Method for producing a multilayer film

Abstract

The invention relates to a method for producing a multilayer film (2) for generating or storing electrical energy, using a film extrusion system (4), comprising the steps of supplying (100) a starting material (2.1) via a supply unit (8), processing (200) the starting material (2.1) into a homogeneous melt (2.2) within an extruder (6), conveying (300) the melt (2.2) through the extruder (6) to an extruder nozzle head (14) by a conveying means (6.1), uniformly distributing (400) the melt (2.2) within the extruder nozzle head (14) by means of a melt distributor (14.1), guiding (500) the melt (2.2) out from the extruder nozzle head (14) through an opening (9) in a nozzle (10) of the extruder nozzle head (14) to form a continuous multilayer material film (2.3), and post-processing (600) the continuous multilayer material film (2.3) in order to form the multilayer film (2) by post-processing means (16).

Description

[0001] Method for producing a multilayer film

[0002] Description

[0003] The present invention relates to a method and a film extrusion plant for producing a multilayer film for generating or storing electrical energy, and to a multilayer film produced by such a method using such a film extrusion plant.

[0004] Currently, high-performance electrical energy storage devices are primarily manufactured using lithium-ion technology. Lithium-ion batteries consist of an anode, a cathode, an electrolyte, and a separator. The cathode typically consists of lithium metal oxides such as lithium cobalt(II) oxide (LiCoCh), lithium manganese(IV) oxide (LiM^C i), or lithium nickel cobalt manganese oxide (LiNiCoMnCh), while the anode is made of graphite. The electrolyte consists of a lithium-ion-conducting liquid or a solid polymer. The separator separates the anode and the cathode.

[0005] On the downside, manufacturing lithium-ion batteries requires complex processes and high-quality materials, making the production process costly and expensive. The necessary components, lithium and cobalt, are limited resources. Furthermore, lithium-ion batteries are thermally unstable and can overheat, catch fire, or explode under certain conditions. Disposal and recycling of lithium-ion batteries are also difficult. Additionally, lithium-ion batteries are relatively large and heavy.

[0006] Polymer-based batteries have proven particularly promising as replacements for established lithium-ion batteries. These batteries, such as those described in WO 2020 / 092213 A1, do have a lower energy density than lithium-ion batteries, but they overcome most of the other disadvantages of lithium-ion batteries mentioned above.

[0007] Unfortunately, even the novel polymer-based batteries can currently only be manufactured using complex layer-by-layer processes, which require a high degree of precision, cleanliness and process control, and consequently increase production time and production costs.

[0008] It is therefore the object of the present invention to at least partially overcome the aforementioned disadvantages of known products and systems for generating or storing electrical energy. In particular, it is the object of the invention to provide a product or system for generating or storing electrical energy that can be produced and disposed of sustainably and in an environmentally friendly manner, can be operated safely, and can be manufactured in a simple, quick, and cost-effective way.

[0009] The foregoing problem is solved by a method with the features of the independent method claim, a film extrusion plant with the features of the independent apparatus claim, and a multilayer film with the features of the independent product claim. Further features and details of the invention will become apparent from the respective dependent claims and the description. Features and details described in connection with the method according to the invention naturally also apply in connection with the apparatus and the product according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention is always, or can always be, mutually referenced. According to the invention, a method for producing a multilayer film for generating or storing electrical energy is provided.The inventive method comprises the steps of feeding a starting material via a feeding unit, processing the starting material into a homogeneous melt within an extruder, conveying the melt through the extruder to an extruder die head by means of a conveying means, distributing the melt uniformly within the extruder die head by means of a melt distributor, conveying the melt out of the extruder die head through an opening of a nozzle of the extruder die head to form a continuous multilayer material film, and post-processing the continuous multilayer material film to form the multilayer film by means of post-processing means.

[0010] Within the scope of the present invention, it has been recognized that, in particular, by combining the inventive process steps of processing and conveying a supplied starting material through an extruder, uniformly distributing a melt of the starting material within an extruder die head, conveying the melt through a nozzle opening of a nozzle of the extruder die head, and post-processing a continuous multilayer material film, a multilayer film for generating or storing electrical energy can be produced in a simple, fast, and cost-effective manner, which is sustainably and environmentally friendly produced and disposed of, and enables the safe generation or storage of electrical energy.According to the invention, it can be provided that in one process cycle all layers of the multilayer film for generating or storing electrical energy are produced, but at least more than one layer.

[0011] Within the scope of the invention, a multilayer film can be understood to be, in particular, a composite of a plurality of layers of different materials, each fulfilling different functions. With regard to its suitability for generating or storing electrical energy, the multilayer film can be intended, in particular, for use as a battery or for use in a battery. Likewise, the multilayer film can also be used as a solar cell or as part of a solar cell, as an illuminating material, as an electrochromatic material, as a piezoelectric or electrokinetic material. The starting material can be introduced into the extruder as a powder, granules, melt, gel, liquid, or gas. It is understood that several different starting materials can also be fed in, preferably via different extruders, with secondary components (e.g.,...) being added to each starting material.up to four secondary components) can be added. A homogeneous melt can be understood, in particular, as a state of the starting material in which the material is completely melted and forms a uniform, consistent liquid without any visible differences in composition or structure. It is understood that processing the starting material to a homogeneous melt can also be understood as homogenization when the starting material has reached a liquid state. The starting material can be in the form of an electrically conductive polymer or be suitable for the production of an electrically conductive polymer (e.g., within the film extrusion plant). A continuous multilayer material film can preferably be understood as a continuous, uninterrupted multilayer film of a material that is arranged on a surface or, for example,is formed in the form of a film bubble. Post-processing, in its simplest form, can be understood as simply cooling and / or rolling the continuous material film, so that a continuous material film can be post-processed into a tangible multi-layered film after just cooling and / or rolling. However, it is understood that post-processing can also encompass a multitude of other possible processing steps.

[0012] With a view to achieving a uniform distribution and, if necessary, activation of the starting material for the targeted structural assembly of a multilayer film for generating or storing electrical energy, it is advantageously provided that the starting material is tempered after being fed into the extruder, preferably by means of a plurality of temperature control devices arranged along the extruder in a temperature control unit. The temperature control devices can, for example, be in the form of heating (or cooling) sleeves arranged around the extruder. A uniform distribution of the starting material is particularly relevant with regard to the uniform conductivity of the extruded multilayer film. The melting of the extruded material can preferably be achieved by friction within the extruder, by generating heat through the screw.More precise temperature control (especially cooling) can then be achieved using temperature control devices. To ensure precise process control, it is advantageous to feed the starting material to the extruder via a metering device, preferably in the form of granules or pellets. It is understood that the starting material can also be added as a powder, melt, gel, liquid, or gas. Multiple metering devices can also be provided, which, for example, can be distributed along the extruder and allow for the targeted addition of additional material at suitable process steps. Advantageously, several auxiliary components can be added together with a single starting material at the beginning of the extruder. For example,Initially, a starting material and up to four secondary components are added within an extruder, which can then be melted and mixed within the extruder.

[0013] With a view to material-friendly conveying to ensure high-quality production of a multilayer film for generating or storing electrical energy, the present design can further provide that the starting material is continuously conveyed within the extruder by means of a screw conveyor up to the extruder die head. Preferably, the screw can be designed such that material arrives continuously at the extruder die head and no excessive melt pressures are generated on the path from the extruder inlet to the extruder outlet that would damage a pressure-sensitive material. Alternatively, for example, a bypass extrusion of a sensitive material could be provided. For example,A robust but difficult-to-melt material, such as PA, is melted in a main extruder, while a sensitive but easily meltable material is gently melted in a bypass extruder. The bypass extruder can then introduce its melt into the main extruder at a point where both melts are liquid and only need to be mixed by the main extruder. It would also be material-friendly if a chemical reaction occurred during the mixing of the two melts, producing a material that would not have survived a melting process otherwise. The use of LT screws (low-temperature screws) can also be material-friendly. These screws can plasticize the material at a lower temperature than conventional screws.Gentle material handling is particularly important because electrically conductive polymers often have a higher viscosity than conventional polymers, which can make extrusion more difficult and lead to problems such as poor flowability or clogging of the extrusion die.

[0014] As part of a material-friendly treatment of the continuous multilayer material film to ensure high-quality production of a multilayer film for generating or storing electrical energy, it can also be advantageous if the post-processing of the continuous multilayer material film to form the multilayer film includes cooling, wherein the cooling of the continuous multilayer material film is preferably carried out by air cooling and / or water cooling. Cooling can preferably be performed from several sides. Particularly rapid cooling with water can be advantageous to promote the formation of amorphous structures in the extruded materials, which, when the conductive films are used in batteries, can improve the power density because the redox reaction in the battery can then proceed more quickly.

[0015] For the production of customized layers (different layers within a multilayer material film or within a foil) or customized layer complexes of stacked layers (e.g., a battery pouch), it can advantageously also be provided that the post-processing of the continuous multilayer material film to form the multilayer foil includes cutting, wherein the continuous multilayer material film is preferably cut to predetermined surface dimensions (which can then, for example, be optionally connected in series in battery pouches). Cutting preferably takes place later outside of an extrusion line.

[0016] Similarly, for the production of customized, compact units of multilayer films, it can be advantageous if the post-processing of the continuous multilayer material film to form the multilayer film includes rolling it into a coiled multilayer film unit (e.g., for the production of cylindrical battery cells). This rolling can preferably take place within an extrusion line.

[0017] For precise control of the layer thickness of the multilayer film and for improving its mechanical stability, it is further advantageous if the post-processing of the continuous multilayer material film for its formation includes stretching of the continuous multilayer material film, wherein the stretching is preferably carried out as oriented stretching and / or temperature-controlled stretching and / or multiaxial stretching. Stretching the material can also improve layer homogeneity and thus ensure consistent conductivity. In the case of a separator layer or a redox-active layer, stretching can advantageously also open or create the porosity. Stretching can be performed inside or outside an extrusion line.

[0018] To protect the multilayer film produced and to increase safety, it is also conceivable that the post-processing of the continuous multilayer material film to form the multilayer film includes laminating individual layers and / or sealing layer complexes. Lamination here preferably refers to a type of bonding of individual layers. Sealing can be used, for example, to produce battery pouches or to seal them externally. By connecting individual layer complexes in series, an output voltage of the battery pouches can be specifically generated. For an electrical connection of individual layers, bonding or welding of individual layers can be used, for example.

[0019] With regard to the targeted production of high-performance electrical power generators or energy storage devices, it can also be advantageous that the post-processing of the continuous multilayer material film to form the multilayer foil includes drying and / or coating, wherein the coating is preferably carried out with a redox-active material, in particular with a metal. Advantageously, redox-active material can also be coated with a metal. For example, redox-active layers can be extruded under exclusion of oxygen and subsequently coated with a metal. The redox-active layer can then facilitate the chemical reaction, while the metal layer can collect the electrons.The production of redox-active layers presents a particular challenge, as these layers must fulfill several functions simultaneously. In particular, they must be able to perform a reversible redox reaction as both cathode and anode, as well as conduct charges without changing their thickness or size, ensuring that contact with other layers is maintained for as long as possible, even after repeated redox reactions. The synthesis of redox-active polymers can, for example, take place directly in the extruder. A conventional thermoplastic extrudable material, such as PE, PA, PET, PP, etc., could be used as the base material, to which redox-active side groups are attached. These redox-active groups could be, for example, phenothiazine (PT), phenoxazine (PO), or phenazine (PZ) for completely metal-free electrodes, or dilithium terephthalate (U₂TP) as a redox-active group with a metal ion.The synthesis of a redox-active polymer can take place in the liquid melt under desirable pressure and temperature conditions.

[0020] In view of the wide variety of processes for manufacturing a multilayer film for generating or storing electrical energy, it can also be advantageous if the post-processing includes the use of at least one of the following influencing factors: chemicals, heat, cold, pressure, mechanical vibrations, electromagnetic radiation. For example, even after extrusion, the entire composite of a multilayer film, or a part of it, can be completed, modified, or activated by a downstream process step.

[0021] To increase product quality and process stability, it can also be advantageously provided that excess solids, liquids or gases are discharged from the extruder, wherein the discharge of excess solids, liquids or gases is preferably carried out via a discharge device.

[0022] With a view to the targeted production of a multilayer film, preferably starting from a separator film, the invention further provides that the starting material is a thermoplastic material, wherein the starting material preferably comprises at least one of the following polymers: polyethylene, polyamide, polyethylene terephthalate, polypropylene. Redox-active side groups, such as phenothiazine (PT), phenoxazine (PO), phenazine (PZ) for completely metal-free polymers, or, for example, dilithium terephthalate (Li₂TP) as a redox-active group with a metal ion, can then preferably be added to the starting material. The synthesis of a redox-active polymer can preferably take place in the liquid melt under desirable pressure and temperature conditions. The use of a catalyst and electrolyte, such as a hydrogen ion (preferably in the form of a sulfonic acid), is also conceivable.Sulfonic acids are particularly suitable for this application due to their environmental friendliness and lack of flammability. It can be especially advantageous if, on the one hand, polymers are synthesized under extreme pressure and temperature conditions in the extruder using a catalyst, and on the other hand, the catalyst later serves as an electrolyte at room temperature. Liquid reagents used in the reaction can preferably be washed out after extrusion.

[0023] With regard to achieving electrical conductivity for effective use as an electrical energy storage device or electrical energy generator, it is advantageously further provided that the starting material comprises a conjugated polymer, wherein the starting material preferably comprises at least one of the following conjugated polymers: polyacetylene, polyaniline, polypyrrole, poly(p-phenylenevinylene), polyfluorene, polythiophene. Such a conjugated polymer can, for example, be made conductive only by doping, whereby, for example, the doping can also be integrated into the extrusion process. For example, an oxidizing agent such as oxygen could be introduced into the extruder to slightly oxidize a conjugated polymer (e.g., PAC) and make it conductive. In addition, doping with conductive additives can also be carried out.Furthermore, in combination with the addition of redox-active side groups, an electrode material with a desirable dual function can be obtained, which can significantly increase the capacity of an electrical energy storage device.

[0024] In order to specifically increase the strength of the multilayer film, it can advantageously be further provided that the starting material comprises strength-stabilizing additives, wherein the strength-stabilizing additives preferably comprise a binder.

[0025] It is also conceivable to add bonding agents in a targeted manner, which can, for example, help to bond certain layers together.

[0026] To save costs compared to using adhesion promoters, or to avoid the undesirable properties of such promoters, an electrostatic treatment, preferably plasma treatment, can be employed to selectively modify the surface of otherwise incompatible materials so that they adhere well to one another. This particularly expands the range of possible combinations. The electrostatic treatment can preferably be carried out using an electrode with a high-frequency alternating high voltage (e.g., up to 60 kV). Specifically, this can be implemented as follows: If, for example, a 7-layer composite is to be extruded, but layers 2 and 3 and layers 5 and 6 cannot be bonded together, an extrusion process using three individual slot dies of a casting system can be implemented, all extruding onto the same roller, resulting in a 7-layer composite on the roller.The three individual slot dies can be spaced a certain distance apart due to their design, creating two gaps between the three melt strips. Electrostatic pretreatments can preferably be applied within these gaps, ideally each generating a plasma to "pretreat" the surfaces of the melt strips. Alternatively, a treatment can be provided for each surface to be joined, radiating directly onto that surface. When the melt strips merge on the roller, they can thus form a much stronger bond than if they were untreated. Advantageously, the composite can be compressed again after the third slot die, as well as after the second, for example, to remove any residual air between the joining surfaces.

[0027] With a view to a wide variety of processes for the targeted modification of individual layers of a multilayer film and a simple method for producing a multilayer structure, it is advantageously further provided that a plurality of extruders are used simultaneously for the production of the multilayer film, wherein preferably the plurality of extruders are used simultaneously for the production of the continuous multilayer material film, wherein in particular the plurality of extruders each simultaneously convey a homogeneous melt to a central extruder die head and the continuous multilayer material film is discharged through an opening of a nozzle in the extruder die head. Thus, a starting material (or several different starting materials with various minor components) can be processed in parallel in a plurality of extruders, e.g.Two to nine extruders feed the material into a single extruder die head, where the continuous multilayer material film is then produced. Preferably, a separate extruder can be used for each layer of the continuous multilayer material film. Likewise, two or more extruders can be used to produce a single layer. In this case, for example, one extruder can extrude laterally into another extruder tube, for instance, if the material mixture contains materials or reactants with a comparatively low melting point and / or high mechanical sensitivity. Such a reactant can then be melted in a separate bypass extruder and fed into the main extruder at a suitable point. In this way, the materials in the bypass extruder can be treated differently, preferably more gently, than in the main extruder.

[0028] With a view to the simple and rapid production of the multilayer film in question, it is advantageously provided that the starting material contains an electrically conductive polymer, wherein the electrically conductive polymer is preferably present in the starting material in a proportion of at least 40 wt.%, particularly preferably in a proportion of at least 60 wt.%, and especially in a proportion of at least 80 wt.%. The electrically conductive polymer can be a conjugated polymer and exhibit its conductivity based on conjugation, or it can be doped with electrically conductive particles.

[0029] Alternatively, it is also conceivable that the electrically conductive polymer is synthesized only after the starting material has been added during the process, wherein the electrically conductive polymer is preferably contained in the continuous multilayer material film to a proportion of at least 40 wt.%, particularly preferably to a proportion of at least 60 wt.%, and especially to a proportion of at least 80 wt.%.

[0030] With a view to achieving high electrical conductivity for effective use as an electrical energy storage device or electrical energy generator, it may also be advantageously provided that the electrically conductive polymer has an electrical conductivity of at least 10⁻⁵. 2 S / cm, preferably of at least 1 S / cm, in particular of at least 10 2 exhibits S / cm.

[0031] In the context of high electrical conductivity for effective use as an electrical energy storage device or electrical energy generator, it is further conceivable that the electrically conductive polymer is formed in the form of a doped polymer, wherein the electrically conductive polymer is preferably formed in the form of an n-type doped polymer.

[0032] Similarly, for effective use as an electrical energy storage device or generator, it is conceivable that the electrically conductive polymer, with its high electrical conductivity, exhibits an energy density of at least 40 kJ / kg, preferably at least 50 kJ / kg, and particularly at least 60 kJ / kg. The assignment of an energy density to a polymer can be understood particularly in relation to its use as an active material within an electrical energy storage device, whereby the energy density of an electrically conductive polymer may preferably depend on the electrochemical properties of the polymer and its ability to store and transport charge carriers. The energy density of an electrically conductive polymer can be determined, for example, using electrochemical methods such as cyclic voltammetry, galvanostatic charge-discharge cycles, or electrical impedance spectroscopy.To determine the energy density, a (stored) energy can be divided by the mass of a polymer.

[0033] For the targeted modification of properties of the multilayer film in question, it can also be provided that the electrically conductive polymer comprises electron-donating aromatic monomers, preferably pyrrole, thiophene, aniline, benzene or mixtures and / or derivatives thereof.

[0034] Likewise, for the targeted modification of properties of the multilayer film in question, it can be provided that the electrically conductive polymer comprises electron-donating aromatic monomers, wherein preferably at least some of the electron-donating aromatic monomers are at least partially halogenated.

[0035] To selectively adjust the properties of the multilayer film, it can further be provided that, in addition to the starting material, at least one further material is supplied to the extruder, wherein the further material is preferably supplied in liquid form, wherein the further material is in particular an electrolyte and / or a solvent and / or a liquid that does not chemically combine with the starting material, wherein the electrolyte is particularly preferably N-ethyl-N-(2-methoxyethyl)-N,N-dimethylammonium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate,

[0036] The electrolyte comprises ethylene carbonate solutions, dimethyl carbonate solutions, propylene carbonate solutions, dimethyl carbonate, ethyl methyl carbonate, or mixtures and derivatives thereof, and / or the solvent water, benzene, carbonate, acetonitrile, dichloromethane, chloroform, or mixtures and derivatives thereof. An electrolyte preferably serves to create or improve nanoporosity and conductivity. Sulfonic acid can also be used as an electrolyte, provided the organic residue is sufficiently long, e.g., comprising at least 6 carbon atoms. Addition in gel or solid form is also possible. The additional material should withstand the extrusion conditions without evaporating; in particular, it should not be washed out but remain in the continuous multilayer material film.

[0037] To precisely control the properties of the multilayer film, the additional material can be a catalyst or comprise a catalyst, the catalyst preferably enabling the addition of redox-active groups to the starting material. Advantageously, the electrolyte and the catalyst can be the same substance. It can be particularly beneficial if the catalyst, on the one hand, synthesizes polymers under the extreme pressure and temperature conditions in the extruder and, on the other hand, later serves as the electrolyte at room temperature. This allows the catalyst to remain in the composite after extrusion.

[0038] Furthermore, in the context of improved mass transfer within the layer structure of the multilayer film, it can be advantageous if the porosity within the starting material is increased by the addition of the further material, preferably creating nanoporosity within the starting material.

[0039] To improve the electrical conductivity of a layer comprising the additional material, the additional material can also include a conductive carbon black to enhance the electrical conductivity of the layer in question. The conductive carbon black can preferably be added to the starting material before or after its addition.

[0040] The invention also relates to a film extrusion plant for producing a multilayer film for generating or storing electrical energy, preferably using a method described above. The film extrusion plant according to the invention comprises a feeding unit for supplying a starting material, an extruder equipped with an extruder die head for processing the starting material into a homogeneous melt, for conveying the melt to the extruder die head and for expelling the melt through an opening of a nozzle in the extruder die head to form a continuous multilayer material film, a melt distributor for uniformly distributing the melt within the extruder die head, and finishing means for post-processing the continuous multilayer material film to form the multilayer film.The film extrusion plant according to the invention thus offers the same advantages as those already described in detail with regard to the inventive method for producing a multilayer film for generating or storing electrical energy. The film extrusion plant can be designed as a blown film plant or a caster plant.

[0041] With regard to a uniform distribution or activation of the starting material for the targeted structural formation of a multilayer film for generating or storing electrical energy, it is advantageously provided that the extruder has a temperature control unit, wherein the temperature control unit preferably comprises a plurality of temperature control elements arranged along the extruder, and wherein the temperature control elements are particularly arranged symmetrically along the extruder. The temperature control elements can, for example, be in the form of heating (or cooling) sleeves arranged around the extruder. A uniform distribution of the starting material is particularly relevant with regard to the uniform conductivity of the extruded multilayer film.

[0042] To ensure precise process control, a metering device for feeding the starting material into the extruder can be advantageously provided. This metering device is designed such that the starting material can be fed via the metering device in the form of granules or pellets. It is understood that the starting material can also be added as a powder, melt, gel, liquid, or gas. Multiple metering devices can also be provided, which, for example, can be distributed along the extruder and allow for the targeted addition of additional material at suitable process steps. The metering device(s) can preferably include a gravimetric system capable of metering up to five different materials as a weighed mixture.

[0043] For efficient conveying of a melt through the extruder, it is advantageous for the extruder to include a conveying element in the form of a screw for the continuous transport of the feed material. The screw is preferably designed as a single screw, a twin screw, a conical screw, a sheared screw, or a degassing screw. The extruder can, for example, be designed as a single-screw or multi-screw extruder, include a downstream melt pump, and have different temperature and pressure zones along the screws. Depending on the process requirements, additives or reactants can be introduced at suitable points in the extruder tube, allowing the extruder to also be used as a reactor.

[0044] In the context of a material-friendly treatment of the continuous multilayer material film to ensure high-quality production of a multilayer film for generating or storing electrical energy, it can also be advantageous if post-processing means are provided for cooling the continuous multilayer material film, wherein the post-processing means preferably have air cooling and / or water cooling. Cooling can preferably be carried out from several sides.

[0045] For the production of customized layers or customized layer complexes of stacked layers, for precise control of the layer thickness of the multilayer film, and for improving mechanical stability, as well as for protecting the multilayer film produced in question and increasing safety, it is also conceivable that the post-processing equipment includes a cutting device for cutting the continuous multilayer material film to predetermined surface dimensions and / or a winder for winding the continuous multilayer material film into a multilayer film unit and / or a stretching device for stretching the continuous multilayer material film and / or a sealing device for sealing individual layer complexes of the continuous multilayer material film.

[0046] With a view to a wide variety of processes for the targeted modification of individual layers of a multilayer film and a simple method for producing a multilayer structure, it is advantageous to provide for a plurality of extruders for producing the multilayer film, wherein preferably the plurality of extruders are connected to one and the same central extruder die head for feeding a melt. Thus, a starting material (or different starting materials) can be fed in parallel through a plurality of extruders, e.g., two to nine, to a single extruder die head, in which the continuous multilayer film is then produced. Preferably, a separate extruder can be used for each layer of the continuous multilayer film. Likewise, for example,Two or more extruders can also be used to produce a single layer. For example, one extruder can extrude laterally into another extruder tube, such as when the material mixture contains materials or reactants with a comparatively low melting point and / or high mechanical sensitivity. In this way, such a reactant can be melted in a separate bypass extruder and fed into the main extruder at a suitable point. This allows the materials in the bypass extruder to be treated differently, preferably more gently, than in the main extruder.

[0047] To enable maximally amorphous structures, the extruder die head can advantageously be designed as a blow head, preferably with an annular die. Such an annular blow head allows extrusion from top to bottom into a preferably equally sized water calibrator at a blow ratio of approximately 1:1. The blow head is advantageously located directly adjacent to the water calibrator, so that the melt is cooled so rapidly that hardly any crystalline structures can form within it and the melt experiences little or no longitudinal elongation.

[0048] The melt distributor in question can advantageously be frustoconical in shape and have a plurality of frustoconical units for producing one layer each of a continuous multilayer material film, wherein preferably each of the frustoconical units has a channel for supplying a melt.

[0049] To increase product quality and process stability, it may also be advantageous to provide a discharge device for removing excess solids, liquids or gases from the extruder.

[0050] The invention also relates to a multilayer film for generating or storing electrical energy, produced by a method described above, preferably using a film extrusion plant described above. The multilayer film comprises a second layer, a third layer, and a first layer arranged between the second and third layers. Thus, the multilayer film according to the invention has the same advantages as those already described in detail with regard to the method and the film extrusion plant according to the invention.

[0051] With a view to the simple, fast and cost-effective production of a functional multilayer film for generating or storing electrical energy, it can advantageously be provided that the multilayer film comprises at least three, preferably at least 5, particularly preferably at least 7, and in particular at least 9 layers.

[0052] In the design of a multilayer film for use as an electrical energy storage device, at least one layer can be configured as an insulator, electrode, anode, cathode, electrolyte, or separator. In a three-layer composite, for example, the separator and both redox-active layers can be extruded together. The functional materials can then be washed out. If necessary, the structure can then be stretched longitudinally and / or transversely and subsequently impregnated with an electrolyte. The impregnated film can then be laminated on both sides with a two-layer composite consisting of an insulator and an electrode layer. Alternatively, it is also conceivable to vapor-deposit the metal on both sides of the impregnated film to create electrode layers and then laminate it on one or both sides with an insulating film.

[0053] To form a multilayer film that can be easily manufactured for generating or storing electrical energy, it can in particular be provided that the multilayer film is designed in such a way that a reversible chemical reaction, preferably a redox reaction, can be carried out by selectively applying an electrical voltage to parts of the multilayer film.

[0054] For the effective generation and storage of electrical energy, it can further be provided that the amorphous fraction of the multilayer film is between 35% and 70%, wherein the multilayer film preferably has an amorphous fraction of > 40%, particularly preferably > 60%, and especially > 80%. In this case, the second layer and the third layer can in particular comprise an electrically conductive polymer, wherein the first layer is designed as a separator layer for electrical insulation between the second and third layers.

[0055] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail, partly with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination.

[0056] They show:

[0057] Fig. 1 shows a schematic representation of the individual steps of a method according to the invention for producing a multilayer film for generating or storing electrical energy,

[0058] Fig. 2 shows a schematic representation of a film extrusion plant according to the invention for the production of a multilayer film for the generation or storage of electrical energy according to a first embodiment in a sectional view,

[0059] Fig. 3 shows a schematic representation of a film extrusion plant according to the invention for the production of a multilayer film for the generation or storage of electrical energy according to a further embodiment in a block view,

[0060] Fig. 4a-d shows a schematic representation of a multilayer film for storing electrical energy in a sectional view according to a first to fourth embodiment.

[0061] Fig. 1 shows a schematic representation of the individual steps of a method according to the invention for producing a multilayer film 2 for generating or storing electrical energy. As can be seen in Fig. 1, the method according to the invention comprises the steps of feeding 100 a starting material 2.1 via a feeding unit 8, processing 200 of the starting material 2.1 to a homogeneous melt 2.2 within an extruder 6, conveying 300 of the melt 2.2 through the extruder 6 to an extruder die head 14 by means of a conveying means 6.1, distributing 400 of the melt 2.2 uniformly within the extruder die head 14 by means of a melt distributor 14.1, and drawing 500 of the melt 2.2 out of the extruder die head 14 through an opening 9 of a nozzle 10 of the extruder die head 14 to form a continuous multilayer material film 2.3 as well as a post-processing 600 of the continuous multilayer material film 2.3 to form the multilayer film 2 using post-processing means 16.

[0062] The starting material 2.1 can be tempered after being fed 100 inside the extruder 6, preferably via a plurality of tempering devices 12.1 of the tempering unit 12 arranged along the extruder 6.

[0063] The starting material 2.1 can be fed to the extruder 6 via a metering device 8.1, preferably in the form of granules or pellets.

[0064] Furthermore, the starting material 2.1 can be continuously conveyed within the extruder 6 by means of a conveying device 6.1 in the form of a screw up to the extruder nozzle head 14.

[0065] The post-processing 600 of the continuous multilayer material film 2.3 to form the multilayer film 2 can include cooling, e.g., via air cooling 16.1 and / or water cooling. Cooling by contact with a solid, preferably cooled, surface is also conceivable.

[0066] Similarly, the post-processing 600 of the continuous multilayer material film 2.3 to form the multilayer film 2 can include stretching the continuous multilayer material film 2.3, sealing individual layer complexes, or laminating individual layers. Furthermore, the post-processing 600 of the continuous multilayer material film 2.3 can include drying and / or coating, e.g., with metal or redox-active material.

[0067] Advantageously, a plurality of extruders 6 can be used simultaneously to produce the multilayer film 2, wherein the plurality of extruders 6 preferably each simultaneously convey their own homogeneous melt 2.2 to a central extruder die head 14 and a continuous multilayer material film 2.3 is conveyed out through an opening 9 of a nozzle 10 of the extruder die head 14.

[0068] Fig. 2 shows a schematic representation of a film extrusion plant 4 according to the invention for the production of a multilayer film 2 for the generation or storage of electrical energy according to a first embodiment in a sectional view.

[0069] As can be seen in Fig. 2, the film extrusion system 4 according to the invention comprises a feeding unit 8 for feeding 100 of a starting material 2.1, an extruder 6 (shown in detail by way of example) equipped with an extruder die head 14 for processing 200 of the starting material 2.1 into a homogeneous melt 2.2, for conveying 300 of the melt 2.2 to the extruder die head 14 and for conveying 500 of the melt 2.2 through an opening 9 of a nozzle 10 of the extruder die head 14 to form the continuous multilayer material film 2.3, a melt distributor 14.1 for uniformly distributing 400 of the melt 2.2 within the extruder die head 14, and finishing means 16 for finishing 600 of the continuous multilayer material film 2.3 to form the multilayer film. 2.

[0070] The melt distributor 14.1 is predominantly frustoconical in shape and comprises a plurality of frustoconical units for producing one layer each of a continuous multilayer material film 2.3.

[0071] The extruder 6 includes a temperature control unit 12 with a plurality of temperature control devices 12.1 arranged symmetrically along the extruder 6.

[0072] The feeding unit 8 further comprises a metering device 8.1 for feeding the feed material 2.1 into the extruder 6 in the form of granules or pellets. The extruder 6 also comprises a conveying element 6.1 in the form of a screw for the continuous conveying of the feed material 2.1.

[0073] Likewise, the post-processing means 16 for cooling the continuous multilayer material film 2.3 can be seen, which in this case are designed in the form of an air cooling system 16.1 and in the form of a roller 16.2 for rolling the continuous multilayer material film 2.3 before it is transported in the form of a multilayer film 2 over the deflection rollers 18 and wound in the winder 20.

[0074] In addition, (to simplify matters) a plurality of further extruders 6 are provided for the production of the multilayer film 2, which are connected to one and the same central extruder die head 14 for the supply of a melt 2.2.

[0075] Fig. 3 shows a schematic representation of a film extrusion plant 4 according to the invention for the production of a multilayer film 2 for the generation or storage of electrical energy according to a further embodiment in a block view.

[0076] As can be seen in Fig. 3, the film extrusion plant 4 according to the invention comprises a total of five extruders 6, in each of which starting material 2.1 is added at the extruder inlet together with up to four different auxiliary components 3. The mixture is then melted and homogenized in the extruders 6. Optionally, another product can also be synthesized from the mixture within the extruder 6.

[0077] In addition, further auxiliary components 3 can also be added to the extruders 6 later during extrusion.

[0078] Residual materials 5 can be discharged from the extruders during extrusion.

[0079] Furthermore, as can be seen in Fig. 3, extruded material can also be fed from one extruder 6 (see the upper and lower extruder 6) into another extruder.

[0080] As shown in Fig. 3, the material extruded from the three central extruders 6 is fed into the extruder head 14 in the form of a homogeneous melt 2.2. The extruder head 14 has a blow head with a wide-slot die in which the homogeneous melt 2.2 (in the form of melt layers) is layered on top of each other.

[0081] The continuous multilayer material film 2.3 is then extracted from the extruder head 14, from which, after post-processing 600, e.g. in the form of cooling and / or stretching, the multilayer film 2 is formed.

[0082] The multi-layered film 2 can comprise three, five, seven, or nine layers and can then be cut to size and assembled into battery pouches. Individual layers or layer complexes can optionally be laminated and / or coated.

[0083] Fig. 4a shows a schematic representation of a multilayer film 2 in the form of a battery for storing electrical energy in a sectional view according to a first embodiment.

[0084] The multilayer film 2 according to the first embodiment comprises 9 layers, two outerly arranged insulator layers 38, two electrode layers 36, an anode layer 34.1 and a cathode layer 34.2, two electrolyte layers 32 and a centrally arranged separator layer 30.

[0085] All layers of the multilayer film 2 can be produced in one process cycle, but at least more layers than the separator layer 30, which provides electrical insulation between the anode layer 34.1 and the cathode layer 34.2.

[0086] The electrode layers 36 represent the inactive part of an electrode, which is in electrical contact with the redox-active part of the electrode. They collect the electrons from the redox-active layers and establish the electrical contact with other conductors, such as cables or other battery cells. (In conventional batteries, these layers are often made of metal foils. These foils are preferably coated with a cream of redox-active material and dried.) According to the invention, it can advantageously be provided that they are manufactured together with all other layers. Their function is "only" to conduct electricity. They contain no electrolyte and preferably consist only of a conjugated polymer that has been made intrinsically conductive by doping. However, an extrinsically conductive mixture of materials, e.g., a normal PE with conductive carbon black, is also conceivable.

[0087] It is also conceivable to combine the active and passive layers of an electrode into one layer, especially if the active layer itself consists of an intrinsically conductive polymer.

[0088] The insulating layers 38 consist of electrically non-conductive polymers. In addition to their insulating function, the outer layers can also contribute to the mechanical stabilization of the composite. This makes it possible to use mechanically less stable materials in the interior of the composite.

[0089] To enable electrical contact between the battery cells, the outer layers can have at least a partially less rigid connection with their neighboring layers. This allows the outer layer to be partially detached from the rest of the composite to expose the electrically conductive layers.

[0090] Fig. 4b shows a schematic representation of a multilayer film 2 in the form of a battery for storing electrical energy in a sectional view according to a second embodiment, in which the separator layer 30.1, the anode layer 34.3 and the cathode layer 34.4 are mixed with an electrolyte or the electrolyte layer 32, which can be achieved by simultaneously extruding a liquid in the form of a suitable electrolyte with the respective solid of a layer.

[0091] Fig. 4c shows a schematic representation of a multilayer film 2 in the form of a battery for storing electrical energy in a sectional view according to a third embodiment.

[0092] The multilayer film 2 according to the third embodiment comprises only seven layers, in that the electrolyte layers 32 are integrated into the separator layer 30.1, so that the separator layer 30.1 can conduct ions but prevents charge exchange.

[0093] The separator layer 30.1 can be extruded with a larger quantity of homogeneously mixed electrolyte so that the required nanoporosity can be achieved without stretching. The electrolyte is preferably not washed out, but remains within the layer structure and can thus participate in the subsequent redox reaction.

[0094] The lower stability of the separator layer 30.1 compared to a conventional separator layer 30 can be compensated for by integrating the layer into a composite of several other layers, such as the directly adjacent electrode layers 36.

[0095] Fig. 4d shows a schematic representation of a multilayer film 2 in the form of a battery for storing electrical energy in a sectional view according to a fourth embodiment.

[0096] The multilayer film 2 according to the fourth embodiment comprises only three layers: an anode layer with electrolyte 34.3, a cathode layer with electrolyte 34.4 and a separator layer with electrolyte 30.1 arranged between them.

[0097] References list multilayer film Starting material homogeneous melt continuous multilayer material film Auxiliary components Film extrusion plant Residues Extruder Conveyor Feeding unit Metering device Opening Nozzle Temperature control unit Temperature control agent Extruder die head Melt distributor Post-processing agent Air cooling Roller Deflection roller Winder First layer / separator layer First layer / separator layer with electrolyte Electrolyte layer Second layer / anode layer Third layer / cathode layer Second layer / anode layer with electrolyte Third layer / cathode layer with electrolyte Electrode layer Insulator layer Feeding of a starting material

[0098] Processing the starting material into a homogeneous melt

[0099] Conveying the melt through an extruder

[0100] Even distribution of the melt within an extruder die head

[0101] Extracting the melt from the extruder nozzle head to form a continuous multilayer material film.

[0102] Post-processing of the continuous multi-layered material film

Claims

1. Method for producing a multilayer film (2) for generating or storing electrical energy using a film extrusion plant (4), comprising the steps: - Feeding (100) a starting material (2.1) via a feeding unit (8), - Processing (200) the starting material (2.1) into a homogeneous melt (2.2) within an extruder (6), Conveying (300) the melt (2.2) through the extruder (6) to an extruder die head (14) by means of a conveying means (6.1), - Uniform distribution (400) of the melt (2.2) within the extruder die head (14) by means of a melt distributor (14.1), Extraction (500) of the melt (2.2) from the extruder die head (14) through an opening (9) of a nozzle (10) of the extruder die head (14) to form a continuous multilayer material film (2.3), post-processing (600) of the continuous multilayer material film (2.3) to form the multilayer film (2) by means of post-processing means (16).

2. Method according to claim 1, characterized in that the starting material (2.1) is tempered after being fed (100) inside the extruder (6), preferably via a plurality of tempering means (12.1) of a tempering unit (12) arranged along the extruder (6).

3. Method according to claim 1 or 2, characterized in that the starting material (2.1) is fed to the extruder (6) via a metering device (8.1), wherein the starting material (2.1) is preferably fed in the form of granules or pellets.

4. Method according to one of the preceding claims, characterized in that the starting material (2.1) is conveyed continuously within the extruder (6) by means of a conveying means (6.1) in the form of a screw up to the extruder die head (14).

5. Method according to one of the preceding claims, characterized in that the post-processing (600) of the continuous multilayer material film (2.3) to form the multilayer film (2) comprises cooling, wherein the cooling of the continuous multilayer material film (2.3) is preferably carried out via air cooling (16.1) and / or water cooling.

6. Method according to one of the preceding claims, characterized in that the post-processing (600) of the continuous multilayer material film (2.3) to form the multilayer film (2) comprises cutting, wherein the continuous multilayer material film (2.3) is preferably cut to predetermined area dimensions.

7. Method according to one of the preceding claims, characterized in that the post-processing (600) of the continuous multilayer material film (2.3) to form the multilayer film (2) comprises rolling it into a rolled multilayer film unit.

8. Method according to one of the preceding claims, characterized in that the post-processing (600) of the continuous multilayer material film (2.3) to form the multilayer film (2) comprises stretching the continuous multilayer material film (2.3), wherein the stretching preferably takes the form of oriented stretching and / or temperature-controlled stretching and / or multi-axial stretching.

9. Method according to one of the preceding claims, characterized in that the post-processing (600) of the continuous multilayer material film (2.3) to form the multilayer film (2) comprises sealing individual layer complexes.

10. Method according to one of the preceding claims, characterized in that the post-processing (600) of the continuous multilayer material film (2.3) to form the multilayer film (2) comprises drying and / or coating, wherein the coating is preferably carried out with redox-active material, in particular with a metal.

11. Method according to one of the preceding claims, characterized in that the post-processing (600) comprises the use of at least one of the following influencing factors: chemicals, heat, cold, pressure, mechanical vibrations, electromagnetic radiation.

12. Method according to one of the preceding claims, characterized in that excess solids, liquids or gases are discharged from the extruder (6), wherein the discharge of excess solids, liquids or gases is preferably carried out via a discharge device.

13. Method according to one of the preceding claims, characterized in that the starting material (2.1) is a thermoplastic material, wherein the starting material (2.1) preferably comprises at least one of the following polymers: polyethylene, polyamide, polyethylene terephthalate, polypropylene.

14. Method according to one of the preceding claims, characterized in that the starting material (2.1) comprises a conjugated polymer, wherein the starting material (2.1) preferably comprises at least one of the following conjugated polymers: polyacetylene, polyaniline, polypyrrole, poly(p-phenylenevinylene), polyflurene, polythiophene.

15. Method according to one of the preceding claims, characterized in that the starting material (2.1) comprises strength-stabilizing additives, wherein the strength-stabilizing additives preferably comprise a binder.

16. Method according to one of the preceding claims, characterized in that a plurality of extruders (6) are used simultaneously for the production of the multilayer film (2), wherein preferably the plurality of extruders (6) are used simultaneously for the production of the continuous multilayer material film (2.3), wherein in particular the plurality of extruders (6) simultaneously each convey a homogeneous melt (2.2) to a central extruder die head (14) and the continuous multilayer material film (2.3) is discharged through an opening (9) of a nozzle (10) of the extruder die head (14).

17. Method according to one of the preceding claims, characterized in that the starting material (2.1) contains an electrically conductive polymer, wherein the electrically conductive polymer is preferably contained in the starting material (2.1) to a proportion of at least 40 wt.%, particularly preferably to a proportion of at least 60 wt.%, and in particular to a proportion of at least 80 wt.%.

18. Method according to one of the preceding claims, characterized in that the electrically conductive polymer is synthesized only after the addition (100) of the starting material (2.1) during the method, wherein the electrically conductive polymer is preferably contained to a proportion of at least 40 wt.% in the continuous multilayer material film (2.3), particularly preferably to a proportion of at least 60 wt.%, and in particular to a proportion of at least 80 wt.%.

19. Method according to one of the preceding claims, characterized in that the electrically conductive polymer has an electrical conductivity of at least 10' 2 S / cm, preferably of at least 1 S / cm, in particular of at least 10 2 exhibits S / cm.

20. Method according to one of the preceding claims, characterized in that the electrically conductive polymer is in the form of a doped polymer, wherein the electrically conductive polymer is preferably in the form of an n-type doped polymer.

21. Method according to one of the preceding claims, characterized in that the electrically conductive polymer has an energy density of at least 40 kJ / kg, preferably at least 50 kJ / kg, in particular at least 60 kJ / kg.

22. Method according to one of the preceding claims, characterized in that the electrically conductive polymer comprises electron-donating aromatic monomers, preferably pyrrole, thiophene, aniline, benzene or mixtures and / or derivatives thereof.

23. Method according to one of the preceding claims, characterized in that the electrically conductive polymer comprises electron-donating aromatic monomers, wherein preferably at least some of the electron-donating aromatic monomers are at least partially halogenated.

24. A method according to one of the preceding claims, characterized in that, in addition to the starting material (2.1), at least one further material is supplied to the extruder (6), wherein the further material is preferably supplied in liquid form, wherein the further material is in particular an electrolyte and / or a solvent, wherein the electrolyte particularly preferably comprises N-ethyl-N-(2-methoxyethyl)-N,N-dimethylammonium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, ethylene carbonate solutions, dimethyl carbonate solutions, propylene carbonate solutions, dimethyl carbonate, ethyl methyl carbonate or mixtures and derivatives thereof, and / or the solvent comprises water, benzene, carbonate, acetonitrile, dichloromethane, chloroform or mixtures and derivatives thereof.

25. Method according to one of the preceding claims, characterized in that the further material is a catalyst or comprises a catalyst, wherein the catalyst preferably enables the attachment of redox-active groups to the starting material (2.1).

26. Method according to one of the preceding claims, characterized in that the porosity within the starting material (2.1) is increased by the addition of the further material, preferably generating nanoporosity within the starting material (2.1).

27. Method according to one of the preceding claims, characterized in that the further material comprises a conductive carbon black to improve the electrical conductivity.

28. Film extrusion plant (4) for producing a multilayer film (2) for generating or storing electrical energy, preferably using a method according to one of the preceding claims, comprising: - a feeding unit (8) for feeding (100) a starting material (2.1), - an extruder (6) equipped with an extruder die head (14) for processing (200) the starting material (2.1) into a homogeneous melt (2.2), for conveying (300) the melt (2.2) to the extruder die head (14) and for expelling (500) the melt (2.2) through an opening (9) of a nozzle (10) of the extruder die head (14) to form a continuous multilayer material film (2.3), - a melt distributor (14.1) for the uniform distribution (400) of the melt (2.2) within the extruder die head (14), Post-processing means (16) for post-processing (600) of the continuous multilayer material film (2.3) to form the multilayer film (2).

29. Film extrusion plant (4) according to one of the preceding claims, characterized in that the extruder (6) has a temperature control unit (12), wherein the temperature control unit (12) preferably has a plurality of temperature control means (12.1) arranged along the extruder (6), wherein the temperature control means (12.1) are in particular arranged symmetrically along the extruder (6).

30. Film extrusion plant (4) according to one of the preceding claims, characterized in that a metering device (8.1) is provided for feeding the starting material (2.1) into the extruder (6), wherein the metering device (8.1) is designed such that the starting material (2.1) can be fed via the metering device (8.1) in the form of granules or in the form of pellets.

31. Film extrusion plant (4) according to one of the preceding claims, characterized in that the extruder (6) has a conveying means (6.1) in the form of a screw for the continuous conveying of the starting material (2.1), wherein the screw is preferably designed in the form of a simple screw, a twin screw, a conical screw, a sheared screw or a degassing screw.

32. Film extrusion plant (4) according to one of the preceding claims, characterized in that post-processing means (16) are provided for cooling the continuous multilayer material film (2.3), wherein the post-processing means (16) preferably have air cooling (16.1) and / or water cooling.

33. Film extrusion plant (4) according to one of the preceding claims, characterized in that the post-processing means (16) comprise a cutting device for cutting the continuous multilayer material film (2.3) to predetermined area dimensions and / or a winder (20) for winding the continuous multilayer material film (2.3) into a multilayer film unit and / or a stretching device for stretching the continuous multilayer material film (2.3) and / or a sealing device for sealing individual layer complexes of the continuous multilayer material film (2.3).

34. Film extrusion plant (4) according to one of the preceding claims, characterized in that a plurality of extruders (6) are provided for the production of the multilayer film (2), wherein preferably the plurality of extruders (6) for the supply of a melt (2.2) are connected to one and the same central extruder die head (14).

35. Film extrusion system (4) according to one of the preceding claims, characterized in that the extruder die head (14) is designed in the form of a blow head, wherein the blow head preferably has a ring die.

36. Film extrusion plant (4) according to one of the preceding claims, characterized in that the melt distributor (14.1) is frustoconical and has a plurality of frustoconical units for producing one layer each of a continuous multilayer material film (2.3), wherein preferably each of the frustoconical units has a channel for supplying a melt (2.2).

37. Film extrusion plant (4) according to one of the preceding claims, characterized in that a discharge device is provided for the discharge of excess solids, liquids or gases from the extruder (6).

38. Multilayer film (2) for generating or storing electrical energy, produced by a method according to one of the preceding claims, preferably using a film extrusion system (4) according to one of the preceding claims, comprising: - a second layer (34.1 , 34.3), - a third layer (34.2, 34.4), - a first layer (30, 30.1) arranged between the second layer (34.1, 34.3) and the third layer (34.2, 34.4).

39. Multilayer film (2) according to one of the preceding claims, characterized in that more than three different layers (34.1, 34.3), (34.2, 34.4), (30, 30.1) are provided, preferably more than five different layers, in particular more than seven different layers.

40. Multilayer film (2) according to one of the preceding claims, characterized in that at least one layer is designed as an insulator layer (38) or as an electrode layer (36) or as an anode layer (34.1, 34.3) or as a cathode layer (34.2, 34.4) or as an electrolyte layer (32) or as a separator layer (30, 30.1).

41. Multilayer film (2) according to one of the preceding claims, characterized in that the multilayer film (2) is designed such that a reversible chemical reaction, preferably a redox reaction, can be carried out by selectively applying an electrical voltage to parts of the multilayer film (2).

42. Multilayer film (2) according to one of the preceding claims, characterized in that the multilayer film (2) has an amorphous content of > 40%, preferably of > 60%, in particular of > 80%.

43. Multilayer film (2) according to one of the preceding claims, characterized in that the second layer (34.1, 34.3) and the third layer (34.2, 34.4) comprise an electrically conductive polymer and the first layer (30, 30.1) is formed in the form of a separator layer for electrical insulation between the second layer (34.1, 34.3) and the third layer (34.2, 34.4).

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