WO2013017217A1

WO2013017217A1 - Lithium-ion battery

Info

Publication number: WO2013017217A1
Application number: PCT/EP2012/003122
Authority: WO
Inventors: Tim Schaefer
Original assignee: Li-Tec Battery Gmbh
Priority date: 2011-08-01
Filing date: 2012-07-24
Publication date: 2013-02-07
Also published as: WO2013017216A1

Abstract

Lithium-ion battery, at least having: a positive electrode, a negative electrode, a separator; characterized in that the positive electrode and the negative electrode or the positive electrode or the negative electrode have/has an electrode material which contains active material used for the first time in an electrochemical cell and a proportion of recycled active material, wherein the active material is selected from a material which can absorb or emit lithium ions or lithium, and wherein the recycled active material differs from the active material used for the first time in an electrochemical cell in terms of at least one of the following properties: stoichiometry, structure or particle size.

Description

Lithium Ion Battery

Hereby, the entire contents of the priority application DE 10 201 1 109 137.1 by reference is part of the present application.

description

The invention relates to a lithium-ion battery containing recycled electrode material. The invention further relates to a method of manufacturing the battery, its use and the use of the recycled electrode material.

Lithium ion batteries can contain a variety of components such as chromium-nickel steel, lithium compounds, copper and aluminum and electrolytes. Some of these materials are recyclables and are therefore recycled. Corresponding recycling methods are known in principle from the prior art. These provide for disassembling the deactivated batteries into their components by means of mechanical separation, milling and classification methods. Subsequently, electrode material can be recycled and used to make new electrodes for lithium-ion batteries.

It has been proposed to convert recycled electrode material, which is to be used for the production of new electrodes for lithium ion batteries, into nanopowders according to the principle of ultrasound spray electrolysis, the Particles for improving electrical conductivity can also be coated with carbon (SciTechs extra 2/2009, page 14).

An object of the present invention was to provide a lithium ion battery using recycled electrode material, and to provide a method of manufacturing the battery.

This object has been achieved with a lithium ion battery according to claim 1 and a method for producing the battery according to claim 13. Advantageous further developments are described in the dependent claims.

According to a first aspect of the invention, this relates to a lithium ion battery, comprising at least:

• a positive electrode; · A negative electrode;

• a separator; characterized in that

the positive electrode and the negative electrode or the positive electrode or the negative electrode comprises an electrode material containing first active material used in an electrochemical cell and a content of recycled active material, wherein the active material is selected from a material comprising lithium ions or lithium and wherein the recycled active material differs from the first active material used in an electrochemical cell in at least one of the following properties: stoichiometry or structure or particle size. Batte e

Hereinafter, the terms "lithium ion battery" and "lithium ion secondary battery" are used interchangeably. The terms also include the terms "lithium battery", "lithium ion secondary battery" and "lithium ion cell". A lithium-ion battery generally consists of a serial or series connection of individual lithium-ion cells. This means that the term "lithium-ion battery" is used as a generic term for the terms used in the prior art and means both rechargeable batteries (secondary batteries) as well as non-rechargeable batteries (primary batteries).

electrodes

In the following, the term "positive electrode" means the electrode which, when the battery is connected to a load, for example to an electric motor, is able to pick up electrons. It then represents the cathode.

The term "negative electrode" in the following means the electrode which, in use, is capable of giving off electrons. It then represents the anode. The term "electrode material" in the following means inorganic material or inorganic compounds or substances which are used for or in or on an electrode or as an electrode.

These are preferably compounds or substances which under the working conditions of the lithium-ion battery can absorb (intercalate) and also release lithium ions or metallic lithium due to their chemical nature. In the prior art, such material is also referred to as "active material" for the electrode.This material is preferably applied to a carrier for application in the battery, preferably to a metallic carrier, preferably aluminum or copper. Positive electrode

As the electrode material for the positive electrode, lithium phosphates of the molecular formula LiXPO 4 can be used, where X = Mn, Fe, Co or Ni, or combinations thereof.

Further suitable compounds are lithium manganate, lithium cobaltate, lithium nickelate, or mixtures of two or more of these oxides or their mixed oxides. The positive electrode may also contain mixtures of two or more of said substances.

Negative electrode

The negative electrode may be fabricated from a variety of materials known for use in a prior art lithium-ion battery. For example, the negative electrode may contain lithium metal or lithium in the form of an alloy, either in the form of a foil, a grid, or in the form of particles held together by a suitable binder.

The use of lithium metal oxides such as lithium titanium oxide is also possible.

Suitable materials for the negative electrode are also graphite, synthetic graphite, carbon black, mesocarbon, doped carbon, fullerenes. As electrode material for the negative electrode and niobium pentoxide, tin or tin alloys, titanium dioxide, tin dioxide, silicon can be used. Preferably, tin or tin alloys, titanium dioxide, tin dioxide, silicon exist in a matrix of carbon, for example in graphite. The materials used for the positive as well as for the negative electrode are preferably held together by a binder holding these materials on the electrode. For example, polymeric binders can be used. As the binder, for example, polyvinylidene fluoride, polyethylene oxide, polyethylene, polypropylene, polytetrafluoroethylene, polyacrylate, ethylene (propylene-diene monomer) copolymer (EPDM), and mixtures and copolymers thereof may be used.

The term "recycled active material" in the following means that the active material used is an active material which has already been used at least once in an electrochemical cell and / or has undergone at least one separation and / or grinding and / or classification process For example, a material that has been previously deposited on a metallic support, such as preferably aluminum or copper, is also used The term also includes that the material may include other materials besides materials that can accept or dispense lithium ions or metallic lithium come from the recycling process, for example, binders or inorganic substances that have been used as electrode material.

In one embodiment, this recycled active material originates from a battery which has already been used as a power source at least once, that is, in the case of a secondary battery, has been charged and / or discharged at least once. The term "active material used for the first time in an electrochemical cell" in the following means that the active material used is an active material which has not yet been used in an electrochemical cell and has not undergone a separation and grinding and / or classification process, that is or not even once applied to a metallic support such as preferably aluminum or copper, or which is not a battery that was already used at least once as a power source, so in the case of a secondary battery was charged and / or discharged at least once. The term "active material used for the first time in an electrochemical cell" in the following means that this material is used for the first time as an active material in an electrode material for an electrode (quasi "brand new").

In one embodiment, the active material used for the first time in an electrochemical cell has hitherto only been subjected to at least one charge and / or discharge cycle for the purpose of conditioning.

In one embodiment, both the recycled and the first active material used in an electrochemical cell are selected from a material that can take up or dissipate lithium ions or metallic lithium.

The term "proportion" in the following means that the recycled active material is used in an amount of 0.1 to 99.9% by weight, preferably 0.1 to 60% by weight, more preferably 0.1 to 50% by weight. % may be present in addition to the first active material used in an electrochemical cell, wherein the total amount of recycled and used for the first time in an electrochemical cell active material is 100 wt .-%.

In one embodiment, the recycled active material differs from the first active material used in an electrochemical cell in at least one of the following properties: stoichiometry, structure or particle size, or in two or three of these properties.

The term "stoichiometry" in the following means the composition, preferably the chemical composition of the active material, ie the composition ratio of the chemical elements in the active material. This can be determined by elemental analysis.

The term "structure" in the following means the arrangement, preferably the spatial arrangement, of the chemical elements in the active material This arrangement can be determined by X-ray structure analysis Examples of a structure are an arrangement of suitable elements in a spinel lattice or an olive lattice or in a layer structure , for example, a "03" layer structure.

In the following, the term "particle size" means the particle size of the particles from which the recycled material or active material used for the first time in an electrochemical cell is determined The particle size can be determined by known methods, for example by mechanical methods such as sieve analysis or optical methods like laser light scattering.

In one embodiment, the recycled active material differs from the active material used in an electrochemical cell for the first time in stoichiometry.

In another embodiment, the recycled active material differs from the active material used in an electrochemical cell for the first time in the structure. In another embodiment, the recycled active material differs in particle size from the first active material used in an electrochemical cell.

In one embodiment, the recycled active material differs from the active material used in an electrochemical cell for the first time in the disturbance. chiometry and the structure; or in stoichiometry and particle size; or in structure and particle size; or in stoichiometry and structure and particle size. In one embodiment, this active material, and in particular the recycled active material, is converted into nanoparticles for the application according to the invention.

In one embodiment, the term "nanoparticles" means that these particles have a particle size measured as a D95 value of less than 15 μm. Preferably, the particle size is less than 10 μm.

In a further embodiment, the particles have a particle size measured as D95 value between 0.005 pm to 10 m, or a particle size measured as D95 value of less than 10 pm, wherein the D50 value is 4 pm ± 2 m and the D10 Value is less than 1.5 μηι.

The values given are determined by measurement using static laser light scattering (laser diffraction, laser diffractometry). Such methods are known from the prior art.

Suitable methods for preparing such nanoparticles are known in the art. In one embodiment, ultrasound spray pyrolysis can be used to prepare the nanoparticles (SciTechs extra 2/2009, page 14). In Ultraschallsprühpyrolyse an ultrasonic nebulizer is used in which by electrostriction a crystal is excited to high-frequency vibrations. As a result, an aerosol containing the resulting nanoparticles can be produced from any solution of the starting compounds. In another embodiment, a microwave plasma process may be used to prepare the nanoparticles. The starting compounds are vaporized and converted into a plasma with the aid of microwaves. As a reaction product nanoparticles are obtained. Usually, the particle sizes are well below 10 nm.

In a particularly preferred embodiment, the nanoparticles can be coated with other substances. This results in so-called "nanocomposite particles" or "core / shell particles". In a further preferred embodiment, the nanoparticles are coated with carbon.

For the purposes of the present invention, the recycled active material is used in combination with active material used for the first time in an electrochemical cell.

In one embodiment, the positive and / or the negative electrode contains the nanoparticles obtained via the recycling process in a proportion of 0.01 to 5 wt .-% together with first used in an electrochemical cell active material, wherein the total amount of nanoparticles and only - Each used in an electrochemical cell active material in each case 100 wt .-% is.

In one embodiment, the proportion is 0.05 to 4 wt .-%, or 0.1 to 3 wt .-%

In another embodiment, the positive electrode contains the nanoparticles in an amount of 5 to 30 wt .-% together with the first used in an electrochemical cell active material, wherein the total amount of nanoparticles and first used in an electrochemical cell active material is 100 wt .-% , In one embodiment, the amount is 10 to 25 wt% or 15 to 20 wt%.

In a further embodiment, the negative electrode contains the nanoparticles in an amount of 5 to 45 wt .-% together with first used in an electrochemical cell active material, wherein the total amount of nanoparticles and first used in an electrochemical cell active material 100 wt. % is. In one embodiment, the proportion is 10 to 40 wt .-%, or 15 to 35 wt .-%, or 20 to 25 wt .-%.

According to the invention can be used as active material materials, such as are commonly used for cathodes.

In one embodiment, the recycled active material is introduced into an active material used for the first time in an electrochemical cell, which has a spinel structure or an olivine structure, or vice versa. In one embodiment, the active material used for the first time in an electrochemical cell, into which the recycled material is introduced, has a spinel structure. It is possible to use lithium manganate, lithium cobaltate, lithium nickelate, or mixtures of two or more of these oxides or mixed oxides.

In one embodiment, the active material used for the first time in an electrochemical cell has an olivine structure of the molecular formula LiXPO4, where X = Mn, Fe, Co or Ni, or combinations thereof. It is also possible to use mixtures of two or more of the substances mentioned.

Furthermore, it is also possible that the active material used for the first time in an electrochemical cell, into which the recycled material is introduced, contains carbon to increase the conductivity. Such particles can be prepared by known methods, for example by coating with carbon compounds such as acrylic acid or ethylene glycol. It is then pyrolyzed, for example at a temperature of 2,500 ° C.

In one embodiment, the recycled positive electrode active material is selected from the group consisting of lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, or a mixture of two or three of these oxides, or lithium manganese cobalt nickel mixed oxide. Preferably, the positive electrode active material used for the first time in an electrochemical cell is selected from the group consisting of: lithium iron phosphate, lithium manganese phosphate, or lithium cobalt phosphate, or a mixture of two or three of these phosphates. In another embodiment, the recycled positive electrode active material is selected from the group consisting of: lithium iron phosphate, lithium manganese phosphate, lithium cobalt phosphate, or a mixture of two or three of these phosphates. Preferably, the positive electrode active material used for the first time in an electrochemical cell is selected from the group consisting of lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, or a mixture of two or three of these oxides, or lithium manganese cobalt nickel mixed oxide.

Surprisingly, it has been found that when using recycled lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, or a mixture from two or three of these oxides, or lithium-manganese-cobalt-nickel mixed oxide, in particular in the form of carbon-coated nanoparticles, when added to an active material used in an electrochemical cell with olivine structure, ie lithium iron phosphate, lithium manganese phosphate, lithium cobalt phosphate, or a Mixture of two or three of these phosphates, the conductivity of the electrode can be increased by 10 to 15% relative to an electrode having only the first active material used in an electrochemical cell. Surprisingly, it has also been found that when recycled lithium iron phosphate, lithium manganese phosphate, lithium cobalt phosphate, or a mixture of two or three of these phosphates, in particular in the form of carbon-coated nanoparticles, are added to a spinel-structured active material used for the first time in an electrochemical cell , Thus, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, or a mixture of two or three of these oxides, or lithium-manganese-cobalt-nickel mixed oxide, the conductivity of the electrode can be increased by 10 to 15% based on an electrode, only the first time having active material used in an electrochemical cell.

In another embodiment, the recycled active material is selected from the group consisting of lithium titanium oxide, tin or tin alloys, silicon and carbon, or two or more of these elements or compounds, preferably lithium titanium oxide, silicon or tin. In this embodiment, the recycled active material is preferably used together with an active material of the negative electrode used for the first time in an electrochemical cell, which is likewise selected from lithium titanium oxide, tin or tin alloys, silicon and carbon. In one embodiment, the recycled active material is silicon or tin, and the first active material used in an electrochemical cell is carbon, for example in the form of graphite. In one embodiment, the battery has a separator.

The term "separator" as used herein means a material that separates the negative and positive electrodes of the lithium ion battery, and the separator used for the battery must be permeable to lithium ions in order to control the ion transport of lithium ions between the positive and negative ions On the other hand, the separator has to be insulating for electrons, in one embodiment the separator comprises a nonwoven web of non-woven polymer fibers which are not electrically conductive, Such nonwovens are produced in particular by spinning processes with subsequent solidification.

An embodiment of the lithium ion battery is characterized in that it comprises a separator comprising a nonwoven web of nonwoven polymer fibers coated on one or both sides with an inorganic material.

The term "nonwoven" is used synonymously with terms such as "nonwoven fabrics", "knits" or "felt". Instead of the term "unwoven" the term "not woven" is used.

Preferably, the polymer fibers are selected from the group of polymers consisting of polyacrylonitrile, polyolefin, polyester, polyimide, polyether imide, polysulfone, polyamide, polyether. Suitable polyolefins are, for example, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride.

Preferred polyesters are polyethylene terephthalates.

For the purposes of the present invention, the nonwoven contained in the separator is preferably coated on one or both sides with an ion-conducting inorganic material. The term "coating" also includes below that the ion-conducting inorganic material can be located not only on one side or both sides of the nonwoven, but also within the nonwoven.

The ionically conductive inorganic material is ion conducting in a temperature range of -40 ° C to 200 ° C, i. ion-conducting for lithium ions. The material used for the coating is at least one compound from the group of oxides, phosphates, sulfates, titanates, silicates, aluminosilicates at least one of zirconium, aluminum, silicon or lithium.

In a preferred embodiment, the ion-conducting material comprises or consists of alumina or zirconia or alumina and zirconia.

In one embodiment, a separator is used in the battery according to the invention, which consists of an at least partially permeable carrier, which is not or only poorly electron-conducting. This support is coated on at least one side with an inorganic material. As at least partially permeable carrier an organic material is used, which is designed as a non-woven fleece. The organic material is in the form of polymer fibers, preferably polymer fibers of polyethylene terephthalate (PET). The nonwoven fabric is coated with an inorganic ion-conducting material which is preferably ion-conducting in a temperature range of -40 ° C to 200 ° C. The inorganic one ion-conducting material preferably has at least one compound from the group of oxides, phosphates, sulfates, titanates, silicates, aluminosilicates with at least one of the elements zirconium, aluminum, lithium, particularly preferably zirconium oxide. The inorganic ion-conducting material preferably has particles with a maximum diameter of less than 100 nm.

Such a separator is marketed in Germany, for example, under the trade name "Separion ^®" by the company Evonik AG. Method for producing such separators are known from the prior art, for example from EP 1017476 B1, WO 2004/021477 and WO 2004 / 021,499th

In the following, particularly preferred embodiments of the separator used in the battery according to the invention as well as advantages of the battery will be summarized, in particular with regard to safety aspects.

In principle, too large pores and holes in separators used in secondary batteries can lead to an internal short circuit. The battery can then discharge itself very quickly in a dangerous reaction.

In this case, such large electrical currents can occur that a closed battery cell can even explode in the worst case. For this reason, the separator can contribute significantly to the safety or lack of security of a lithium high performance or lithium high energy battery.

In general, polymer separators inhibit any current transport through the electrolyte above a certain temperature (the so-called "shut-down temperature", which is typically around 120 ° C.). This happens because at this temperature, the pore structure of the separator collapses and all pores are closed. The fact that no ions can be transported, the dangerous reaction that can lead to an explosion, comes to a standstill. However, if the cell continues to heat due to external circumstances, so at about 150 to 180 ° C, the so-called "break-down temperature" is exceeded. From this temperature it comes in conventional separators to melt the separator, which contracts. In many places in the battery cell there is now a direct contact between the two electrodes and thus a large internal short circuit. This leads to an uncontrolled reaction, which can end with an explosion of the cell, or the resulting pressure must be reduced by a pressure relief valve (a rupture disk) often under fire phenomena. In the separator used in the battery according to the invention comprising a non-woven of nonwoven polymer fibers and the inorganic coating, it can only come to shut-down (shutdown), when the polymer melted by the high temperature of the carrier material and penetrates into the pores of the inorganic material and this thereby closing. On the other hand, there is no such break-down (collapse) as the inorganic particles ensure that complete melting of the separator can not occur. This ensures that there are no operating states in which a large-area short-circuit can occur. Due to the type of nonwoven used, which has a particularly suitable combination of thickness and porosity, separators can be produced which can meet the requirements for separators in high-performance batteries, in particular lithium high-performance batteries. By the simultaneous use of precisely matched in their particle size oxide particles for the preparation of the porous (ceramic) coating a particularly high porosity of the finished separator is achieved, the pores are still small enough to unwanted growth of "lithium whiskers" through to prevent the separator.

Due to the high porosity in conjunction with the small thickness of the separator, it is also possible to completely or at least close the separator. hezu completely soak with the electrolyte, so that no dead spaces in individual areas of the separator and thus in certain windings or layers of the battery cells may arise in which there is no electrolyte. This is achieved in particular by the compliance of the particle size of the oxide particles, the resulting separators are free or virtually free of closed pores, in which the electrolyte can not penetrate. The separators used for the invention also have the advantage that the anions of the conductive salt partly adhere to the inorganic surfaces of the separator material, which leads to an improvement in the dissociation and thus to a better ion conductivity in the high-current range. Another not inconsiderable advantage of the separator is the very good wettability. Due to the hydrophilic ceramic coating, wetting with electrolytes takes place very rapidly, which likewise leads to improved conductivity.

The separator used for the battery according to the invention, comprising a flexible nonwoven with a porous inorganic coating located on and in this nonwoven, wherein the material of the nonwoven is selected from unwoven, non-electrically conductive polymer fibers, is also characterized in that the nonwoven a thickness of less than 30 pm, a porosity greater than 50%, preferably from 50 to 97% and a pore radius distribution in which at least 50% of the pores have a pore radius of 75 to 150 pm. The separator particularly preferably has a nonwoven which has a thickness of 5 to 30 μm, preferably a thickness of 10 to 20 μm. Also particularly important is a homogeneous distribution of pore radii in the web as indicated above. An even more homogeneous pore radius distribution in the nonwoven, in combination with optimally matched oxide particles of a certain size, leads to an optimized porosity of the separator. The thickness of the substrate has a large ßen influence on the properties of the separator, since on the one hand, the flexibility but also the sheet resistance of the electrolyte-impregnated separator depends on the thickness of the substrate. Due to the small thickness, a particularly low electrical resistance of the separator is achieved in the application with an electrolyte. The separator itself has a very high electrical resistance, since it itself must have insulating properties. In addition, thinner separators allow increased packing density in a battery pack so that one can store a larger amount of energy in the same volume.

Preferably, the web has a porosity of 60 to 90%, more preferably from 70 to 90%. The porosity is defined as the volume of the web (100%) minus the volume of the fibers of the web, ie the proportion of the volume of the web that is not filled by material.

The volume of the fleece can be calculated from the dimensions of the fleece. The volume of the fibers results from the measured weight of the fleece considered and the density of the polymer fibers. The large porosity of the substrate also allows a higher porosity of the separator, which is why a higher uptake of electrolytes with the separator can be achieved. In order to obtain a separator having insulating properties, as the polymer fibers for the nonwoven fabric, it preferably has non-electrically conductive fibers of polymers as defined above, which are preferably selected from polyacrylonitrile (PAN), polyesters such as e.g. Polyethylene terephthalate (PET) and / or polyolefin (PO), such as e.g. Polypropylene (PP) or polyethylene (PE), or mixtures of such polyolefins.

The polymer fibers of the nonwovens preferably have a diameter of from 0.1 to 10 μm, more preferably from 1 to 4 μm. Particularly preferred flexible nonwovens have a basis weight of less than 20 g / m ² , preferably from 5 to 10 g / m ² .

Preferably, the nonwoven is flexible and has a thickness of less than 30 μητι on.

The separator has a porous, electrically insulating, ceramic coating on and in the fleece. The porous inorganic coating on and in the nonwoven preferably has oxide particles of the elements Li, Al, Si and / or Zr with an average particle size of 0.5 to 7 μm, preferably 1 to 5 μm and very particularly preferably 1 , 5 to 3 pm up.

Particularly preferably, the separator has a porous inorganic coating on and in the nonwoven, which has aluminum oxide particles. Preferably, these have an average particle size of 0.5 to 7 pm, preferably from 1 to 5 pm and most preferably from 1, 5 to 3 pm. In one embodiment, the alumina particles are bonded to an oxide of the elements Zr or Si. In order to achieve the highest possible porosity, more than

50 wt .-% and particularly preferably more than 80 wt .-% of all particles in the abovementioned limits of the average particle size. As already described above, the maximum particle size is preferably 1/3 to 1/5 and particularly preferably less than or equal to 1/10 of the thickness of the nonwoven used.

The separator preferably has a porosity of from 30 to 80%, preferably from 40 to 75% and particularly preferably from 45 to 70%. The porosity refers to the achievable, ie open pores. The porosity can be determined by the known method of mercury porosimetry or can be calculated from the volume and density of the used be calculated if it is assumed that only open pores are present. The separators used for the battery according to the invention are also distinguished by the fact that they can have a tensile strength of at least 1 N / cm, preferably of at least 3 N / cm and very particularly preferably of 3 to 10 N / cm. The separators can preferably be bent without damage to any radius down to 100 mm, preferably down to 50 mm and most preferably down to 1 mm. The high tensile strength and the good bendability of the separator have the advantage that changes in the geometries of the electrodes occurring during the charging and discharging of a battery can be through the separator without being damaged. The flexibility also has the advantage that commercially standardized winding cells can be produced with this separator. In these cells, the electrode / separator layers are spirally wound together in a standardized size and contacted.

In one embodiment, it is possible to design the separator to have the shape of a concave or convex sponge or pad, or the shape of wires or a felt. This embodiment is well suited to compensate for volume changes in the battery. Corresponding preparation methods are known to the person skilled in the art.

In a further embodiment, the polymer fleece used in the separator has a further polymer. Preferably, this polymer is disposed between the separator and the negative electrode and / or the separator and the positive electrode, preferably in the form of a polymer layer.

In one embodiment, the separator is coated with this polymer on one or both sides. Said polymer may be in the form of a porous membrane, ie as a film, or in the form of a nonwoven, preferably in the form of a nonwoven web of nonwoven polymer fibers. These polymers are preferably selected from the group consisting of polyester, polyolefin, polyacrylonitrile, polycarbonate, polysulfone, polyethersulfone, polyvinylidene fluoride, polystyrene, polyetherimide.

Preferably, the further polymer is a polyolefin. Preferred polyolefins are polyethylene and polypropylene.

The separator is preferably coated with one or more layers of the further polymer, preferably of the polyolefin, which is preferably also present as a nonwoven, that is to say as nonwoven polymer fibers.

Preferably, a non-woven of polyethylene terephthalate is used in the separator, which is coated with one or more layers of the further polymer, preferably of the polyolefin, which is preferably also present as non-woven, so as non-woven polymer fibers.

Particular preference is given to a separator of the above-described type of separation which is coated with one or more layers of the further polymer, preferably of the polyolefin, which is preferably likewise present as a nonwoven, that is to say as nonwoven polymer fibers.

The coating with the further polymer, preferably with the polyolefin, can be achieved by gluing, lamination, by a chemical reaction, by welding or by a mechanical connection. Such polymer composites and processes for their preparation are known from EP 1 852 926. The fiber diameters of the polyethylene terephthalate fleece are preferably larger than the fiber diameters of the further polymer fleece, preferably the polyolefin fleece, with which the separator is coated on one or both sides.

Preferably, the nonwoven made of polyethylene terephthalate then has a higher pore diameter than the nonwoven, which is made of the other polymer. Preferably, the nonwovens usable in the separator are made of nanofibers of the polymers used, whereby nonwovens are formed which have a high porosity with formation of small pore diameters. Thus, both the risk of short-circuit reactions can be further reduced. The use of a polyolefin in addition to the polyethylene terephthalate ensures increased safety of the electrochemical cell, since in unwanted or excessive heating of the cell, the pores of the polyolefin contract and the charge transport through the separator is reduced or terminated. Should the temperature of the electrochemical cell increase to such an extent that the polyolefin begins to melt, the polyethylene terephthalate effectively counteracts the melting together of the separator and thus an uncontrolled destruction of the electrochemical cell.

The use of a separator of the type described above is important because due to the increased conductivity of the electrodes in the battery according to the invention the formation of whiskers can be effectively counteracted and the risk of melt through of the separator or the formation of short circuits can be minimized. In another embodiment, the lithium-ion battery comprises a nonaqueous electrolyte.

The term "electrolyte" preferably means a liquid and a conducting salt in the following: Preferably, the liquid is a solvent for the conducting salt, and the electrolyte is then preferably in the form of an electrolyte solution Suitable electrolytes are known from the prior art.

Suitable solvents are preferably inert. Suitable solvents are preferably solvents such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, methyl propyl carbonate, butylmethyl carbonate, ethylpropyl carbonate, dipropyl carbonate, cyclopentanones, sulfolanes, dimethylsulfoxide, 3-methyl-1,3-oxazolidine-2-one. on, γ-butyrolactone, 1, 2-diethoxymethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1, 3-dioxolane, methyl acetate, ethyl acetate, nitromethane, 1, 3-propanesultone.

In one embodiment, ionic liquids may also be used as the solvent.

Ionic liquids are known in the art. They contain only ions. Examples of useful cations which may in particular be alkylated are imidazolium, pyridinium, pyrrolidinium, guanidinium, uronium, thiuronium, piperidinium, morpholinium, sulfonium, ammonium and phosphonium cations. Examples of useful anions are halide, tetrafluoroborate, trifluoroacetate, triflate, hexafluorophosphate, phosphinate and tosylate anions.

Examples of ionic liquids which may be mentioned are: N-methyl-N-propylpiperidinium bis (trifluoromethylsulfonyl) imide, N-methyl-N-butylpyrrolidiniumbis (trifluoromethylsulfonyl) imide, N-butyl-N-trimethylammonium bis (trifluoromethyl- sulfonyl) imide, triethylsulfonium bis (trifluoromethylsulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) -ammonium bis (trifluoromethane

Two or more of the above liquids can be used.

Preferred conductive salts are lithium salts which have inert anions and which are non-toxic. Suitable lithium salts are preferably lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium bis (trifluoromethylsulfonyl imide), lithium trifluoromethanesulfonate, lithium tris (trifluoromethylsulfonyl) methide, lithium tetrafluoroborate, lithium perchlorate, lithium tetrachloroaluminate, lithium bisoxalatoborate, lithium difluorooxalatoborate and / or lithium chloride; and mixtures of one or more of these salts. Preferably, the lithium battery according to the invention can be operated at ambient temperatures of -40 to +100 ° C.

Preferred discharge currents of a battery according to the invention are greater than 100 A, preferably greater than 200 A, preferably greater than 300 A, more preferably greater than 400 A.

According to a second aspect of the invention, it relates to a method for producing a lithium ion battery according to the invention, which comprises the steps (i) and (ii):

(i) transferring a recycled active material of an electrode of a lithium ion battery into nanoparticles;

(ii) introducing the nanoparticles of step (i) into an active material for the first time used in an electrochemical cell Electrode and the negative electrode or for the positive electrode or the negative electrode of the lithium-ion battery.

The introduction of the nanoparticles into an electrode material of step (ii) can be carried out by known methods.

In one embodiment, the nanoparticles of the recycled active material are processed into an aqueous suspension with further components of the electrode material, for example the spinels or olivines as explained above. This can be prepared by the methods customary in ceramic technology, for example by mixing the components used, preferably by mixing or by stirring the components. The mixing can also be supported by sonication.

The term "suspension" is used interchangeably below with the terms "emulsion", "dispersion", "colloid" or "slurry" Preferably, the suspension is an aqueous suspension It is possible to use organic solvents, preferably ethanol, isopropanol, acetone or dimethylformamide, or mixtures of these solvents in the suspension.

In one embodiment, the suspension may also contain binders which promote adhesion of the nanoparticles and the other components on the metallic support of the electrode. Suitable binders are known in the art. Preferably, polymeric binders can be used, preferably polyvinylidene fluoride, polyethylene oxide, polyethylene, polypropylene, polytetrafluoroethylene, polyacrylate, ethylene (propylene-diene monomer) copolymer (EPDM) and blends and copolymers thereof. The suspension may be applied by known methods to the metallic support used in the electrode, preferably by extrusion or calendering methods. After drying, the electrode is obtained.

According to a third aspect of the invention, this relates to the use of a lithium-ion battery according to the invention or a lithium-ion battery produced by the method according to the invention for operating a hybrid vehicle or a plug-in hybrid vehicle.

The term "hybrid vehicle" in the sense of the invention means a vehicle which has an electric drive as well as an internal combustion engine The accumulator required for the electric drive is charged from the internal combustion engine after or at discharge via energy.

The term "plug in hybrid vehicle" in the sense of the invention means a vehicle which has an electric drive as well as an internal combustion engine, wherein the battery required for the electric drive can be externally charged after or during discharge.

According to a fourth aspect of the invention, this relates to the use of nanoparticles obtained by converting a recycled active material, preferably a recycled active material of an electrode of a lithium ion battery, into nanoparticles, wherein the nanoparticles are coated with carbon, in or as a conductive ink or in one or more as a primer or in an electrode or as an active material of an electrode.

The nanoparticles according to these uses are prepared as described in the first aspect of the invention. The term "conductive ink" in the context of the invention means an electrically conductive lacquer.

In one embodiment, the nanoparticles are embedded in a binder. The binder component may comprise a solvent and a synthetic resin in one embodiment. Suitable solvents and synthetic resins are known from conductive ink technology. With the help of conductive paints, for example, defective conductor tracks can be repaired in electronic devices. The term "primer" in the context of the invention means a primer or an adhesion promoter.

Claims

claims

Lithium ion battery, at least comprising:

a positive electrode;

a negative electrode;

a separator;

characterized in that

the positive electrode and the negative electrode or the positive electrode or the negative electrode comprises an electrode material containing first active material used in an electrochemical cell and a content of recycled active material, wherein the active material is selected from a material comprising lithium ions or lithium and wherein the recycled active material differs from the first active material used in an electrochemical cell in at least one of the following properties: stoichiometry or structure or particle size.

The lithium-ion battery according to claim 1, wherein the recycled active material is different from the active material in stoichiometry first used in an electrochemical cell.

A lithium ion battery according to claim 1 or 2, wherein the recycled active material is different from the active material used in an electrochemical cell for the first time in the structure.

A lithium ion battery according to any one of the preceding claims, wherein the recycled active material is different in particle size from the active material used for the first time in an electrochemical cell.

A lithium-ion battery according to any one of the preceding claims, wherein the recycled active material is in the form of nanoparticles.

The lithium ion battery of claim 5, wherein the nanoparticles are carbon coated.

Lithium ion battery according to one of the preceding claims, wherein the conductivity of the lithium ion battery is increased with recycled active material compared to an otherwise identical lithium ion battery with a corresponding additional proportion of active material used for the first time in an electrochemical cell.

Lithium ion battery according to claim 5 or 6, wherein the nanoparticles are introduced in a proportion of 0.01 to 5 wt .-% in the first used in an electrochemical cell electrode material of the positive electrode and / or the negative electrode, the total amount of Nanoparticles and electrode material introduced for the first time in an electrochemical cell is in each case 100 wt .-%, or wherein the positive electrode contains nanoparticles in an amount of 5 to 30 wt .-% together with first used in an electrochemical cell active material, wherein the total amount of nanoparticles and 100% by weight of active material used in an electrochemical cell for the first time.

Lithium ion battery according to claim 5 or 6, wherein the negative electrode nanoparticles in an amount of 5 to 45 wt .-% together with first used in an electrochemical cell active material, wherein the total amount of nanoparticles and first used in an electrochemical cell active material 100th Wt .-% is.

10. The lithium-ion battery according to claim 1, wherein the recycled active material is in a positive electrode having an active material having an olive structure or a spinel structure first used in an electrochemical cell.

11. The lithium ion battery of claim 10, wherein the recycled active material is selected from the group comprising: lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, or a mixture of two or three of these oxides, or lithium manganese cobalt nickel mixed oxide, and the first time active material used in an electrochemical cell is selected from the group comprising: lithium iron phosphate, lithium manganese phosphate, or lithium cobalt phosphate, or a mixture of two or three of these phosphates; or wherein the recycled active material is selected from the group comprising: lithium iron phosphate, lithium manganese phosphate, lithium cobalt phosphate, or a mixture of two or three of these phosphates, and the first active material used in an electrochemical cell is selected from the group comprising: lithium manganese oxide, lithium cobalt oxide, Lithium nickel oxide, or a mixture of two or three of these oxides, or lithium-manganese-cobalt-nickel mixed oxide.

12. The lithium ion battery according to claim 1, wherein the recycled negative electrode active material is selected from the group consisting of lithium titanium oxide, tin or tin alloys, silicon and carbon, or two or more of these elements or compounds active material used in an electrochemical cell is selected from the same group.

13. A method of manufacturing a lithium ion battery according to any one of claims 5 to 12, comprising steps (i) and (ii): (i) transferring a recycled active material of an electrode of a lithium ion battery into nanoparticles;

(ii) introducing the nanoparticles from step (i) into an active material for the positive electrode and the negative electrode or for the positive electrode or the negative electrode of the lithium ion battery which is first used in an electrochemical cell.

14. The use of a lithium ion battery according to any one of claims 1 to 12, or a lithium ion battery prepared according to claim 13, for operating a hybrid vehicle or a plug in hybrid vehicle.

15. Use of nanoparticles obtained by converting a recycled active material of an electrode into nanoparticles, wherein the nanoparticles are coated with carbon, as a conductive ink or as a primer or as an active material for an electrode.