DE102010013294A1 - Lithium ion battery cell comprises components, which contain inorganic multifunctional component having a low thermal conductivity, where the inorganic multifunctional component has a reciprocal of the thermal diffusivity - Google Patents

Abstract

The lithium ion battery cell (10) comprises components, which contain inorganic multifunctional component having a low thermal conductivity for reducing thermal anomalies. The inorganic multifunctional component has a reciprocal of the thermal diffusivity, the slope of the viscosity curve as a function of temperature, and the absolute value of the transformation temperature, which are defined as given in the specification. The thermal conductivity of the inorganic multifunctional component is less than 1.5 W.K ->1>.m ->1>. The inorganic multifunctional component is a glass based material. The lithium ion battery cell (10) comprises components, which contain inorganic multifunctional component having a low thermal conductivity for reducing thermal anomalies. The inorganic multifunctional component has a reciprocal of the thermal diffusivity, the slope of the viscosity curve as a function of temperature, and the absolute value of the transformation temperature, which are defined as given in the specification. The thermal conductivity of the inorganic multifunctional component is less than 1.5.W.K ->1>.m ->1>. The inorganic multifunctional component is a glass based material, a glass, a ceramic, a phase segregated or multi phase glass. The glass or glass ceramic is dissolved in the liquid electrolyte such as stable lithium hexafluorophosphate leading electrolyte. The chemically stable means are dissolved with a week-long storage of the glass powder in the electrolyte solution at 60[deg] C less than 0.1 wt.% of glass-based material. The glass: is a oxidic glass element and oxide-based multicomponent glass; does not exceed the non-oxidic element portion of 35 wt.%; comprises oxygen (95%) as anion; and is free of chalcogenide anions (except oxygen). The glassese blending ratios are present: at 50:50 until 60:40 related to low to refractory glasses and particularly prefers at 50:50 until 80:20 related to low to refractory glasses. The inorganic multi-functional component comprises glass in the form of agglomerated powder. The agglomerated glass or ceramic powder: has an ionic conductivity of less than 10 ->5>S/cm at room temperature, a specific surface area of 2-100 m 2>/g and dielectric properties, where the electricity constant is 5-25000; exists in grain sizes of less than 1-50 micron; and is present in geometries fibrous as rod-shaped, round, oval, square, square (primary particle), dumbbell-shaped or pyramidal, a chips or flakes. The glass powder wettability of the components increases with liquid electrolyte. The glass particles of glass powder are structured or surface-modified, and silanized. The lithium ion cell is rechargeable. The component is a separator (13), cathode (12), anode (14), and the liquid electrolyte. The glass or glass ceramic powder functions as an additive in the anode, the cathode, the electrolyte, the separator or in function layers between these components. The components are evenly distributed in the volume individual or all and/or in ranges near the surface or on the surface area individual or all of these components. The glass or glass ceramic powder is added or is applied during the manufacture of the cell or single components of the cell or individual rechargeable battery components in form of a slip, contains up to 20 microns of glass or glass ceramic, an aqueous or organic liquid and additives, and the stability of the slip, rheological properties, pH or other properties are modified. An independent claim is included for an inorganic component such as glasses for a lithium ion cell.

Description

The invention relates generally to battery cells, preferably lithium-ion cells and in particular components for rechargeable lithium-ion cells with inorganic components of low thermal conductivity.

• – zwei Elektroden (Anode/Kathode) aus denen bzw. in die Li Ionen austreten/eingelagert werden
• – einen Separator, der den elektrischen Kurzschluss verhindert
• – einem Flüssigelektrolyt der die Li-Ionen-Migration ermöglicht

Current rechargeable lithium-ion cells essentially comprise

• - Two electrodes (anode / cathode) from which or into the Li ions emerge / be stored
• - a separator that prevents the electrical short circuit
• - A liquid electrolyte allows the Li-ion migration

Today's separators for lithium ion batteries or secondary batteries use either membranes of polyethylene, polypropylene or combinations thereof ( Zhang: "A review on the separators of liquid electrolyte Li Ion batteries". J. of Power Sources 164 (2007) 351-364 ). Alternatively, fiber wafers, called nonwovens, are discussed which are superior to conventional membranes in a number of properties, particularly shrinkage and thermal stability.

In the course of increasing safety requirements through applications in electromobility, separators coated or infiltrated with inorganic particles are based on both membranes and polymer fleece (EVONIK DE 10208277 . DE 10238944 ; Freudenberg WO2009103537 ; BASF DE19850826 ; LG CHEM WO09069928 ) has been proposed. For example, crystalline oxide materials of simple composition, such as Al ₂ O ₃ , SiO ₂ , BaTiO ₃ or the like, are mentioned as particles. The integration of inorganic particles increases the thermal stability of the component in the case of heating of the cell and delays or even prevents their electrical short circuit.

The use of "glass" in Separatorumfeld is described in the following writings. The glass is either incorporated directly into the carrier as fiber (EVONIK DE 10142622 , FHG / ICT DE19838800C1 , Freudenberg DE10336380 ) or as powder particles a possible component of a coating or impregnation (Freudenberg WO2009103537 , LG CHEM WO09069928 , BASF DE 19850826 ). According to the cited documents, the range of glasses used ranges from "glass flour / micro glass" (BASF see above) to alkali / alkaline earth sulfates, carbonates or Li borates (Freudenberg, supra).

More specific information on the chemistry of glass in Separatorverbund makes Teijin in the Japanese Patent Application JP2005011614 , The document describes the use of glass z. B. in powder form without, however, that the powder - apart from the grain size - is specified in more detail. In addition to the particle size, specific surfaces, degrees of agglomeration and other factors in particular have an influence on the adhesion or chemical interaction.

One disadvantage of the previous approaches is, inter alia, the increasing costs due to the coating of the already quite expensive separators. The guarantee of increased safety such as the resistance to increased external influence, avoiding a collapse of the Separatorfunktion in uncontrolled temperature increase of the cell is recognized by the user, a further active function of particles in addition to the simple distance, especially in the case of local damage, however, is desirable to further improve the cell properties. Exemplary additional functions can be electrical in nature, such as ion conduction or dielectric properties. As an example, BASF may be mentioned here DE19850826 and LG CHEM WO09069928 Here again expensive and chemically and thus property-side little variable ceramic particles like BaTiO ₃ are used. Only in WO09069928 are also called ion-conducting glasses of the type (LiAlTiP) xO _y or essentially sulfidic glasses. In FhG / Itzehoe DE10101299 these are ion-conducting ceramic particles such as Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ , OHARA JP ( US20070048617 . US20070048619 ) Glass ceramic particles with crystalline phases (NaSiCon) of high conductivity.

The presence of a very temperature-stable crystalline material, for example in the region of the separator, is in principle helpful in the case of an already occurred, overall cell-comprehensive "Thermal Runaways" as in a homogeneous increase in temperature in the course of overcharging or by operation at high temperatures. Due to the presence of z. B. Al ₂ O ₃ particles is melted away or shearing the Polymerseparators due z. As elevated global temperatures continue to ensure the distance between the two electrodes. However, in this case, the cell is generally unusable.

• • Dendritenbildung aus Li-Metall von der Anode in Richtung Kathode, hervorgerufen z. B. bei Überladen oder fehlerhaftem Laden bei niedrigen Temperaturen,
• • Scharfkantige metallische Partikel, die im Zuge der Zellproduktion unkontrolliert in die Zelle gelangt sind, beispielsweise beim Ausstanzen von Stromableitern/Fahnen aus Aluminium oder Kupfer,
• • Verletzungen einer Zelle von aussen, insbesondere bei Pouch-Zellen.

In addition to the global, that is, the total cell concerned nationwide heating of the cell due to improper operation / use or by general aging phenomena, however, can also be abnormal local disturbances of cell operation. This includes, in particular, the occurrence of an "internal short circuit" (ISC), which means the formation of an undesired connection between the anode and cathode from an electronically highly conductive metallic material. This generates locally occurring anomalous thermal effects - this means local heating or overheating. Such metallic interconnects can be caused inter alia by

• • Dendritic formation of Li metal from the anode in the direction of the cathode, caused z. In case of overcharging or faulty charging at low temperatures,
• Sharp-edged metallic particles which have entered the cell in an uncontrolled manner in the course of cell production, for example when punching out current conductors / lugs made of aluminum or copper,
• • Injuries to a cell from outside, especially pouch cells.

Depending on cell type and capacitance, depth or starting point of the short circuit as well as short circuit area (eg 1 × 1 mm ² ), the short circuit resistances may be in the range of a few mΩ, currents in the range of several 100 A and correspond to current densities of several hundred amperes / mm ² . Depending on the location of the contact closure, for example between electrode layers or the arresters, the situation leads to local anomalous heating with temperatures in the penetration range of up to 800 ° C., see, for example Kim et al .: Lithium ion battery safety study using multi-physics internal short circuit model. The 5th International Symposium on Large Lithium Ion Battery Technology and Application in Junction with AABC2009, Long Beach, CA, 09.-10.6.2009 ,

A thermally conductive inorganic, crystalline particle introduced into separator or electrode, due to its high thermal conductivity (Al ₂ O ₃ : about 45 W · K ^-1 · m ^-1 at room temperature or 30 W · K ^-1 · m ^{- 1} at 130 ° C) does not prevent the heat at the point of penetration from spreading over large areas of the area, leading to the unwanted and dangerous thermal runaway. Damage limitation can not occur due to crystalline Al2O3

With regard to the integration of crystalline particles on one or in a separator, the comparatively low thermal conductivity of the separator material (polyethylene: about 0.4 W · K ^-1 · m ^-1 , polypropylene about 0.2 W · K ^{) 1} · m ^-1 ) due to the high conductivity of z. B. Al ₂ O ₃ adversely affected.

Other requirements besides safety are increased efficiencies. Today's lithium-ion cells have energy densities and power densities of 150 Wh / kg and 400 Wh / l, respectively; The target for electromobility applications in particular is 200 Wh / kg, ideally even more than 1000 Wh / kg. A lever for higher efficiencies is the increase of the ionic conductivity of the normally used liquid electrolytes based on the conductive salt LiPF ₆ . Their conductivities are ideally in the range of 10 ^-2 to 10 ^-3 S / cm. Attempts to increase the dissociation of the conducting salt (or positive effects on the solvation shell) are in EP 1505680 nanoscale particles of mostly amorphous SiO ₂ are expected to increase the conductivity of conventional liquid electrolyte by up to a factor of 3.

The addition of SiO ₂ , however, can adversely affect the viscosity and thus the processability of a liquid electrolyte adjusted specifically for these applications.

Another alternative for increasing specific energy or power densities involves increasing the operating voltage. Currently, voltages of up to 3.7 V are reached, and charging is about 4.2 V. The materials currently used, in particular the organic-conducting ones, are today incompatible with the higher operating / charging voltages.

Also in terms of lifespan, today's cells should undergo new developments. The shelf lives prescribed by electromobility and above all stationary applications should be more than 10 or even more than 20 years. Therefore, provisions are desired which do not allow or at least mitigate aging.

One aspect of the degradation over time is the release of hydrofluoric acid, HF, in the case of an excessively high initial or, if appropriate, later induced water entry into the cell.

Today's solutions essentially consist in leading processes for the production of materials as well as components and cell production in a very dry, anhydrous environment or the components Absorption of moisture to protect (see lamination process Fraunhofer DE10101299 ). In addition, organic HF getters can be used.

The object of the invention is to provide damage-limiting solutions with regard to locally occurring anomalous thermal effects, such as these are caused in particular by internal short circuits, and thus contribute to improving the safety and longevity of battery cells, in particular of rechargeable lithium-ion cells, afford to.

It is a further object of the invention to provide materials and constituent components for lithium-ion cells which improve further properties such as efficiency or lifetime considering the cost of the lithium-ion system.

The object is achieved with a battery cell, preferably lithium-ion cell, comprising components which contain at least one inorganic, preferably multi-functional constituent, wherein the constituent has a low thermal conductivity and in particular is thereby suitable for reducing thermal anomalies or at least locally limit.

Values of less than 2.5 W · K ^-1 · m ^{-1 are} considered as low thermal conductivity.

The inorganic, preferably multifunctional constituent may comprise or consist essentially of oxidic, temperature-stable, poorly heat-conductive particles of the material glass or of another glass-based material, such as, for example, glass-ceramic, phase-mixed or multiphase glass composites.

For the purposes of this description, glass is understood to mean a structurally at least partially amorphous, preferably inorganic, material which results from a melting process and subsequent rapid cooling or from a sol-gel process.

For the purposes of this application, a glass ceramic is a material which has been obtained by melting and which has become partially crystalline by means of a subsequent thermal process or contains certain crystals in a glassy matrix. The glass ceramic can also be ground up

The glasses have a viscosity adapted to the respective integration location (in / on the separator, in / at anode or cathode, in liquid or polymer electrolyte) and the temperatures occurring at an internal short circuit.

The glasses are usually inexpensive to produce and well adapted to manufacturing processes of components and the entire cell. In a further embodiment, the glasses preferably have additional functions, for example to increase the efficiencies and / or the longevity of battery cells.

In detail, the glasses preferably have the following volume properties: property preferred values thermal conductivity <2.5 W · K ^-1 · m ^-1 d90 <150 μm, in particular <25 μm and very particularly <5 μm; particle size > 100 nm low electronic conductivity <1 × 10 ^-5 S / cm at RT thermal stability > 2000 ° C mechanical stability > 400 ° C volume fraction 0.001-90% by volume

The glass-based materials, in particular glasses or glass ceramics or powders produced therefrom, are stable to fluorine- and phosphorus-containing organic liquid-electrolyte chemistry, even under application of voltage, even under the application of voltage.

a

reziproke thermische Diffusivität

b

Steigung der Viskositätskurve als Funktion der Temperatur

c

Absoluter Wert der Transformationstemperatur

The preferred properties of the inorganic ingredients described herein include the three quantities defined below:

a

reciprocal thermal diffusivity

b

Slope of the viscosity curve as a function of temperature

c

Absolute value of the transformation temperature

a:

mit ρ als Dichte in g/cm³, c_P als spezifische Wärmekapazität in J/(g·K) und λ als Wärmeleitfähigkeit in W/(m·K). Die Wärmeleitfähigkeit wird hierbei jeweils bei 90°C gemessen oder für diese Temperatur angegeben.The glass should absorb the heat as well as possible locally and not pass on, resulting in a ratio corresponding to the reciprocal thermal diffusivity:

with ρ as density in g / cm ³ , c _P as specific heat capacity in J / (g · K) and λ as thermal conductivity in W / (m · K). The thermal conductivity is in each case measured at 90 ° C or specified for this temperature.

To b:

mit T in K, wobei T_7.6 und T₁₃ die Temperaturen bezeichnen, bei denen der dekadische Logarithmus der jeweiligen Viskosität η in der Maßeinheit Pa·s die Werte 7.6 bzw. 13 einnimmt.The glass particles should be sufficiently plastically deformable from a minimum temperature (see section on parameter c), so that an encapsulation process is made possible or facilitated. The glass particles must not become so low-viscosity during melting that they "drip off". However, they should be so malleable that they can enclose the hot spot in a battery and thereby limit or even delete. It is advantageous if the viscosity of the softening glass particles decreases so much that they can coagulate and thereby encapsulate the hotspot.

with T in K, where T _7.6 and T ₁₃ denote the temperatures at which the decimal logarithm of the respective viscosity η in the unit of measurement Pa · s assumes the values 7.6 and 13, respectively.

To 3:

The lower T _g , the sooner the glass softens or melts. The higher the thermal-mechanical stability c = _Tg [K]

Too low a value for T _g (approx. <250 ° C) must be avoided so that the glass granules do not soften too early, even at high thermal loads during normal operation of the battery.

The following key figure is defined as the parameter for the ability to locally limit a hotspot by encapsulation: a / (b * c) ≥ 20 s / (m ² * K ² ) with a / (b · c) preferably from 40 s / (m ² · K ² ) to 1200 s / (m ² · K ² ) particularly preferably from 60 s / (m ² · K ² ) to 1100 s / (m ² · K ² ), very particularly preferably from 80 s / (m ² · K ² ) to 1000 s / (m ² · K ² ), very particularly preferably from 100 s / (m ² · K ² ) to 800 s / (m ² · K ² ).

Especially in the preferred ranges, these fast, relatively low melting glasses provide a very beneficial protective function for the particular cell. These form a melt with low to moderate viscosity, which is mobile but does not drip on the other side. This allows local thermal anomalies, such as local overheating, to be separated and, as a rule, localized.

Already this protective function of individual glasses is very advantageous. In addition, mixtures such as particulate mixtures can provide further benefits. For example, high-melting glasses, ie glasses with a processing point VA (temperature at which the viscosity of the melt is 10 ⁴ dPas) tend to have sufficient mechanical strength above 1000 ° C. with glasses melting at lower temperatures (VA rather <1000 ° C.) Provide stability, so that mechanical stability is still present even if the cell or parts of this greatly overheat.

For example, preferred mixing ratios are 80:20 based on low to high melting glasses. Other conditions of z. B. 50:50, depending on the application and glass properties, possible. However, the respective glasses are generally in the following preferred and particularly preferred mixing ratios: at 50:50 to 60:40 based on low to high melting glasses and more preferably at 50:50 to 80:20 based on low to high melting glasses.

In an analogous manner, the mixture, in particular the particulate mixture, ceramic components or crystalline fractions can be added.

The glasses / glass ceramics may be in the form of powder, fibrous, agglomerated, homogeneous, phase-separated or polyphase. The particles may be surface structured including z. B. a shell-like core-shell construction. Also surface modified particles, eg. B. silanized particles are conceivable. As a coupling layer can be used, for example
3-aminopropyl triethoxy silanes
Vinyl trimethoxy silanes
gamma-glycidoxypropyltrimethoxy silanes
Methacryloxypropyltrimethoxy silanes

It has surprisingly been found that the use of glass particles in lithium-ion batteries (that is, particles introduced into components of lithium-ion cells) has the effect of limiting damage with regard to unwanted internal short circuits - abbreviated to "ISC" here.

Although the glass particles do not prevent the fundamental occurrence of an internal short circuit, ISC, they can level, weaken, or locally localize the locally occurring anomalous thermal effects caused thereby.

Advantageously, the thermal conductivity of these glasses is less than 2.5 W · K ^-1 · m ^-1 , preferably less than 2.0 W · K ^-1 · m ^-1 and particularly preferably less than 1.5 W · K ^-1 · m ^-1 .

In principle, the glass or the glass ceramic is stable in the liquid electrolyte, in particular in LiPF ₆ leading electrolytes.

It is likewise advantageous if the glass is a predominantly oxidic glass and the non-oxide element content does not exceed 35% by mass

The glass may in this case contain at least 80%, preferably 90%, preferably 95%, of oxygen as anion and preferably be free from chalcogenide anions (apart from oxygen itself).

In particular, the glass may also be an oxide-based multicomponent glass.

The glass may be selected from the group comprising the families of the silicate, borate, phosphate or aluminate glasses.

• – Boratgläser wie bspw. Lanthanboratgläser, Borosilikatgläser, Lithium-Boratgläser und weitere
• – Phosphatgläser wie bspw. Fluorphosphatgläser, Lithium-Phosphatgläser, Zinn-Phosphatgläser und weitere
• – Aluminatgläser wie bspw. Boroaluminatgläser, Erdalkali-Aluminatgläser Lithium-Aluminatgläser und weitere
• – Silikatgläser wie bspw. Alumoborosilikatgläser, Lithiumsilikatgläser Tantal-Silkatgläser Allgemein sind auch gewisse optische Gläser für die Verwendung in Batterien geeignet.

In particular, these are the following glasses:

• Boratgläser such as Lanthanboratgläser, borosilicate glasses, lithium borate glasses and more
• - Phosphate glasses such as, for example, fluorophosphate glasses, lithium phosphate glasses, tin phosphate glasses and others
• Aluminate glasses such as boroaluminate glasses, alkaline earth aluminate glasses, lithium aluminate glasses and others
• - Silicate glasses such as Alumoborosilikatgläser, lithium silicate glasses Tantalum-Silkatgläser In general, certain optical glasses are suitable for use in batteries.

Preferably, the glass has a composition (in wt%) of Silicate glass min Max SiO2 45 100 TiO2 0 10 ZrO2 0 10 Al2O3 0 42 B2O3 0 30 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 10 SrO 0 10 Halogen (elemental) 0 20 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 25 SnO 0 1.5 SrO 0 20 or Phosphate glass min Max SiO2 0 30 TiO2 0 40 ZrO2 0 10 Al2O3 0 30 B2O3 0 30 Fe2O3 0 7.5 P2O5 20 100 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 20 Li2O 0 50 Na2O 0 35 K2O 0 30 La2O3 0 10 SrO 0 10 Halo (elemental) 0 35 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 65 SrO 0 20 CuO 0 20 Bi2O3 0 30 Sb2O5 0 5 or Borate glass min Max SiO2 0 30 TiO2 0 10 ZrO2 0 10 Al2O3 0 30 B2O3 20 100 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 50 SrO 0 10 Halogen (elemental) 0 20 As2O3 0 1.5 5b2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 1.5 SrO 0 20 or Aluminate glass min Max SiO2 0 30 TiO2 0 10 ZrO2 0 10 Al2O3 25 100 B2O3 0 30 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 10 SrO 0 10 Halogen (elemental) 0 20 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 1.5 SrO 0 20

As an alternative to bulk material or fibers, the at least one inorganic, preferably multifunctional constituent may also comprise powder, in particular glass powder.

In another preferred embodiment, the glass may also trap HF to form Si-F bonds.

Advantageously, the glass powder has an ionic conduction of less than 10 ^-5 S / cm at room temperature.

In this case, the glass powder may preferably be present in particle sizes d ₉₀ between 100 nm and 10 μm, preferably between 150 nm and 5 μm, and particularly preferably between 250 nm and 1 μm.

In addition, the glass powder can be present as a primary grain in geometries rod-shaped, fibrous, round, oval, angular, angular, dumbbell-shaped or pyramidal.

Also platelets or flakes are usable. Their production can, for. B. carried out by centrifugal or tube blowing.

In a further advantageous embodiment, the glass powder may be locally present in a higher volume fraction, in this way particularly endangered areas, especially areas with expected high current densities or areas with higher risk of mechanical damage, such as in the vicinity of external electrical connections or in the range of electrical feedthroughs , to protect.

Further mechanical stability can also be provided for the cell by sintered glass particles. As a result, for example, electrolyte-conducting regions can provide their own stability, so that even with a melt of the separator, the cell does not permit any short circuits between the anode and the cathode. In addition, a sintered body filled with electrolyte can be advantageous in terms of manufacturing technology since it can now be handled independently and can subsequently be attached to this electrode and separator. Here, the increased wettability is also of considerable advantage.

Internal short circuits are also suppressed, since the sintered body can permanently ensure that simple direct paths between the anode and cathode are greatly prolonged and thus dendrites can only be reduced.

Even in the much less likely case of dendrite formation, however, its growth and, advantageously, its avalanche-like growth is successfully suppressed by the constituents of the sintered body. Not only longitudinal but also lateral growth can only extend to the next sintered particle and thus remains limited.

Due to the locally restricted cross-section, however, currents can no longer become arbitrarily high. It is then just at the most vulnerable places this limited in their width and thus limited in their current carrying capacity dendrites by the registered by their resistance heat by the desired melting and encapsulation processes and encapsulated. In this way, the dendrite and thus the flow of current through it can be interrupted in the melt in many cases, in particular by local chemical reactions.

The sintered body may also comprise glasses with different melting temperatures, preferably in particulate mixture, in order to define the ratio of melting, enveloping fraction as well as of still mechanically stable fraction also in this case.

As an alternative or in addition to the higher-melting glass components or glass particles, ceramic or crystal particles may be integrated into the sintered body, in particular in order to provide defined stability even in the case of thermal anomalies.

Insofar as mechanically elastic temperature-stable portions are desired in order, for example, to alleviate mechanical stresses due to thermal expansion differences, for example in the separator, fiber braids or fiber wafers made of fibers of the glasses described here can also be used throughout the volume or in some areas.

These fiber braids can provide desired mechanical strength and corresponding elasticity predefined by the nature of their intertwining while being directional.

These fibers can be incorporated in particulate mixture or even proportionally in the above-described sintered body. In this latter case, even extreme temperature differences no longer lead to breakage or rupture of the sintered body, since its elastic fiber portions keep these predefined stable. Although patented in completely different fields, one skilled in the art may make constructive references to reinforced concrete structures, for example, to use tensile strength with ceramic materials to produce mechanically strong structures.

However, it may generally be the component of the separator, the cathode, the anode and / or the liquid electrolyte. Furthermore, the preferably multifunctional component can also be arranged or realized in functional layers between these components or components.

The preparation may be carried out using a preferably inexpensive melt processing step at temperatures less than 2000 ° C, preferably less than 1700 ° C and with rapid cooling.

The multifunctional constituent may be distributed uniformly in particular as a glass or glass ceramic powder in a lithium-ion cell in the volume of individual or all of the named components and / or in near-surface regions or on the surface of individual or all of these components.

Advantageously, the glass or glass ceramic powder is added or applied during the production of the battery or individual battery components in the form of a slurry, which in addition to a powder of glass or glass ceramic with a grain size of less than 1 .mu.m to 50 .mu.m, preferably up to 20 μm contains only water and is still stable.

It has been shown that it may be particularly useful to set a slightly acidic pH range for the slip. For this purpose, acids, particularly preferably monohydric acids such as the inorganic acids nitric acid HNO ₃ or hydrochloric acid HCl or organic acids such as formic acid or acetic acid are suitable. If an alkaline pH range is to be adjusted in a targeted manner, ammonia NH3 is suitable in particular for this purpose. If particularly high fill levels of the slip of> 40% solids are desired, it may be necessary to use condenser. In particular, polymethacrylates are suitable for this purpose.

The settling behavior of such a slurry can also be improved by the addition of a rheology agent or thickener. For this purpose, polysaccharides such as celluloses or cellulose derivatives such as ethyl cellulose are suitable.

The invention will now be described in more detail by means of preferred embodiments and with reference to the accompanying drawings.

Show it:

1 a sectional view through a lithium-ion cell 10 with various stages of thermal anomaly with effects of particulate inorganic constituents provided by the invention

2 another sectional view through a lithium-ion cell 10 with various stages of thermal anomaly with effects of particulate inorganic constituents provided by the invention

3 a sectional view through a principle structure 27 for conducting melt tests of different powders under the action of electricity,

4 a supervision of the principle experiment 3 in which different test materials were used as powder bed,

5 the geometry of a lithium-ion cell, in which only a quadrant around the cylindrical lithium dendrite, light green, is shown,

6 the time course of the maximum temperature for version 1 (red curve) and version 2

7 a quasi-stationary temperature field in the region of the lithium dendrite, wherein in the left image, the maximum temperature with good thermal conductivity reaches about 204 ° C, while in the case of poorer thermal conductivity, as shown in the right image, about 340 ° C can be achieved.

Detailed Description of the Preferred Embodiments

In the following description as well as in the claims, all information on glass compositions are given in% by weight, unless expressly stated otherwise.

1 shows a sectional view through a lithium-ion cell 10 consisting of aluminum conductor 11 , Cathode 12 , Separator 13 , Anode 14 and copper conductors 15 , Shown are in the top section of the drawing and the incident 16 , which describes a short circuit from anode to cathode, as well as the incident 17 , which causes a short circuit between the two arrester foils 11 and 15 represents.

In the middle section of the 1 is the failure case 16 shown in more detail. The schematic enlargement shows the cathode material 18 , the anode material 19 as well as the separator 20 which in turn is glass particles 21 contains. Also shown is the dendrite of lithium metal which triggers the short circuit and thus the fault 22 ,

In the lower section of the drawing is shown how in the case of the presence of glass particles 21 the system behaves at such a dendrite formation. In principle, two ways are conceivable here: In the lower left section is the dendrite 22 from a glass jacket 23 surrounded, which dissipates in this way the resulting heat short-circuit locally and thus ultimately prevents the short circuit. In the lower right section you can see that the "capping" of such a dendrite is also possible.

2 again shows in the upper section a sectional view through a lithium-ion cell 10 consisting of aluminum conductor 11 , Cathode 12 , Separator 13 , Anode 14 and copper conductors 15 , Shown are in the top section of the drawing and the incident 16 , which describes a short circuit from anode to cathode, as well as the incident 17 , which causes a short circuit between the two arrester foils 11 and 15 represents.

In the middle section of the 1 is the failure case 17 shown in more detail. The schematic enlargement shows the cathode material 24 , which also contains glass material in this special version, the arrester 11 , the anode material 25 also in a special embodiment with glass material, the arrester 15 as well as the separator 20 which in turn is glass particles 21 contains. Also shown is the short circuit and thus the accident triggering metal chip 26 , In the lower section of the drawing is shown how in the case of the presence of glass particles 21 and with glass material added anode material 25 or cathode material 24 the system behaves in such a case of damage. In principle, two ways are conceivable here: in the lower left section is the metal chip 26 from a glass jacket 23 surrounded, which dissipates in this way the resulting heat short-circuit locally and thus ultimately prevents the short circuit. In the lower right section you can see that also the "caps" of such a metal chip is possible.

3 shows the section through the principle structure 27 for determining the behavior when heat is introduced by electric current onto a powder bed 28 , Shown is the powder bed 28 in a container 29 as well as with the guided through the powder bed wire 30 from, for example, copper.

4 shows the supervision from the principle structure 27 out 3 , wherein different materials were used as a powder and also the influence of different strong currents and thus different strong heat input are shown in the system.

Thus, on the top left, the behavior of a powder at a current I _{1 is} seen when the powder is polyethylene. Clearly visible next to the unchanged powder bed 28 and the container 29 as well as the conductor wire 30 the area 31 , which consists of a mixture of molten and in particular already decomposed polyethylene. In the illustration to the right, it can be seen that the current I ₂ with I ₂ > I _{1 has} significantly increased the area of decomposition of polyethylene.

In the middle left you can see the behavior of a ceramic material with a high melting point at a current I ₁ : Visible here is the range 32 , in which it has come only to a slight sintering of the ceramic material.

In a current I ₂ , two areas are recognizable, namely the area 32 with only very loose sintered material, which has become significantly larger compared to the state at current I ₁ , as well as the range 33 with slightly denser sintered material.

In the illustration on the bottom left, the behavior of glass particles according to the invention at the current I _{1 is} shown. Already at this relatively low current, a loosely sintered region is formed 32 and a densely sintered area 33 , In addition, however, are already clearly a melt sintered area 34 and a melting zone 35 recognizable. When I ₂ current, the four mentioned area 32 . 33 . 34 and 35 also found, with the melting range has become much larger and the remaining areas at a greater distance from the center of the container 29 and thus from the live conductor 30 are located.

An exemplary scenario comprises a situation in which a metal dendrite, splitter or the like penetrates the separator of a charged cell in the area of an area of <1 mm × 1 mm. An internal short circuit between the anode and cathode or the corresponding current conductors is produced.

With an operating voltage of 3.7 V and assumed 100 A current flow results in an integral heat generation of about 400 W along a very thin cross section of the connecting bridge. The temperature rises sharply to several 100 ° C, d. H. the temperature is well above the melting point of PE (130 ° C) or PP (about 165 ° C), which can lead to the destruction of the separators.

A non-inorganic particle d. H. pure organic separator shrinks or burns with the result of the planar short circuit of the electrodes. If the cell does not catch fire, this is usually at least no longer operational.

The use of z. As crystalline particles with very high thermal conductivity such as. Al ₂ O ₃ conditions that the resulting heat spreads quickly. However, there is no contribution to heat containment.

• 1. Bedingt durch dessen geringe thermische Leitfähigkeit wird die Ausbreitung der Wärme stark behindert. Die Dissipation der Wärme in die Gesamtzelle läuft moderater ab, Wärmespitzen werden bei gleichen integralen Werten über einen längeren Zeitraum aber bei niedrigeren absoluten Werten verteilt.

The advantage of a glass-based material such. As glass or glass ceramic is varied.

• 1. Due to its low thermal conductivity, the propagation of heat is severely hampered. The dissipation of heat into the total cell proceeds more moderately, whereas heat peaks are distributed at the same integral values over a longer period of time but at lower absolute values.

For a better understanding of the invention, model calculations were also carried out, which were based on a simulation model.

This simulation model was mathematically realized as follows:
The stationary Poisson equation for the electric potential ∇ → · ((σ∇ → U)) = 0 and the transient heat equation for the temperature T pc _p ∂T / ∂t = ∇ → · (k∇ → T) + Q are coupled under specification of physical boundary conditions, as they are present for a battery cell, for the electrical potential U and for the temperature T dissolved.

Material parameters require the electrical conductivity σ, the density ρ, the specific heat c _p and the thermal conductivity k of the materials involved. The source term Q for the Joule heat results from the current density j (vector) j → = -σ∇ → U to Q = 1 / σj → ²

By doing so, one obtains realistic values for heat sources and the temperature distribution in the considered area of the battery.

In the simulation model, in addition to practical experiments, which were not carried out for each individual glass because of the large number of glasses, it was evaluated to what extent the temperature profile inside a lithium ion battery can be influenced by measuring the thermal conductivity of the particle-infiltrated lithium ion cell so changes that ceramic good thermal conductivity materials replaced by poor thermal conductivity of glass.

Due to the low thermal conductivity of glass, the spread of heat is very much hindered and thus the heat is limited locally. This means that their spread is reduced to prevented if the heat can be converted in situ in other ways, such as in local melting processes. However, such local melting processes lead to a further stronger local shielding, since an internal heating can further increase the viscosity in the interior, without having to bring the viscosity at the edge of the inclusion to the molten liquid.

5 shows the geometry of a lithium-ion cell (only one quadrant around the cylindrical lithium dendrite, light green, is shown). The applied voltage in this simulation is 3.7 V.

The following shows the geometry of the simulation model; the dissipative foils as copper (Cu) and aluminum (Al) are each 20 .mu.m thick, and in each case 60 .mu.m thick electrodes impregnated with electrolyte (light blue above or orange below) adjoin each other. In the middle is the 20 μm thick separator, also soaked in electrolyte, at the corner of which a cylindrical dendrite of lithium metal with a radius of 5 μm has been modeled.

This dendrite causes a short-circuit current between the electrodes and local heating due to finite electrical conductivities of the adjacent electrodes.

The following table shows the material data used for the model calculations. material Density [kg / m ³ ] WLF [W / Km] c _P [J / kgK] σ [S / m] copper 8920 400 381 59.8e6 Electrolyte top (graphite) 2300 m07: 110m08: 55 709 1000 separator 1000 m07: 1 m08: 0.5 1000 1e-6 lithium 535 85 3482 11.7e6 Electrolyte bottom (LiCoO ₂ ) 5000 m07: 4 m08: 2 946 1000 aluminum 2719 202 871 37.7e6

Between model 07 and model 08, the thermal conductivities have been halved in order to better represent the effect of reduced by thermal conductivity of glass particles compared to ceramic particles.

The thermal conductivity of a mixture of the added particles together with graphite or LiCoO 2 particles and the electrolyte results approximately from the volume fraction-weighted individual heat conductivities.

If the volume fraction of the ceramic particles is high (> 50%), the resulting mean thermal conductivity is predominantly characterized by the high thermal conductivity of the crystalline phase.

According to the invention, the replacement of the crystalline particles by those made of glass (in a comprehensive sense), because of the poor thermal conductivity of all glasses, also significantly reduces the average thermal conductivity of the composite.

In the table above, two variants of thermal conductivity (WLF) mixtures of different composition have been used: m07 (representative of ceramic particles) and m08 (representative of glass particles).

The figure below shows the time course of the warming.

6 shows the chronological progression of the maximum temperature for version 1 (red curve) and version 2 (halved thermal conductivity, green curve) It is clearly evident that the temperature rise for the variant with the lower thermal conductivity (m08) is faster and at significantly higher temperatures levels off.

7 shows a quasi-stationary temperature field in the region of the lithium dendrite. In the left image with good thermal conductivity, the maximum temperature reaches about 204 ° C, while in the case of poorer thermal conductivity, as shown in the right image, about 340 ° C are reached at maximum temperature.

In the left image, the temperature is sufficient to cause the decomposition of organic components, but can not "decapsulate" the hot zone.

By lowering the thermal conductivity, as shown in the right image, in conjunction with a softening, but not decomposing glass with very poor electrical conductivity, an electrical encapsulation of the dendrite zone is achieved.

According to the invention, the short-term local temperature increase is desirable to facilitate the melting of the glass particles and in a further step, which is not shown in these model calculations, the interruption of contact by embedding the critical hot zone in a glass of this abnormal temperature, thus This thermal anomaly, to extinguish or at least locally limit their negative effects and thereby reduce.

In this way, protection of the lithium-ion cell is achieved because, despite short-term local heat spikes over an extended period, the average temperatures can be kept at lower absolute values.

A thermal breakthrough or collapse, thermal runaway, becomes much less likely.

• 3. In einer weiteren Ausführungsform hat die sich bildenende Schmelze oder Schmelzsinterphase mit dem metallischen Partikel chemisch reagiert unter Kappung der den Kurzschluss verursachenden Verbindung.
• 4. In einer weiteren Ausführungsform hat bei der Schmelzbildung durch lokale Elektrolyse des Glases bevorzugt auf der Kathodenseite Legierungsbildung z. B. zwischen Si des Glases und dem Kathodenmaterial stattgefunden. Auch hierdurch wird der Widerstand gegen einen thermal runaway heraufgesetzt.

Preferably, the glass even encapsulates a heat pole. If the viscosity of the glass-based material is suitably adapted to the temperature regime of the hot spot, the glass sinters tightly or preferably even melts due to its preferably low to moderate viscosity in combination with its not too high Tg's. The re-cooled Regulus then wrapped this hotspot damage limited.

• 3. In another embodiment, the forming melt or melt sintering phase has reacted chemically with the metallic particle, capping the compound causing the short circuit.
• 4. In another embodiment, in the formation of melt by local electrolysis of the glass preferably on the cathode side alloying z. B. between Si of the glass and the cathode material took place. This also increases resistance to a thermal runaway.

Crucial for all effects is that at the moment of the formation of the internal short circuit, ISC, existing low-impedance metallic transition is converted into a high-impedance junction.

Al2O3 or other simple crystalline substances are not able to do so: they can not be dense sintered or melted at <1000 ° C. within a short period of time, nor are they suitably chemically reactive.

Another advantage of glass is the chemical variability. By suitable variations of the compositions, viscosities, melting points, etc. can be adjusted.

Thus, depending on the place of integration of the particulate glass, this can be adjusted in terms of its viscoelastic properties.

Also z. As several types of glass, those with low and those with high viscosity, as a mixture in z. B. separator or electrode dressing are introduced.

Another advantage of certain glass, glass-ceramic, phase-mixed glasses or other glass-based materials is the relatively low density. For the same volume fraction of added inorganic particles, a specific lighter material such as glass is clearly preferred for Al2O3 (density Al2O3 ~ 3.5-4 g / ccm).

The introduction of glass can be done in many forms, sizes, etc. The glass may be powder, rod or fibrous, either homogeneous or with core shell structures of the individual grains. The particles may be agglomerated or fused. The glasses can be porous and provided with specifically set surface texture. The glass particles can be silanized on the surface.

The integration of particulate glass / glass ceramic can take place in or on the separator / anode / cathode / electrolyte

The volume fraction of the glass is exemplified at 0.001-90 vol%

A decisive factor for the mode of action of powder from the glass-based material is the specific surface.

Upwards, values up to 50 m2 / g, if not even> 100 m2 / g, make sense. The lower limit is 1 m2 / g, preferably not less than 2 m2 / g.

The glasses / glass ceramics preferably have at least one additional active additional function. The additional function may relate to the application itself, but also the production of the cell or its components.

Due to the temperature stability and inertness, the material is at least usable as a spacer (or at least part of the spacer in combination with other separator components or constituents of an electrode layer) of cathode and anode in lithium-ion cells. The use can also be extended to all other components (anode, cathode, electrolyte, packaging).

• – Getterwirkung z. B. gegenüber HF
• – Dielektrische Eigenschaften bzw. dadurch indirekt/direkt hervorgerufene Erhöhung der Ionenleitfähigkeit eines Flüssigelektrolyten

As exemplary additional functions, the following are provided in an inventive manner:

• - Getterwirkung z. B. to HF
• - Dielectric properties or thereby indirectly / directly caused increase in the ionic conductivity of a liquid electrolyte

EXAMPLES

• – Das Material besteht im technischen Sinne aus einem Glas, einer Glaskeramik, oder aus einem Komposit der beiden.
• – Das Material kann sowohl in sich homogen sein als auch aus einem phasenentmischten Glas bzw. einer durch Phasenentmischung hergestellten Glaskeramik bestehen.
• – für die Erfindung verwendbare Materialien bestehen aus monolithischen oder aus porösem Material.
• – Die Komponenten des Materials sind im wesentlichen oxidisch. Es können geringe nicht-oxidische Aniondotierungen auftreten.
• – Das Material ist partikulär, wobei die Kornfom verschieden sein kann, wie z. B. kugelig, kantig, oval, flake-artig, fasrig, als Core/Shell-Typ oder oberflächenstrukturiert.

By definition, the term "glass" in the present invention is a material having the following properties:

• - The material consists in the technical sense of a glass, a glass ceramic, or a composite of the two.
• The material can be homogeneous as well as consist of a phase-mixed glass or a glass-ceramic produced by phase-disassembly.
• - Materials usable for the invention consist of monolithic or of porous material.
• The components of the material are essentially oxidic. There may be low non-oxide anion doping.
• - The material is particulate, the Kornfom may be different, such. B. spherical, edged, oval, flake-like, fibrous, as a core / shell type or surface-structured.

A glass of the composition described above and the properties described above was melted by a continuous or discontinuous melting process in a furnace and / or a suitable crucible under air and> 1500 ° C, the melt is rapidly cooled and the cullets are converted by grinding in powder form.

Alternatively, such particles can also be prepared via the sol-gel process. For this purpose, a sol of the alkoxides or similar compounds, such as the alkoxides easily by hydrolysis and Condensation reactions capable of carrying out crosslinking reactions are made of the corresponding elements.

The resulting colloidal solution is treated by suitable means such as adjusting the pH or adding water to cause gelling of the sol.

The sol may alternatively be subjected to spray drying.

The solid formed in this way, which consists of particles, can be further subjected to a calcination reaction in order to eliminate any organic impurities. In this way, nanoparticles of the corresponding material are often obtained.

The glass particles are as few micron large (<150 microns), preferably <25 microns and <5 microns to even nanoscale (> 100 nm) powder z. B. introduced into liquid electrolytes. Due to the high dielectric constant, the dissociation of the conducting salt LiPF _{6 is} increased or the solvation shell is modified with the advantage of increased ion conductivity of the entire liquid electrolyte system

Alternatively, the powder is integrated in a Separatorverband. Powders of the inventive glass of the grain fraction are compounded together with binders, polymer monomers and as a slurry and optionally applied to a separator membrane or a polymer nonwoven.

Advantageously, the glass particles fulfill not only the task of the spacer in the case of thermal runaway but also locally the task of increasing the ionic conductivity of the liquid electrolyte.

In a particular embodiment, the glass powders are part of an anode or cathode composite. The latter are usually characterized by a porous structure of electrochemically active storage materials and pores.

The pores can have sizes of up to 20 microns and are impregnated with the liquid electrolyte. The pores can now be at least partially filled by the glass powder. According to the present invention, if the powder is increased in ionic conductivity, the electrode can be packed more densely, resulting in an increase in the specific capacity of the electrode.

As an alternative to the above-mentioned glass, a glass-ceramic containing BaTiO ₃ as a dielectric crystal phase may be used. Their dielectric constant is due to the crystallite size (of the order of magnitude of the ferroelectric domains or below) up to epsilon = 5000, preferably up to 10000, more preferably up to 15000. But also conventional glasses with dielectric constants between 5 and 20 are effective in terms of a better dissociation of the conducting salt or for trapping the electrolyte salt anion.

In a further embodiment, instead of the glass described above, a glass is used which adsorbs the harmful HF in the cell or binds it permanently by surface or volume reaction.

The glass particles are preferably in particle sizes between 100 nm and 10 .mu.m, preferably between 150 nm and 5 .mu.m, and particularly preferably between 250 nm and 1 .mu.m, and optionally have a round, spherical, oval, angular shape and were produced by milling. Alternatively, fine powders can also be adjusted by the manufacturing process itself (eg, sol-gel, flame spray pyrolysis, chemical precipitation). The particles are either clamped on top of the separator / clamped or coated analogously or integrated in the electrode assembly or coated on the same.

According to the invention, a composite component (separator or electrode) with glass content is advantageous for preventing / delaying the thermal runaway, that is, the self-ignition of a lithium-ion cell in the case of z. B. an internal local short circuit. If, for example, the external action (pressure, penetration of an object) or internal processes (eg dendrite growth) punctures the separator locally, the locally occurring heating in the short-circuit region can not or only with difficulty spread to the entire cell. The occurring heat remains lokalisert or is encapsulated in the low thermal conductivity composite.

The cell remains safe, possibly in spite of efficiency losses.

In another embodiment, the glass is chosen to be locally melted at the location of the internal short circuit. This results in a lubricating film which prevents the further propagation of the thermal spots.

Glass particles help due to their low heat conduction continue to level the differences in the thermal conductivity in the axial and radial cell direction, for example, different up to a factor of 10 to level.

In a further embodiment, a layer or a phase composite in the separator or electrode region is produced which leads or comprises a glass as a functional additive.

The glass advantageously shows a very high wettability of liquid electrolyte. Compared to an additive-free component, therefore, the manufacturing process is facilitated.

The glass-conducting components continue to show a higher resistance to higher operating voltages.

• – Silicatgläser, z. B. z. B. SiO2-B2O3-Gläser, besonders bevorzugt Gläser mit Li2O-B2O3 und SiO2
• – Phosphatgläser, z. B. mit mehr als 70 Ma.-% 2205, besonders bevorzugt mit P2O5 > 80 Ma.-%
• – Boratgläser, z. B. Boro-Phospho-Silicatgläser oder aus dem System B2O3-Al2O3-RO mit R = Mg, Ca
• – Aluminatgläser, z. B. aus dem System Al2O3-B2O3-RO mit R = Mg, Ca.

Exemplary glass families are

• - Silicate glasses, z. B. z. As SiO2-B2O3 glasses, particularly preferably glasses with Li2O-B2O3 and SiO2
• - Phosphate glasses, z. With more than 70% by mass 2205, more preferably with P2O5> 80% by mass
• - Boratgläser, z. Boro-phospho-silicate glasses or from the system B2O3-Al2O3-RO with R = Mg, Ca
• - Aluminatgläser, z. From the system Al2O3-B2O3-RO with R = Mg, Ca.

Exemplary glass compositions are also given in Table 1 below. Table 1 Glasses for use in lithium-ion cells (in% by weight) Silicate glass min Max SiO2 45 100 TiO2 0 10 ZrO2 0 10 Al2O3 0 42 B2O3 0 30 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 10 SrO 0 10 Halo (elemental) 0 20 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 25 SnO 0 1.5 SrO 0 20 such as Phosphate glass min Max SiO2 0 30 TiO2 0 40 ZrO2 0 10 Al2O3 0 30 B2O3 0 30 Fe2O3 0 7.5 P2O5 20 100 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 20 Li2O 0 50 Na2O 0 35 K2O 0 30 La2O3 0 10 SrO 0 10 Halogen (elemental) 0 35 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 65 SrO 0 20 CuO 0 20 Bi2O3 0 30 Sb2O5 0 5 such as Borate glass min Max SiO2 0 30 TiO2 0 10 ZrO2 0 10 Al2O3 0 30 B2O3 20 100 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 50 SrO 0 10 Halogen (elemental) 0 20 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 1.5 SrO 0 20 such as Aluminate glass min Max SiO2 0 30 TiO2 0 10 ZrO2 0 10 Al2O3 25 100 B2O3 0 30 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 10 SrO 0 10 Halogen (elemental) 0 20 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 1.5 SrO 0 20 wherein the above glasses are also preferably usable in particulate mixture with each other with preferred mixing ratios, for example to set defined viscosities for specific temperature ranges.

In this way, melting portions which enclose or encapsulate a hot spot can be present with temperature-stable components which still provide sufficient mechanical stability despite deflagrating portions, in each case causing a mechanical collapse of the cell with possibly extensive, short-circuit between anode and Avoid cathode.

Particularly preferred glasses with a / (b × c) of more than 80 s / (K ² · m ² ) are better still more than 100 s / (K ² · m ² ). According to the invention, even in the case of internal short circuits with low temperature development, these glasses can quickly deform or even tend to melt on / off.

For such glasses, the embodiments given in Table 2 below, Table 2 further preferred glasses for use in lithium-ion cells (in wt%) Type borate glass phosphate glass Aluminatglas silicate glass phosphate glass (1) (1) (1) (1) (2) SiO2 20 60 1 TiO2 ZrO2 Al2O3 15 25 17 4 B2O3 25 45 7 1 Fe2O3 Cr2O3 P2O5 35 70 MgO 15 2 1 CaO 10 15 10 3.5 BaO 15 3.5 10 MnO ZnO 5 5 PbO Li2O 3 Na2O 2 0.5 K2O 10 2 SnO 60 SnO2 0.5 NiO 1 CoO 1 ABC) 99 780 116 42 139 [s / (K ² · m ² )] or Type phosphate glass phosphate glass phosphate glass phosphate glass phosphate glass ^{( 3 )} (4) (5) (6) (7) SiO2 0.9 TiO2 0.5 ZrO2 Al2O3 1.5 0.9 5.6 12.7 B2O3 Fe2O3 6.6 Cr2O3 P2O5 59.3 58.0 81.5 65.3 70.4 MgO 0.9 CaO SrO 2.7 BaO 1.4 MnO ZnO 16.0 7.0 PbO Li2O 0.5 5.15 Na2O 32.4 1.5 10.3 K2O 1.5 0.2 28.2 CuO 8.3 Bi2O3 19.5 Sb2O3 0.25 SnO2 1.0 a / (b * c) [s / (K ² * m ² )] 702 288 494 1085 393

• • Oxide wie Al2O3, SiO2, Perowskite, Spinelle, Niobate, Tantalate kristalline Ionenleiter wie Li_1,3Al_0,3Ti_1,7(PO₄)₃ oder andere
• • Carbide wie bsp. WC, B4C3 oder andere
• • Nitride wie bspw. Si3N4 oder andere

Furthermore, ceramics or crystalline bodies can also be used as temperature-stable components, such as, for example:

• • oxides such as Al2O3, SiO2, perovskites, spinels, niobates, tantalates, crystalline ionic conductors such as Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ or others
• Carbides such as WC, B4C3 or others
• • Nitrides such as Si3N4 or others

Here are preferred mixing ratios:
0-95 vol% ceramic

In the present invention, it is advantageous if the glass or the glass ceramic in the liquid electrolyte is particularly stable, in particular in LiPF ₆ leading electrolyte, wherein chemically stable means that in particular in a one-week storage of the glass powder in the electrolyte solution at 60 ° C not more than 1 wt% of the glass-based material is dissolved, preferably not more than 0.5 wt%, and most preferably no more than 0.1 wt%.

Furthermore, it is advantageous if the glass / glass ceramic powder has dielectric properties and in particular has a dielectric constant ε _r in a range from 3 to 25,000, preferably from 5 to 20,000.

During the manufacture or during the production of the battery cells, which are also referred to as rechargeable batteries or rechargeable batteries, it is furthermore advantageous if the glass or glass ceramic powder is added or applied to the cell or individual components of the cell of the rechargeable battery or of individual rechargeable battery components in the form of a slip , which in addition to a powder of glass or glass ceramic with a grain size of less than 1 .mu.m to 50 .mu.m, preferably up to 20 microns only contains water and is still stable.

In this case, the glass or glass ceramic powder can be added or applied during the production of the cell or individual components of the cell in the form of a slurry, which in addition to a powder having a grain size of less than 1 .mu.m to 50 .mu.m, preferably up to 20 microns of glass or glass ceramic , an aqueous or organic liquid and additives which specifically modify the stability of the slip, its rheological properties, its pH or other properties.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

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Cited non-patent literature

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Claims (33)

Battery cell, preferably lithium-ion cell, comprising components which contain at least one inorganic, preferably multifunctional constituent, wherein the constituent has a low thermal conductivity and in particular is thereby suitable for reducing or at least locally limiting thermal anomalies. Lithium-ion cell according to claim 1, wherein the at least one inorganic, preferably multifunctional constituent is valid, with: a reciprocal thermal diffusivity b slope of the viscosity curve as a function of the temperature c absolute value. the transformation temperature

with ρ as density in g / cm ³ , c _P as specific heat capacity in J / (g · K) and λ as thermal conductivity in W / (m · K). The thermal conductivity is in each case measured at 90 ° C or specified for this temperature.

with T in K, where T _7.6 and T ₁₃ denote the temperatures at which the decadic logarithm of the respective viscosity η in the unit of measure Pa · s assumes the values 7.6 and 13, respectively, c = _Tg [K] Too low a value for T _g (approx. <250 ° C) must be avoided so that the glass granules do not soften too early, even at high thermal loads during normal operation of the battery. The following key figure is defined as the parameter for the ability to locally limit a hotspot by encapsulation: a / (b * c) ≥ 20 s / (m ² * K ² ) with a / (b · c) preferably from 40 s / (m ² · K ² ) to 1200 s / (m ² · K ² ) particularly preferably from 60 s / (m ² · K ² ) to 1100 s / (m ² · K ² ), very particularly preferably from 80 s / (m ² · K ² ) to 1000 s / (m ² · K ² ), and also very particularly preferably from 100 s / (m ² · K ² ) to 800 s / (m ² .K ² ). Lithium-ion cell according to claim 1 or 2, in which the thermal conductivity is <2.5 W · K ^-1 · m ^-1 , preferably <2.0 W · K ^-1 · m ^-1 , particularly preferably <1, 5 W · K ^-1 · m ^-1 . Lithium-ion cell according to claim 1, 2 or 3, wherein the inorganic multifunctional constituent is a glass-based material, in particular glass, glass-ceramic, phase-mixed or multi-phase glass. Lithium-ion cell according to claim 1, 2, 3 or 4, wherein the glass or the glass-ceramic in the liquid electrolyte is particularly stable, in particular in LiPF _6- conducting electrolyte, wherein chemically stable means that in particular in a one-week storage of the glass powder in the Electrolytic solution is dissolved at 60 ° C not more than 1 wt .-% of the glass-based material, preferably not more than 0.5 wt .-%, and most preferably not more than 0.1 wt .-% is dissolved. A lithium-ion cell according to any one of the preceding claims, wherein the glass is a predominantly oxidic glass and the non-oxide element content does not exceed 35% by mass A lithium-ion cell according to any one of the preceding claims, wherein the glass comprises at least 80%, preferably 90%, preferably 95% oxygen as the anion and is preferably free of chalcogenide anions (excluding oxygen) A lithium-ion cell according to any one of the preceding claims, wherein the glass is a multi-component oxide-based glass. A lithium-ion cell according to any one of claims 1 to 8, wherein the glass is selected from the group comprising the families of silicate, borate, phosphate or aluminate glasses. A lithium-ion cell according to any one of claims 1 to 9, wherein the glass (in weight%) is a composition of Silicate glass min Max SiO2 45 100 TiO2 0 10 ZrO2 0 10 Al2O3 0 42 B2O3 0 30 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 10 SrO 0 10 Halogen (elemental) 0 20 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 25 SnO 0 1.5 SrO 0 20 or Phosphate glass min Max SiO2 0 30 TiO2 0 40 ZrO2 0 10 Al2O3 0 30 B2O3 0 30 Fe2O3 0 7.5 P2O5 20 100 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 20 Li2O 0 50 Na2O 0 35 K2O 0 30 La2O3 0 10 SrO 0 10 Halogen (elemental) 0 35 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 65 SrO 0 20 CuO 0 20 Bi2O3 0 30 Sb2O5 0 5 or Borate glass min Max SiO2 0 30 TiO2 0 10 ZrO2 0 10 Al2O3 0 30 B2O3 20 100 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 50 SrO 0 10 Halogen (elemental) 0 20 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 1.5 SrO 0 20 or Aluminate glass min Max SiO2 0 30 TiO2 0 10 ZrO2 0 10 Al2O3 25 100 B2O3 0 30 Fe2O3 0 0.5 P2O5 0 10 MgO 0 20 CaO 0 20 BaO 0 20 MnO 0 20 ZnO 0 10 Li2O 0 50 Na2O 0 10 K2O 0 10 La2O3 0 10 SrO 0 10 Halogen (elemental) 0 20 As2O3 0 1.5 Sb2O3 0 1.5 Cs2O 0 10 Nb2O3 0 40 SE (except La2O3) 0 5 SnO2 0 1.5 NiO 0 20 CoO 0 20 Ta2O5 0 10 SnO 0 1.5 SrO 0 20 having. A lithium-ion cell according to any one of the preceding claims from 1 to 9, wherein the glass (expressed in% by weight) is a composition of Type borate glass phosphate glass Aluminatglas silicate glass phosphate glass ^{( 1 )} (1) (1) (1) (2) SiO2 20 60 1 TiO2 ZrO2 Al2O3 15 25 17 4 B2O3 25 45 7 1 Fe2O3 Cr2O3 P2O5 35 70 MgO 15 2 1 CaO 10 15 10 3.5 BaO 15 3.5 10 MnO ZnO 5 5 PbO Li2O 3 Na2O 2 0.5 K2O 10 2 SnO 60 SnO2 0.5 NiO 1 CoO 1 a / (b * c) [S / (K ² * m ² )] 99 780 116 42 139 or Type phosphate glass phosphate glass phosphate glass phosphate glass phosphate glass (3) (4) (5) (6) (7) SiO2 0.9 TiO2 0.5 ZrO2 Al2O3 1.5 0.9 5.6 12.7 B2O3 Fe2O3 6.6 Cr2O3 P2O5 59.3 58.0 81.5 65.3 70.4 MgO 0.9 CaO SrO 2.7 BaC 1.4 MnO ZnO 16.0 7.0 PbO Li2O 0.5 5.15 Na2O 32.4 1.5 10.3 K2O 1.5 0.2 28.2 CuO 8.3 Bi2O3 19.5 Sb2O3 0.25 SnO2 1.0 a / (b * c) [S / (K ² * m ² )] 702 288 494 1085 393 having. Lithium-ion cell according to one of the preceding claims, in particular according to claim 10 or 11, wherein the respective glasses in the following preferred and particularly preferred mixing ratios are present: at 50:50 to 60:40 based on low-to-high melting glasses and more preferably at 50:50 to 80:20 based on low to high melting glasses. Lithium-ion cell according to one of the preceding claims, in which up to 95% by volume of crystalline ceramic particles are present in volume ratio to the respective glasses. Lithium-ion cell according to one of the preceding claims, in which the at least one inorganic, preferably multifunctional constituent comprises glass in the form of powder. Lithium-ion cell according to one of the preceding claims, wherein the glass, in particular the glass powder, HF traps to form Si-F bonds. A lithium-ion cell according to any one of the preceding claims, wherein the glass / glass-ceramic powder has an ionic conduction <10 ^-5 S / cm at room temperature. Lithium-ion cell according to one of the preceding claims, in which the glass powder has a specific surface area in the range between 1 m ² / g and 50 m ² / g, particularly preferably 2 m ² / g to 100 m ² / g has. Lithium-ion cell according to one of the preceding claims, in which the glass / glass-ceramic powder has dielectric properties, in particular a dielectric constant ε _r in a range from 3 to 25,000, preferably from 5 to 20,000 A lithium-ion cell according to any one of the preceding claims, wherein the glass powder increases the wettability of the components with liquid electrolyte. Lithium-ion cell according to one of the preceding claims, in which the glass powder in particle sizes d90 is between 100 nm and 10 μm, preferably between 150 nm and 5 μm, and particularly preferably between 250 nm and 1 μm. Lithium-ion cell according to one of the preceding claims, wherein the glass powder in geometries fibrous, rod-shaped, round, oval, angular, edged (primary), dumbbell-shaped and or pyramidal or as platelets or flakes. Lithium-ion cell according to one of the preceding claims, in which glass particles of the glass powder are surface-structured or modified, in particular also silanized. Lithium-ion cell according to one of the preceding claims, in which the glass powder is agglomerated. Lithium-ion cell according to one of the preceding claims, characterized in that the lithium-ion cell is rechargeable. A lithium-ion cell according to any one of the preceding claims, wherein the component is the separator. A lithium-ion cell according to any one of the preceding claims, wherein the component is the cathode. A lithium-ion cell according to any one of the preceding claims, wherein the component is the anode. A lithium-ion cell according to any one of the preceding claims, wherein the component is the liquid electrolyte. An inorganic constituent, in particular glass for a lithium-ion cell according to any one of the preceding claims, which is prepared using a preferably inexpensive process step of melting at temperatures <2000 ° C, preferably <1700 ° C and rapid cooling. Use of an inorganic constituent, in particular of glass or glass ceramic powder in a lithium ion cell according to one of the preceding claims, as a functional additive in the anode, the cathode, the electrolyte, the separator or in functional layers between these components. Use of an inorganic constituent, in particular of glass or glass ceramic powder in a lithium ion cell according to one of the preceding claims, evenly distributed in volume of individual or all of said components and / or in near-surface regions or on the surface of individual or all of these components. Use of an inorganic constituent, in particular of glass or glass ceramic powder in a lithium ion cell according to one of the preceding claims, wherein the glass or glass ceramic powder during manufacture of the cell or individual components of the cell of the battery or individual battery components in the form of a Is added or applied slip, which contains next to a powder of glass or glass ceramic with a grain size of less than 1 micron to 50 microns, preferably up to 20 microns only water and is still stable. Use of an inorganic constituent, in particular of glass or glass ceramic powder in a lithium ion cell according to any one of the preceding claims, wherein the glass or glass ceramic powder is added or applied during manufacture of the cell or individual components of the cell in the form of a slurry, which beside a powder with a grain size of less than 1 micron to 50 microns, preferably up to 20 microns of glass or glass ceramic, an aqueous or organic liquid and additives containing the stability of the slurry, its rheological properties, its pH or other properties targeted modify.

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