DE102018127716A1 - Membrane manufacturing plant - Google Patents

Abstract

The present invention relates to a plant for producing a film, the plant having at least one film coating source for carrying out a physical or chemical deposition process, and wherein the film coating source can be used to deposit a material forming the film in order to separate the film by the deposition train, as well as a method for producing the film. The objects of the present invention are to demonstrate a simple, inexpensive and universally applicable method for producing films and a system suitable for carrying out the method. The object is achieved by a system for producing a film which has a cyclically circulable, permanent auxiliary substrate, the system and the auxiliary substrate being designed to provide adhesion of the film to the auxiliary substrate during a coating carried out with the at least one coating source and after to cause the coating to detach the film produced.

Description

The present invention relates to a plant for producing a film, the plant having at least one film coating source for carrying out a physical or chemical deposition process, and wherein the film coating source can be used to deposit a material forming the film in order to separate the film by the deposition train, as well as a method for producing the film.

Films have many uses, for example as packaging films. In some cases, films are also coated with physical or chemical deposition processes. For example, polymer films can be coated with metal layers and lacquer layers in order to improve the tightness of packaging made from the films with the metal layers and to protect the metal layers from corrosion with color layers and to produce an advertising-effective appearance. Films can also be used as components of components, for example in batteries, accumulators (in short, rechargeable batteries), electrolysis cells or solar cells. Electrochemical cells are often produced from electrode foils, for example a cathode foil and an anode foil in a battery, and insulation foils or separator foils between the electrode foils. In lithium-ion batteries, the separator foils, which are arranged in the battery cell between the anode and the cathode, have pores through which lithium ions can diffuse during charging and discharging processes. The separator films used in electrochemical cells can be polymer films coated with ceramic layers or films made entirely from a ceramic. In this context, foils are to be understood as flat, almost 2-dimensional bodies which have large lateral dimensions, usually of at least several centimeters, and clearly small thicknesses, mostly of at most one millimeter. The ceramic layers used in separator films can consist, for example, of aluminum oxide. In the manufacture of solar cells, too, there are manufacturing processes that produce thin, flexible films of crystalline semiconductor materials by splitting off a larger, solid semiconductor crystal, the split-off layer thickness then being newly produced using CVD and then split off again. In this way, for example, thin, flexible GaAs solar cells are produced, which e.g. can be installed in arched car roofs. Problematic with high-quality foils and foil-based components, e.g. Accumulators or fuel cells are high manufacturing costs, some of which stand in the way of the cost-effectiveness and widespread use of the high-quality foils or the components made from the foils.

DE 39 27 132 A1 discloses a method for producing a self-supporting film, in which an at least single-layer particle layer is first poured onto a tape and a film material is deposited thereon to form a self-supporting film, for example by PECVD. The loosely poured-on particle layer used is complex to implement in terms of plant technology, and the required particle layer can also lead to functional and or qualitative restrictions in the layer produced.

It is therefore the object of the present invention to propose a simple process for the production of high-quality films and a plant suitable for carrying out the process.

The object is achieved by a system for producing a film which has a cyclically circulable, permanent auxiliary substrate, the system and the auxiliary substrate being designed to provide adhesion of the film to the auxiliary substrate during a coating carried out with the at least one coating source and after to cause the coating to detach the film produced. In the prior art, coatings are generally applied to substrate films provided as substrates. The system according to the invention, on the other hand, enables a production process for the production of high-quality films that is simplified by saving the substrate film. In the system according to the invention, the film is produced by coating an auxiliary substrate and subsequently detaching it. The film is therefore a self-supporting film which, by itself, has sufficient mechanical stability without being dependent on a substrate film. In electrochemical cells, there is a requirement to achieve as much functionality as possible from the smallest possible volume. In other words, high energy densities and power densities should be achieved. For the individual components of the components, this means that they should be as compact as possible and as thin as possible in the case of foils.

For example, in the case of separator films in electrochemical cells, the functionality required there for reliable separation of the adjacent electrodes is better solved by the coating components of a coated separator film than from the substrate film part of this separator film because the ceramic layers or partial layers are resistant even at temperatures above 200 ° C and therefore reliably prevent thermal runaway of the cells even with thin layers below 10 µm.

By providing the cyclically rotating auxiliary substrate, the system according to the invention opens up the possibility of producing reliable thin films, for example separator films, inexpensively. The auxiliary substrate can be reused many times without suffering major wear and tear. The provision of a substrate film required in the prior art was associated with operating costs which are eliminated in the system according to the invention. It is also an important effect that, by eliminating the functionally unnecessary substrate film, more compact films can be produced, which can contribute to an improved functionality of the components produced therefrom. For example, lithium ion batteries can be manufactured with thinner all-ceramic separator foils and correspondingly higher energy densities.

Corresponding to the diverse compositions, functionalities and thicknesses of different films, different coating sources are used to produce them. High coating speeds can be achieved with the physical deposition process "thermal spraying" and with the chemical deposition process "plasma spraying". ETP (expanding thermal plasma sources) can be used for plasma spraying. These processes are often carried out at atmospheric pressure or a pressure close to or above atmospheric pressure. High deposition rates with simultaneously dense and homogeneous layers are achieved by the chemical deposition process of plasma-assisted chemical vapor deposition with microwave energy input (µW-PECVD) and by the physical deposition process of sputtering. The reactive sputtering process is usually also assigned to the physical deposition process, although in the gas phase the target atoms (e.g. Ar) dusted by inert gas atoms (e.g. Al) react chemically with reactive gas molecules (e.g. O ₂ ) ( eg with the formation of Al ₂ O ₃ layers). Various physical or chemical gas-phase coatings are used in various configurations of the plant according to the invention at negative pressure or in a vacuum or at higher pressures up to above atmospheric pressure.

The auxiliary substrate can have a cylindrical jacket-shaped or a band-shaped surface. A revolving cylinder with its geometrically simple shape is a particularly simply constructed and accordingly reliable and low-maintenance system component. The films produced on the outer surface of the cylinder can be used in various applications as planar or spirally wound films. In the case of the foils wound into rolls, the curvature present in the manufacture can be used to produce low-stress foils, which can be particularly important in the case of brittle materials with low elasticity. Band-shaped surfaces of auxiliary substrates can have flat or planar sections on which planar foils can advantageously be produced. If necessary, convex or concave band sections can also be implemented to support the desired high-quality layer properties. The cross-sectional areas of the surfaces of the cylindrical jacket-shaped or band-shaped auxiliary substrate have straight surface contours through an axis of rotation of the auxiliary substrate and parallel to the axis of rotation. In other embodiments, the auxiliary substrates have curved surfaces.

The surface of the auxiliary substrate can be formed from a material to which the coating material adheres during the coating by means of adhesive forces, the adhesive forces being smaller than the material load capacities of the film when detached. With this option, a material is used as the surface material of the auxiliary substrate, between which and the film material there is adhesion based adhesion, which prevents the film from detaching during the deposition, but which is sufficiently small to make the film simple after the deposition to be able to peel off without damaging the film due to loads going beyond material load limits. Options with other small adhesive forces when peeling are also possible. It is sufficient if the small adhesive forces are present under certain conditions, for example at elevated or reduced temperatures by cooling, if these conditions can be produced for detachment. The surface of the auxiliary substrate and a coating current can alternatively also be electrostatically chargeable in order to hold the coating material during the coating by electrostatic forces and to be able to bring about a detachment of the film by electrostatic reloading. In this case, the required adhesion of the film material to the auxiliary substrate is achieved by electrostatic forces.

The system according to the invention can have at least one adhesive layer coating source, an adhesive layer being able to be produced with the adhesive layer coating source. The system according to the invention can have several coating sources, which can also be designed to deposit different materials. Consequently, in addition to coating sources for the deposition of the predominant film material, the system can also have one or more adhesive layer coating sources for the deposition of an adhesive layer with suitable adhesive properties. The adhesive layer can be a layer that later becomes a sub-layer of the manufactured film is used. For example, the adhesive layer can be a metal layer which, together with a layer of an active anode layer deposited thereon in an anode foil or with a partial cathode layer in a cathode foil, is later used in an accumulator. The adhesive layer can also be a thermally fusible, a sublimable layer, a layer which can be removed by thermal expansion or a layer which can be removed from a solvent or an etchant. The adhesive layer can therefore be a temporary layer that is later removed, for example an organic layer that is sublimed later, or a salt layer that is later dissolved in a solvent.

The system according to the invention can have a peeling device for peeling off the film from the auxiliary substrate, the peeling device being a mechanically acting blade, a liquid steel or a gas jet. The system can therefore have a tool with which the detachment of the layer from the auxiliary substrate is carried out or supported. In various exemplary embodiments, this tool or the peeling device is a mechanically acting blade or a gas surge or a liquid surge, which acts similarly to a mechanical blade. In other exemplary embodiments, other tools are used, e.g. cause the film to detach via thermal or acoustic effects.

The system can be designed as a continuously operating system, the entire layer thickness of the film produced being produced during a cyclic circulation of the auxiliary substrate and a different section of the film being produced in the next circulation. The film can therefore be produced on a peripheral section of the auxiliary substrate, the film produced being continuously detached from the auxiliary substrate in such a way that a point on the surface of the auxiliary substrate to be coated no longer bears the previously deposited film after a complete cyclic circulation, but again uncoated for re-coating with the film material is available. In the case of a cyclic auxiliary substrate, the point lies on a line parallel to the axis of rotation of the cylinder. In the case of a truncated cone-shaped auxiliary substrate, the point lies on a line inclined to the axis of rotation.

The system can be designed as a discontinuously operating system, the film being separated in more than one cyclical cycle in a separation step and the separated film being removed as a tube or as a cut tube in a removal step. The layer can thus also be produced in several revolutions of the auxiliary substrate, in which case there is no beginning and end of a deposition area on the auxiliary substrate, which enable continuous operation, instead, e.g. a full-length coating of the auxiliary substrate produces a tubular film with no beginning and no end along a circumferential line. The coated periphery of the auxiliary substrate can be an outer periphery or an inner periphery. The auxiliary substrate for discontinuous operation can also have non-round shapes, for example it can be a flat, round plate which can be rotated around its center. In discontinuous operation, the existing coating sources can be used several times to produce the layer, which is particularly important if the coating source deposits only a small amount of material in a single use. For example, gas showers for atomic layer deposition (ALD) sometimes only produce one single atomic layer of the layer per coating. The cyclical repetition of atomic layer depositions enables high-quality foils to be produced from ALD layers even with large layer thicknesses, for example having a few thousand or several million atomic layers. E.g. Such layers can be produced quickly and economically on a rapidly rotating cylinder. Manufactured films are often not required in the tube form initially produced, but rather, for example, as flat film sections. In these cases, the film tube can be cut open, for example cut open or broken, in order to produce the required film sections from the film tube. Very high-quality film materials can be produced by layer-by-layer separation and intermediate compression of the individual layers.

In addition to the film coating sources, the system according to the invention can also have other tools influencing the layer, for example ion beam sources for compacting layer layers or etching tools for producing a desired roughening (texture) in the layer or in a partial layer of the film.

The system can have several identical film coating sources, it being possible to use the same film coating sources for the successive production of the film from several strips and / or layers of the same film material. If several identical coating sources are used, which extend over the width of the auxiliary substrate, then the number of coating sources is a multiplication factor for the achievable layer thickness. Given the size of coating sources, correspondingly large auxiliary substrates, for example in the form of cylinders with correspondingly large ones, are required for an arrangement of a plurality of coating sources in succession Diameters or as long tapes can be provided. Films can be produced which are composed of different material layers in their cross section through the film thickness. However, films can also be produced which laterally have different material strips. For example, metal layers can be embedded in insulator layers in such a way that the metal layers on the lateral edges of the film are electrically insulated. Depending on the required layer thicknesses, several identical film coating sources can be present for the individual layers or partial layers to be produced. The system can have different film coating sources in order to produce an internal structure of the film consisting of different materials. The combination of different layer components can be advantageous for very different reasons. For example, alternating layers of different dense layers can be used to produce very dense foils, in which diffusion paths through the foil are interrupted at the interfaces between two layers. The active electrodes in electrochemical cells, on which electrochemical reactions take place on surfaces, require large active electrode surfaces in the available installation space. The large surfaces required can be achieved by multi-layer deposition, at least some of the layers being deposited as porous layers, for example with a sponge-like or a grass-like inner structure. Other less porous layers can be provided to achieve the required mechanical stability of the entire film.

The object of the invention is also achieved by a method for producing a film, in which the film is produced by physical or chemical deposition of material forming the film on an auxiliary substrate, and after the deposition the film is detached from the auxiliary substrate, the method is carried out in a plant according to the invention. The method according to the invention and the system according to the invention are technically closely linked. Options of the system according to the invention have direct correspondences to the method according to the invention. To avoid repetitions, reference is made to the above descriptions of the corresponding options of the system for various options of the method.

Various optional features presented can be designed and combined with one another in the art at the skill of the art without departing from the scope of the presented invention. Features that are presented in a random sequence must not be misunderstood as a mandatory combination of features.

• 1 schematisch ein Ausführungsbeispiel einer erfindungsgemäßen Anlage zur Herstellung einer Folie zeigt.

The present invention is to be explained in more detail below on the basis of an exemplary embodiment and a figure, wherein

• 1 schematically shows an embodiment of a plant for producing a film according to the invention.

Figure 1 outlines an embodiment of a system according to the invention 1 to carry out a method according to the invention. In the exemplary embodiment presented there are thirteen film coating sources 3rd concentric around a rotatable, as an auxiliary substrate 4th serving cylinder arranged. Specifically, the exemplary embodiment presented is linear microwave plasma sources (such as from a patent EP 1 665 324 B1 known) for the deposition of aluminum oxide, the axes of which extend out of the display axis and which can achieve a homogeneous coating over the entire width of the film web to be produced. The film coating sources 3rd each separate alumina on the as the auxiliary substrate 4th serving cylinder. The outer surface of the cylinder consists of silver, on which the aluminum oxide layer has poor adhesion. As a peeling device 5 an arrangement of gas showers is used, which blow cold nitrogen in the detachment area against the layer applied to the cylinder and temporarily cool it locally. Due to different coefficients of thermal expansion, thermal stresses and intrinsic stresses in the deposited layer, the film is detached from the cylinder or is supported in continuous operation. The ceramic aluminum oxide film produced can be used as a separator film in batteries.

Reference list

1

Plant for the production of a film

2nd

foil

3rd

Foil coating source

4th

Auxiliary substrate

5

Peeling device

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for better information for 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.

Patent literature cited

• DE 3927132 A1 [0003]
• EP 1665324 B1 [0020]

Claims (12)

Plant (1) for producing a film (2), the plant having at least one film coating source (3) for carrying out a physical or chemical deposition process, and wherein the film coating source (3) can be used to deposit a material forming the film in order to form the film (2) by the deposition, characterized in that the system (1) has a cyclically circulating, permanent auxiliary substrate (4), the system (1) and the auxiliary substrate (4) being designed to assume liability to provide the film (2) on the auxiliary substrate (4) during a coating carried out with the at least one coating source (3) and to cause the film (2) produced to be detached after the coating. Appendix (1) to Claim 1 , characterized in that the auxiliary substrate (4) has a cylindrical or band-shaped surface. Appendix (1) to Claim 1 or 2nd , characterized in that the surface of the auxiliary substrate (4) is formed from a material to which the coating material adheres during the coating by adhesive forces, the adhesive forces being smaller than the material load capacities of the film (2) when detached. Appendix (1) to Claim 1 or 2nd , characterized in that the surface of the auxiliary substrate (4) and a coating current are oppositely electrostatically chargeable, in order to hold the coating material during coating by electrostatic forces and by electrostatically reloading the auxiliary electrode and / or the film (2) produced, detaching the film (2) to be able to effect. Appendix (1) to Claim 1 or 2nd , characterized in that the system (1) has at least one adhesive layer coating source, an adhesive layer being producible with the adhesive layer coating source. Appendix (1) to Claim 5 , characterized in that the adhesive layer is a thermally fusible or sublimable layer, a layer which can be removed by thermal expansion or a layer which can be removed from a solvent or an etchant. Appendix (1) to Claim 1 or 2nd , characterized in that the system (1) has a peeling device (5) for peeling the film (2) from the auxiliary substrate (4), the peeling device (5) being a mechanically acting blade, a liquid steel or a gas jet. Appendix (1) to Claim 1 or 2nd , characterized in that the system (1) is designed as a continuously operating system (1), the entire layer thickness of the film (2) being produced during one cycle of the auxiliary substrate (4) and another section of the in the next cycle Foil (2) is produced. Appendix (1) to Claim 1 or 2nd , characterized in that the system (1) is designed as a discontinuously operating system, the film (2) being separated in more than one cyclical cycle in a separation step and the separated film (2) as a hose or as a cut hose in a removal step or is removed as a flat piece of film. Plant (1) according to at least one of the preceding claims, characterized in that the plant (1) has a plurality of identical film coating sources (3), the same film coating sources (3) for successively producing the film (2) from a plurality of strips and / or layers of the same film material can be used. Plant (1) according to at least one of the preceding claims, characterized in that the plant (1) has different film coating sources (3) in order to produce an inner structure of the film (2) consisting of different materials. Method for producing a film (2) by physical or chemical deposition of the material forming the film on an auxiliary substrate (4), from which the film (2) is detached after the deposition, characterized in that the method is carried out on a system (1) after at least one of the Claims 1 - 11 is carried out.

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