport and minimizing self-discharge; - is inert to other components in rechargeable battery cells, such as for example the separator, the electrode materials and the cell casing; and - is robust against electrical, mechanical or thermal abuse.

[0015] Electrolytes of this type 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, and a particularly high number of usable charge / discharge cycles, without the electrolyte being decomposed during operation of the rechargeable battery cell.

[0016] On the other hand, the object of the present invention is to base The object is to propose a rechargeable battery cell which comprises an electrolyte and which, compared to rechargeable battery cells known from the prior art, has: improved electrical performance data, in particular a high energy density; improved overcharge and deep discharge properties; low self-discharge properties; a longer service life, in particular a high number of usable charge / discharge cycles.

[0017] The problem is solved by the device having the features of claim 1 Charging Rechargeable battery cell To This is resolved by the present invention. Rechargeable Battery Cell Advantageous embodiments of the invention are defined in claims 2 to 5. 15 is defined in 。 [Means for solving the problem]

[0018] SO2 for rechargeable battery cells according to the present invention base The electrolyte is a compound of formula (I) [ka] In formula (I), M represents a metal selected from the group consisting of alkali metals, alkaline earth metals, metals of Group 12 of the Periodic Table of Elements, and aluminum. B represents boron, an element of the Periodic Table of Elements. X represents a halogen, i.e., an element belonging to main group 7 or group 17 of the Periodic Table of Elements. A, m, and n are integers, independent of one another.

[0019] SO2 according to the present invention baseThe electrolyte contains SO2 not only in low concentrations as an additive, but also in concentrations such that the mobility of the ions of the first conductive salt contained in the electrolyte that effectuates the charge transport is at least partially, mostly, or completely ensured by SO2.

[0020] The first conductive salt is dissolved in the electrolyte and exhibits good solubility therein. 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, depending on the chemical structure of the first conductive salt according to formula (I), it is also within the scope of the present invention to prevent a reduction in vapor pressure during the preparation of the electrolyte according to the present invention. In the latter case, it is preferable to work at low temperature or under pressure, preferably using liquid SO2, during the preparation of the electrolyte according to the present invention. The electrolyte can also contain multiple conductive salts according to formula (I), each with a different chemical structure.

[0021] 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 as described below, and further comprising an active metal, at least one positive electrode, at least one negative electrode, and a housing.

[0022] The electrolyte according to the invention and the rechargeable battery cell according to the invention containing such an electrolyte have the advantage over electrolytes and rechargeable battery cells known from the prior art that the first conductive salt contained in the electrolyte has higher oxidative stability, resulting in no or very little decomposition occurring at higher cell voltages, thereby improving the long-term stability of the electrolyte and the rechargeable battery cell.

[0023] electrolyte In the following, advantageous embodiments of the electrolyte according to the invention are described.

[0024] SO2 base In a first advantageous embodiment of the electrolyte, M is lithium (Li). The composition of such a lithium compound of formula (I) is Li a B m X n where A, m, and n are integers, each independently of the others, as described above. In another advantageous embodiment, X is selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). X is preferably fluorine or chlorine. base In yet another advantageous embodiment of the electrolyte, M is lithium and X is chlorine. The composition of such a compound is Li a B m Cl n where a, m, and n are, as described above, independent integers. An example of a compound having this composition is Li2B 10 Cl 10 and Li2B 12 Cl 12 Furthermore, in the above formula (I), M can be lithium and X can be fluorine. Compounds of this type have the composition Li a B m F n where a, m, and n are, as described above, independent integers. An example of a compound having this composition is Li2B 10 F 10 and Li2B 12 F 12 is.

[0025] In another advantageous embodiment of the rechargeable battery cell according to the invention, the electrolyte contains at least 1 mole of SO per mole of conductive salt, preferably at least 10 moles of SO, more preferably at least 30 moles of SO, and particularly preferably at least 50 moles of SO. The electrolyte can also contain higher molar ratios of SO, with a preferred upper limit of 2600 moles of SO per mole of conductive salt, with upper limits of 1500, 1000, 500, and 100 moles of SO 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.

[0026] SO2 with such a concentration ratio between SO2 and the conductive salt base The electrolyte has the advantage that it can dissolve a larger amount of conductive salt than electrolytes known in the prior art, for example, based on organic solvent mixtures. The SO2 concentration in the electrolyte affects the conductivity of the electrolyte. Therefore, by selecting the SO2 concentration, the conductivity of the electrolyte can be adapted to the intended use of the rechargeable battery cell operated by the electrolyte.

[0027] The total content of SO and the first conductive salt may 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 even more preferably greater than 99 wt%.

[0028] The electrolyte may contain at least 5 wt% SO2, with 20 wt%, 40 wt% SO2, and 60 wt% SO2 being more preferred, based on the total amount of electrolyte contained in the rechargeable battery cell. The electrolyte may contain up to 95 wt% SO2, with maximums of 80 wt% SO2 and 90 wt% SO2 being more preferred, in that order.

[0029] In another advantageous embodiment, the electrolyte comprises at least one second conductive salt different from the first conductive salt according to formula (I) in order to adjust the conductivity and / or further properties of the electrolyte to the desired values. This means that the electrolyte may contain, in addition to the first conductive salt, one or more second conductive salts that differ from the first conductive salt not only in their chemical composition but also in their chemical structure. The second conductive salt is preferably an alkali metal compound, in particular a lithium compound. The alkali metal compound or the lithium compound is selected from the group consisting of aluminates, halides, oxalates, borates, phosphates, arsenates, and gallates. Furthermore, the second conductive salt is a lithium tetrahaloaluminate, in particular LiAlCl4.

[0030] The electrolyte can have the following composition by weight of the total electrolyte composition: (i) 5 to 99.4% by weight of sulfur dioxide; (ii) 0.6 to 95 wt. % of the first conductivity salt, and (iii) 0 to 25 wt. % of said second conductive salt.

[0031] As mentioned above, the electrolyte may contain not only the first conductive salt and the second conductive salt according to the formula (I) but also a plurality of first conductive salts and a plurality of second conductive salts, respectively, according to the formula (I). In the latter case, the aforementioned ratios include the plurality of first conductive salts and the plurality of second conductive salts.

[0032] Preferably, the proportion of at least one organic solvent in the electrolyte is small, or even absent. For example, the proportion of organic solvent in the electrolyte, present in the form of a solvent or a mixture of organic solvents, can be 50% by weight or less of the weight of the electrolyte. Preferably, it is a smaller proportion, such as 40% by weight or less, more preferably 30% by weight or less, more preferably 20% by weight or less, more preferably 15% by weight or less, more preferably 10% by weight or less, more preferably 5% by weight or less, or even more preferably 1% by weight or less, based on the weight of the electrolyte. It is particularly preferred that the electrolyte is substantially free of organic solvents. With a small or even complete absence of organic solvents, the electrolyte has little or no flammability. This means that this type of SO2 base In another advantageous embodiment, the electrolyte has the following composition, based on the total weight of the electrolyte composition: (i) 5 to 99.4 wt. % sulfur dioxide, (ii) 0.6 to 95 wt. % of the first conductivity salt, (iii) 0 to 25 wt. % of the second conductivity salt, and (iv) 0 to 50 wt. % of an organic solvent.

[0033] active metal Advantageous developments of the rechargeable battery cell according to the invention with regard to the active metal are described below:

[0034] In a first advantageous development of the rechargeable battery cell, the active metal is: alkali metals, in particular lithium or sodium, - alkaline earth metals, especially calcium, -metals of group 12 of the periodic table, in particular zinc, or -aluminum.

[0035] negative electrode In the following, advantageous embodiments of the rechargeable battery cell according to the invention with respect to the negative electrode are described:

[0036] In another advantageous development of the rechargeable battery cell, the negative electrode is an insertion electrode. The insertion electrode contains an insertion material as an active material, and ions of the active metal are stored in the insertion material during charging of the rechargeable battery cell and can be 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 a lithium-based conductive salt is used, lithium ions can be stored in the insertion material during charging of the rechargeable battery cell and can be released from the insertion material during discharging of the rechargeable battery cell. The negative electrode preferably contains carbon, in particular modified graphite, as the active or insertion material. However, it is also within the scope of the present invention that the carbon be in the form of natural graphite (flaked promoter or round), synthetic graphite (mesophase graphite), graphitized mesocarbon microbeads (MCMB), carbon-coated graphite, or amorphous carbon.

[0037] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode is made of, for example, lithium titanate (e.g. Li4Ti5O 12 ) and other carbon-free lithium intercalation negative electrode active materials.

[0038] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode comprises an active negative electrode material that forms an alloy with lithium, such as metals and metal alloys that 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.

[0039] 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 such as magnesium hydride (MgH2), titanium hydride (TiH2), aluminum hydride (AlH3) and boron-, aluminum- and magnesium-based ternary hydrides.

[0040] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode comprises a metal, in particular metallic lithium.

[0041] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode is porous, with a porosity of preferably 50% or less, more preferably 45% or less, more preferably 40% or less, more preferably 35% or less, more preferably 30% or less, more preferably 20% or less, and particularly preferably 10% or less. Porosity refers to the void volume relative to the total volume of the negative electrode, and the void volume is formed by so-called pores or voids. This porosity increases the internal surface of the negative electrode. Furthermore, this porosity reduces the density and thus the weight of the negative electrode. The individual pores of the negative electrode can preferably be completely filled with the electrolyte during operation.

[0042] In another advantageous development of the rechargeable battery cell according to the invention, the negative electrode comprises a conductor element. This means that the negative electrode contains a conductor element in addition to the active material or the insertion 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 in a planar form in the form of a thin metal sheet or foil. The thin metal foil preferably has a perforated or mesh structure. The active material of the negative electrode is preferably applied to the surface of the thin metal sheet or foil. Such planar conductor elements 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 200 μm or less, preferably 150 μm or less and particularly preferably 100 μm or less. The area-specific capacitance of the negative electrode is preferably at least 0.5 mAh / cm when planar conductor elements are used. 2 and the following values ​​in this order are preferred: 1 mAh / cm 2 , 3mAh / cm 2 , 5mAh / cm 2 , 10mAh / cm 2 .

[0043] Furthermore, the conductor element may be formed in the form of a three-dimensional porous metal structure, particularly a metal foam. The term "three-dimensional porous metal structure" refers to any metallic structure that extends not only the length and width of the planar electrode, such as the thin metal sheet or metal foil, but also the thickness 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 incorporated or applied active material refers to the charge of the negative electrode. When the conductor element is formed in the form of a three-dimensional porous metal structure, particularly 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, even more preferably at least 0.5 mm, and particularly preferably at least 0.6 mm. In this case, the thickness of the electrode is significantly greater than that of negative electrodes used in organic lithium-ion batteries.

[0044] In another advantageous embodiment, when using a metal foam, in particular a three-dimensional conductor element formed in the form 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 charge of the electrode relative 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 , more preferably at least 80 mg / cm 2 and particularly preferably at least 100 mg / cm 2This charge at the negative electrode has a positive effect not only on the charging process but also on the discharging process of the rechargeable battery cell.

[0045] In another advantageous development of the battery cell according to the invention, the negative electrode comprises at least one binder, which is a fluorine-based binder, in particular polyvinylidene fluoride and / or a terpolymer formed from tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride. However, conjugated carboxylic acids are not preferred. Acid or an alkali metal salt, alkaline earth metal salt or ammonium salt of the conjugated carboxylic acid, or a combination thereof. Monomer structural unit The binder may be a polymer consisting of a carboxymethyl cellulose group. The binder may also be a polymer based on styrene and butadiene monomer structural units. The binder may also be a binder consisting of a carboxymethyl cellulose group. The binder is present in the negative electrode at a concentration of 20% by weight or less, more preferably 15% by weight or less, more preferably 10% by weight or less, even more preferably 7% by weight or less, even more preferably 5% by weight or less, and particularly preferably 2% by weight or less, based on the total weight of the negative electrode.

[0046] positive electrode Advantageous developments of the rechargeable battery cell according to the invention with respect to the positive electrode are described below:

[0047] In a first advantageous development of the rechargeable battery cell according to the invention, the positive electrode is chargeable to an upper potential of at least 4.0 volts, preferably to a potential of 4.4 volts, more preferably to a potential of at least 4.8 volts, even more preferably to a potential of at least 5.2 volts, even more preferably to a potential of at least 5.6 volts and particularly preferably to a potential of at least 6.0 volts.

[0048] In another advantageous development of the rechargeable battery cell according to the invention, the positive electrode comprises at least one active material capable of storing ions of the active metal and releasing and reaccommodating said ions of the active metal during operation of the electric cell.

[0049] In another advantageous development of the rechargeable battery cell according to the invention, the positive electrode comprises at least one intercalation compound. The term "intercalation compound" in the sense of the present invention is understood to be a subcategory of the aforementioned insertion materials. The intercalation compound acts 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 occur in the host matrix during this accumulation of the ions of the active metal.

[0050] In another advantageous development of the rechargeable battery cell according to the invention, the positive electrode comprises at least one conversion compound as the active material. The term "conversion compound" in the sense of the present invention is understood to mean a material that forms other materials during electrochemical activity, i.e., chemical bonds are broken and reformed during charging and discharging of the battery cell. A structural change occurs in the matrix of the conversion compound upon the acceptance and release of the ions of the active metal.

[0051] In another advantageous development of the rechargeable battery cell according to the invention, the active material is x M' y M” z O a The composition A has the following composition. x M' y M” z O a In A is at least one metal selected from the group consisting of alkali metals, alkaline earth metals, metals of group 12 of the periodic table, or aluminum; M' is at least one metal selected from the group consisting of the elements Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, -M" is at least one element selected from the group consisting of 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 greater than or equal to 0, and -a is a number greater than 0. -A is preferably metallic lithium, i.e. the compound is Li x M' y M” z O a The composition may be:

[0052] Composition A x M' y M” z O a The indices y and z in the formula represent the sum of the metal and element represented by M' or M'', respectively. For example, M' is a metal with two M' 1 and M' 2 In the case where the index y is y=y1+y2, y1 and y2 are the metals M' 1 and M' 2 The indices x, y, z, and a must be selected so that the charge in the composition is neutral. An example of a compound where M' contains two metals is M' 1 =Ni, M' 2 Composition Li where M" = Mn and M" = Co x Ni y1 Mn y2 Co z An example of a compound where z=0, i.e., without another metal or element M″, is lithium cobalt oxide, Li x Co y O a For example, M" has two elements, one is metal M" 1 and on the other hand M” 2When the compound contains phosphorus as a metal, then for the index z, z=z1+z2, and z1 and z2 are the metals M" 1 and Lynn (M 2 The indices x, y, z and a must be chosen so that the charge in the composition is neutral. A represents lithium, M" represents the metal M" 1 and M” 2 Examples of compounds containing phosphorus as A are A=Li, M'=Fe, M" 1 =Mn, M” 2 Lithium iron manganese phosphate Li = P and z = 1 x Fe y Mn z1 P z2 O4. In other compositions, M" can be two nonmetals, e.g., M" 1 as fluorine, M” 2 Examples of such compounds include A=Li, M'=Fe, M" 1 =F,M” 2 Lithium iron fluorosulfate Li = P x Fe y F z1 S z2 There is O4.

[0053] 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, x Ni y1 Mn y2 Co z Lithium with a composition of O2(NMC), i.e., a layered oxide structure D Kuckel Ma Ngan Ko Examples of the active material made of such lithium nickel manganese cobalt oxide include LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2(NMC111), LiNi 0.6 Mn 0.2 Co 0.2 O2 (NMC622) and LiNi 0.8 Mn 0.1 Co0.1 O2 (NMC811). Other compounds made of lithium nickel manganese cobalt oxide have the composition LiNi 0.5 Mn 0.3 Co 0.2 O2, LiNi 0.5 Mn 0.25 Co 0.25 O2, LiNi 0.52 Mn 0.32 Co 0.16 O2, LiNi 0.55 Mn 0.30 Co 0.15 O2, LiNi 0.58 Mn 0.14 Co 0.28 O2, LiNi 0.64 Mn 0.18 Co 0.18 O2, LiNi 0.65 Mn 0.27 Co 0.08 O2, LiNi 0.7 Mn 0.2 Co 0.1 O2, LiNi 0.7 Mn 0.15 Co 0.15 O2, LiNi 0.72 Mn 0.10 Co 0.18 O2, LiNi 0.76 Mn 0.14 Co 0.10 O2, LiNi 0.86 Mn 0.04 Co 0.10 O2, LiNi 0.90 Mn 0.05 Co 0.05 O2, LiNi 0.95 Mn 0.025 Co 0.025 O2 or a combination thereof. The compounds can be used to prepare positive electrodes for rechargeable battery cells having cell voltages greater than 4.6 volts.

[0054] In another advantageous development of the rechargeable battery cell according to the invention, the active material is a lithium- and manganese-rich metal oxide (in English: Lithium- and Manganese-Rich Oxide Material), which has the composition Lix Mn y M” z O a may have. Thus, M’ is the above formula Li x M’ y M” z O a represents metallic manganese (Mn) therein. The exponent x here is 1 or more, and the exponent y is larger than the sum such as the exponent z or the exponent z1 + z2 + z3. For example, when M” includes two metals M” 1 and M” 2 (for example, M” 1 = Ni z1 = 0.175 and M” 2 = Co z2 = 0.1 in Li 1.2 Mn 0.525 Ni 0.175 Co 0.1 O2), for the exponent y, y > z1 + z2 holds. The exponent z is 0 or more, and the exponent a is greater than 0. The exponents x, y, z, and a must be selected so that the charge in the composition is neutral. The lithium- and manganese-rich metal oxide can also be represented by the formula mLi2MnO3(1 - m)LiM’O2 where 0 < m < 1. Examples of this type of compound are Li 1.2 Mn 0.525 Ni 0.175 Co 0.1 O2, Li 1.2 Mn<000017​​​​​​​​​​​​​​​​​​​​The compound has a spinel structure. For example, A can be lithium, M' can be cobalt, and M" can be manganese. In this case, the active material is lithium cobalt manganese oxide (LiCoMnO4). LiCoMnO4 can be used to fabricate positive electrodes for rechargeable battery cells with cell voltages greater than 4.6 volts. LiCoMnO4 contains Mn 3+ In another example, M' can be nickel and M" can be manganese. In this case, the active material is lithium nickel manganese oxide (LiNiMnO4). The molar ratio of both metals M' and M" can be different. The lithium nickel manganese oxide is, for example, LiNi 0.5 Mn 1.5 It may have a composition of O4.

[0056] In another advantageous development of the rechargeable battery cell according to the invention, the positive electrode comprises at least one active material that is a conversion compound. When the conversion compound accepts an active metal, such as lithium or sodium, a solid-state redox reaction occurs, during which the crystalline structure of the material changes. This occurs through the breaking and recombination of chemical bonds. A fully reversible reaction of the conversion compound can be, for example, as follows: Type A: MX z +yLi ⇔ M+zLi (y / z) X Type B: X+yLi ⇔ Li y X

[0057] Examples of conversion compounds are FeF2, FeF3, CoF2, CuF2, NiF2, BiF3, FeCl3, FeCl2, CoCl2, NiCl2, CuCl2, AgCl, LiCl, S, Li2S, Se, Li2Se, Te, I and LiI.

[0058] In another advantageous development, the compound has composition A x M' y M” z1 M” z2 O4, M″ is phosphorus, and the value of z2 is 1. x M'y M” z1 M” z2 Compounds with O4 are so-called lithium metal phosphates. Such compounds have the composition Li x Fe y Mn z1 P z2 Examples of lithium metal phosphates are lithium iron phosphate (LiFePO4) or lithium iron manganese phosphate (Li(Fe y Mn z )PO4). An example of lithium manganese iron phosphate is Li(Fe 0.3 Mn 0.7 )PO4. An example of lithium iron manganese phosphate is Li(Fe 0.3 Mn 0.7 )PO4. Lithium metal phosphates with other compositions may also be used in the battery cell according to the present invention.

[0059] Many of the positive electrode active materials described above are high voltage active materials, which means that they can be used to fabricate electrodes that can be charged to a maximum potential of at least 4.0 volts, and preferably to a maximum potential of 4.4 volts.

[0060] 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 consisting of 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.

[0061] In another advantageous development of the rechargeable battery cell according to the invention, the positive electrode comprises at least one metal compound with the chemical structure of a spinel, a layered oxide, a conversion compound or a polyanionic compound.

[0062] It is within the scope of the present invention that the positive electrode comprises as an active material at least one of the aforementioned compounds or combinations of compounds, where combinations of compounds refer to positive electrodes comprising at least two of the aforementioned materials.

[0063] In another advantageous development of the rechargeable battery cell according to the invention, the positive electrode comprises a conductor element. This means that the positive electrode contains a conductor element in addition to the active material. The conductor element is used to enable the required electronically conductive connection of the active material of the positive electrode. For this purpose, the conductor element is in contact with the active material participating in the electrode reaction of the positive electrode. The conductor element can be formed in a planar form in the form of a thin metal sheet or a thin metal foil. The thin metal foil preferably has a perforated or mesh structure. However, the planar conductor element can also consist of a metal-coated plastic foil. The metal coating has a thickness in the range of 0.1 μm to 20 μm. The active material of the positive electrode is preferably applied to the surface of the thin metal sheet, the thin metal foil, or the metal-coated plastic foil. The active material can be applied to the front and / or back of the planar conductor element. Such planar conductor elements 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 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 positive electrode with respect to the coating on one side is preferably at least 0.5 mAh / cm when planar conductor elements are used. 2 and the following values ​​in this order are preferred: 1 mAh / cm 2 , 3mAh / cm 2 , 5mAh / cm 2 , 10mAh / cm 2 , 15mAh / cm 2, 20mAh / cm 2 .

[0064] Furthermore, the conductive element of the positive electrode can be formed in the form of a three-dimensional 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 incorporated or applied active material refers to the charge of the positive electrode. When the conductive element is formed in the form of a three-dimensional 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, even 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, in particular when using a three-dimensional conductive element 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 , 15mAh / cm 2 , 25mAh / cm 2 , 35mAh / cm 2 , 45mAh / cm 2 , 55mAh / cm 2 , 65mAh / cm 2 , 75mAh / cm 2 .

[0065] 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 charge of the electrode relative 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 , more preferably at least 80 mg / cm 2 and particularly preferably at least 100 mg / cm 2This charge at the positive electrode has a positive effect not only on the charging process but also on the discharging process of the rechargeable battery cell.

[0066] In another advantageous development of the battery cell according to the invention, the positive electrode comprises at least one binder, which is a fluorine-based binder, in particular polyvinylidene fluoride and / or a terpolymer formed from tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride. Acid or an alkali metal salt, alkaline earth metal salt or ammonium salt of the conjugated carboxylic acid, or a combination thereof. Monomer structural unit The binder may be a polymer consisting of a carboxymethyl cellulose group. The binder may also be a polymer based on styrene and butadiene monomer structural units. The binder may also be a binder consisting of a carboxymethyl cellulose group. The binder is present in the positive electrode at a concentration of 20% by weight or less, more preferably 15% by weight or less, more preferably 10% by weight or less, even more preferably 7% by weight or less, even more preferably 5% by weight or less, and particularly preferably 2% by weight or less, based on the total weight of the positive electrode.

[0067] Rechargeable battery cell structure In the following, advantageous developments of the configuration of the rechargeable battery cell according to the invention are described:

[0068] In order to further improve the functionality of the rechargeable battery cell, in another advantageous development of the rechargeable battery cell according to the invention, the rechargeable battery cell has a plurality of negative electrodes and a plurality of positive electrodes arranged in an alternating stack in the housing, the positive electrodes and the negative electrodes being preferably electrically separated from each other by separators.

[0069] The separator can be formed using a nonwoven fabric, a membrane, a woven fabric, a knitted fabric, an organic material, an inorganic material, or a combination thereof. Organic separators can be made of unsubstituted polyolefins (e.g., polypropylene or polyethylene), partially to fully halogen-substituted polyolefins (e.g., partially to fully fluorinated, particularly PVDF, ETFE, PTFE), polyesters, polyamides, or polysulfones. Separators containing a combination of organic and inorganic materials are, for example, woven glass fiber materials in which glass fibers are coated with an appropriate polymer coating.

[0070] The coating is a fluorine-containing polymer such as polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene (ETFE), perfluoroethylenepropylene (FEP), THV (a terpolymer of tetrafluoroethylene, hexafluoroethylene, and vinylidene fluoride), perfluoroalkoxy polymer (PFA), aminosilane, polypropylene, or polyethylene (PE). The separator can be folded, for example, in a so-called "Z-fold" shape within the housing of the rechargeable battery cell. In the Z-folding, the separator strip is folded in a Z shape so that it passes through the electrodes or is centered around the electrodes. The separator may also be formed as separator paper.

[0071] It is also within the scope of the present invention that the separator may be formed as a coating, and the positive electrode or the negative electrode may be covered with 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.

[0072] The coating of the positive electrode allows for uniform ion migration and distribution in the rechargeable battery cell. A more uniform ion distribution, especially in the negative electrode, allows for a higher possible loading of active material into the negative electrode, thereby increasing the usable capacity of the rechargeable battery cell. At the same time, the risk of uneven loading and the resulting precipitation of the active metal is avoided. This advantage is particularly pronounced when the positive electrode of the rechargeable battery cell is covered with the coating.

[0073] The surface dimensions of the electrode and the coating are preferably adjusted to one another so that the outer dimensions of the coating on the electrode and the outer dimensions of the uncoated electrode match in at least one dimension.

[0074] The surface area of ​​the coating is preferably 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 can be connected to each other by an edge connection at the edge of the positive electrode.

[0075] In another advantageous embodiment of the battery cell according to the invention, the negative electrode has a coating, whereas the positive electrode has no coating.

[0076] Further advantageous properties of the present invention are described and explained in detail below with the aid of figures, examples and experiments. [Brief explanation of the drawings]

[0077] [Figure 1] 1 is a cross-sectional view of a first example embodiment of a rechargeable battery cell according to the present invention; [Figure 2] 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. [Figure 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. [Figure 5] FIG. 10 is an exploded view of a third example embodiment of the present invention with the housing removed. [Figure 6] FIG. 1 shows the potential (in [V]) in an experimental complete cell filled with electrolyte 1 and a reference electrolyte as a function of capacity relative to the theoretical capacity of the negative electrode during the formation of a surface layer on the negative electrode. [Figure 7] FIG. 1 shows the potential curve (in [V]) as a function of charge rate for an experimental complete cell filled with Electrolyte 1 and nickel manganese cobalt oxide as the positive electrode active material, with an end-of-charge voltage of 4.4 volts and an end-of-discharge voltage of 2.5 volts. [Figure 8] FIG. 1 shows the discharge capacity as a function of cycle number for experimental complete cells containing either Electrolyte 1 or the reference electrolyte. [Figure 9] FIG. 1 shows the discharge capacity as a function of cycle number for experimental complete cells containing either electrolyte 2 or the reference electrolyte. [Figure 10] FIG. 1 shows the conductivity (unit [mS / cm]) of electrolyte 1 depending on the concentration. [Figure 11] FIG. 1 is a diagram showing the conductivity (unit [mS / cm]) of electrolyte 2 depending on the concentration. DETAILED DESCRIPTION OF THE INVENTION

[0078] FIG. 1 illustrates a cross-sectional view of a first example embodiment of a rechargeable battery cell 2 according to the present invention. The rechargeable battery cell 2 is configured 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 negative electrodes 5 are arranged alternately in a stack in the electrode unit 3. However, the housing 1 can also accommodate a plurality of positive electrodes 4 and / or negative electrodes 5. It is generally 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 thereby formed by the electrode surface of the negative electrode 5. The electrodes 4, 5 are connected to corresponding connection contacts 9, 10 of the rechargeable battery cell 2 via electrode connections 6, 7. The rechargeable battery cell 2 is provided with SO2 base The electrolyte is filled in such a way that it penetrates as completely as possible into all pores or cavities, especially on the inside, of the electrodes 4, 5. The electrolyte is not shown in FIG.

[0079] In this embodiment, the positive electrode 4 contains an intercalation compound as an active material. 0.6 Mn 0.2 Co 0.2 O2. In this embodiment, the electrodes 4, 5 are formed as planar layers, i.e., layers with a small thickness relative to their surface area. The electrodes are separated from each other by a separator 11. The housing 1 of the rechargeable battery cell 2 is formed substantially cubic, with the electrodes 4, 5 and the walls of the housing 1, shown in cross section, extending perpendicular to the plane of the drawing and being substantially straight and flat. However, the rechargeable battery cell 2 may 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, particularly to ions of the active metal. This creates a large electrochemically effective surface, which allows a correspondingly high current yield.

[0080] Furthermore, the electrodes 4, 5 each have a conductive element used to provide the necessary electronically conductive connection of the active material of the electrode. The conductive element is in contact with the active material (not shown in FIG. 1 ) involved in the electrode reaction of the electrode 4, 5. The conductive element is formed in the form of a porous metal foam 18. The metal foam 18 extends across the thickness dimension of the electrodes 4, 5. The active material of the positive electrode 4 and the negative electrode 5, respectively, is incorporated into the pores of the metal foam 18, so that the active material uniformly fills the pores of the metal foam across the entire thickness of the metal structure.

[0081] The positive electrode 4 contains a binder to improve mechanical strength. The binder is a fluoropolymer. The negative electrode 5 contains carbon as the active material and a binder, and the carbon is formed as an insertion material and is used to accept lithium ions. The structure of the negative electrode 5 is similar to that of the positive electrode 4.

[0082] Figure 2 shows an electron microscope image of the three-dimensional porous structure of the metal foam 18 of the first 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. The metal foam 18 is made of nickel.

[0083] FIG. 3 shows a cross-sectional view of a second embodiment of a rechargeable battery cell 20 according to the present 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 are separated from each other by separators 21 and surrounded by a housing 28. The positive electrode 23 has a conductor element 26 in the form of a planar metal foil, on both sides of which the active material 24 of the positive electrode 23 is applied. The negative electrode 22 also has a conductor element 27 in the form of a planar metal foil, on both sides of which the active material 25 of the negative electrode 22 is applied. Both electrodes further comprise a binder. Alternatively, the edge electrodes, i.e., the electrodes that close the electrode stack, can be coated with active material on only one side of the planar conductor element. 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.

[0084] Figure 4 illustrates a planar metal foil used as the conductor elements 26, 27 of the positive electrode 23 and the negative electrode 22, respectively, in the second example embodiment of Figure 3. The metal foil has a perforated or mesh-like structure with a thickness of 20 μm.

[0085] Figure 5 shows an exploded view of a third embodiment of a rechargeable battery cell 40 according to the present invention. This third embodiment differs from the previous two embodiments in that the positive electrode 44 is covered with a coating 13. The surface area of ​​the coating 13 is larger than that of the positive electrode 44, and the boundary 14 of the positive electrode is indicated by a dashed line in Figure 5. 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. The negative electrodes 45 are uncoated. The electrodes 44 and 45 can be contacted via electrode connections 46 and 47.

[0086] Example 1: Preparation of reference electrolyte The reference electrolyte used in the examples described below was prepared according to the procedure described in patent specification EP2954588 B1.

[0087] First, lithium chloride (LiCl) was dried under vacuum at 120°C for three days. Aluminum particles (Al) were dried under vacuum at 450°C for two days. LiCl, aluminum chloride (AlCl), and Al were mixed together in a glass bottle with an opening for gas release to form a molar ratio of AlCl:LiCl:Al of 1:1.06:0.35. The mixture was then heated in stages to produce a molten salt. After cooling, the resulting molten salt was filtered and then cooled to room temperature. Finally, SO2 was added until the desired molar ratio of LiAlCl to SO2 was formed. The reference electrolyte thus formed had the composition LiAlCl4*xSO2, where x depends on the amount of SO2 added.

[0088] Example 2: Preparation of two embodiments of the electrolyte according to the invention, examples 1 and 2 For the experiments described below, two examples 1 and 2 of the electrolyte according to the invention were prepared (hereinafter referred to as Electrolytes 1 and 2).

[0089] For this purpose, two different first conductive salts according to formula (I) were prepared according to the preparation procedures described in the following documents [V3], [V4] and [V5]: [V3] Geiss et al., Dalton Transactions, 2009, 2687-2694 [V4] Danks et al., Inorganic Synthesis, 1983, 22, 202; M.F. Hawthorne and R.L. Pilling, Inorganic Synthesis, 1967, 9, 16 [V5] J.W. Johnson, J.F. Brodie, J. Electrochemical Society, 1982, 129, 2213-2219

[0090] The molecular formula of the two first conductive salts according to formula (I) thus prepared is LiB 12 Cl 12(Compound 1) and Li2B 10 Cl 10 (Compound 2).

[0091] After synthesis of each conductive salt, compounds 1 and 2 were dissolved in SO2 to prepare electrolytes 1 and 2. The preparation of each electrolyte was carried out at low temperature or under pressure according to steps 1 to 4 of each procedure listed below: 1) Each compound 1 or 2 is placed in a pressure flask equipped with a riser pipe. 2) evacuating the pressure flask; 3) Injecting liquid SO2, and 4) Repeat steps 2 and 3 until the target amount of SO2 has been added.

[0092] The concentrations of Compounds 1 and 2 in Electrolytes 1 and 2 were 0.25 mol / L (substance concentration per liter of electrolyte) unless otherwise specified in the following experimental description. The experiments described below were carried out using Electrolytes 1 and 2 and a reference electrolyte.

[0093] Example 3: Preparation of a complete experimental cell The experimental complete cells used in the examples described below were rechargeable battery cells containing two negative electrodes and one positive electrode, each separated by a separator. The positive electrode contained an active material, a conductivity enhancer, and a binder. The active materials are described in each experiment. The negative electrode contained graphite as the active material and also a binder. Each experimental complete cell was filled with the electrolyte required for the experiment, i.e., the reference electrolyte, electrolyte 1, or electrolyte 2.

[0094] One or more identical complete experimental cells, e.g., two to four, were fabricated for each experiment, and the results shown for each experiment, where present, are the average of measurements obtained on identical complete test cells.

[0095] 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 a battery cell. This surface layer is formed on the negative electrode during the first charge of an experimental cell. The formation of this surface layer irreversibly consumes lithium ions (surface capacity), reducing the cyclable capacity available for the experimental full cell in subsequent cycles. The surface capacity (in %) relative to the theoretical value used to form the surface layer on the negative electrode is calculated using the following formula: Surface capacitance [% of theoretical value] = (Q lad (xmAh)-Q ent (ymAh) / Q NEL Q lad is the charge amount (unit: mAh) specified in each experiment, Q ent is the charge (in mAh) obtained during subsequent discharge of the complete experimental cell. Q NEL is the theoretical capacity of the negative electrode used. For example, in the case of graphite, the theoretical capacity is calculated at 372 mAh / g.

[0096] Discharge capacity: In measurements on experimental complete cells, for example, the charge capacity is determined by the number of cycles. To this end, the experimental complete cell is charged to a predetermined upper limit potential at a predetermined charging current. The corresponding upper limit potential is maintained until the charging current drops to a certain value. Then, the cell is discharged at a predetermined discharge current until the predetermined discharge potential is reached. This charging method is called I / U charging. This process is repeated for the desired number of cycles.

[0097] The upper limit potential or charge capacity and the respective charge and discharge currents are given in each experiment, as well as the value to which the charge current should be reduced.

[0098] The term "upper potential limit" is used synonymously with the terms "charging potential," "charging voltage," "end-of-charge voltage," and "upper potential limit." Each term refers to the voltage or potential that a complete experimental cell or battery must reach when being charged by a battery charger. Charging of the battery is preferably performed at a current rate of C / 2 and an ambient temperature of 22°C. By definition, a 1C charge or discharge rate charges or discharges the nominal capacity of a complete experimental cell in one hour. Therefore, a current rate of C / 2 means a charging time of two hours.

[0099] The term "discharge potential" is used interchangeably with the term "lower cell voltage." This term refers to the voltage or potential that a complete experimental cell or battery must reach when discharged by a battery charger. Battery discharge is preferably performed at a current rate of C / 2 and an ambient temperature of 22°C. Discharge capacity is determined by the discharge current and the time until the termination criteria are met. The associated figures show the average discharge capacity as a function of cycle number. This average discharge capacity is often normalized to the maximum capacity achieved in each experiment and expressed as a percentage of the nominal capacity.

[0100] (Experiment 1) Investigation of the surface capacitance of experimental complete cells using either electrolyte 1 or the reference electrolyte In the first experiment, the capacity consumed in the first cycle to form a surface layer on the negative electrode was investigated. To this end, a complete experimental cell according to Example 3 was filled with either the reference electrolyte or electrolyte 1. Electrolyte 1 was the conductive salt Li2B at a concentration of 0.25 mol / L. 12 Cl 12 The reference electrolyte had the composition LiAlCl4*6SO2. The positive electrode active material was nickel manganese cobalt oxide (NMC622) in both the reference and electrolyte 1 cases.

[0101] Figure 6 shows the potential (in volts [V]) of each experimental complete cell during charge as a function of capacity relative to the theoretical capacity of the negative electrode. In this case, the dashed and dotted line shows the results for the experimental complete cell using the reference electrolyte, and the solid line shows the results for the experimental complete cell using electrolyte 1. First, the experimental complete cell with a capacity of 125 mAh (Q lad The rechargeable battery cell was then charged at a current of 15 mA until the potential reached 2.5 volts. The discharge capacity (Q ent The capacity for surface layer formation was 6.9% of the theoretical capacity of the negative electrode in the case of electrolyte 1, which is slightly lower than when the reference electrolyte was used, which had a value of 7.1%.

[0102] (Experiment 2) Investigation of the potential curve of an experimental complete cell using electrolyte 1 and nickel manganese cobalt oxide as the positive electrode active material Figure 7 shows the first-cycle potential curve (in volts [V]) as a function of charge rate relative to the maximum charge capacity of an experimental complete cell [% of maximum charge capacity]. During the first cycle of a rechargeable battery cell, a surface layer forms on the negative electrode. Because lithium ions are irreversibly consumed to form this surface layer, the discharge and charge capacities of the experimental complete cell are low. The experimental complete cell was charged to a maximum potential of 4.4 V at a charge rate of 100 mA. It was then discharged to a discharge potential of 2.5 V at a discharge rate of 100 mA. It is possible to charge the experimental complete cell to a high maximum potential of 4.4 V and then discharge it again. Because nickel manganese cobalt oxide is a high-voltage active material, successful cycling is possible with electrolyte 1. No electrolyte decomposition was detected, even at high potentials.

[0103] (Experiment 3) Examination of the capacity curve of an experimental complete cell using electrolyte 1 and nickel manganese cobalt oxide as the positive electrode active material A capacity curve study of the discharge capacity was performed using the experimental complete cells of Experiment 1 filled with the reference electrolyte or electrolyte 1. To determine the discharge capacity (see Example 4), the experimental complete cells were charged to an upper potential of 4.4 V at a current of 100 mA. They were then discharged at a discharge rate of 100 mA to a discharge potential of 2.5 volts. Figure 8 shows the average discharge capacity, normalized to 100% of the maximum capacity, of the two experimental complete cells as a function of cycle number. The average discharge capacity values ​​are each expressed as a percentage of the nominal capacity. Both experimental complete cells show a stable behavior of discharge capacity with respect to cycle number.

[0104] (Experiment 4) Examination of the capacity curve of an experimental complete cell using electrolyte 2 and lithium iron phosphate as the positive electrode active material The discharge capacity curve was investigated using the experimental complete cell of Experiment 3, filled with the reference electrolyte or electrolyte 2. Electrolyte 2 was the conductive salt Li2B at a concentration of 0.25 mol / L. 10 Cl 10 The reference electrolyte used had the composition LiAlCl4*6SO2. The positive electrode active material was lithium iron phosphate. To determine the discharge capacity (see Example 4), the complete experimental cell was charged to an upper potential limit of 3.6 V at a current of 100 mA. It was then discharged at a discharge rate of 100 mA until a discharge potential of 2.5 volts was reached.

[0105] Figure 9 shows the average discharge capacity, normalized to 100% of the maximum capacity, of two experimental full cells as a function of cycle number. The average discharge capacity is expressed as a percentage of the nominal capacity. Both experimental full cells show a stable behavior of discharge capacity versus cycle number.

[0106] (Experiment 5) Measurement of the conductivity of electrolytes 1 and 2 Different concentrations of Li2B were used to measure the conductivity. 12 Cl 12 and Li2B 10 Cl 10Electrolytes 1 and 2 were prepared for each compound. The conductivity of each electrolyte was measured for each concentration of each compound using a conductivity measurement method. After tempering, a four-electrode sensor was placed in contact with the solution and measured in the measurement range of 0.02 to 500 mS / cm.

[0107] Figure 10 shows the compound Li2B 12 Cl 12 1 illustrates the conductivity of Electrolyte 1 as a function of the concentration of the conductive salt. For a conductive salt concentration of 0.3 mol / L, the maximum conductivity is seen to be around 24.7 mS / cm.

[0108] Figure 11 shows the compound Li2B 10 Cl 10 1 illustrates the conductivity of electrolyte 2 as a function of the concentration of the conductive salt. For a conductive salt concentration of 1.2 mol / L, it can be seen that the maximum conductivity is high at about 71.2 mS / cm.

[0109] In comparison, organic electrolytes known from the prior art, such as LP30 (1M LiPF6 / EC-DMC (1:1 wt)), have a conductivity of only about 10 mS / cm.

Claims

1. An active metal, at least one positive electrode (4, 23, 44), at least one negative electrode (5, 22, 45), a housing (1, 28), and SO ２ a base electrolyte; and a rechargeable battery cell (2, 20, 40) comprising: The SO ２ The base electrolyte has the formula (I): 【Chemical 1】 and at least a first conductivity salt having the formula: M is a metal selected from the group consisting of alkali metals, alkaline earth metals, metals of Group 12 of the Periodic Table of the Elements, and aluminum; B is boron, an element in the periodic table of elements; X is a halogen, and a, m, and n are integers, each independently; the first conductive salt is closoborane; SO ２ and the first conductive salt have a total content of more than 50 weight percent (wt%) of the weight of the electrolyte; The negative electrode (5, 22, 45) is an insertion electrode, the positive electrode (4, 23, 44) comprises at least one intercalation compound or a combination thereof as an active material; the intercalation compound is selected from the group consisting of LixNiy1Mny2CozO2, LixCoyOa, and LixFeyM"zPO4; M″ is Mn; x and y are each independently greater than 0; y=y1+y2, z is 0 or greater, and A rechargeable battery cell (2, 20, 40) characterized in that a is greater than 0.

2. 2. The rechargeable battery cell (2, 20, 40) according to claim 1, characterized in that M is lithium.

3. 3. A rechargeable battery cell (2, 20, 40) according to claim 1 or 2, characterized in that X is selected from the group consisting of fluorine, chlorine, bromine and iodine.

4. The M is lithium, the X is chlorine, and the first conductive salt is Li ａ B ｍ Cl ｎ 4. A rechargeable battery cell (2, 20, 40) according to any one of claims 1 to 3, characterized in that it has the composition:

5. The electrolyte contains at least 1 mole of SO per mole of conductive salt. ２ 5. A rechargeable battery cell (2, 20, 40) according to any one of claims 1 to 4, characterized in that it comprises:

6. 6. A rechargeable battery cell (2, 20, 40) according to any one of claims 1 to 5, characterized in that it comprises at least one second conductive salt different from the first conductive salt according to formula (I), the second conductive salt being an alkali metal compound selected from the group consisting of aluminates, halides, oxalates, borates, phosphates, arsenates and gallates.

7. The active metal is alkali metals, alkaline earth metals, a metal from group 12 of the periodic table, or aluminum A rechargeable battery cell (2, 20, 40) according to any one of claims 1 to 6, characterized in that:

8. The rechargeable battery cell (2, 20, 40) according to any one of claims 1 to 7, characterized in that the negative electrode (5, 22, 45) contains carbon as an active material.

9. 9. The rechargeable battery cell (2, 20, 40) according to claim 1, wherein the positive electrode (4, 23, 44) comprises at least one metal compound selected from the group consisting of metal oxides, metal halides and metal phosphates, and the metal of the metal compound is a transition metal of atomic numbers 22 to 28 of the periodic table of the elements.

10. The positive electrode (4, 23, 44) and / or the negative electrode (5, 22, 45) Planar in the form of thin metal sheets or thin metal foils, or A rechargeable battery cell (2, 20, 40) according to any one of claims 1 to 9, characterized in that it has three-dimensional conductor elements (26, 27) in the form of a porous metal structure.

11. The positive electrode (4, 23, 44) and / or the negative electrode (5, 22, 45) are at least one Fluorine-based binder, or a binder comprising a polymer comprising monomer structural units of a conjugated carboxylic acid, an alkali metal salt, an alkaline earth metal salt, or an ammonium salt of the conjugated carboxylic acid, or a combination thereof; or It contains a binder consisting of a polymer based on styrene and butadiene monomer structural units or a binder consisting of the carboxymethyl cellulose group, 11. The rechargeable battery cell (2, 20, 40) according to any one of claims 1 to 10, characterized in that the binder is present in a concentration of 20% by weight or less, relative to the total weight of the positive electrode (4, 23, 44) or the negative electrode (5, 22, 45).

12. The rechargeable battery cell (2, 20, 40) according to any one of claims 1 to 11, comprising a plurality of positive electrodes (4, 23, 44) and a plurality of negative electrodes (5) arranged in an alternating stack within the housing (1, 28), the positive electrodes (4, 23, 44) and the negative electrodes (5, 22, 45) being electrically isolated from each other by separators (11, 13, 21), respectively.

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