DE102015109991A1 - Electrical storage system with disc-shaped discrete element, process for its manufacture and its use - Google Patents

Abstract

The invention comprises an electrical storage system with a thickness of less than 2 mm, including at least one disk-shaped discrete element, characterized in that the element has a thickness variation of not greater than 25 .mu.m, preferably not greater than 15 .mu.m, particularly preferably not greater than 10 .mu.m and most preferably not greater than 5 microns, based on the wafer or substrate sizes in the range of> 100 mm diameter, in particular at a lateral dimension of 100 mm x 100 mm, preferably based on the wafer or substrate sizes in Range> 200 mm in diameter, in particular with a lateral dimension of 200 mm x 200 mm and particularly preferably based on the wafer or substrate sizes in the range> 400 mm diameter, in particular with a lateral dimension of 400 mm x 400 mm.

Description

Electrical storage systems have long been prior art and include in particular batteries, but also so-called supercaps. Due to the high energy density that can be achieved with them, especially so-called lithium-ion batteries are discussed in the field of novel applications such as electromobility, but have also been used for some years in portable devices such as smartphones or laptops. These conventional rechargeable lithium-ion batteries are characterized in particular by the use of organic, solvent-based liquid electrolytes. However, these are flammable and lead to safety concerns regarding the use of said lithium-ion batteries. One way to avoid organic electrolytes is to use solid-state electrolytes. The conductivity of such a solid electrolyte is usually clear, i. several orders of magnitude lower than that of a corresponding liquid electrolyte. In order to still obtain acceptable conductivities and to be able to use the advantages of a rechargeable lithium-ion battery, such solid-state batteries are nowadays produced in particular in the form of so-called thin-film batteries (TFB) or thin-film memory elements. These are used in particular in mobile applications, for example in so-called smart cards, in medical technology and sensor technology, as well as smartphones and other applications which require smart, miniaturized and possibly even flexible energy sources.

An exemplary lithium-based thin film memory element is disclosed in U.S.P. US 2008/0001577 described and usually consists of a substrate to which the electronically conductive arrester for the two electrodes are coated in a first coating step. In the further manufacturing process, the cathode material is then first deposited on the arrester for the cathode, generally lithium-cobalt oxide LCO. In the next step, the deposition of a solid electrolyte, which is usually an amorphous material made of the substances lithium, oxygen, nitrogen and phosphorus takes place and which is referred to as LiPON. In the next step, an anode material is deposited in such a way that it is in connection with the substrate, the arrester for the anode and the solid electrolyte. The anode material used is in particular metallic lithium. If the two arresters are electrically conductively connected, lithium ions migrate in the charged state through the solid-state ion conductor from the anode to the cathode, which results in a current flow from the cathode to the anode due to the electrically conductive connection of the two arresters. Conversely, in the uncharged state, the application of an external voltage can force the migration of the ions from the cathode to the anode, thereby charging the battery.

Another thin film memory element is exemplified in the US 2001/0032666 A1 and also includes a substrate on which various functional layers are deposited.

The deposited for such a thin-film memory element layers usually have layer thicknesses in the range of 20 microns or less, typically less than 10 microns or even less than 5 microns; as the total thickness of the layer structure can be assumed 100 microns or smaller.

For the purposes of this application, the term thin-film memory elements is understood as meaning, for example, rechargeable lithium-based thin-film memory elements and supercaps; however, the invention is not limited to these systems but may also be used in other thin film memory elements, e.g. rechargeable and / or printed thin film cells are used.

The production of a Dünnschichtspeicherlements usually takes place via complex coating processes, which also include the structured deposition of the individual materials. In this case, extremely complicated structuring of the precise thin-film memory elements are possible, as exemplified by the US 7494742 B2 can be removed. Special difficulties also arise in lithium-based thin film memory elements through the use of metallic lithium as the anode material due to its high reactivity. Thus, the handling of metallic lithium under conditions as anhydrous as possible, since it reacts otherwise to lithium hydroxide and its function as an anode is no longer present. Also, a lithium-based thin film memory element must be protected accordingly with a moisture encapsulation.

The US 7494742 B2 describes such encapsulation for the protection of non-stable constituents of a thin film memory element, such as lithium or certain lithium compounds. The encapsulation function is exercised by a coating or a system of different coatings, which can fulfill other functions within the overall structure of the battery.

In addition it comes, as for example in the writing US 2010/0104942 described under the manufacturing conditions of a lithium-based thin-film memory element, in particular in so-called Annealing- or Temperschritten, which is necessary for the formation of lithium intercalation suitable crystal structures, for an undesirable side reaction of the mobile lithium ions with the substrate, since the lithium has high mobility and can easily diffuse into common substrate materials.

Another problem with thin-film memory elements is the substrate materials used. The prior art describes a variety of different substrate materials such as silicon, mica, various metals and ceramic materials. The use of glass, but essentially without further details of the specific composition or exact properties, is often mentioned.

The US 2001/0032666 A1 describes a capacitor-like energy storage, which may also be a lithium-ion battery. As substrate materials are mentioned here among other semiconductors.

The US 6906436 B2 describes a solid-state battery in which, for example, metal foils, semiconductor materials or plastic films can be used as substrate materials.

The US 6906436 B2 describes as a possible substrate materials a variety of possibilities, for example metals or metal coatings, semiconducting materials or insulators such as sapphire, ceramics or plastics. Different geometries of the substrate are possible.

The US 7494742 B2 describes as substrate materials, inter alia, metals, semiconductors, silicates and glass as well as inorganic or organic polymers.

The US 7211351 B2 names as substrates metals, semiconductors or insulating materials as well as combinations thereof.

The US 2008/0001577 A1 calls as substrates semiconductors, metals or plastic films.

The EP 2434567 A2 mentions as substrates electrically conductive materials such as metals, insulating materials such as ceramics or plastics and semiconducting materials such as silicon as well as combinations of semiconductors and conductors or more complex structures for adjusting the thermal expansion coefficient. These or similar materials are also in the scriptures US 2008/0032236 A1 . US 8228023 B2 such as US 2010/0104942 A1 called.

In contrast, the substrate materials relevant in practice only describe substrates of metals or metal alloys having a high melting point and dielectric materials such as high quartz, silicon wafers, aluminum oxide and the like. This is due to the fact that for the production of a cathode from the lithium-cobalt oxide (LCO) usually used, a temperature treatment at temperatures of more than 400 ° C, quite well more than 500 ° C and greater is required to a for the storage of Li ⁺ ions in this material to obtain particularly favorable crystal structure, so that materials such as polymers or inorganic materials with low softening temperatures can not be used. However, both metals and dielectrics have various difficulties. For example, dielectric materials are typically brittle and can not be used in low-cost roll-ro-roll processes, while metals or metal alloys tend to be damaged during high temperature treatment of the cathode material to oxidize. To circumvent these difficulties, is in the US 2010/0104942 A1 proposed a substrate made of different metals or silicon, wherein the redox potentials of the combined materials are coordinated so that it comes to a controlled oxide formation.

In many places, a circumvention of, for example, the above mentioned is also discussed US 2010/0104942 A1 demanded high temperature resistance of the substrate. For example, by adapting the process conditions, substrates with temperature ratings of 450 ° C or below can be used. Prerequisites for this, however, are deposition methods in which there is heating of the substrate and / or optimization of the sputtering gas mixture of O ₂ and Ar and / or the application of a bias voltage and / or the application of a second sputtering plasma and the vicinity the substrate comes. For this information can be found for example in the US 2014/0030449 A1 , in Tintignac et al., Journal pf Power Sources 245 (2014), 76-82 , or even in Ensling, D., Photoelectronic investigation of electronic structure of thin lithium cobalt oxide layers, dissertation, Technische Universität Darmstadt 2006 , In general, however, such procedural adjustments are expensive and, depending on the processing, in particular if the continuous coating of wafers is to take place, can hardly be implemented cost-acceptably.

The US 2012/0040211 A1 describes as a substrate a glass film which is at most 300 μm thick and has a surface roughness of not larger than 100 Å. This low surface roughness is needed because the layers of a thin film memory element usually have very small layer thicknesses. In this case, even small unevenness of the surfaces can lead to a critical disturbance of the functional layers of the thin-film memory element and thus to the failure of the battery as a whole.

Problems of conventional thin-film memory elements thus consist in summary of the susceptibility to corrosion of the materials used, especially when it comes to the use of metallic lithium, which has complicated layer structures result and thus high costs, and the nature of the substrate, in particular non-conductive, but flexible, high temperature resistant and should be as inert as possible to the functional layers of the storage element used and should enable the deposition of as error-free as possible layers with good layer adhesion to the substrate. This shows, however, that even with substrates having a particularly low surface roughness, such as in the US 2012/0040211 A1 proposed glass film, layer failure due to cracks and / or delamination of the layers occurs, as for example in the US 2014/0030449 A1 are described. The method proposed therein to avoid high annealing temperatures by applying a bias voltage in the production of the lithium-cobalt-oxide layer is, as already described above, however, in the usual inline processes for the production of Thin-film memory elements are difficult to integrate, so that it is more favorable from a process engineering point of view to use a substrate with a correspondingly high temperature resistance.

Another difficulty faced by all substrate materials, regardless of their exact composition, is one of the possible handling solutions of ultra-thin glass. The so-called carrier solution is to temporarily fix ultra-thin glass on a substrate before or during the coating process or the transfer process steps. This can be done either with electrostatic forces or by using an organic releasable adhesive. In particular, in the latter case must be ensured by a suitable choice of the substrate or the carrier, which are usually made of the same material, that the debonding, ie the detachment of the substrate from the carrier, is possible. The debonding often leads to the occurrence of torsional stresses in the substrate, whereby these stresses can also be transferred to the layers located on the substrate, which likewise results in cracks and delamination of the layers, as a consequence of which the layer defects caused by thickness variations of the substrate even further reinforce.

Some processing steps in the production of thin-film electrical storage elements can in principle also be done by using energy-rich optical energy sources such as excimer lasers. In order to enable all processing options here, for example for laser cutting of wafers or curing of organic adhesive materials by UV sources, a specifically modifiable UV transmission of a substrate material is advantageous.

The object of the invention comprises the provision of an electrical storage system which includes a disk-shaped discrete element, the disk-shaped discrete element and its manufacture and use.

It is a further object of the present invention to provide an electrical storage element, particularly a thin film memory element, which mitigates the shortcomings of the current state of the art and enables low cost production of thin film memory elements. A further object of the invention comprises the provision of a disk-shaped element for use in an electrical storage element as well as its production and use.

The disk-shaped discrete element is intended to mitigate the deficiencies of the prior art and to have sufficient thermal stability of> 400 ° C, coupled with sufficient stability against contamination by battery components, a high barrier to moisture, and the manufacturing processes and needs of the particular cell designs adapted optical transmissivity or blocking against UV radiation. The substrate must also contribute to good adhesion of applied layers, i. in particular a suitable coefficient of expansion with regard to the deposition of the closest layer, as a rule the LCO.

The object according to the invention can be achieved surprisingly simply by inserting into a thin-film memory element a disc-shaped discrete element which has a total thickness variation (ttv) in the range of <25 μm, preferably <15 μm, particularly preferably <10 microns and most preferably of <5 microns based on the used wafer or substrate size, based on the wafer or substrate sizes in the range of> 100 mm diameter, in particular at a lateral dimension of 100 mm x 100 mm, preferably based on the wafer or substrate sizes in the range> 200 mm diameter, in particular with a lateral dimension of 200 mm × 200 mm and particularly preferably based on the wafer or substrate sizes in the range> 400 mm diameter, in particular with a lateral dimension of 400 mm x 400 mm.

In the context of this application, a disc-shaped is understood to be a shaped body in which the extent of the element in a spatial direction is smaller by at least half an order of magnitude than in the other two spatial directions. As a discrete form of a body is understood in the context of this application, if it is as such separable from the considered electrical storage system, i. in particular may be alone.

The large uniformity of the thickness distribution of the disk-shaped discrete element is essential for maintaining comparable quality from cell to cell. Thin-film batteries are usually manufactured at wafer level with or without masking and then cut out. With insufficient thickness constancy, cells on a wafer, or at any rate from wafer to wafer, may have different thicknesses and thus specifications, e.g. with regard to weight / energy density. This is particularly disadvantageous if the application requires an extremely homogeneous consistency of the product specifications of the electrical storage element. Due to a low total thickness variance, costs can be saved in the quality inspection or production scrap can be avoided.

The large uniformity of the thickness distribution of the disk-shaped discrete element in its use as a substrate for the deposition of a thin-film memory element beyond the consequence that the layers are deposited thereon also level and without a lateral variation of the layer thickness distribution. This in turn means that in subsequent process steps, for example, the annealing of the LCO layer after deposition, not to local stresses in the individual layers themselves or between the individual layers at the respective interfaces, especially not at the interfaces between layer and Substrate can come. In this way, cracks and detachments are efficiently avoided.

It has been found that the failure of layers, which is particularly the occurrence of cracks in the layer or in the separation of the layers from the substrate, less by the presence of surface irregularities of the substrate, but rather by a combination of thickness variations of the substrate and caused by forces that are transferred to the substrate during the detachment of the substrate from the so-called carrier.

In addition, it proves to be further advantageous if the disc-shaped, discrete element is selectively adjustable in terms of its properties in the UV range, ie the absorption or transmission, depending on the exact selected compositions

• – Unterstützung beim Debonding des Substrats vom Carrier, da auf diese Weise die organischen Haftschichten besonders wirkungsvoll gelöst werden können,
• – Aushärtung von Verkapselungsschichten zum Schutz des Speicherelements gegenüber dem Angriff korrosiver Medien, beispielsweise Sauerstoff und / oder Wasserdampf, beschrieben beispielsweise in der DE 10 2012 206 273 A1 , sowie
• – Annealing der Lithium-Cobalt-Oxid-Schicht durch hochenergetische Strahlung, um die gewünschte kristallographische Hochtemperaturphase mit dessen hoher spezifischer Speicherdichte möglichst quantitativ bereitzustellen.

This targeted transmission makes it possible to perform a series of process steps simply by treatment with electromagnetic radiation, for example

• Support in debonding the substrate from the carrier, since in this way the organic adhesive layers can be solved particularly effectively,
• Curing of encapsulation layers to protect the storage element against the attack of corrosive media, for example oxygen and / or water vapor, described for example in US Pat DE 10 2012 206 273 A1 , such as
• Annealing of the lithium-cobalt-oxide layer by high-energy radiation in order to provide the desired crystallographic high-temperature phase with its high specific storage density as quantitatively as possible.

The disk-shaped discrete element according to the invention has a thickness not greater than 2 mm, preferably less than 1 mm, particularly preferably less than 500 μm and very particularly preferably less than or equal to 200 μm. Most preferred is a substrate thickness of at most 100 microns.

In one embodiment of the invention, the disc-shaped discrete element has a water vapor transmission rate (WVTR) of <10 ^-3 g / (m ² · d), preferably <10 ^-5 g / (m ² · d), and more preferably of <10 ^-6 g / (m ² · d).

In another embodiment, the disk-shaped discrete element has an electrical resistivity at a temperature of 350 ° C and an alternating current having a frequency of 50 Hz of greater than 1.0 x 10 ⁶ ohm cm.

The disk-shaped discrete element is further characterized by a maximum temperature resistance of at least 300 ° C., preferably of at least 400 ° C., particularly preferably of at least 500 ° C., and by a linear thermal expansion coefficient α in the range of 2.0 × 10 ^-6 / K to 10 x 10 ^-6 / K, preferably from 2.5 10 ^-6 / K to 9.5 10 ^-6 / K and particularly preferably from 3.0 × 10 ^-6 / K to 9.5 · 10 ^-6 / K. It has been shown that particularly good layer qualities can be achieved in a thin-film memory element if the following relationship exists between the maximum load temperature θ _Max in ° C and the linear thermal expansion coefficient α: 600 × 10 ^-6 ≦ θ _Max × α ≦ 8000 × 10 ^-6 , particularly preferably 800 × 10 ^-6 ≦ θ _Max × α ≦ 5000 × 10 ^-6

Within the scope of this application, the maximum load temperature θ _Max is a temperature at which the dimensional stability of the material is still fully guaranteed and has not yet used any decomposition and / or degradation reactions of the material. Naturally, this temperature is defined differently depending on the material used. For oxide crystalline materials, the maximum load temperature is usually given by the melting temperature; For glasses, the glass transition temperature T _g is usually assumed, with organic glasses, the decomposition temperature may be below T _g , and for metals or metal alloys, the maximum load temperature can be approximately indicated by the melting temperature, unless the metal or the Metal alloy reacts below the melting temperature in a degradation reaction.

In a further embodiment, the disk-shaped discrete element has on at least one side a surface which is designed such that it is inert and / or impermeable to materials applied to this surface.

In a further embodiment, this at least one surface is designed as a barrier layer with respect to the diffusion of metals.

In a further embodiment, this at least one surface is formed as a barrier layer against alkali and / or alkaline earth metal ions.

Preferably, this metal is lithium.

In a preferred embodiment of the invention, the vertically structured composition variation is produced by a coating of the disc-shaped element, preferably by a plasma-assisted coating method.

In a further embodiment of the invention, the coating method used is a PECVD method, atomic layer deposition (ALD) or pulsed magnetron sputtering.

The barrier layer is according to a further embodiment of the invention, which is preferably deposited with one of the abovementioned coating methods, is characterized in that it is amorphous, at least X-ray amorphous.

According to a further preferred embodiment of the invention, the coating is an oxide, nitride and / or carbide and furthermore contains at least one of the elements Si, Al, Cr, Ta, Zr, Hf and / or Ti.

In a further embodiment, this barrier layer formed on at least one surface of the disk-shaped element is formed by doping or overdoping with an alkali and / or alkaline earth metal such as, for example, lithium. It turns out that even low levels of lithium prevent or reduce the diffusion of this element from the layer materials of the electrical storage element, such as LiPON or metallic lithium, for example.

In a further embodiment, the barrier layer is formed by a vertically structured compositional variation of the surface such that no direct diffusion paths into the bulk are possible.

In another embodiment, atoms are present in the vertically structured surface zone that effectively gasses harmful metals.

In a further embodiment, the vertically structured composition variation of the surface is formed by a succession of layers, wherein at least two meeting layers differ in their composition and the composition of the layers and the disc-shaped element differ from one another.

In a preferred embodiment of the invention, the vertically structured composition variation is produced by a coating of the disc-shaped element, preferably by a plasma-assisted coating method.

In a further embodiment of the invention, the coating method used is a PICVD method, atomic layer deposition (ALD) or MF sputtering.

The disk-shaped element according to the invention is composed of at least one oxide or a mixture or compound of oxides.

In a further embodiment of the invention, this at least one oxide is SiO ₂ .

In a further embodiment of the invention, the disk-shaped element is made of glass. For the purposes of this application, the term "glass" refers to a material which is of essentially inorganic structure and consists predominantly of compounds of metals and / or semimetals with elements of groups VA, VIA and VIIA of the Periodic Table of the Elements, but preferably with oxygen characterized by an amorphous, ie not periodically ordered three-dimensional state and a specific electrical resistance at a temperature of 350 ° C and an alternating current having a frequency of 50 Hz of greater than 1.0 · 10 ⁶ Ohmcm. Not as a glass in the sense of this application is thus in particular the amorphous material LiPON used as a solid-state ion conductor.

The disc-shaped element according to the invention is obtained according to a further embodiment of the invention by a melting process.

Preferably, the disk-shaped element is disc-shaped in a shaping process subsequent to the melting process. This shaping can be followed directly by the melt (so-called hot forming). However, it is also possible for a solid, essentially unshaped body to be obtained first, which is converted into a disk-shaped state only in a further step by renewed heating and mechanical deformation.

If the shaping of the disk-shaped element takes place by means of a hot-forming process, in one embodiment of the invention it is a drawing process, for example down-draw, up-draw or overflow-fusion processes. But other hot forming processes are possible, for example, the shaping in a float process.

Examples

The following tables list some exemplary compositions of disk-shaped elements according to the invention.

Embodiment 1

The composition of the disk-shaped discrete element is given by way of example by the following composition in% by weight: SiO ₂ 30 to 85 B ₂ O ₃ 3 to 20 Al ₂ O ₃ 0 to 15 Na ₂ O 3 to 15 K ₂ O 3 to 15 ZnO 0 to 12 TiO ₂ 0.5 to 10 CaO 0 to 0.1

Embodiment 2

The composition of the disc-shaped discrete element is further exemplified by the following composition in% by weight: SiO ₂ 58 to 65 B ₂ O ₃ 6 to 10.5 Al ₂ O ₃ 14 to 25 MgO 0 to 3 CaO 0 to 9 BaO 0 to 8, preferably 3-8 ZnO 0 to 2, with the sum of the content of MgO, CaO and BaO being in the range of 8 to 18 wt.

Embodiment 3

The composition of the disc-shaped discrete element is further exemplified by the following composition in% by weight: SiO ₂ 55 to 75 Na ₂ O 0 to 15 K ₂ O 0 to 14, preferably 2 to 14 Al ₂ O ₃ 0 to 15 MgO 0 to 4 CaO 3 to 12 BaO 0 to 15 ZnO 0 to 5 TiO ₂ 0 to 2

Embodiment 4

The composition of the disc-shaped discrete element is further exemplified by the following composition in% by weight: SiO ₂ 50-66 B ₂ O ₃ 0 to 5.5 Al ₂ O ₃ 13 to 35 MgO 0 to 7 CaO 5 to 14 SrO 0 to 8 BaO 6 to 18 P ₂ O ₅ 0 to 2 ZrO ₂ 0 to 3 TiO ₂ 0 to 5 CeO ₂ 0 to 5 MoO ₃ 0 to 5 Fe ₂ O ₃ 0 to 5 WO ₃ 0 to 5 Bi ₂ O ₃ 0 to 5

Embodiment 5

The composition of the disc-shaped discrete element is further exemplified by the following composition in% by weight: SiO ₂ 50-66 B ₂ O ₃ 0 to less than or equal to 0.5 Al ₂ O ₃ 14 to 35 MgO 0 to 7 CaO 5 to 14 SrO 0 to 8 BaO 6 to 18 P ₂ O ₅ 0 to 2 ZrO ₂ 0 to 3

Embodiment 6

A possible disc-shaped discrete element is further exemplified by the following composition in weight percent: SiO ₂ 61 B ₂ O ₃ 10 Al ₂ O ₃ 18 MgO 2.8 CaO 4.8 BaO 3.3

Embodiment 7

Another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 64.0 B ₂ O ₃ 8.3 Al ₂ O ₃ 4.0 Na ₂ O 6.5 K ₂ O 7.0 ZnO 5.5 TiO ₂ 4.0 Sb ₂ O ₃ 0.6 Cl ^- 0.1

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 7.2 · 10 ^-6 / K T _g 557 ° C density 2.5 g / cm ³

Embodiment 8

Another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 69 +/- 5 Na ₂ O 8 +/- 2 K ₂ O 8 +/- 2 CaO 7 +/- 2 BaO 2 +/- 2 ZnO 4 +/- 2 TiO ₂ 1 +/- 1

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 9.4 · 10 ^-6 / K T _g 533 ° C density 2.55 g / cm ³

Embodiment 9

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 80 +/- 5 B ₂ O ₃ 13 +/- 5 Al ₂ O ₃ 2.5 +/- 2 Na ₂ O 3.5 +/- 2 K ₂ O 1 +/- 1

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 3.25 x 10 ^-6 / K T _g 525 ° C density 2.2 g / cm ³

Embodiment 10

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 62.3 Al ₂ O ₃ 16.7 Na ₂ O 11.8 K ₂ O 3.8 MgO 3.7 ZrO ₂ 0.1 CeO ₂ 0.1 TiO ₂ 0.8 As ₂ O ₃ 0.7

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 8.6 · 10 ^-6 / K T _g 607 ° C density 2.4 g / cm ³

Embodiment 11

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 62.2 Al ₂ O ₃ 18.1 B ₂ O ₃ 0.2 P ₂ O ₅ 0.1 Li ₂ O 5.2 Na ₂ O 9.7 K ₂ O 0.1 CaO 0.6 SrO 0.1 ZnO 0.1 ZrO ₂ 3.6

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 8.5 · 10 ^-6 / K T _g 505 ° C density 2.5 g / cm ³

Embodiment 12

Another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 52 Al ₂ O ₃ 17 Na ₂ O 12 K ₂ O 4 MgO 4 CaO 6 ZnO 3.5 ZrO ₂ 1.5

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 9.7 · 10 ^-6 / K T _g 556 ° C density 2.6 g / cm ³

Embodiment 13

A further disc-shaped discrete element is given by way of example by the following composition in% by weight: SiO ₂ 62 Al ₂ O ₃ 17 Na ₂ O 13 K ₂ O 3.5 MgO 3.5 CaO 0.3 SnO2 0.1 TiO ₂ 0.6

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 8.3 x 10 ^-6 / KT _g 623 ° C density 2.4 g / cm ³

Embodiment 14

Another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 61.1 Al ₂ O ₃ 19.6 B ₂ O ₃ 4.5 Na ₂ O 12.1 K ₂ O 0.9 MgO 1.2 CaO 0.1 SnO2 0.2 CeO ₂ 0.3

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 8.9 x 10 ^-6 / K T _g 600 ° C density 2.4 g / cm ³

Embodiment 15

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 50 to 65 Al ₂ O ₃ 15 to 20 B ₂ O ₃ 0 to 6 Li ₂ O 0 to 6 Na ₂ O 8 to 15 K ₂ O 0 to 5 MgO 0 to 5 CaO 0 to 7, preferably 0 to 1 ZnO 0 to 4, preferably 0 to 1 ZrO ₂ 0 to 4 TiO ₂ 0 to 1, preferably substantially TiO ₂ -free

Further, in the glass may be contained at 0 to 1 wt .-%: P ₂ O ₅ , SrO, BaO; and refining agents to 0 to 1 wt .-%: SnO ₂ , CeO ₂ or As ₂ O ₃ or other refining agents.

Embodiment 16

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 58 to 65 B ₂ O ₃ 6 to 10.5 Al ₂ O ₃ 14 to 25 MgO 0 to 5 CaO 0 to 9 BaO 0 to 8 SrO 0 to 8 ZnO 0 to 2

Embodiment 17

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 59.7 Al ₂ O ₃ 17.1 B ₂ O ₃ 7.8 MgO 3.4 CaO 4.2 SrO 7.7 BaO 0.1

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 3.8 · 10 ^-6 / K T _g 719 ° C density 2.51 g / cm ³

Embodiment 18

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 59.6 Al ₂ O ₃ 15.1 B ₂ O ₃ 9.7 CaO 5.4 SrO 6.0 BaO 2.3 ZnO 0.5 Sb ₂ O ₃ 0.4 As ₂ O ₃ 0.7

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 3.8 · 10 ^-6 / K density 2.5 g / cm ³

Embodiment 19

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 58.8 Al ₂ O ₃ 14.6 B ₂ O ₃ 10.3 MgO 1.2 CaO 4.7 SrO 3.8 BaO 5.7 Sb ₂ O ₃ 0.2 As ₂ O ₃ 0.7

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 3.73 x 10 ^-6 / K T _g 705 ° C density 2.49 g / cm ³

Embodiment 20

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 62.5 B ₂ O ₃ 10.3 Al ₂ O ₃ 17.5 MgO 1.4 CaO 7.6 SrO 0.7

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 3.2 ppm / K Density: 2.38 g / cc

Embodiment 21

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 55 to 75 Na ₂ O 0 to 15 K ₂ O 0 to 14 Al ₂ O ₃ 0 to 15 MgO 0 to 4 CaO 3 to 12 BaO 0 to 15 ZnO 0 to 5

Embodiment 22

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 74.3 Na ₂ O 13.2 K ₂ O 0.3 Al ₂ O ₃ 1.3 MgO 0.2 CaO 10.7

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 9.0 ppm / K Tg: 573 ° C

Embodiment 23

Yet another disc-shaped discrete element is exemplified by the following composition in weight percent: SiO ₂ 72.8 Na ₂ O 13.9 K ₂ O 0.1 Al ₂ O ₃ 0.2 MgO 4.0 CaO 9.0

With this composition, the following properties of the disc-shaped discrete element are obtained: α _(20-300) 9.5 ppm / K Tg: 564 ° C Embodiment 24 SiO ₂ 60.7 Al ₂ O ₃ 16.9 Na ₂ O 12.2 K ₂ O 4.1 MgO 3.9 ZrO ₂ 1.5 SnO2 0.4 CeO ₂ 0.3

In all of the abovementioned exemplary embodiments, if not already mentioned, refining agents may optionally contain from 0 to 1% by weight, for example SnO ₂ , CeO ₂ , As ₂ O ₃ , Cl ^- , F ^- , sulfates.

Embodiment 25

In order to obtain a coated disc-shaped discrete element, a substrate material as mentioned in one of the embodiments 1-8 is introduced into a sputtering system and pumped to a pressure of <10 ^ -5 mbar. The substrate is heated to a temperature of at least 200 ° C. The process gas, typically argon, is admitted so that a process pressure of <10 ^ -2 mbar is established. The sputtering system is equipped with Si-containing targets, so that can be deposited using the reactive gas nitrogen, a Si ₃ N ₄ -containing material system. A good barrier can be created by the sputtering method when the power density is over 10W / cm ² . With the mentioned parameters, for example, a layer of 300 nm thickness can be deposited. The thickness of the barrier layers may generally be between 10 nm and 1 μm. Preferred thicknesses of the barrier layer are between 80 and 200 nm and a particularly preferred barrier layer thickness is about 100 nm. Subsequently, the element is discharged.

Description of the drawings

1 shows a schematic representation of an electrical storage system which has at least one disc-shaped discrete element.

2 shows a schematic representation of an inventive disk-shaped discrete element.

In 1 is schematically an electrical storage system 1 shown in accordance with the present invention. It comprises a disc-shaped discrete element 2 , which is used as a substrate. Furthermore, on the substrate 2 a layer may be applied, which is formed as a diffusion barrier to metals, preferably to alkali and / or alkaline earth metals or ions of these metals. Unless a coating 21 is applied, this includes an oxide, nitride and / or carbide and further includes at least one of the elements Si, Al, Cr, Ta, Zr, Hf and / or Ti. On the substrate 2 or the barrier layer 21 Furthermore, a sequence of different layers is applied. By way of example and without limitation to the present example, the discrete element is disc-shaped 2 first the two arrester layers 3 for the cathode and 4 applied to the anode. Such arrester layers are usually a few micrometers thick and consist of a metal, for example of copper, aluminum or titanium. Superimposed on the arrester layer 3 is the cathode layer 5 , As far as the electrical storage system 1 is a lithium-based thin film battery, the cathode is formed of a lithium transition metal compound, preferably an oxide formed, for example, LiCoO ₂ , LiMnO ₂ or LiFePO. ₄ Furthermore, on the substrate and at least partially overlapping with the cathode layer 5 is the electrolyte 6 applied, wherein this electrolyte in the case of the presence of a lithium-based thin-film battery is usually LiPON, a compound as lithium with oxygen, phosphorus and nitrogen. Furthermore, the electrical storage system comprises 1 an anode 7 , Which may be, for example, lithium titanium oxide or to metallic lithium. The anode layer 7 overlaps at least partially with that with the electrolyte layer 6 as well as the arrester layer 4 , Furthermore, the battery includes 1 an encapsulation layer 8th ,

As encapsulation or sealing of the electrical storage system 1 is understood in the context of the present invention, a material which the attack of fluids or other corrosive materials on the electrical storage system 1 prevented or greatly reduced.

2 shows the schematic illustration of a disk-shaped discrete element of the present invention, here formed as a disk-shaped molding 10 , In the context of the present invention, a shaped body is referred to as a disk-shaped or disk when its extent in a spatial direction is at most half as large as in the other two spatial directions. A tape in the present invention is referred to as tape when the following relationship exists between its length, its width and its thickness: its length is at least ten times greater than its width and this in turn is at least twice as large as its thickness. Further, and without limitation of generality, here is exemplified on the disk-shaped discrete element 10 a layer is applied, which is designed as a diffusion barrier to metals, preferably against alkali and / or alkaline earth metals or ions of these metals. The exemplary coating 101 comprises an oxide, nitride and / or carbide and further includes at least one of Si, Al, Cr, Ta, Zr, Hf and / or Ti.

LIST OF REFERENCE NUMBERS

1

 electrical storage system

2

 disc-shaped discrete element in use as a substrate

21

 layer formed as a diffusion barrier on the substrate

3

 Conductor layer for the cathode

4

 Ableitschicht for the anode

5

 cathode

6

 electrolyte

7

 anode

8th

 encapsulation

10

 disk-shaped discrete element as disk-shaped molding

101

 layer formed as a diffusion barrier on the disc-shaped discrete element

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.

Cited patent literature

• US 2008/0001577 [0002]
• US 2001/0032666 A1 [0003, 0010]
• US 7494742 B2 [0006, 0007, 0013]
• US 2010/0104942 [0008]
• US 6906436 B2 [0011, 0012]
• US 7211351 B2 [0014]
• US 2008/0001577 A1 [0015]
• EP 2434567 A2 [0016]
• US 2008/0032236 A1 [0016]
• US 8228023 B2 [0016]
• US 2010/0104942 A1 [0016, 0017, 0018]
• US 2014/0030449 A1 [0018, 0020]
• US 2012/0040211 A1 [0019, 0020]
• DE 102012206273 A1 [0032]

Cited non-patent literature

• Tintignac et al., Journal pf Power Sources 245 (2014), 76-82 [0018]
• Ensling, D., Photoelectronic investigation of the electronic structure of thin lithium cobalt oxide layers, dissertation, Technische Universität Darmstadt 2006 [0018]

Claims (46)

Electrical storage system with a thickness of less than 2 mm, comprising at least one disc-shaped discrete element, characterized in that the element has a thickness variation of not greater than 25 microns, preferably not greater than 15 microns, more preferably not greater than 10 microns, and most preferably of not greater than 5 microns, based on the wafer or substrate sizes in the range of> 100 mm diameter, in particular at a lateral dimension of 100 mm x 100 mm, preferably based on the wafer or substrate sizes in the range> 200 mm Diameter, in particular with a lateral dimension of 200 mm × 200 mm and particularly preferably with reference to the wafer or substrate sizes in the range> 400 mm diameter, in particular with a lateral dimension of 400 mm × 400 mm. Electrical storage system according to the preceding claim, characterized in that the at least one disk-shaped discrete element has a water vapor transmission rate (WVTR) of <10 ^-3 g / (m ² · d), preferably of <10 ^-5 g / (m ² · D) and more preferably of <10 ^-6 g / (m ² · d). Electrical storage system according to one of the preceding claims, characterized in that the at least one disk-shaped discrete element has a thickness of less than 2 mm, preferably less than 1 mm, more preferably less than 500 μm, most preferably less than or equal to 200 μm and most preferably not more than 100 μm having. Electrical storage system according to one of the preceding claims, characterized in that the at least one disk-shaped discrete element has a maximum load temperature θ _Max of at least 300 ° C, preferably of at least 400 ° C, more preferably of at least 500 ° C. Electrical storage system according to one of the preceding claims, characterized in that the at least one disc-shaped discrete element has a linear coefficient of thermal expansion α in the range of 2.0 · 10 ^-6 / K to 10 · 10 ^-6 / K, preferably 2.5 10 ^-6 / K to 9.5 10 ^-6 / K, and more preferably from 3.0 x 10 ^-6 / K to 9.5 x 10 ^-6 / K. Electrical storage system according to one of the preceding claims, characterized in that the following relationship applies to the product of maximum load temperature θ _Max and linear thermal expansion coefficient α of the at least one disc-shaped discrete element: 1000 × 10 ^-6 ≦ θ _Max × α ≦ 4600 × 10 ^-6 Electrical storage system according to one of the preceding claims, characterized in that at least one surface of the at least one disc-shaped discrete element is designed such that it is inert and / or impermeable to opposite with this surface material in contact. Electrical storage system according to claim 7, characterized in that the at least one surface is formed as a barrier. Electrical storage system according to claim 8, characterized in that the barrier is designed as a barrier to the diffusion of metals. Electrical storage system according to claim 9, characterized in that the barrier layer is formed as a barrier to the diffusion of alkali and / or alkaline earth metals. Electrical storage system according to claim 10, characterized in that the barrier layer is formed by doping or overdoping with at least one alkali and / or alkaline earth metal. Electrical storage system according to one of claims 7 to 11, characterized in that the barrier layer is achieved by a vertical composition variation of the at least one surface such that there are no direct diffusion paths in the bulk. Electrical storage system according to claim 12, characterized in that in the vertical composition variation of the at least one surface getter materials for alkali and / or alkaline earth metals are included. Electrical storage system according to one of claims 12 and 13, characterized in that the vertical composition variation of the at least one surface is formed by a sequence of at least two layers, wherein adjacent layers each have a different composition. Electrical storage system according to one of claims 12 to 14, characterized in that the vertical composition variation of the at least one surface is obtained by a coating. Electrical storage system according to claim 15, characterized in that the coating is obtained by a plasma-assisted process, preferably by a PICVD process. Electrical storage system according to one of claims 7 to 16, characterized in that the barrier effect of the at least one surface is formed against lithium. Electrical storage system according to one of the preceding claims, characterized in that the at least one disk-shaped discrete element is composed of at least one oxide or of a mixture or compound of a plurality of oxides. Electrical storage system according to one of the preceding claims, characterized in that the at least one disc-shaped discrete element contains SiO ₂ as an oxide. Electrical storage system according to one of the preceding claims, characterized in that the at least one disk-shaped discrete element is present as a glass. Electrical storage system according to claim 20, characterized in that the at least one disc-shaped discrete element is formed disc-shaped by a melting process with subsequent molding process. Electrical storage system according to claim 21, characterized in that it is a drawing process in the subsequent molding process. Disc-shaped discrete element for use in an electrical storage system, characterized in that the element has a thickness variation of not greater than 25 microns, preferably not greater than 15 microns, more preferably not greater than 10 microns, and most preferably not greater than 5 μm, based on the wafer or substrate sizes in the range of> 100 mm diameter, in particular with a lateral dimension of 100 mm × 100 mm, preferably based on the wafer or substrate sizes in the range> 200 mm diameter, in particular at a lateral dimension of 200 mm × 200 mm and particularly preferably based on the wafer or substrate sizes in the range> 400 mm diameter, in particular with a lateral dimension of 400 mm × 400 mm. Disc-shaped discrete element according to claim 23 for use in an electrical storage system, characterized in that the element has a thickness of less than 2 mm, preferably less than 1 mm, more preferably less than 500 μm, most preferably less than or equal to 200 μm, and most preferably has a maximum of 100 microns. Disc-shaped discrete element according to one of the preceding claims 23 or 24 for use in an electrical storage system, characterized by a water vapor transmission rate (WVTR) of <10 ^-3 g / (m ² · d), preferably <10 ^-5 g / (m ² · d) and more preferably <10 ^-6 g / (m ² · d). Disc-shaped discrete element according to one of the preceding claims 23 to 25 for use in an electrical storage system, characterized by a maximum load temperature θ _Max of at least 300 ° C, preferably of at least 400 ° C, particularly preferably of at least 500 ° C. Disc-shaped discrete element according to one of the preceding claims 23 to 26 for use in an electrical storage system, characterized by a linear thermal expansion coefficient α in the range of 2 · 10 ^-6 / K to 10 · 10 ^-6 / K, preferably 2.5 10 ^-6 / K to 9.5 10 ^-6 / K, and more preferably from 3.0 x 10 ^-6 / K to 9.5 x 10 ^-6 / K. Disc-shaped discrete element according to one of the preceding claims 23 to 27 for use in an electrical storage system, characterized by a product of maximum load temperature θ _Max and linear thermal expansion coefficient α, for which the following relationship applies: 1000 × 10 ^-6 ≦ θ _Max × α ≦ 4600 × 10 ^-6 Disc-shaped discrete element according to one of the preceding claims 23 to 28 for use in an electrical storage system, characterized in that on at least one surface of the element it is formed such that it is inert and / or impermeable to materials in contact with this surface , Disc-shaped discrete element according to claim 29 for use in an electrical storage system, characterized in that the at least one surface is formed as a barrier. Disc-shaped discrete element according to claim 30 for use in an electrical storage system, characterized in that the barrier layer is formed as a barrier to the diffusion of metals. Disc-shaped discrete element according to claim 31 for use in an electrical storage system, characterized in that the barrier layer is formed as a barrier to the diffusion of alkali and / or alkaline earth metals. Disc-shaped discrete element according to claim 32 for use in an electrical storage system, characterized in that the barrier layer is formed by doping or overdoping with at least one alkali and / or alkaline earth metal. Disc-shaped discrete element according to one of claims 29 to 33 for use in an electrical storage system, characterized in that the barrier layer is achieved by vertical structuring of the at least one surface in such a way that there are no direct diffusion paths into the bulk. Disc-shaped discrete element according to claim 34 for use in an electrical storage system, characterized in that getter materials for alkali and / or alkaline earth metals are contained in the vertical structure. Disc-shaped discrete element according to one of claims 34 and 35 for use in an electrical storage system, characterized in that the vertical composition variation of the at least one surface is formed by a sequence of at least two layers, wherein adjacent layers each have a different composition. Disc-shaped discrete element according to one of claims 34 to 36, characterized in that the vertical composition variation of the at least one surface is obtained by a coating. Disc-shaped discrete element according to claim 37 for use in an electrical storage system, characterized in that the coating is obtained by a plasma-assisted method, preferably by a PICVD method. Disc-shaped discrete element according to one of the preceding claims 23 to 38 for use in an electrical storage system, characterized in that it is composed of at least one oxide or of a mixture or compound of a plurality of oxides. Disc-shaped discrete element according to claim 39 for use in an electrical storage system, characterized in that the at least one oxide is SiO ₂ . Disc-shaped discrete element according to one of the preceding claims 23 to 40 for use in an electrical storage system, characterized in that the element is present as a glass.  Preparation of a disk-shaped discrete element according to one of claims 23 to 41 for use in an electrical storage system, characterized by a melting process followed by hot forming. Preparation of a disc-shaped discrete element according to claim 42 for use in an electrical storage system, characterized in that the hot forming process is a drawing process.  Use of a disc-shaped discrete element according to any one of claims 23 to 41 in an electrical storage system as a substrate.  Use of a disc-shaped discrete element according to any one of claims 23 to 41 in a superstrate electrical storage system.  Use of a disc-shaped discrete element according to any one of claims 23 to 41 in an electrical storage system as a cover.

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