WO2023020934A1

WO2023020934A1 - Methods for producing a solid state battery having a porous support body, and solid state battery having a porous support body

Info

Publication number: WO2023020934A1
Application number: PCT/EP2022/072571
Authority: WO
Inventors: Micheal ROTH; Christian WACHINSKI; Andreas Georg; Daniel Biro; Tobias Neumann
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e. V.; Freudenberg Se
Priority date: 2021-08-17
Filing date: 2022-08-11
Publication date: 2023-02-23
Also published as: DE102021121361A1

Abstract

The invention relates to methods for producing a solid state battery having a porous support body and to solid state batteries having a porous support body, which are distinguished by particularly good mechanical properties, high storage densities and low material cost.

Description

Process for producing a solid-state battery with a porous support body, and solid-state battery with a porous support body

The present invention relates to methods for producing a solid-state battery with a porous supporting body and solid-state batteries with a porous supporting body, which are characterized by particularly good mechanical properties, high storage densities and reduced material costs.

State of the art

For the energy transition to be successful, electrical energy storage devices are required that enable the electrical power generated by means of regenerative energy sources to be temporarily stored. In addition, there will also be an increasing change in mobility in the coming years. The proportion of electric vehicles will increase sharply, and with it the technical demands on the batteries, especially with regard to safety and energy density.

Currently almost all batteries in electric vehicles are conventional Li-ion batteries (LIB). Lithium-ion batteries mostly use liquid electrolytes with highly flammable solvents. This poses a risk of "thermal runaway". As the energy density of LIBs increases due to the use of new electrode materials, this safety risk will only increase in the coming years. In connection with lithium-metal anodes, which would enable a significant increase in energy density, there is the problem, for example, that repeated charging and discharging of such a battery causes lithium-metal dendrites to form, which initially lead to a loss of capacity, but in extreme cases to this can also lead to short circuits and, as a result, to thermal runaway.

Due to the inherent high level of danger of Li-ion batteries with liquid, flammable electrolytes and the increasing energy density of Li-ion batteries, they do not meet the increased safety requirements, especially for electromobility. While solid ion conductors prevent "thermal runaway" and facilitate the use of lithium-metal anodes, they typically have comparatively low ionic conductivity, which leads to high overvoltages during charging and discharging.

In order to be able to meet the increased safety requirements, Li-ion batteries with "solid" electrolytes are increasingly being researched, so that liquid electrolytes are no longer required. One focus here is on research into batteries with solid polymer ion conductors. However, polymers have a low ion conductivity, especially at low temperatures, and can only offer a low mechanical resistance to the growth of lithium dendrites. This makes the advantageous use of Si anodes or Li metal anodes in combination with polymeric electrolytes more difficult. In addition to the poor mechanical and electrochemical properties, organic polymeric ion conductors such as polyethylene glycol (PEG) still have a high flammability due to their chemical nature, so that these materials are not intrinsically safe. As a result, they cannot meet the increased requirements.

"Inorganic" solid-state batteries represent a new, promising approach in battery research that is intended to solve this problem. These are based on the use of inorganic solid-state electrolytes between and also in the electrodes, which carry the charge carriers in the battery, e.g. Li ⁺ or Na ⁺ , can transport. As a result, the use of a conventional battery separator impregnated with a liquid electrolyte can be dispensed with. There is also no need to fill the battery cell with liquid electrolyte before sealing the battery cell. This can drastically increase the safety of the batteries. This approach allows the use of high-voltage oxides as electrode material.

For the production of inorganic solid-state batteries, mostly inorganic solid ion conductors are produced by pressing powders of the ion-conducting material to form discs. In a subsequent step, electrodes, also in the form of powder mixtures, are pressed onto these so-called "pellets" or deposited in the form of pastes, e.g. by doctor blade processes. The disadvantages of this method are the resulting large thicknesses of the solid-state electrolytes and separators, which are significantly more than 100 μm, which results in high ionic resistances and a very low energy density of the solid-state batteries.

US 2011/0003211 A1 describes electrodes for solid polymer electrolyte batteries in which a solid polymer electrolyte of an electrode has sufficient strength to be able to use very thin conductors. A thin battery with a separator layer and electrode layers is proposed.

In ACS Energy Lett. 5, 2020, 718-727 describes the production of a solid electrolyte with a nonwoven carrier, in which an electrospun polyimide nonwoven is infiltrated with a solution of a sulfidic ion conductor, dried and then sintered.

The sintering takes place at a comparatively high temperature (approx. 400 °C), which is necessary due to the use of a solution instead of a dispersion in order to achieve sufficient ion conductivity of the sulfide. This in turn necessitates the use of a nonwoven material that is resistant to this high temperature. The resulting one Solid-state electrolyte has a high thickness of 40 to 70 μm, so that the resulting solid-state battery has a low resulting energy density, which makes use in electric vehicles, for example, impossible. In addition, electrospun nonwovens have a very low mechanical strength, which prevents the continuous manufacture of solid-state batteries, for example by means of roll-to-roll processes, with electrospun nonwovens.

In Nano Lett. 15, 2015, 3317-3323, the production of a solid-state battery is described by using a highly porous polyaramid non-woven fabric. A dispersion of an ion-conducting powder is squeegeed onto a nickel foil and dried. Two of these layers are then pressed onto both sides of the polyaramid nonwoven fabric using a decal process in order to obtain a solid electrolyte with a thickness of 70 μm. In a further step, the electrode powder is sprinkled onto this and then the entire composite is pressed again to obtain the electrodes. The electrodes are contacted to form a battery using two titanium rods that are pressed onto the electrodes. The resulting energy density of such a battery is too low to meet the electromobility requirements for LIBs due to the use of the 70 pm thick solid electrolyte and the titanium conductor. In addition, the overall process is very complex and time-consuming, so that it is not possible to develop commercial production for solid-state batteries using this process. The high porosity of the weakly bonded nonwoven used means that it cannot be directly coated by means of a doctor blade process, since the mechanical strength of the nonwoven used is not sufficient for a continuous coating process.

Conventional manufacturing processes are not able to reduce the electrode thickness without increasing the weight and volume of a battery cell while maintaining the same capacity. If the electrode thickness is reduced in order to keep overvoltages low, this effect is usually compensated by a larger electrode area in order to achieve the same total capacity in a battery cell. As a result, the relative proportion of metallic conductor foils and thus the weight and volume increases.

The approaches from the prior art use metallic conductor foils, which must have a sufficient layer thickness in order to ensure sufficient mechanical strength for the coating and roll-to-roll process. This layer thickness leads to high material costs, but also to an increase in the weight and volume of the battery cell, and thus to a reduction in the gravimetric and volumetric energy density. A further problem arises from the use of electrodes with the usual layer thicknesses of 100 to 200 μm in connection with solid ion conductors. Solid ion conductors typically have significantly lower conductivities than liquid ion conductors. This creates high internal resistances in the battery cells. Individual solid ion conductors with similarly high conductivities as liquid ion conductors are known, but are often expensive and difficult to synthesize or process. This applies in particular to the high moisture sensitivity of sulphides. There are also limitations in the processing of the ion-conducting materials in cost-effective production processes, which limit the resulting ion conduction in the finished battery cell.

A binder is usually added to the solid electrolyte pastes to ensure the processability of the coated foils, such as flexibility for roll-to-roll processes. However, these binders reduce the ionic conductivity of the separators, in particular with high binder proportions, with a proportion of more than 1% by weight already being classified as “high”. Inorganic ionic conductors require high compression to improve contact between the individual powder particles and minimize porosity. However, this compression of the battery cell harbors the risk of a short circuit, which is particularly relevant for thin separator layers below 100 μm, i.e. the thinner the separator is designed.

It would therefore be desirable to develop a manufacturing process and a solid-state battery that reduces or even completely avoids the problems of the prior art.

In this context, it is desirable to develop a manufacturing process that ensures sufficient tensile strength for the roll-to-roll processing of the individual components in a solid-state battery, which avoids thermal runaway as with lithium-ion battery cells with liquid electrolyte and their Energy density meets the growing requirements, e.g. when used in electric vehicles.

The subject of the invention solves the problems described in the prior art.

Summary of the Invention

In a first aspect, the invention relates to a method for producing a solid-state battery, with the steps

Providing a separator layer, comprising a nonwoven material and a solid ion conductor, wherein the provision of a separator layer comprises in particular the provision of a nonwoven fabric and the infiltration of the nonwoven fabric with a solid electrolyte paste, Coating of the separator layer with a cathode layer and an anode layer, preferably followed by pressing or calendering the coated separator layer, in particular in a roll-to-roll process, the fleece material having z through-pores, ie pores that have no interruptions in the z-direction have fibers, or have pores that penetrate the fleece material essentially perpendicularly to the separator layer, in the z-direction, the pore density being at least 1000 mm ^-2 , more preferably at least 10000 mm ^-2 , and/or the fibers of the Fleece material have an average titre of 0.06 dtex to 3.3 dtex.

In a second aspect, the invention relates to a solid-state battery comprising a separator layer comprising a fleece material and a solid ion conductor, a cathode layer and an anode layer, the fleece material having z through pores, ie pores that are not interrupted by fibers in the z direction have, or pores that penetrate the fleece material essentially perpendicular to the separator layer, in the z-direction, the pore density being at least 1000 mm ^-2 , more preferably at least 10000 mm ^-2 , and/or the fibers of the fleece material having a have an average titre of 0.06 dtex to 3.3 dtex.

The inventors discovered that the ion-conductive separator can be given sufficient tensile strength in roll-to-roll processes by being supported by a non-woven fabric. The inventors have surprisingly discovered that the manufacturing process for solid state batteries can be started with a self-supporting separator foil. In particular, the manufacturing process begins by providing a non-woven fabric and infiltrating the non-woven fabric with a solid electrolyte paste in order to produce an ion-conducting separator layer. The electrodes, i.e. a cathode layer and an anode layer, are then applied to this separator layer, and these electrodes can be made much thinner than known from the prior art.

According to the invention, the use of a non-woven fabric is advantageous since this enables easy production of self-supporting films, e.g. This plays an important role in roll-to-roll processes, among other things.

Due to the increased mechanical strength, less binder can be used, which reduces the internal resistance. According to the invention, the problem is avoided or minimized that when pressing or calendering the individual layers or solid-state battery components, the cathode material is pressed through a separator that is too thin towards the anode. This avoids or minimizes short circuits, which can occur in particular with thin separators without non-woven material.

According to the invention, the use of a non-woven fabric is also advantageous because short circuits caused by lithium dendrites can be better suppressed.

In a related aspect, the invention relates to a solid-state battery that can be produced or is produced by the method according to the invention.

Brief description of the figures

FIG. 1 shows an SEM photograph of a separator layer used according to the invention made of a fleece material filled with solid electrolyte after drying.

FIG. 2 shows an SEM photograph of a separator layer used according to the invention made of a fleece material filled with solid electrolyte after drying and subsequent pressing.

FIG. 3 shows a comparison of the ion conductivities of pellets according to the prior art, measured by means of electrochemical impedance spectroscopy, in comparison with the separator layers of the invention.

FIG. 4 shows the result of cycling tests with solid-state batteries according to the invention. The charging or discharging voltage is shown as a function of the charge based on the cathodic active material.

FIG. 5 shows the results of viscosity measurements on solid electrolyte pastes.

Description of the invention

The method according to the invention and the solid-state battery according to the invention ensure that the ion-conducting separator has sufficient tensile strength in roll-to-roll processes by being supported by a non-woven fabric. It is advantageous that the manufacturing process for solid-state batteries can be started with a self-supporting separator film. In particular, the manufacturing process begins by providing a non-woven fabric and infiltrating the non-woven fabric with a solid electrolyte paste in order to produce an ion-conducting separator layer. Consequently, the electrodes, i.e. a cathode layer and an anode layer, are applied to this separator layer and can be made much thinner than has been customary up to now.

The method is advantageous when providing thin conductors by vapor deposition onto thin electrodes instead of using conventional conductor foils. This allows the use of ion conductors with low ion conductivities, such as the use of sulfides that can be produced inexpensively.

The method according to the invention is characterized by significantly reduced manufacturing costs, partly because the individual steps on which it is based are less expensive. For example, it is possible Apply calendering via a roll-to-roll process instead of pressing individual sheet elements.

The use of a nonwoven brings a number of advantages, such as the simple production of self-supporting films for the separator and/or the electrodes, with an improved, i.e. higher, tensile strength compared to free-standing solids separator films without a nonwoven. Furthermore, the use of a binder in the solid electrolyte pastes can be further reduced or omitted entirely. This has an advantageous effect on the internal resistance of the solid-state battery.

If the separator layer is coated with a cathode layer and an anode layer with subsequent pressing, the use of a nonwoven is advantageous because it makes it more difficult for the cathode material or anode material to push through the separator layer and thus avoids short circuits, especially with thin separator layers.

separator layer

The separator layer comprises a fleece material and a solid ion conductor. In particular, the separator layer is provided by infiltrating a nonwoven fabric with a solid electrolyte paste.

The infiltration of a non-woven fabric with a solid electrolyte paste can also be understood as filling or impregnating the non-woven fabric with the solid electrolyte paste. Those skilled in the art know and understand that the aim of this process is to fill the cavities of the nonwoven with the paste as completely as possible. It is not sufficient that the fibers of the non-woven material or the non-woven material are only coated with the paste, but the cavities are not filled.

In a preferred embodiment, the separator layer has one or more of the following properties: a maximum tensile force transverse to the machine direction, measured according to DIN EN 29073-3 (1992-08), from 5 N/5 cm to 50 N/5 cm, more preferably from 5 N/5 cm to 40 N/5 cm, in particular from 7 N/5 cm to 40 N/5 cm, an elongation in the machine direction, measured according to DIN EN 29073-3 (1992-08), from 5% to 50% , preferably from 6% to 30%, in particular from 8% to 20%, and/or in the case of a square area, has an area shrinkage up to 200° C. of 0.01 area% to 10.0 area%, preferably 0.01 area % to 2.0% by area, more preferably from 0.1% by area to 2.0% by area. The parameters (ranges) mentioned are linked to advantageous mechanical properties, such as toughness and stability, and thus allow the solid-state battery to be designed as thin and light as possible without running the risk of short circuits.

For suitable infiltration into the fleece material, the viscosity of the solid electrolyte paste is less than 500 mPa*s, preferably less than 200 mPa*s, particularly preferably less than 100 mPa*s, but higher than 20 mPa*s, preferably higher than 50 mPa*s to enable favorable infiltration behavior. For suitable infiltration into the fleece material, the viscosity of the solid electrolyte paste is between 20 mPa*s and 500 mPa*s, preferably between 50 mPa*s and 200 mPa*s. Too high a viscosity makes it difficult to fill the cavities quickly and evenly. If the viscosity is too low, the paste does not carry enough material into the non-woven fabric and there is a risk that the paste will leak out of the non-woven fabric after infiltration before drying.

non-woven material

The terms “nonwoven material” and “nonwoven fabric” are used interchangeably herein.

Nonwoven fabrics have the advantage that they have isotropic mechanical properties and comparatively high tear propagation resistance, in particular in comparison to woven, knitted, knitted and net fabrics, which essentially consist of endless filaments.

Nonwovens can be spunbonded nonwovens, meltblown nonwovens, wet-laid nonwovens, dry-laid nonwovens, nanofiber nonwovens, and solution-spun nonwovens. In one embodiment, the nonwoven is a wet nonwoven because it can be manufactured with a very uniform fiber distribution, low weight, particularly low thickness, very high air permeability and high mechanical strength at the same time. This enables a high degree of filling (through infiltration) with ion-conducting material. A small thickness of the porous nonwoven substrate enables electrochemical energy storage and converters with a high energy density and power density.

According to the invention, the nonwoven material has z through pores, ie pores that are not interrupted by fibers in the z direction, or pores that penetrate the nonwoven material essentially perpendicularly to the separator layer in the z direction, the pore density being at least 1000 mm ^-2 is more preferably at least 10000 mm ^-2 and/or wherein the fibers of the fleece material have an average titer of 0.06 dtex to 3.3 dtex.

The number of z-through pores in the fleece material can be determined using scanning electron microscopy

(REM) can be quantified. In this case, a SEM image, preferably at 500x Magnification, taken, the number of z-pores in an area of 100 x 100 pm ² counted and the average determined at three different locations.

The nonwoven, in particular in its embodiment as a wet nonwoven, can have short-cut fibers. Short-cut fibers are fibers with a length of preferably 1 mm to 12 mm, preferably 3 mm to 6 mm. The mean titer of the fibers can vary depending on the desired structure of the nonwoven fabric. The use of fibers with an average titer of 0.06 dtex to 3.3 dtex, of 0.06 dtex to 1.7 dtex, or of 0.06 dtex to 1.0 dtex has proven to be particularly advantageous according to DIN EN ISO 1973:1995-12.

Practical tests have shown that the at least partial use of microfibers with an average titer of less than 1 dtex, preferably from 0.06 dtex to 1 dtex, has an advantageous effect on the size and structure of the pore sizes and inner surface as well as on the density of the nonwoven . Proportions of at least 5% by weight, from 5% by weight to 35% by weight, in particular 5% by weight to 20% by weight, of microfibers, based in each case on the total amount of fibers in the nonwoven fabric, have proven to be particularly favorable . In practical tests it was found that a particularly homogeneous infiltration can be achieved with the aforementioned parameters. A homogeneous infiltration also enables a homogeneous function of the solid electrolyte introduced by the solid electrolyte paste. The fibers of the non-woven fabric can be in the form of matrix fibers and/or binding fibers. Binding fibers are fibers that can form bonding points and/or bonding areas at least at some crossing points of the fibers, for example during the production process of the nonwoven fabric by heating to a temperature above their melting point and/or softening point. At these crossing points, the binding fibers can form integral connections with other fibers and/or within one and the same fiber. By using binding fibers, a framework can therefore be built up and a thermally bonded nonwoven fabric can be obtained. Alternatively, the binding fibers can also melt completely and thus strengthen the nonwoven. The binding fibers can be designed as core-sheath fibers, in which the sheath represents the binding component, and/or as undrawn fibers.

The advantage of using binder fibers is that non-woven fabrics can be produced without the use of any binders. This improves the electrochemical stability of the porous substrate and thus the lifespan of the battery. Another advantage of using binder fibers is that they have less of an adverse effect on the air permeability of the nonwoven fabric than binders that are applied onto and into the fibers. The use of binding fibers thus makes it possible to produce mechanically stable nonwovens with a high level of air permeability. In one embodiment of the solid state battery, the non-woven material comprises one or more fibers, wherein the one or more fibers comprise a high-melting point core and a low-melting point shell. This is advantageous since such fibers allow a particularly homogeneously bonded fleece material.

In one embodiment, the proportion of binding fibers in the fiber-based substrate is from 95% by weight to 50% by weight, or from 95% by weight to 65% by weight, based on the total weight of the nonwoven fabric before infiltration. This is advantageous because very high mechanical strength of the entire fiber substrate is achieved in this area, which has a positive effect on calendering stability.

In one embodiment, the nonwoven has matrix fibers, i.e., fibers that are substantially unfused. The matrix fibers preferably have a melting point of over 160°C, preferably over 200°C, in particular over 250°C and/or a decomposition point of over 250°C, in particular over 350°C. These properties improve the structural stability of the nonwoven under pressure and/or temperature stress and result in low area shrinkage, preferably up to 200°C.

In one embodiment, the proportion of matrix fibers in the nonwoven is from 5% by weight to 70% by weight, from 5% by weight to 50% by weight, or from 5% by weight to 35% by weight, based on the total weight of the nonwoven an infiltration. This is advantageous because in this area a very high geometric stability compared to calendering processes and a very high structural homogeneity are achieved.

The fibers in the nonwoven can be formed in a wide variety of shapes, for example as flat, hollow, round, oval, trilobal, multilobal, bico and/or “island in the sea” fibers. In one embodiment, the cross section of the fibers is round.

In one embodiment, the fleece material is selected from the list of polyacrylonitrile, polyimide, polyamide, in particular polyamide 6 and polyamide 6.6, aramid, in particular polyparaphenylene terephthalamide (PPTA), polyvinyl alcohol, polyester, in particular polyethylene terephthalate and/or polybutylene terephthalate, copolyester, polyolefins, in particular polyethylene and /or polypropylene and/or mixtures thereof, viscose, cellulose and Al2O3.

In one embodiment, the fleece material has one or more of the following properties before the solid ion conductor or the solid electrolyte paste is applied: an air permeability, measured according to EN ISO 9237, from 300 I rrr ² s ^-1 to 1000 I rrr ² s ^-1 , preferably from 400 I rrr ² s ^-1 to 1000 I rrr ² s ^-1 , in particular from 450 I rrr ² s ^-1 to 850 I rrr ² s ^-1 , an average porosity of at least 30%, more preferably at least 50%, even more preferably at least 70%, most preferably at least 85%, average pore sizes, measured according to DIN ISO 4003, from 1 μm to 100 μm, 3 μm to 90 μm, 5 pm to 85 pm, 10 pm to 80 pm, or 20 pm to 75 pm.

Alternatively, the porosity of the non-woven fabric is preferably from 40% to 90%, from 50% to 80%, in particular from 55% to 70%.

The average porosity P of the fleece material relates to the porosity of the substrate itself, ie in the state before infiltration with the solid ion conductor or the solid electrolyte paste. The average porosity of the fleece material (in %) is calculated from the actually measured (apparent) density d _app and the density of the polymer, or the density of the fleece material itself, dp _oiy mer, using the following formula

P [%] = 100 - 100 * ( Öapp / Cfpolymer )

The advantage of a high porosity is that large volumes are available for infiltration with solid electrolyte, which in turn increases the conductivity of the separator layer.

A high air permeability is advantageous because it favors a high degree of filling with the solid electrolyte paste in the porous substrate and thus results in a low resistance of the resulting separator sheet.

The average pore sizes mentioned are advantageous, since this enables the solid electrolyte paste to be infiltrated correctly into the nonwoven fabric. This reduces the ion transport resistance of the solid electrolyte.

The fleece material preferably has a thickness, measured according to DIN EN ISO 9073-2, of 5 μm to 30 μm, preferably 8 μm to 20 μm, in particular 8 μm to 16 μm. A small thickness is advantageous because it enables the battery to have a high energy density and power density. A minimum thickness is appropriate since a certain strength is required for the manufacturing process.

solid electrolyte

The terms “solid ion conductor”, “solid electrolyte”, “solid electrolyte” and “solid electrolyte” are used synonymously herein.

The solid electrolyte can e.g. from the group of sodium-supra-ionic conductors (acronym

NASICON for sodium (Na) Super Ionic CONductor), such as LiM2(PÜ4)3 (where M is a cation is), Nai _+x Zr2SixP3-xOi2 (0<x<3) or Lii _+x Al _x Ti2-x(PO4)3 (LATP), garnet-type electrolytes, such as Li?La3Zr20i2 (LLZO), perovskite-type Electrolytes such as Li3xLa2/3-xTiC>3 (LLTO) can be selected.

The solid electrolyte can be a sulfide ion conductor containing lithium and sulfur. The solid electrolyte can be a glass, a glass-ceramic or a ceramic. Exemplary glasses are xLi2S(100-x)P2Ss, xÜ2S(100-x)B2S3 and xÜ2S(100-x)SiS2, xLi2S(100-x)SiS2, optionally doped with U3PO4, Li4SiO4, and/or Li4GeO4.

Exemplary glass ceramics come from the group with the general formula Li _w M _x PySz, such as Li4-tGeit- _t PtS4 (0<t<1).

The solid electrolyte can be from the group of argyrodite-type Li-ion solid electrolytes, such as LiePSsX (where X = CI, Br, I) or from the group of thio-lisicon, formed from the systems Li2S-GeS2, Li2S-GeS2- ZnS and Li2S-GeS2-Ga2S3. The in Feng Zheng et al. (Review on solid electrolytes for all-solid-state lithium-ion batteries, Journal of Power Sources 389, 2018, 198-213) reviewed Li-ion solid electrolytes are incorporated herein by reference.

The solid electrolyte can be applied to and into the nonwoven by various application methods, preferably coating methods, such as in particular doctor blades, roller application, gravure coating, application from a slot die, with which infiltration of the nonwoven with the solid electrolyte paste can be achieved. Application methods such as application by means of a slot die and by means of roller application methods are particularly preferred here. These are advantageous because they allow the solid electrolyte pastes to be distributed very evenly in and on the nonwoven.

Sulphide Solid Electrolytes

In one embodiment of the method or of the solid-state battery, the solid ion conductor is an inorganic ion conductor. In particular, the solid ion conductor is selected from the group of sulfides and thiophosphates, with the solid ion conductor preferably being in the form of sulfide particles, with particle sizes D50 of less than 2 μm, less than 1 μm, less than 500 nm, less than 200 nm , or less than 100 nm based on the mass distribution and the diameter of the sulfide particles.

As a result of the subsequent process steps, such as calendering, the sulfide particles sinter together, so that the specified particle size is no longer necessarily evident in the separator layer obtained. The specified particle size refers to the sulfide particles in the paste used to infiltrate the nonwoven. The use of sulfides or sulfide particles is advantageous because they have high ductility and high ionic conductivity compared to many other solid electrolytes. The high ductility allows sintering at moderate temperatures using appropriate pressures.

In one embodiment, the separator layer is pressed and/or calendered at a temperature of at least 25° C., at least 50° C., at least 100° C., at least 150° C., at least 200° C., at least 250° C., or at least 300° C instead. In one embodiment, the pressing and/or calendering of the separator layer takes place at a temperature of at most 400°C.

In one embodiment, the separator layer is pressed at a pressure of at least 10 MPa, at least 50 MPa, at least 100 MPa, at least 200 MPa, at least 500 MPa, or at least 1000 MPa. In one embodiment, the separator layer is pressed at a pressure of at most 10,000 MPa.

In one embodiment, the separator layer is calendered with a line force of at least 0.05 kN/mm, at least 0.25 kN/mm, at least 0.5 kN/mm, at least 1 kN/mm, at least 2.5 kN/mm, or at least 5 kN/mm.

The value D50 describes the point in the particle size distribution at which 50% of the particles have a smaller or the same particle size as D50. Other D values are to be understood analogously. If the D value refers to the mass distribution, the D50 means that 50% of the total particle mass consists of particles that are smaller than or equal to the D50 value.

In one embodiment, the sulfides or sulfide particles can be present in and/or on one or both surfaces of the nonwoven. It is advantageous if the sulfides or sulfide particles are homogeneously distributed in the xy and/or z direction of the separator layer. With this configuration, short circuits and dendrite growth can be prevented particularly effectively. Furthermore, the solid electrolyte, supported by the fleece material, can thereby have a particularly high level of homogeneity, which in turn has a positive effect on the cycle stability of the battery. It is advantageous if all the pores of the nonwoven are filled homogeneously with the sulfide particles.

In one embodiment, the sulfide particles have a particle size distribution with a D50 value, or preferably a D90 value, which is smaller than the mean pore size of the nonwoven fabric. In a preferred embodiment, the sulfide particles have a particle size distribution with a D90 value that is 0.5 times the mean pore size of the non-woven fabric corresponds to 0.2 times the mean pore size of the non-woven fabric, or 0.1 times the mean pore size of the non-woven fabric.

In one embodiment, the sulfide particles are in a proportion of 60% to 90% by weight, 65% to 85% by weight, or 70% to 80% by weight, based on the total weight of the separator layer. These proportions by weight are advantageous and enable the separator layer to have particularly good ion conductivity.

In one embodiment of the invention, the modulus of elasticity of the sulfide particles is from 10 to 40 GPa. Due to a low modulus of elasticity, the sulfide particles can be pressed better at low temperatures, which is advantageous in connection with roll-to-roll processability.

lead additive

Carbon-containing materials such as artificial graphite, carbon black, acetylene black, ketjen black or metal powder can be used as conductive additives. In particular, the conductive additives can be rod-shaped, e.g. as carbon nanotubes, carbon nanofibers, and vapor-grown carbon fibers.

anode layer and cathode layer

The separator layer (produced in this way) is coated with a cathode layer and an anode layer.

The coating of the separator layer with an anode layer can be printing, for example. A paste made of anodic active material, such as carbon or silicon, can be used for this, for example. In the case of a lithium-metal anode, the coating can be implemented using a thin-film process.

In one embodiment, an anode foil based on copper with lithium is coated with a protective layer in a thin-layer process and then laminated onto the separator layer. In an alternative embodiment, an anode foil can be produced by producing a lithium-copper foil composite by means of a rolling process, then coating it with a protective layer in a thin-layer process and then laminating it onto the separator layer.

It is also advantageous if the coating of the separator layer with the cathode layer or the anode layer is followed by pressing or calendering of the separator layer coated in this way, in particular in a roll-to-roll process. In particular, it is advantageous if the separator layer is compressed in a first pressing or calendering, then coated with the cathode layer or the anode layer, and this separator layer coated in this way is in turn compressed by pressing or calendering. After the separator layer has been coated with a cathode layer and an anode layer, the coated separator layer is pressed or calendered, the contact pressure or the contact force being lower than the contact pressure or the contact force during compression and/or calendering before coating with the cathode layer and/or the anode position.

A particular advantage results when the first compression step is carried out at a higher pressure or at a higher linear force than the second compression step. In one embodiment, the pressure or line force in the first compression step is 20% higher than in the second compression step, 50% higher, 100% higher, 200% higher, or 500% higher.

binder

In one embodiment, the solid ion conductor or the solid electrolyte paste also has a binder in a proportion of 0.5% by weight to 10% by weight, 0.5% by weight to 5% by weight, or 0.5% by weight % by weight to 3% by weight, based on the total weight of the solid ion conductor or the solid electrolyte paste and the binder. The advantage of using binder in a proportion of less than 10% by weight is increased ionic conductivity.

In one embodiment, the solid ion conductor or the solid electrolyte paste also has a binder in a proportion of less than 10% by weight, less than 1.0% by weight, or less than 0.1% by weight, based on the Total weight of the solid ion conductor or the solid electrolyte paste and the binder. In a preferred embodiment, the solid ion conductor or the solid electrolyte paste is essentially free of a binder. According to the invention, the nonwoven takes over the supporting function of the binder partially or even completely, so that a binder is not necessary. This is advantageous, for example, for the ion conduction of the sulfide particles if there is no or a minimized proportion of binder between the sulfide particles.

In one embodiment, the binder is an organic binder, for example selected from the group consisting of polyvinylidene difluoride (PVF), hexafluoropropylene (HFP), perfluoromethyl vinyl ether (PFMV) and tetrafluoroethylene and its copolymers, polyolefins such as polyethylene, polyacrylate, perfluoropolyacrylate, polymethacrylate, polystyrene butadiene ( SBR), acrylonitrile butadiene copolymers (NBR) and mixtures thereof. In one embodiment, the organic binder is selected from the group consisting of polystyrene butadiene (SBR), polystyrene acrylonitrile, acrylonitrile butadiene copolymers (NBR), polyvinylidene difluoride, and mixtures thereof.

In one embodiment, the organic binder is selected from the group consisting of fluorine-based synthetic resins such as polytetrafluoroethylene, fluororubber, carboxymethyl cellulose and polyimide or mixtures thereof.

In one embodiment, the binder is applied in the form of a solution. This is advantageous because the binder in this form can be processed particularly well with the sulfide particles to form a homogeneous solid electrolyte paste, which promotes homogeneity in the end product.

In a preferred embodiment, the binder has a glass transition temperature TG of -100.degree. C. to +75.degree. C., in particular of -50 to +50.degree. The advantage of a binder with this glass transition temperature is that it results in impact-resistant solid electrolyte layers, which in turn can be easily processed in a roll-to-roll manufacturing process.

anode arrester and cathode arrester

In one embodiment, the method comprises the steps of coating the cathode layer with a cathode conductor and/or coating the anode layer with an anode conductor, with the coating of the cathode layer with a cathode conductor and/or the coating of the anode layer with an anode conductor preferably taking place using a thin-film process, i.e. via physical vapor deposition such as thermal evaporation or sputtering, or chemical vapor deposition such as plasma enhanced chemical vapor deposition or atomic layer deposition. In a preferred embodiment, the cathode layer is coated with a cathode collector and/or the anode layer is coated with an anode collector by a vapor deposition process.

In an analogous embodiment, the solid-state battery includes a cathode collector and/or an anode collector. It is possible to save material for the conductors compared to using conductor foils, which is advantageously based on the thinner design of the electrodes. This saves both material costs and weight and volume, which also increases the volumetric and gravimetric energy density. Savings on copper in particular increase the gravimetric energy density due to the high material density of copper itself.

For example, the anode collector consists of copper, stainless steel, titanium, iron, cobalt, nickel, indium, magnesium, zinc, aluminum, germanium, lithium or a mixture thereof. For example, the cathode conductor consists of aluminum, copper, magnesium, stainless steel, titanium, iron, nickel, zinc or a mixture thereof.

In one embodiment, coating the cathode layer with a cathode conductor includes evaporating an aluminum conductor onto the cathode layer.

In one embodiment, providing the anode layer and the anode conductor includes providing a copper conductor foil, evaporating lithium as an active material, optionally with a protective layer, onto the copper conductor foil, and then laminating the lithium anode layer obtained in this way the separator layer.

In another embodiment, coating the cathode layer with a cathode conductor comprises evaporating an aluminum conductor onto the cathode layer and coating the anode layer with an anode conductor comprises evaporating a copper conductor onto a silicon-carbon (Si—C) anode.

In one embodiment of the method or the solid-state battery, the cathode conductor and/or the anode conductor has a layer thickness of not more than 5.0 μm, not more than 3.0 μm, not more than 2.0 μm, or not more than 1.0 pm. In one embodiment of the method or of the solid-state battery, the cathode conductor and/or the anode conductor has a layer thickness of at least 0.1 μm, or at least 0.2 μm.

Such small arrester thicknesses are advantageous because they increase the energy density compared to thicker arresters and at the same time save material and thus costs. This advantage comes into play more in the case of thin electrode layers, since here the proportion of conductor materials relative to the electrochemically active material in the electrodes is high.

The mentioned layer thicknesses in the range from 0.1 μm to 5.0 μm can be realized, for example, by vapor deposition or a thin-film process, for example via physical vapor deposition, such as thermal evaporation or sputtering, or chemical vapor deposition, such as plasma-enhanced chemical vapor deposition or atomic layer deposition. The thin conductor layers obtained in this way are a result of the manufacturing process described, which begins with a separator layer and then coats it with an anode layer and/or a cathode layer. The combination of layers obtained is self-supporting and has sufficient tensile strength so that it can be further processed in roll-to-roll processes. Comparatively thin conductor layers are sufficient for the electrical conductivity of the conductors. Thickness of the separator layer, cathode layer, anode layer and the layered composite

In one embodiment of the method or the solid-state battery, the solid-state battery has one or more of the following parameters:

- a separator layer with a thickness of not more than 50 μm, in particular not more than 40 μm, not more than 30 μm, not more than 20 μm, not more than 15 μm, or not more than 10 μm, measured according to the DIN EN test specification ISO 9073-2,

- a cathode layer with a thickness of not more than 50 μm, not more than 40 μm, not more than 30 μm, in particular not more than 25 μm or not more than 20 μm,

- wherein the thickness of the anode layer is selected as a function of the material of the anode layer and the thickness of the cathode layer, e.g. by the storage capacity (in mAh/cm ² ) of the anode corresponding to that of the cathode, or being at least 10% higher than that of the cathode, and /or

- wherein the layered composite of separator layer, anode layer with anode collector and cathode layer with cathode collector has a thickness of not more than 100 μm, in particular not more than 90 μm or not more than 80 μm.

Advantageously, the thickness of the cathode layer is made thin, and the thickness of the anode layer associated with this is selected to match the thickness of the cathode layer, in order to keep the requirements for the specific ion conduction of the ion conductor in the cathode layer, the anode layer and/or the separator layer low.

In one embodiment based on lithium nickel manganese cobalt (NMC) oxide as the cathode material and graphite as the anode material, the thickness of the cathode layer is no more than 50 μm, no more than 40 μm, no more than 30 μm , in particular not more than 25 μm or not more than 20 μm, the corresponding thickness of the anode layer is essentially 30% higher, i.e. essentially not more than 65 μm, not more than 52 μm, not more than 39 μm, in particular not more than 33 pm or not more than 26 pm.

In an analogous embodiment based on Li-NMC oxide as cathode material and graphite as anode material, the ratio of the thickness of the cathode layer to the thickness of the anode layer is between 1.5 and 1.0, preferably between 1.35 and 1.25.

In an embodiment based on Li-NMC oxide as cathode material and a mixture of silicon and carbon as anode material, the thickness of the cathode layer is no more than 50 μm, no more than 40 μm, no more than 30 μm, in particular no more than 25 μm or not more than 20 µm, the corresponding thickness of the anode sheet is substantially no more than 20 pm, not more than 16 pm, not more than 12 pm, in particular not more than 10 pm or not more than 8 pm.

In an analogous embodiment based on Li-NMC oxide as the cathode material and a mixture of silicon and carbon as the anode material, the ratio of the thickness of the cathode layer to the thickness of the anode layer is between 0.45 and 0.25, preferably between 0.4 and 0 ,3.

In one embodiment based on Li-NMC oxide as the cathode material and lithium as the anode material, the thickness of the cathode layer is no more than 50 pm, no more than 40 pm, no more than 30 pm, in particular no more than 25 pm or no more than 20 pm, the corresponding thickness of the anode layer is essentially no more than 2 pm, no more than 1.6 pm, no more than 1.2 pm, in particular no more than 1.0 pm or no more than 0.8 pm.

In an analogous embodiment based on Li-NMC oxide as cathode material and lithium as anode material, the ratio of the thickness of the cathode layer to the thickness of the anode layer is between 0.06 and 0.02, preferably between 0.05 and 0.03.

An advantage of the above-mentioned embodiments based on Li-NMC oxide as cathode material and the various anode materials—graphite, a mixture of silicon and carbon, and lithium—is that high energy densities are made possible.

The smaller electrode thickness must i.a. be compensated by a larger electrode area in order to achieve the same total capacity in a battery cell. This requires a larger surface area of the arrester foil (and the ion-conducting separator), which increases the weight and volume of a fixed-capacity battery cell, and thus lowers the energy density.

According to the invention, however, it is possible to replace the metallic collector foils, which are usually about 15 μm thick, with thin metallic collector layers that are 0.1 to 5.0 μm thick, preferably 0.5 to 1.5 μm thick, thereby reducing weight and volume are saved and a similarly high energy density is achieved.

Conventional manufacturing processes produce metallic conductor foils with a thickness of approx. 15 μm and are coated with the electrodes in roll-to-roll processes. A porous foil is then placed between the anodic and cathodic electrodes and the liquid electrolyte is subsequently filled in to fill or infiltrate the pores. For these conventional manufacturing processes, a certain thickness of the metallic conductor foils of approx. 15 μm is required in order to ensure sufficient tensile strength of the roll-to-roll processes. Thinner metal foils cannot be produced with this process. According to the invention, the order of coating is reversed. In one embodiment, one starts with the production of a self-supporting ion-conducting separator, coats it with the electrodes, for example in a roll-to-roll printing process, and then coats the electrodes with thin metallic collector layers, for example via vapor deposition processes. Advantageously, the (ion-conducting) separator layer has a thickness of not more than 50 μm, in particular not more than 40 μm, not more than 30 μm, not more than 20 μm, not more than 15 μm, or not more than 10 μm. measured according to test specification DIN EN ISO 9073-2. The thicknesses of the separator layer mentioned make it possible to maximize the energy density. The suitably selected non-woven fabric ensures sufficient tensile strength of the (ion-conducting) separator layer, for example in roll-to-roll processes. According to the invention, the manufacturing process begins with the infiltration of a non-woven fabric with a solid ion conductor in order to produce an ion-conducting separator on which the electrodes and finally the conductors are then deposited.

anode material

The anode layer includes, for example, anodic active material selected from the list of amorphous carbon, for example carbon black (CB), acetylene black (AB), furnace black (FB), and ketjen black (KB), graphene, graphite, TiO2; Li^isO^; carbon-tin (C-Sn) composites, tin alloys, carbon-silicon (C-Si) composites; SiO _n -based composites, silicon alloys, lithium metal, and lithium alloys is selected. Preferred lithium alloys are alloys of lithium with silver, zinc, tin, indium, silicon, aluminum and bismuth.

In addition to anodic active material, the anode layer optionally also includes a binder, a conductive additive and a solid electrolyte.

cathode material

The cathode layer comprises, for example, cathodic active material that is selected from the list of layered oxides based on nickel-manganese-cobalt oxide (LiNi _x Mn _y Co _z O2, where x+y+z=1, preferably x>0.5), e.g LiNio.sMno Coo O), lithium nickel cobalt aluminum oxide (LiNixCo _y AlzO2, where x + y + z = 1), e.g. LiNio,84Coo,i2Alo,o402, lithium-rich layered oxides (Lii _+x Mi- xO2), e.g. Lii,2Nio,2Mno,e02), high-voltage spinel-type oxides (LiMn2- _x M _x O4, where M is a transition metal), e.g. LiNio,5Mni,s02, olivines (UMPO4, e.g. LiFePO4), TiS2, LiTiS2, and U2S is selected.

In addition to cathodic active material, the cathode layer optionally also includes a binder, a conductive additive and a solid electrolyte. Configuration of the separator layer

In one embodiment of the method, providing the separator layer comprises the following steps:

- Infiltrating the fleece material with the solid ion conductor, in particular in the form of a paste, a slip or slurry, containing the solid ion conductor in particle form, and

- Drying of the filled fleece material.

In this embodiment, the separator sheet is produced without subsequent calendering. The drying of the filled fleece material takes place at a temperature of at least 50.degree. C., at least 100.degree. C., at least 150.degree. C., at least 200.degree. C., or at least 250.degree. Depending on the fleece material selected, the drying takes place at a temperature of no more than 400 °C, no more than 350 °C, no more than 300 °C, no more than 250 °C, no more than 200 °C, or no more than 150 °C.

In another embodiment of the method, providing the separator layer comprises the following steps:

- Drying of the filled fleece material, and

- pressing and/or calendering before coating with the cathode layer and/or the anode layer.

In this embodiment, the separator layer is produced with subsequent pressing and/or calendering. Advantageously, the mechanical properties of the separator layer are improved by subsequent pressing and/or calendering, which has a positive effect on the toughness, maximum tensile force and elongation of the separator layer and the entire solid-state battery. This also makes it possible to reduce the proportion of binder used in the paste. In particular, the electrical properties are also improved, i.e. higher ion conductivity is achieved. A further advantage is the reduction in porosity, which reduces the likelihood of electronically conductive material being introduced into the separator layer during the subsequent electrode coating and any subsequent second calendering, which in extreme cases could lead to a short circuit.

In a further preferred embodiment, two calendering steps are used, ie one calendering step before and after the coating with the electrodes, which is the mechanical and electrical properties of the solid-state battery further improved. This enables better ion conduction of the ion conductor in the electrodes, better contact at the interface between ion conductor and active material in the electrodes, and lower porosity and, associated therewith, higher energy density. A higher pressing force and/or a higher temperature are preferably used in the first calendering step than in the second calendering step. In calendering, the force is expressed in relation to the width of the roll. The ratio of the pressing force in the first calendering step to the second calendering step is preferably at least 1.5 to 1, at least 2 to 1, at least 5 to 1, or at least 10 to 1, but at most 100 to 1, at most 50 to 1, or at most 20 to 1.

The simultaneous use of a contact pressure and an increased temperature in calendering processes is advantageous since particularly dense solid electrolyte layers form in the nonwoven fabric, which in turn promotes the ionic conductivity of the solid electrolyte. In connection with metallic lithium anodes in particular, the use of a high contact pressure also leads to a reduction in the risk of dendrite formation in the separator layer due to the reduction in porosity.

The pressing and/or calendering of the separator layer before coating with the cathode layer and/or the anode layer preferably takes place at a temperature of at least 50° C., at least 100° C., at least 150° C., at least 200° C., or at least 250° C instead of. Depending on the fleece material selected, the separator layer is pressed and/or calendered before it is coated with the cathode layer and/or the anode layer at a temperature of no more than 400 °C, no more than 350 °C, no more than 300 °C, no more than 250 °C, no more 200 °C, or at most 150 °C.

examples

non-woven material

The fleece material used for the separator layer was on the one hand a PET and on the other hand a material with a core of polyester, coated with polybutylene terephthalate (PBT). The tensile strength (approx. 13 N / 5 cm across) was sufficient for a roll-to-roll coating. The material is electrochemically stable and thermally stable up to 250 °C (PET) or 210 °C (PBT). The porosity is over 65%. The thickness was about 18 μm, the compressibility of which makes it difficult to determine the thickness of the nonwoven.

Production of a separator layer

A non-woven fabric was infiltrated with a solid electrolyte paste to produce a separator layer. The nonwoven, here referred to as "Generation 1", was a wet nonwoven in which the Fibers have a core-sheath structure, with PET as the core and PBT as the sheath material. The porosity was between about 65% and 70%. The thickness was about 18 μm with a weight of 10 g/m ² .

The paste was produced in a glove box under an argon atmosphere (H2O <1 ppm, O2 <1 ppm): The sulfide solid electrolyte LiePSsCI (Argyrodit, "LPSCI", NEI Corporation) was introduced and mixed with a 12% by weight NBR binder solution in toluene . The solid electrolyte binder ratio corresponded to 100:1 (mass fraction). Additional toluene was added to adjust the solid/liquid ratio to 50:50 (wt%). The resulting paste was homogenized in a speed mixer (DAC 150.1 FVZ-K) at 3000 rpm for 10 minutes.

The paste produced was introduced into the fleece on both sides using a doctor blade method. For this purpose, the fleece was attached to an aluminum foil. The squeegee height and squeegee speed were 20 μm and 10 mm/s, respectively, in order to ensure a small separator thickness. The squeegee moved during the application of solid electrolyte paste on the upper side as well as on the underside of the non-woven fabric. After drying the top at room temperature, a solid electrolyte paste was applied to the bottom with a doctor blade process. The resulting separator layer was dried at room temperature in the glove box overnight (FIG. 1).

To measure the ion conduction, the filled non-woven fabric was placed between two aluminum foils and the ion conductivity was determined using electrochemical impedance spectroscopy. The complex impedance was measured on a Zennium X potentiostat from Zahner in the frequency range from 8 MHz to 100 Hz. The resulting impedance spectrum can be modeled using an equivalent circuit diagram of a series circuit made up of an ohmic resistor R1, a parallel circuit made up of an ohmic resistor R2 and a constant-phase element CPE1 and a further constant-phase element CPE2. The ionic conductivity is then determined from the resistance, which results from the sum of R1+R2, and the geometric parameters. A considerable increase in conductivity was achieved by pressing at 510 MPa (FIG. 2) and in particular by pressing at elevated temperature. Table 1 shows the results of the conductivity measurements, which are also shown in FIG.

Table 1: Conductivity measurements

The values show that a higher pressing temperature enables a significant increase in conductivity. A conventional LPSCI pellet achieves a conductivity of about 5.3*10 ^-4 S/cm without a binder and about 4.0*10' ⁴ S/cm with a binder.

By pressing at temperatures higher than the glass transition temperature of the fleece, better conductivities can be achieved because the fleece becomes "softer". In this example, the glass transition temperature of the PBT is about 50°C and that of the PET is about 70°C. Accordingly, such an effect would already be noticeable at temperatures above 50 °C, and more pronounced at temperatures above 70 °C. These values can be higher for plastics with higher glass temperatures, e.g. 80 °C and 100 °C.

8.3*10 ^-5 S/cm (at 510 MPa, 25 °C, thickness approx. 35 μm) was achieved with the “Generation 2” nonwoven (tendency: more porous than “Generation 1”). This non-woven fabric is thinner (thickness 15 μm; weight 7 g/m ² ), has higher air permeability (635 liters/(m ² *s) compared to 347 liters/(m ² *s) for generation 1) and therefore a higher proportion at z pores.

Production of electrodes on the separator layer

Production of the cathode paste

In order to form suitable interfaces between solid electrolyte and cathode material, the composite material LiNio,eMno,2Coo,202 (MSE Supplies, particle size D50 from 3 to 6 pm) was ground with the solid electrolyte LiePSsCI, 70:30 (wt.%) in a ball mill. The NMC/LPSCI powder was initially charged with a 12% by weight NBR binder solution (2-butanone solvent) and conductive carbon black in a mass ratio of 65:27:2:6 and dispersed in 2-butanone.

Application of the cathode layer

The resulting cathode paste was squeegeed onto the separator layer. The wet film thickness was adjusted to 160 μm. The dried cathode layers were about 65 μm thick. Disks with a diameter of 10 mm were punched out of the obtained bilayer of separator layer and cathode layer and covered with an aluminum foil (thickness of 15 pm and a diameter of 10 mm) as a cathode conductor at 520 MPa at room temperature. The compression reduces the thickness of the cathode layer to approx. 45 μm.

Better ionic conductivities and lower-impedance interfaces between solid electrolyte and cathodic active material within the cathode layer and between the separator layer and the cathode layer and between aluminum and the cathode were achieved by hot pressing at 100 °C. Thicknesses of 30 to 170 μm were achieved for the separator layer and thicknesses of about 40 μm for the cathode layer.

Application of the anode layer

Indium anodes (HMW Hauner, thickness 0.1 mm, diameter 9 mm) were applied with a pressure of 25 MPa to characterize the bilayer. These indium foils function both as an anode layer and as a metal conductor. The layered composite was installed in button cells (CR1220 and CR2032).

cycling of cells

The cells were cycled on a Neware CT-4008 in a voltage window of 2.0 to 3.8 V. The formation cycle, which can be seen in the measurement data, took place at a charge/discharge rate of C/10. The cells showed discharge capacities of 0.57 mAh, which corresponds to a specific capacity of the NMC of about 140 mAh/g (based on the mass of the NMC) and an area-specific capacity of 0.72 mAh cm ^-2 (FIG. 4).

viscosity measurement

The viscosity is essential for the processing of the solid electrolyte pastes. FIG. 5 shows the viscosity of the separator paste produced in this example as a function of the rotational frequency of the rotating body or the shear rate, measured using a Visco QC300-L rotational viscometer from Anton Paar.

Claims

Expectations

1. A method of manufacturing a solid state battery, comprising the steps

- providing a separator layer, comprising a nonwoven material and a solid ion conductor, wherein the provision of a separator layer comprises in particular the provision of a nonwoven fabric and the infiltration of the nonwoven fabric with a solid electrolyte paste,

- Coating of the separator layer with a cathode layer and an anode layer, preferably followed by pressing or calendering the coated separator layer, in particular in a roll-to-roll process, the nonwoven material having z through pores, ie pores in the z direction Have interruptions by fibers, or pores that penetrate the fleece material essentially perpendicular to the separator layer, in the z-direction, the pore density being at least 1000 mm ^-2 , more preferably at least 10000 mm ^-2 , and/or the fibers of the fleece material have an average titer of 0.06 dtex to 3.3 dtex.

2. Solid state battery, comprising

- a separator layer comprising a fleece material and a solid ion conductor,

- A cathode layer and an anode layer, wherein the fleece material has z-through pores, ie pores that have no interruptions by fibers in the z-direction, or pores that penetrate the fleece material essentially perpendicular to the separator layer, in the z-direction, wherein the pore density is at least 1000 mm ^-2 , more preferably at least 10000 mm ^-2 , and/or the fibers of the fleece material have an average titer of 0.06 dtex to 3.3 dtex.

3. The method of claim 1, comprising the steps of

- coating the cathode layer with a cathode conductor, and/or coating the anode layer with an anode conductor, the coating of the cathode layer with a cathode conductor and/or the coating of the anode layer with an anode conductor

27 preferably done by a thin-film process, particularly preferably by a vapor deposition process, or

Solid state battery according to claim 2, comprising a cathode conductor and/or an anode conductor. Method according to claim 1 or 3, or solid-state battery according to claim 2 or 3, wherein the solid ion conductor is an inorganic ion conductor, wherein the solid ion conductor comprises in particular sulfides and/or thiophosphates, the solid ion conductor in particular being in the form of sulfide particles , with particle sizes D50 of less than 2 pm, less than 1 pm, preferably less than 500 nm, less than 200 nm, or less than 100 nm, based on the mass distribution and the diameter of the sulfide particles. Method according to claim 1, 3 or 4, or solid-state battery according to one of claims 2 to 4, wherein the cathode conductor and/or the anode conductor has a layer thickness of not more than 5.0 μm, preferably not more than 3.0 μm. Method according to one of claims 1 and 3 to 5, or solid-state battery according to one of claims 2 to 5, wherein the fleece material is selected from the list of polyacrylonitrile, polyimide, polyamide, in particular polyamide 6 and polyamide 6.6, aramide, in particular polyparaphenylene terephthalamide ( PPTA), polyvinyl alcohol, polyester, in particular polyethylene terephthalate and/or polybutylene terephthalate, copolyester, polyolefins, in particular polyethylene and/or polypropylene and/or mixtures thereof, viscose, cellulose and Al2O3. The method according to any one of claims 1 and 3 to 6, or solid-state battery according to any one of claims 2 to 6, wherein the fleece material has one or more of the following properties before application of the solid ion conductor or the solid electrolyte paste:

- an air permeability, measured according to EN ISO 9237, from 300 l rrr ² s ^-1 to 1000 l rrr ² s'1, preferably from 400 l rrr ² s ^-1 to 1000 l rrr ² s ^-1 , in particular from 450 l rrr ² s ^-1 to 850 I rrr ² s ^-1 ,

- an average porosity of at least 30%, more preferably at least 50%, even more preferably at least 70%, most preferably at least 85%,

- Mean pore sizes, measured according to DIN ISO 4003, from 1 pm to 100 pm, 3 pm to 90 pm, 5 pm to 85 pm, 10 pm to 80 pm, or 20 pm to 75 pm. Method according to one of claims 1 and 3 to 7, or solid-state battery according to one of

Claims 2 to 7, wherein the separator layer has a thickness of not more than 50 μm, in particular not more than 40 μm, not more than 30 μm, not more than 20 μm, not more than 15 μm, or not more than 10 μm, measured according to test specification DIN EN ISO 9073-2,

- the cathode layer has a thickness of not more than 50 μm, not more than 40 μm, not more than 30 μm, in particular not more than 25 μm or not more than 20 μm,

- wherein the thickness of the anode layer is selected as a function of the material of the anode layer and the thickness of the cathode layer, and/or

- the layered composite of separator layer, anode layer with anode collector and cathode layer with cathode collector has a thickness of not more than 100 μm, in particular not more than 90 μm or not more than 80 μm. Method according to one of Claims 1 and 3 to 8, or solid-state battery according to one of Claims 2 to 8, in which the anode layer comprises anodic active material, in which case the anodic active material is selected from the list of amorphous carbon, e.g. carbon black (CB), acetylene black (AB), furnace black (FB), and ketjen black (KB), graphene, graphite, TiÜ2, Li4Ti50i2, carbon-tin (C-Sn) composites, tin alloys, carbon-silicon (C-Si) -Composites, SiO _n -based composites, silicon alloys, lithium metal, and lithium alloys. Method according to one of claims 1 and 3 to 9, or solid state battery according to one of claims 2 to 9, wherein the cathode comprises cathodic active material, wherein the cathodic active material is selected from the list of layered oxides based on nickel-manganese-cobalt Oxide (LiNi _x Mn _y Co _z O2, where x + y + z = 1, preferably x > 0.5), e.g. LiNio,sMno,iCoo,i02), lithium nickel cobalt aluminum oxide (LiNi _x Co _y Al _z O2, where x + y + z = 1), e.g. LiNio,84Coo,i2Alo,o402, lithium-rich layered oxides (Lii _+x Mi. _x O2), e.g. Lii,2Nio,2Mno,e02), high-voltage oxides from Spinel type (LiMn2- _x M _x O4, where M is a transition metal), eg LiNio,5Mni,sO2, Olivine (UMPO4, eg LiFePO4), TiS2, LiTiS2, U2S. Method according to one of claims 1 and 3 to 10, or solid-state battery according to one of claims 2 to 10, wherein the separator layer has a maximum tensile force transverse to the machine direction, measured according to DIN EN 29073-3 (1992-08), of 5 N / 5 cm to 50 N/5 cm, more preferably from 5 N/5 cm to 40 N/5 cm, in particular from 7 N/5 cm to 40 N/5 cm, wherein the separator layer has an elongation in the machine direction, measured according to DIN EN 29073-3 (1992-08), from 5% to 50%, preferably from 6% to 30%, in particular from 8% to 20%, and/or wherein the With a square area, the separator layer has an area shrinkage up to 200° C. of 0.01 area% to 10.0 area%, preferably of 0.01 area% to 2.0 area%, more preferably of 0.1 area% to 2.0 Area%. The method according to any one of claims 1 and 3 to 11, wherein the provision of the separator layer comprises the following steps:

- Drying of the filled fleece material. The method according to any one of claims 1 and 3 to 11, wherein the provision of the separator layer comprises the following steps:

- infiltrating the fleece material with the solid ion conductor, in particular in the form of a paste, slip or slurry, containing the solid ion conductor in particle form,

- Drying of the filled fleece material, and

- pressing and/or calendering before coating with the cathode layer and/or the anode layer. The method of claim 13, wherein the pressing and / or calendering of the separator layer before coating with the cathode layer and / or the anode layer at a temperature of at least 50 ° C, at least 100 ° C, at least 150 ° C, at least 200 ° C, or at least 250 °C takes place. The method according to claim 13 or claim 14, wherein after the coating of the separator layer with a cathode layer and an anode layer, the coated separator layer is pressed or calendered, the contact pressure or the contact force being lower than the contact pressure or the contact force during the compression and/or calendering the coating with the cathode layer and/or the anode layer. Solid state battery according to at least one of claims 2 to 11, wherein the fleece material comprises one or more fibers, wherein the one or more fibers comprise a high-melting core and a low-melting shell. Solid-state battery according to one of Claims 2 to 11 and 16, which can be produced or produced by a method according to one of Claims 1 and 3 to 15.

31