DE102008040941A1 - Electrolyte mixture, useful to prepare lithium-ion cells, comprises polypyrrole, conducting salt e.g. lithium hexafluorophosphate, aprotic solvent or mixture of e.g. dimethoxyethane and ethylene carbonate, and mineral additive e.g. cement - Google Patents

Abstract

Electrolyte mixture comprises 20-50 wt.% of polyvinylpyrrolidone homo- and/or copolymer, polyaniline and/or polypyrrole with a molecular weight of 3000-20000; 20-10 wt.% of a conducting salt, preferably on basis of lithium hexafluorophosphate or lithium compounds; 30-20 wt.% of aprotic solvent or a solvent mixture of dimethoxyethane, ethylene carbonate, propylene carbonate or alkyl carbonate; and 30-20 wt.% of a mineral additive, preferably oxide, carbonate, oxalate, silicate and/or borate of lithium, sodium, potassium, calcium, magnesium and/or cement. Electrolyte mixture comprises 20-50 wt.% of polyvinylpyrrolidone homo- and/or copolymer, polyaniline and/or polypyrrole with a molecular weight of 3000-20000; 20-10 wt.% of a conducting salt, preferably on basis of lithium hexafluorophosphate, or lithium compound of formula (LiPF 5R 1), (LiPF 4(R 1) 2) or LiPF 3(R 1) 3; 30-20 wt.% of aprotic solvent or a solvent mixture of dimethoxyethane, ethylene carbonate, propylene carbonate or alkyl carbonate; and 30-20 wt.% of a mineral additive, preferably oxide, carbonate, oxalate, silicate and/or borate of lithium, sodium, potassium, calcium, magnesium and/or cement. R 1CF 3, C 2F 5or C 3H 7. Independent claims are included for: (1) a lithium-ion cell comprising an anode, cathode and separator, where the anode and cathode comprises the electrolyte mixture; and (2) a process for the preparation of the lithium-ion cell comprising degassing an electrically active anode mass e.g. lithium intercalated natural or synthetic graphite at 20-100[deg] C and 0.1-2 Pa, abolishing vacuum by adding the electrolyte mixture, intensively stirring the anode mass under air and moisture exclusion and tribiochemically condensing the mixture, where the subsequent application of the anode mass, as 20-50 mu m thick layer on purified copper arrester also takes place under air and moisture exclusion, or degassing an electro-chemically active cathode mass comprising lithium-intercalated heavy metal oxide or a mixture of cobalt, nickel, chromium, manganese, molybdenum, and lithium-iron-phosphate and/or lithium-vanadium-phosphate at 20-100[deg] C and 0.1-2 Pa; adding the electrolyte mixture to the cathode mass under the abolition of vacuum; intensively stirring (tribiochemically condensed) under air and moisture exclusion and applying the cathode mass as 20-50 mu m thick layer on the primed aluminum foil, or reacting a separator mass comprising 30-40 wt.% of perfluoroelastomer, 20-40 wt.% of aprotic solvents, 20-24 wt.% of the conducting salt and 25-1 wt.% of scaffolding substances, cements, silicates, sodium, potassium, calcium, magnesium carbonate with the electrolyte mixture, intensively mixing under the exclusion of air and moisture, extruding or applying the mixture as a foil with at thickness of 20-50 mu m, or coating one or both side of a porous separator foil with the electrolyte mixture and incorporating the foil as a separate foil between the anode and cathode under the exclusion of air and moisture, or connecting two or more lithium-ion cell preferably by parallel circuit.

Description

The The invention relates to an electrolyte mixture, especially in terms of stability, cycle stability, temperature behavior and reduced internal resistance was significantly improved.

Furthermore, The present invention relates to lithium-ion cells, in which the electrolyte mixture is used.

About that In addition, this invention relates to a method of manufacture of lithium-ion cells in which the electrolyte mixture is used becomes.

After all The present invention relates to the production of lithium Ion batteries in which the above used lithium-ion cells become.

Lithium-ion energy storage are lithium-ion cells that consist of anode, cathode and a polymer electrolyte exist as a separator. Anode, cathode and separator are merged, so that a composite arises in which the separator as an intermediate layer for anode and cathode. The resulting composite becomes then processed into multiple layers and as prismatic cells or Winding cells formed. After Einhausen and Poland lies one Lithium-ion cell before, after forming with voltage of about 4 volts and cycle times> 500 is ready for use.

Details of the preparation and the system are known in the literature and the "Handbook of Battery Materials" (edited by IO Besenhard, Verlag VCH Weinheim, 1999) (Ref. 1). Special manufacturing methods, such. B. the so-called. Bellcore process are in "Lithium Ion Batteries" (edited by M. Wakihara et O. Yamamoto, Verlag VCH Weinheim, 1998 S. 235 and Fig. 10.9) described (Ref 2).

to Production of lithium-ion cells are basically used different processes.

A Variant is the coating process, in which the for solved the cathode or anode mass required polymer binder becomes. For example, fluoroelastomers (homopolymers or copolymers) become 5 to 10% pure in z. B. N-methyl-pyrrolidone (NMP) and dissolved this polymer solution comes with the cathode- or anode-specific additives such as Li-intercalatable metal oxides or Li-intercalatable carbons (carbon black, Graphite or the like) and dispersed. Then this will be Dispersion according to the film coating technique on current collectors (Films, tapes, nets or the like, preferably Cu for the anode, preferably Al for the cathode) applied.

A Variant of the coating technique described above consists in the use of aqueous polymer dispersions instead the polymer solutions with organic solvents. The resulting coatings become prismatic cells upon drying or wound cells processed, wherein as an intermediate layer a so-called. Separator, z. B. from Celgard o. Ä., With porous structures is used. A system made in this way is housed in a housing encapsulated and before sealing with an electrolyte, d. H. one dissolved in aprotic solvents Conducting salt, filled.

Of the Bellcore process is another variant of coating technology. Here, even in the anode or cathode material was a component, z. As dibutyl phthalate (DBP), incorporated before the merger of anode, cathode and separator in the so-called Bellcore process (cf. Lit. 2) is dissolved to ensure sufficient porosity, d. H. Absorption capacity for the electrolyte too create.

A fundamentally different process is the extrusion z. As a separator (polymer gel) and z. B. a cathode (see. US 4,818,643 ; corresponds to EP 0 145 498 B1 and DE 34 85 832 T ), or the extrusion of anode, separator and cathode in parallel extruders and subsequent merging (see. DE 100 20 031 A1 ). The latter patent application discloses a method in which each of the solvent and / or swelling agent-containing anode mass, separator and cathode mass are extruded in parallel extruders and then combined as a unit, which are then laminated with collector films.

The All the methods described so far have all but different ones Disadvantages: In the coating processes must in all cases the organic solvents or the water (entrained by the polymer solution or dispersion) are eliminated. Remaining solvent leads to "fading", d. H. to slow down battery efficiency and lack cycle stability. The organic solvent must be for cost reasons and to be removed for environmental protection, which means high drying temperatures or in the continuous process longer drying times at low drying temperatures and vacuum. The same applies to the separation of water. Disadvantages arise in the film: inhomogeneities, Cracking during tight winding, reduced adhesion to the current collectors, Damage to the current collectors, infiltration of the film through the electrolyte, u. .. When filling With the electrolyte, only insufficient wetting of the anode or cathode material.

Polyethylene oxide (PEO) is used in the extruder process (cf. US 4,818,643 ), that ever but has no long-term stability during battery operation, ie a cycle stability <100. The other extruder process works with electrolytes based on ethylene carbonate / γ-butyrolactone (EC / γ-BL) with LiClO ₄ as conductive salt. This system also shows low cycle stability of <100 (cf. DE 100 20 031 A1 ), since under the operating conditions of the battery the γ-BL reacts and produces disturbing by-products:
PCT / EP 99/06313 (Corr. WO 00/13249 ) describes the use of pasty masses, wherein the masses are applied successively by means of a paste application method.

In PCT / US97 / 08029 (Corr. WO 97/44847 ) Extrusion polymer electrolytes are coated with electrode material by extrusion and then processed into battery electrodes.

The based new lithium ion cells according to the invention on the other hand, on a completely new principle.

Around the defects in terms of high internal electrical resistance, Temperature sensitivity, lack of cycle resistance, solid Electrolyte interphase behavior (SEI behavior), failure mechanisms u. Ä. To counter, the electrolyte was modified and Although a) in terms of its consistency but also b) in terms his application.

The SEI behavior is described in Ref. 3 (in Ref. 1, Chemical Composition and Morphology of the SEI, p. 439, see also p. 420 ).

The formation of the SEI of the insulating and less electrically conductive decomposition layer at the anode and cathode is an elementary problem that leads to significant quality losses in lithium-ion cells, especially in continuous operation, lower cycle times at elevated temperature u. Ä. leads. According to reference 4 ( D. Aurbach et al .; Abstr. 190th Electrochemical Soc. Meeting, San Antonio TX, Vol. 96-2, p. 164 ), the SEI layer consists of at least five different layers and components.

Suggestions, eg. B. by additives such as vinylene carbonate to solve the SEI problem (vg., Ref. 5; EP 1 374 331 B1 ; EP 0 826 862 A1 ; US 2008/003864 A1 ; u. Ä.), did not or only partially to improve or to remedy the problem.

The The object of this invention is side reactions and failure mechanisms to suppress and preferably exclude d. H. the elimination of water and acids, especially HF, the stabilization of the conductive salts, the avoidance of hydrolyses, z. B. of ester groups in homo / copolymers, the elimination of disturbing Contaminants (in the starting materials) u. Ä. To cause.

As already mentioned, the object of this invention also exists therein, the enumerated disadvantages of the usual and to overcome prior art systems.

So z. For example, the electrical conductivity of an Li-oxalato borate (LiOB) electrolyte is 0.6 M in EC / DMC (1/1 ratio) 7 mS and LiPF _{6 is} 1.0 M in EC / DMC (1/1 ratio). 11 mS (see ref. 5; EP 374 331 B1 ) (EC = ethylene carbonate, DMC = dimethyl carbonate, S = Siemens).

1 shows the properties of the batteries according to the invention up to temperatures of 60 ° C over a large range of the current value.

The The object of the invention is preferred by the following aspects solved.

The first aspect relates to an electrolyte mixture consisting of a) polyvinylpyrrolidone homopolymers and / or copolymers having molecular weights of from 2 to 20,000 in amounts of from 20 to 50 percent by weight, b) a conductive salt, preferably based on LiPF ₆ , LiPF ₅ R ₁ , LiPF ₄ (R ₁ ) ₂ , LiPF ₃ (R ₁ ) ₃ , (R ₁ = CF ₃ , C ₂ F ₅ , C ₃ F ₇ ) in amounts of from 20 to 10% by weight, c) an aprotic solvent or solvent mixture of dimethoxyethane, Ethylene carbonate, propylene carbonate or alkyl carbonate in amounts of 30 to 20 weight percent, and d) a mineral additive such as an oxide, carbonate, oxalate, silicate and / or borate of Li, Na, K, Ca, Mg, and / or cement in amounts of 30 to 20 weight percent, wherein the weight percent are each based on the total amount of the electrolyte mixture exists.

Of the second aspect relates to a lithium-ion cell consisting anode, cathode and separator, anode and cathode being the electrolyte mixture of the first aspect.

In a preferred modification is the lithium-ion cell after second aspect, characterized in that the separator, the electrolyte mixture of the first aspect.

To a fourth and fifth aspect of the above lithium-ion cell is the electrolyte mixture in amounts of 3 to 30 parts by weight in anode and cathode, or in the separator is included.

The sixth aspect relates to a method for producing a lithium ion cell according to any one of the second to fifth aspects, wherein an electrically active anode mass, ie, a Li-intercalatable natural or synthetic graphite at temperatures of 20 to 100 ° C and pressures of 0, 1 to 2 Pa is degassed and the vacuum is removed by adding the electrolyte mixture according to claim 1 and this anode mass under air and Exclusion of moisture is intensively stirred and densified tribochemically, wherein the subsequent application of the anode material as a 20 to 50 .mu.m thick layer on the cleaned Cu arrester (Gould film) also takes place with exclusion of air and moisture.

Of the seventh aspect relates to a method for producing a Lithium-ion cell after one of the second to fifth Aspect, wherein an electrochemically effective cathode material, d. H. Li-intercalatable heavy metal oxides or mixtures of Co, Ni, Cr, Mn, Mo u. Ä. And Li-Fe-phosphate and / or Li-V-phosphate at temperatures of 20 to 100 ° C and pressures is degassed from 0.1 to 2 Pa and then to the cathode mass below Lifting the vacuum metered the electrolyte mixture according to claim 1 is intensively stirred, tribochemically compressed and processed under exclusion of air and moisture and also as 20 to 50 μm thick layer on a primed Al foil is applied.

Of the Eighth aspect relates to a method for producing a lithium-ion cell according to one of the second to fifth aspects, wherein a Separator mass of 30 to 40 wt .-% perfluoroelastomers, 20 to 40% by weight aprotic solvents, 20% to 24% by weight Conducting salts and 25 to 1 wt .-% builders such as cement, Silicates, Na, K, Ca, Mg carbonates with the electrolyte mixture after Claim 1 is added and under exclusion of air and moisture intensively mixed and then in thicknesses of 20 to 50 microns extruded or applied as a film.

Of the sixth aspect relates to a method for producing a Lithium-ion cell after one of the second to fifth Aspect, wherein a porous separator film on one or both sides is coated with the electrolyte mixture according to claim 1 and then as separating film between anode and cathode under air and moisture exclusion is installed.

Of the Tenth aspect relates to a method for producing lithium-ion battery, wherein two or more lithium-ion cells after one of the second to fifth aspect, preferably by parallel connection get connected.

Inventive measures

1. Conducting salts

• a) Li-Organoborate, z. B. Oxalatoborate, Salizylatoborate u. ä., Chelatoborate
• b) Li-bis(trifluoromethylsulfonylimide) u. ä. z. B. Li[N(SO₂CF₃)₂], Li[N(SO₂(CF₂)₄(SO₂)] und Methide z. B. Li[C(SO₂(CF₃)₃]
• c) LiPF₆, LiPF₅(C₃F₇), LiPF₄(CF₃)₂, LiPF₃(CF₃)₃ u. ä.

Conducting salts are mentioned in Ref. 6 (in Ref. 1; Liquid Nonaqueous Electrolytes pp. 457-497 ) in question:

• a) Li organoborates, e.g. B. Oxalatoborate, Salizylatoborate u. Ä., Chelatoborates
• b) Li bis (trifluoromethylsulfonylimide) u. Ä. Li [N (SO ₂ CF ₃ ) ₂ ], Li [N (SO ₂ (CF ₂ ) ₄ (SO ₂ )] and methides eg Li [C (SO ₂ (CF ₃ ) ₃ ]
• c) LiPF ₆ , LiPF ₅ (C ₃ F ₇ ), LiPF ₄ (CF ₃ ) ₂ , LiPF ₃ (CF ₃ ) ₃ u. ä.

2. Agrotic solvents

• a) Dimethoxyethan, Dimethoxypropan,
• b) Carbonate wie Ethylencarbonat, Propylencarbonat, Monomethylcarbonat, Dimethylcarbonat, Monoethylcaronat, Diethylcarbonat, Monoisopropylcarbonat, Mono(trifluormethyl)carbonat, Di(trifluormethyl)carbonat, Mono(pentafluorethoxy)carbonat

As aprotic solvents can be used

• a) dimethoxyethane, dimethoxypropane,
• b) Carbonates such as ethylene carbonate, propylene carbonate, monomethyl carbonate, dimethyl carbonate, monoethyl caronate, diethyl carbonate, monoisopropyl carbonate, mono (trifluoromethyl) carbonate, di (trifluoromethyl) carbonate, mono (pentafluoroethoxy) carbonate

3. Complexing agent

Complexing agents z. B. with the conductive salts form relatively stable and electrically conductive complexes may be
Polyvinylpyrrolidone, polyaniline, polypyrrole with molecular weights of 3,000 to 20,000
The molecular weights are determined according to Ref. 7 ( Ullmann's Encyclopedia of Industrial Chemistry, Vol. 20, p. 564/568, Viscometric Method (1992) Verlag VCH, Weinheim ).

4. Preparation of the starting materials

• a) Elektroden: Cu-Folie, Al-Folie als Ableiter. Die Reinigung erfolgt durch Auftragen einer Ruß- oder Graphitschicht mit ca. 0,1 bis 0,5 μm Dicke und Abbürsten dieser Schicht im Walzenstuhl.
• b) Anodenmaterial: natürlicher oder synthetischer Graphit Diese Materialien werden im Vakuum bei ca. 1,3 Pa für 1 bis 5 Stunden bei 20 bis 100°C gerührt und das Vakuum durch Eindosieren z. B. von Elektrolyt (siehe 5.) nach dem Abkühlen der entgasten Materialien auf 20 bis 30°C aufgehoben. Auf 100 Gewichtsteile Anodenmaterial werden 1 bis 5 (vorzugsweise 2–3) Gewichtsteile der Lösung zudosiert.
• c) Kathodenmaterial: Li-interkalierbare Schwermetalloxide wie Co, Ni, Cr, Mo o. ä., sowie deren Gemische und/oder Li-Fe-Phosphat oder Li-V-phosphat werden analog wie die Anodenmaterialien 4b entgast und dann beim Aufheben des Vakuums mit Elektrolyt versetzt.

An essential measure to improve the quality of the lithium-ion cells is the careful cleaning of all starting materials.

• a) Electrodes: Cu foil, Al foil as arrester. The cleaning is carried out by applying a soot or graphite layer with about 0.1 to 0.5 microns thickness and brushing this layer in the roller mill.
• b) anode material: natural or synthetic graphite These materials are stirred in vacuo at about 1.3 Pa for 1 to 5 hours at 20 to 100 ° C and the vacuum by metering z. B. of electrolyte (see 5.) after cooling the degassed materials to 20 to 30 ° C repealed. On 100 parts by weight of anode material 1 to 5 (preferably 2-3) parts by weight of the solution are metered.
• c) cathode material: Li-intercalatable heavy metal oxides such as Co, Ni, Cr, Mo o. Ä., And their mixtures and / or Li-Fe-phosphate or Li-V-phosphate are degassed analogously as the anode materials 4b and then on lifting the Vacuum mixed with electrolyte.

5. electrolyte

The electrolyte used is preferably a mixture of polyvinylpyrrolidone (PVP) and / or copolymers with LiPF ₆ , LiPF ₅ R ₁ , LiPF ₄ (R ₁ ) ₂ or LiPF ₃ (R ₁ ) ₃ salts (R ₁ = CF ₃ , D ₂ F ₅ , C ₂ F ₅ ), Li bis (triflu ormethylsulfonylimide) o. Ä., And a mixture of EC with DEC (DMC) in the ratio 1: 1 (DEC = diethyl carbonate).

The Quantity ratios are 30 parts by weight PVP, 30 parts by weight Li salt, 30 parts by weight EC / DEC (or 30 parts by weight EC / DMC) and 10 parts by weight of MgO (cement, silicate) or the like). This electrolyte mixture is the degassed and modified electrode masses and the Separator added in amounts of 3 to 30 parts by weight. Eg 93 parts by weight modified anode mass according to 4b (AM mod.) And 7 parts by weight of electrolyte mixture (4d) of modified cathode material after 4c (KM mod.) with 90 parts by weight and 10 parts by weight of electrolyte mixture (4d). The added electrolyte mixture becomes air and moisture for 3 to 5 hours at 20 to 40 ° C in a Maxx agitator mill Mill MM1 intensively mixed, tribochemically compacted.

The Electrolyte mixture is the separator in the extrusion production added in bulk, mixed and then extruded as an extruder sheet withdrawn from the extruder or onto the surface (one-sided or both sides) in thicknesses of 5 to 15 μm on the absorbent, applied porous separator surface.

6. Separator

• a) eine poröse Polyolefin-Folie mit Dicken von 10 bis 50 μm und Porositäten von 25 bis 50%, Typ Celgard, oder
• b) ein Extrusionsseparator (vgl. Lit 8; DE 1 2004 044 478 A2 , 0024-0029, Herstellung der Separatorfolie), bestehend aus Polymerbinder, vorzugsweise Polyfluorelastomere, Terpolymere (Dyneon THV 220^® o. ä., 3M Corp.) mit 30 bis 40 Gewichtsteilen, aprotischen Lösungsmitteln (entspr. Lit. 6) mit 20 bis 40 Gewichtsteilen, Leitsalzen (Lit 6, S. 461 bis 463) mit 25 bis 29 Gewichtsteilen und Gerüstsubstanz wie Zement, Silikate, Na, K, Ca, Mg, Carbonat, Phosphat, Oxalat u. ä. mit 25 bis 1 Gewichtsteilen.

As stated above, the separator used in the invention is either

• a) a porous polyolefin film with thicknesses of 10 to 50 microns and porosities of 25 to 50%, type Celgard, or
• b) an extrusion separator (cf Ref 8; DE 1 2004 044 478 A2 , 0024-0029, production of the separator film), consisting of polymer binder, preferably polyfluoroelastomers, terpolymers (Dyneon THV 220 ^® or the like, 3M Corp.) with 30 to 40 parts by weight, aprotic solvents (corresponding to Ref 6) with 20 to 40 parts by weight, Leitsalzen (Lit 6, pp 461-463) with 25 to 29 parts by weight and builder substance such as cement, silicates, Na, K, Ca, Mg, carbonate, phosphate, oxalate u. Ä. With 25 to 1 parts by weight.

Under 5. it was stated that the inventive Electrolyte mixture in amounts of from 3 to 30 parts by weight of the separator mass is added during extrusion. This amount is in proportion 1: 1 of the parts by weight of the aprotic solvent (30 to 40 parts by weight) and of the parts by weight of the conductive salts (20 to 40 parts by weight) deducted.

7. Manufacture of the invention Li-ion cell

a) Anode mass AM (see 4b) and anode (Cu foil + AM):

40 parts by weight graphite (MCMB ^® Osaka Gas), and 45 parts by weight graphite SGB-L ^® (Kropfmühl AG) are stirred in a vacuum mixer at 50 to 60 ° C at 50 U / min in a vacuum of about 1.4 Pa. After 3 hours, the vacuum is removed by metering in 5 parts by weight of a solution of 0.6 M Li-Oxalatoborat in ethylene carbonate / diethyl carbonate (ratio 1: 1).

After further stirring for 1 hour at 30 ° C 10 parts by weight of electrolyte mixture consisting of 3 parts by weight of LiPF ₅ CF ₃ , 3 parts by weight of PVP (molecular weight 15,000), 3 parts by weight of propylene carbonate and 1 part by weight of MgO supplied after 1 hour with exclusion of air and moisture at 30 C. and then applied in a thickness of 40 to 55 .mu.m and a width of 150 mm to a 160 mm wide Cu foil ( ^Gould® ) by means of two applicator rolls (alternative to a Collin extruder). The Cu foil (thickness 8 microns) used was ^® by brushing a pre-coated carbon black Ensaco-layer chromatography (about 0.5 micron thick).

b) cathode compound KM (see 4c) and cathode (primed Al foil + KM):

85 parts by weight of Li-Fe-phosphate (coated, Südchemie) are ent. 7a degassed and treated with 5 GT of a 0.6 M Lioxalatoborat solution. Then, analogously to 7a, 10 parts by weight of an electrolyte mixture according to the invention comprising: 3 parts by weight LiPF ₄ (CF ₃ ) ₂ , 3 parts by weight PVP (molecular weight 8,000 to 10,000, 3 parts by weight propylene carbonate and 1 part by weight Li carbonate added and with exclusion of air and moisture (analog to 7a) and applied to a primed Al foil (thickness 10 to 11 μm) and a width of 155 mm in a thickness of 45 to 55 μm.

c) primer layer for the aluminum Foil (cathode)

The primer layer is composed of a mixture of 30 to 60 wt .-% of electrically conductive carbon black, graphite o. Ä., Preferably Ensaco ^®, and a fluoroterpolymer, preferably Dyneon THV 220 o. Ä .. The preparation of the primer layer is carried out by applying a ca 10% aqueous dispersion z. B. of Dyneon THV 220 D and Ensaco carbon black, wherein the carbon black content based on the solids content in the dispersion is 50 wt .-%. As a dispersant z. B. perfluorooctonate. The dispersion is adjusted to a pH of about 8 to 8.5 with NH ₄ OH. The distribution medium used is 1% by weight of PVP (molar mass 7,000 to 9,000).

The Primer dispersion is applied to the cleaned Al foil and dried at temperatures of 100 to 150 ° C in a vacuum. The thickness of the primer layer is 0.5 to 1.5 microns. The width of the primer on the 160 mm wide Al foil is 157 mm.

d) Separator (see 6) Foil with electrolyte coating

A separator film consisting of 30 parts by weight of perfluoroelastomers (Dyneon, Kynar, etc.), 30 parts by weight of EC / DEC (ratio 1: 1), 30 parts by weight of conductive salts: KPF ₆ / Li-oxalatoborate (weight ratio 1: 1) and 20 parts by weight of cement (Portland-Dyckerhoff ) with a thickness of 30 to 35 microns and a porosity of about 40% is extruded and conditioned via spiked rollers.

This separator was made with a thin layer of electrolyte mixture consisting of 30 parts by weight of PVP (molecular weight 20 to 22,000), 30 parts by weight of LiPF ₃ (CF ₃ ) ₃ , 30 parts by weight of EC / DEC (ratio 1: 1) and 10 parts by weight of cement under air and moisture exclusion coated on one side with an application thickness of 1 to 3 μm. Subsequently, the separator between the anode and cathode was arranged in such a way that the Cu film and Al foil were each the outer films of the laminate and the applied electrolyte mixture was arranged on the anode side.

e) Separator (see Figures 6 and 7d), incorporated electrolyte mixture

The separator mixture according to 7d was composed of 10 parts by weight of electrolyte mixture
3 parts by weight of PVP (molar mass 7,000 to 9,000)
3 parts by weight of LiPF ₃ (CF ₃ ) ₃
3 parts by weight EC / DEC (ratio 1: 1) and
1 part by weight of Li carbonate
added mixed at 30 to 40 ° C, then fed to the extruder (Collin twin-screw extruder) and extruded at 80 to 90 ° C and discharged as a 45 to 48 microns thick film. All work was done under air and moisture exclusion.

to Further processing was the Separatorfolie, as a release film with Anode and cathode foil combined to trilaminate and as a wound cell wound.

8. Cell and battery production

The anodes and cathodes produced are combined with the respective separator types (as intermediate layer) to form trilaminates, wound over a special hollow mandrel (winding tube), wound over a mandrel or without a mandrel, enclosed and contacted, preferably by metal spraying. When using the winding tube contacting with plug or pole screws and then fixation followed by metal spraying. Finally, the soldering of the cell. If necessary, the cell is evacuated and u. U. filled with electrolyte (1 M LiPF ₆ in DEC, or LiPF _n (R) _m , n = 1 to 5, m = Gn, R = CF ₃ , C ₂ F ₅ , C ₃ F ₇ ). The final stage is still to be formed lithium-ion cells, which are preferably connected as needed parallel to Li-ion batteries.

in the Following are the physical and electrical properties listed lithium ion cells listed. Were the respective measurements were respectively formed as described above Cells performed.

Physical Properties:

• Diameter: 32 mm
• Height (without ends): 160 mm
• Weight: 295 g
• Volume (without ends): 120 cm ³
• Housing material: stainless steel

Electrical Properties:

• Specific power (30 s impulse discharge): 1,600 W / kg
• Power density (30 s impulse discharge): 3,900 W / I
• Nominal voltage: 3.6V
• Nominal capacity at 0.3 C: 6 Ah
• Specific energy: 80 Wh / kg
• Energy density: 200 to 250 Wh / I

9th formation

The Formation of the cells takes place with a constant current of 0.60 A up to a potential of 4.2V and then at constant potential of 4.2V until the current drops to <0.12A is (CCCV = constant current constant voltage). The discharge finds with 0.60 A to the lower voltage limit of 3.0V instead. In connection be used for quality assurance and capacity determination two more cycles performed. The charge happens with 1.8 A to 4.2 V and at constant potential until the current is below 0.18 A has fallen. The discharge takes place with 1.8 A until the final voltage of 3.0 V.

10th cycle data

To measure the cycle stability of the formed cells (see 9. above), it is charged with 3 A at 4.2 V, then recharged in a constant potential phase at 4.2 V until the current drops below 0.3 A is. The discharge takes place at 4.8 A, the lower cut-off voltage is 3.0 V. The lithium-ion cell obtained according to the present invention is characterized by a high cycle stability out, ie the specific capacity decreases only insignificantly even over large numbers of cycles. More than 900 cycles (room temperature) are achieved with a fading <0.2%.

11. Safety behavior Ref. 9 (Lithium Ion Batteries edit. M. Wakihara, O. Yamamoto p 83-94, 4,3 safety (1998) VCH, Weinheim)

• • keine Leckage, kein Austreten von Elektrolyt
• • das Sicherheitsventil (Berstscheibe) öffnet ohne Explosion oder Flammen
• • der „Nail-Penetrations-Test” (Einschlagen eines Nagels in die Zelle ohne Explosion) wird bestanden
• • kein Kurzschluss, weder beim Lagern bis 155°C, noch bei Tieftemperatur bis –30°C (Stabilitätstest)
• • externer Kurzschluss: kein Rauch, kein Feuer.

The safety tests according to Ref. 9 are passed, ie

• • no leakage, no leakage of electrolyte
• • the safety valve (rupture disc) opens without explosion or flames
• • passes the Nail Penetration Test (knocking a nail into the cell without explosion)
• • no short circuit, neither at storage up to 155 ° C, nor at low temperature down to -30 ° C (stability test)
• • external short circuit: no smoke, no fire.

12. Stress test at room temperature

The Charge of the formed cells takes place with 6 A to 4.2 V, in one Constant potential phase is recharged at 4.2 V until the current fell below 0.6A. The discharge takes place at different Currents between 6 A (1 C) and 126 A (21 C). The lower one Shutdown voltage is 2.7 V.

there shows over a wide range of discharge capacity only a slight decrease in the voltage value.

Discharging at different temperatures.

This test was carried out analogously, wherein discharge profiles for different operating temperatures at a constant discharge rate of C / 2 were measured. The cells according to the invention exhibit excellent voltage characteristics even at very low and comparatively high temperatures (<30 ° C. at + 60 ° C.), as in 1 will be shown.

stress test

For the cells prepared according to the present invention as above, the relationship between the current on the one hand and the average voltage during the discharge on the other hand was determined for different temperatures. In the 1 The results shown illustrate the excellent characteristics of the batteries according to the invention with respect to a high voltage over a wide range of the current value, only slightly changing average voltage.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 4818643 [0011, 0013]
• EP 0145498 B1 [0011]
• - DE 3485832 T [0011]
• - DE 10020031 A1 [0011, 0013]
• EP 99/06313 [0013]
• WO 00/13249 [0013]
• US97 / 08029 [0014]
• WO 97/44847 [0014]
• - EP 1374331 B1 [0019]
• EP 0826862 A1 [0019]
• US 2008/003864 A1 [0019]
• - EP 374331 B1 [0022]
• - DE 12004044478 A2 [0041]

Cited non-patent literature

• - "Handbook of Battery Materials" (edited by IO Besenhard, Verlag VCH Weinheim, 1999) [0006]
• - "Lithium Ion Batteries" (edited by M. Wakihara et O. Yamamoto, Verlag VCH Weinheim, 1998 pp. 235 and 10.9) [0006]
• - Chemical Composition and Morphology of the SEI, p. 439, see also p. 420 [0017]
• D. Aurbach et al .; Abstr. 190th Electrochemical Soc. Meeting, San Antonio TX, Vol. 96-2, p. 164 [0018]
• Liquid Nonaqueous Electrolytes p. 457-497 [0034]
• - Ullmann's Encyclopedia of Industrial Chemistry, Vol. 20, p. 564/568, Viscometric Method (1992) Verlag VCH, Weinheim [0036]

Claims (10)

Electrolyte mixture consisting of: a) polyvinylpyrrolidone homopolymers and / or copolymers and / or polyaniline and / or polypyrrole having molecular weights of from 3,000 to 20,000 in amounts of from 20 to 50 percent by weight, b) a conductive salt, preferably based on LiPF ₆ , LiPF ₅ R ₁ , LiPF ₄ (R ₁ ) ₂ , LiPF ₃ (R ₁ ) ₃ , (R ₁ = CF ₃ , C ₂ F ₅ , C ₃ F ₇ ) in amounts of 20 to 10 weight percent, c) an aprotic solvent or Solvent mixture of dimethoxyethane, ethylene carbonate, propylene carbonate or alkyl carbonate in amounts of 30 to 20 weight percent, and d) a mineral additive such as an oxide, carbonate, oxalate, silicate and / or borate of Li, Na, K, Ca, Mg, and / or Cement in amounts of 30 to 20 weight percent, wherein the weight percent are based on the total amount of the electrolyte mixture. Lithium-ion cell consisting of anode, cathode and separator, characterized in that the anode and cathode a Electrolyte mixture according to claim 1 included. Lithium-ion cell according to claim 2, characterized in that the separator contains an electrolyte mixture according to claim 1. Lithium-ion cell according to claim 2, characterized in that that the electrolyte mixture in amounts of 3 to 30 parts by weight contained in anode and cathode. Lithium-ion cell according to claim 3, characterized in that that the electrolyte mixture in amounts of 3 to 30 parts by weight contained in the separator. Process for producing a lithium-ion cell according to one of claims 2 to 5, characterized, that an electrically effective anode mass, d. H. a Li-intercalator natural or synthetic graphite at temperatures degassed from 20 to 100 ° C and pressures of 0.1 to 2 Pa is and the vacuum by adding the electrolyte mixture according to claim 1 and this anode mass under air and moisture exclusion intensively stirred and densified tribochemically, in which the subsequent application of the anode material as 20 to 50 μm thick layer on the cleaned Cu arrester (Gould foil) also with exclusion of air and moisture. Process for producing a lithium-ion cell according to one of claims 2 to 5, characterized that an electrochemically effective cathode material, i. H. Li-intercalatable heavy metal oxides or mixtures of Co, Ni, Cr, Mn, Mo u. Ä. And Li-Fe phosphate and / or Li-V-phosphate at temperatures of 20 to 100 ° C. and degassing from 0.1 to 2 Pa and then to the Cathode composition under the vacuum, the electrolyte mixture is added according to claim 1, stirred vigorously (tribochemically compressed) and processed under exclusion of air and moisture and also as a 20 to 50 micron thick layer on a primed Al foil is applied. Process for producing a lithium-ion cell according to one of claims 2 to 5, characterized a separator mass consisting of 30 to 40% by weight of perfluoroelastomers, 20 to 40% by weight of aprotic solvents, 20 to 24% by weight Conducting salts and 25 to 1 wt .-% builders such as cement, Silicates, Na, K, Ca, Mg carbonates with the electrolyte mixture after Claim 1 is added and under exclusion of air and moisture intensively mixed and then in thicknesses of 20 to 50 microns extruded or applied as a film. Process for producing a lithium-ion cell according to one of claims 2 to 5, characterized that a porous Separatorfolie one or both sides with the electrolyte mixture according to claim 1 is coated and then as separating film between anode and cathode under air and moisture exclusion is installed. Method for producing a lithium-ion battery, characterized in that two or more lithium-ion cells according to one of claims 2 to 5, preferably by parallel connection get connected.