Apparatus for coating a sheet-like carrier material with a coating material

Abstract

The invention relates to an apparatus for coating a sheet-like carrier material (1) with at least one, at least partly liquid, coating material (3), such as a ceramic slurry and / or an adhesion promoter, the apparatus comprising a continuously rotating microgravure roll (2), which is designed to transfer the coating material, via a circumference (21) of the microgravure roll, to the sheet-like carrier material transported in an advancing direction (11). It is provided that the apparatus has a pressure-chamber doctor blade (4), which is designed to transfer the coating material under positive pressure to the circumference of the microgravure roll. Also described is an arrangement for producing a coated carrier material and / or substrate, in particular a separator film and / or a current collector.

Description

[0001] DEVICE FOR COATING A WEB-SHAPED CARRIER MATERIAL WITH A COATING MATERIAL

[0002] DESCRIPTION

[0003] The invention relates to the technical field of the production of coatings of a web-shaped carrier material, such as a film, a foil, a nonwoven, a net and / or a fiber composite, for example separator films, in particular devices for the production of carrier materials used in lithium-ion batteries, such as ceramic separator films and / or current collectors optionally provided with at least one adhesion promoter.

[0004] Separator films are used in batteries to spatially separate electrodes. To achieve this, a separator film must act as a barrier to the conduction of electrons to prevent short circuits between the electrodes. Furthermore, the separator film must enable the transport of ions between the electrodes. For these reasons, separator films are often made of ceramic materials, with advantageous properties of the separator film being achieved by specifically adjusting the porosity during production.

[0005] To increase the specific energy density of a battery, the separator should be as thin and light as possible. To prevent battery fire or thermal runaway, however, the film's mechanical strength must be ensured. As such, particularly stringent requirements are placed on the achievable tolerances of the manufacturing process and equipment.

[0006] For this purpose, a web-shaped carrier material can be coated with a coating material or a coating composition comprising and / or consisting of a ceramic slurry. The ceramic slurry is a suspension of a solvent, usually deionized water, and ceramic raw material particles. The ceramic slurry layer is then transferred to a dryer, where the solvent is evaporated. The coating of the web-shaped carrier material already has a decisive influence on the aforementioned critical properties of the separator film.

[0007] Current collectors are used to at least partially form electrodes within batteries, particularly lithium polymer batteries. For this purpose, the current collectors are bonded to the active anode or cathode material. A bonding agent is used to ensure adhesion between the anode or cathode material and the current collector, particularly during charging and / or discharging of the battery. The active anode or cathode material, together with the current collector to which they are applied, then forms the respective electrode.

[0008] In particular, such a current collector can be in the form of a film, fibers, a fleece, a mesh, which can in particular be smooth, rough, or perforated, wherein the current collector can optionally comprise electrically conductive polymers, e.g., polypyrrole, polyaniline, polythiophene, or the like, or at least one filled plastic. The filled plastic can comprise, for example, carbon black, graphite, metal powder, or the like, or can itself be electrically conductive, at least in some areas. Furthermore, the current collector can comprise, at least in some areas, at least one metal, such as silver, copper, tin, aluminum, titanium, chromium, and / or nickel, wherein the metal can also be present as a coating on at least one plastic film or at least one other material.

[0009] From the above it follows that the adhesion promoter is an important component of the electrode, as it ensures the adhesion of the anode or cathode mass and the material comprised by the current collector. The adhesion or bonding of the transition metal oxides or carbons should fulfill the following bonds. The adhesion to the current collector should be stable even over longer cycling periods, in particular more than 200 charge or discharge cycles, i.e. it should not show any detachment and be so stable that even mechanical stress such as kinking or pressing pressure do not lead to cracks, detachment or displacement of the anode or cathode mass from the current collector. The active mass for the cathode is usually transition metal oxides such as Co(III) oxide, Ni(II) oxide, Mn(IV) oxide, tungstates, molybdates, titanates, ferrates and chromates, each in the Li-containing form, e.g. E.g. LiCoO2, LiNiO2, LiMn2O4 etc.- and graphite, carbon, carbon black and fibres are usually considered as active masses for the anode.

[0010] The adhesion promoter can comprise a polymer that is indifferent to the processes and ion exchange reactions in the battery system and ensures the adhesion of the anode or cathode materials to the current collector. For example, the adhesion promoter comprises polyolefins such as polyisobutenes, EPDM rubbers, and styrene-butadiene (isoprene) polymers. The molecular weights of the polymers can be between 20,000 and 2,000,000, preferably between 50,000 and 300,000. The amount used can be between 2 and 25 wt.%, preferably between 3.5 and 15 wt.%.

[0011] This choice of material ensures that sufficient electrical conductivity—a prerequisite for the effectiveness of the electrode system—is provided. It is preferable that the proportion of adhesion promoter in the active anode or cathode mass does not exceed 25% based on the solid mass; for example, it is preferably 5-15% by mass. Furthermore, to improve electrical conductivity, electrically conductive fillers such as conductive carbon black, graphite, polypyrrole, polyaniline, or similar materials can be added to the adhesion promoter in quantities of up to 50% by mass, based on the adhesion promoter.

[0012] A device for coating with a conventional coating fluid, for example ink or adhesive, has a continuously rotating micro-engraving roller which is designed to transfer the coating fluid via a circumference of the micro-engraving roller onto a web-shaped carrier material transported in a feed direction. Such a device is described in EP 0 214 574 A1. In order to transfer the coating fluid to the circumference of the micro-engraving roller, a corresponding device has a rinsing trough, i.e. an open element, and a doctor blade which forms an application gap with the circumference of the micro-engraving roller along a length of the micro-engraving roller. The coating fluid is metered directly into the application gap via the rinsing trough and transferred to the circumference. The problem here is that a ceramic slurry, in particular for a separator film, orAn adhesion promoter, especially for a current collector, differs from a conventional coating fluid. In particular, the slurry or adhesion promoter is a multiphase fluid with solid particles, which is prone to sedimentation. The ceramic raw material particles or solid particles tend to form deposits on the walls of the device, particularly on the doctor blade. As the device's operating time increases, the flow field within the device changes. To ensure precise manufacturing tolerances, operation must be interrupted regularly to thoroughly clean the device of deposits.

[0013] Further problems arise from the ingress of ambient air into the ceramic slurry and / or the adhesion promoter, which inherently occurs in a rinsing chamber. In a device known from the prior art, this ingress results in coating defects, for example insufficiently wetted membrane areas due to microbubbles. If microbubbles within the ceramic slurry or the adhesion promoter are transported onto the web using an engraved roller, defects form there because the air bubble displaces the coating compound or the coating material. This means that there is no or too little ceramic slurry and / or adhesion promoter at these points. These defects reduce the protective effect of the ceramic layer and / or the conductivity and / or adhesive effect of the adhesion promoter.

[0014] In particular, the solid particles contained in the adhesion promoter, particularly those used to achieve electrical conductivity, tend to sediment and foam during application to the carrier material or substrate that at least partially forms the current collector. For example, conductive carbon black, when used as a main component of the adhesion promoter, tends to form chain-like agglomerates. Due to the good affinity of these carbon black agglomerates to air, the resulting microfoam is additionally stabilized. Typical coating defects resulting from such microfoam are "pinholes." These can arise from burst microbubbles after application of the adhesion promoter to the current collector, particularly regardless of whether carbon black or other solid particles are used as the solid particles.Agglomerates and deposits of solid particles can also lead to an uneven, particularly streaky and / or cloudy coating. This can lead to deposits of components of the coating material or coating compound in the application unit due to sedimentation / separation, resulting in uneven transfer to the current collector.

[0015] Furthermore, the ceramic slurry and / or adhesion promoter differs from conventional coating compounds or coating fluids in terms of rheology. As such, the ceramic slurry or adhesion promoter tends to splash even at moderate rotation speeds of the gravure roller or at low feed speeds of the web. Splashes that reach the web lead to coating defects. Furthermore, the surrounding area must be protected against heavy contamination through design measures at the coating unit.

[0016] The conventionally used gravure rollers with a diameter between 250 mm and 400 mm have either excessively large or insufficient curvature radii. In the resulting wide coating line formed between the gravure roller and the substrate, separation processes occur between the ceramic solids and the solvent of the ceramic slurry or the adhesion promoter in the area of ​​the transfer point to the web. This leads to an undesirable, streaky coating.

[0017] It is therefore an object of the invention to further develop the device described above so that it is suitable for coating a web-shaped carrier material with a ceramic slurry or an adhesion promoter. A corresponding device is described in claim 1. Advantageous embodiments are the subject of claims 2 to 14. Claim 15 describes an arrangement for producing a ceramic separator film or a current collector, which has a corresponding device.

[0018] Accordingly, it is provided that the device has a pressure chamber doctor blade which is designed to transfer the ceramic slurry or the adhesion promoter to the circumference of the micro-engraving roller. A device for coating a web-shaped carrier material with at least one coating material which is at least partially liquid is thus supplied, wherein the device comprises a continuously rotating micro-engraving roller which is designed to transfer the coating material over a circumference of the micro-engraving roller to the web-shaped carrier material transported in a feed direction, wherein the device has a pressure chamber doctor blade which is designed to transfer the coating material under excess pressure to the circumference of the micro-engraving roller.

[0019] It is proposed that the at least partially liquid coating material comprises at least one ceramic slurry and / or at least one adhesion promoter.

[0020] When coating the web-like substrate with the ceramic slurry, the micro-engraving roller is characterized by its comparatively small diameter. This small diameter and the associated small radius of curvature counteract unwanted separation processes. The micro-engraving roller can have a diameter between 60 mm and 150 mm.

[0021] However, the smaller diameter of the micro-engraving roller in such devices often has a negative impact on the maximum achievable substrate speed. Especially at high substrate speeds and thus significantly higher rotation speeds of the micro-engraving roller compared to conventional engraved rollers, the low-viscosity ceramic slurry tends to detach from the engraved roller due to centrifugal force, causing it to splash or mist. The pressure chamber doctor blade, however, negates this effect, allowing a high substrate speed to continue. The substrate speed can be up to 500 m / min. The feed direction and the rotation direction of the micro-engraving roller can be opposite.

[0022] The device can thus be characterized in that the feed direction and a rotation direction of the micro-engraving roller are opposite in a region of at least one coating line, which is formed in particular between the micro-engraving roller and the web-shaped carrier material. Furthermore, the pressure chamber doctor blade can have a pressure chamber that borders a first circumferential portion of the micro-engraving roller and is sealed from the surroundings of the device.

[0023] For the device, it is therefore proposed that the pressure chamber doctor blade has at least one pressure chamber, which is open, in particular, to the micro-engraving roller and / or sealed from the environment of the device. Compared to an open element known from the prior art, such as a filling trough, a pressure chamber represents a closed system in which an overpressure can be built up.

[0024] In the pressure chamber, the overpressure applied on the inlet side of the pressure chamber creates a liquid barrier between the adjacent pressure chamber doctor blade and the micro-engraving roller, minimizing air ingress into the pressure chamber. The ceramic slurry in the pressure chamber remains largely free of microbubbles. The overpressure in the pressure chamber can range from 50 to 800 mbar, particularly 100 to 500 mbar.

[0025] It is therefore proposed for the device that an overpressure of 50 to 800 mbar, preferably 100 to 500 mbar, is present in the pressure chamber

[0026] Further advantages of the overpressure in the pressure chamber result from faster filling of the cups and / or engraving lines of the micro-engraving roller. Since only a very small amount of ceramic slurry is applied, the scoop volume of the micro-engraving roller is small, resulting in very fine structures. The device can be configured to coat the substrate with a specific surface weight of the ceramic slurry of less than 10 g / m², in particular less than 5 g / m².

[0027] Especially at high coating speeds, filling problems with the cups and / or engraving lines of the micro-engraving roller often occur in these types of devices. The overpressure in the pressure chamber helps accelerate the filling of cups and / or engraving lines, thus enabling these coating speeds. Furthermore, these fluids can easily be "overdosed" on a doctor blade on the outgoing side. Due to a positive pressure gradient between the pressure chamber and the ambient pressure, additional coating fluid flows downstream below the doctor blade and overfills the engraving roller in a controlled manner, which has a positive influence on the transfer of the fluid to the web and thus on the coating quality.

[0028] The pressure chamber doctor blade can have an outgoing and an incoming doctor blade, which seal the pressure chamber from the environment in the direction of rotation of the micro-engraving roller or against the direction of rotation of the micro-engraving roller.

[0029] The pressure chamber can have a feed line configured to meter the ceramic slurry into the pressure chamber. The pressure chamber can also have an outlet configured to remove the ceramic slurry from the pressure chamber. In this way, a statistical residence time of the ceramic slurry within the device can be precisely adjusted. As such, the slurry is not only removed from the pressure chamber via the circumference of the micro-engraving roller, but can also be discharged via the outlet via a controlled mass flow. If the residence time is too long, the ceramic slurry tends to coagulate the ceramic raw material particles, which increasingly changes the particle diameter distribution. This, in turn, accelerates sediment degradation and significantly affects the porosity of the separator film.

[0030] For the device, it is therefore proposed that the pressure chamber has at least one feed line, which is particularly designed to at least partially meter the coating material, in particular the ceramic slurry and / or the adhesion promoter, into the pressure chamber.

[0031] Alternatively or additionally, it is further proposed for the device that the pressure chamber has at least one outlet through which the coating material, in particular the ceramic slurry and / or the adhesion promoter, is discharged from the pressure chamber. Furthermore, it is preferred that the pressure chamber doctor blade has at least one pressure reservoir upstream of the feed line and / or downstream of the outlet, in particular in each case, which preferably provides an additional volume for the coating material, in particular the ceramic slurry and / or the adhesion promoter, to avoid pressure fluctuations in the pressure chamber.

[0032] The pressure chamber doctor blade can have a pressure reservoir upstream of the feed line and / or downstream of the discharge line to prevent pressure fluctuations in the pressure chamber. This is an additional volume for the ceramic slurry, which is fluidly connected to the pressure chamber and supports the distribution of the ceramic slurry over a length of the pressure chamber doctor blade parallel to the longitudinal axis of the micro-engraving roller. Transient effects, such as fluctuations in the rotational speed of the micro-engraving roller or the mass flow provided by the pump, result in pressure fluctuations within the pressure chamber doctor blade. Large volumes of ceramic slurry within the pressure chamber doctor blade counteract the amplitude of these pressure fluctuations.Thus, the additional volume provided by the pressure reservoir allows the pressure chamber volume to be kept small without pressure fluctuations within the pressure chamber negatively impacting the porosity or coating thickness. The small volume of the pressure chamber, on the other hand, counteracts sedimentation within the pressure chamber.

[0033] In addition, the device may comprise a filter unit for filtering the ceramic slurry, which is fluidically connected to the pressure chamber doctor blade and arranged upstream of the inflow.

[0034] It is therefore proposed for the device that the device has at least one filter unit, in particular for filtering the coating material, in particular the ceramic slurry and / or the adhesion promoter, which is in particular fluidically connected to the pressure chamber doctor blade and / or is preferably arranged upstream of the feed line.

[0035] In particular, the feed line can have at least one nozzle through which the ceramic slurry can be metered into the pressure chamber and which is designed to induce a rotating flow field within the pressure chamber. Due to the constriction of the flow cross-section within the nozzle, the ceramic slurry is accelerated before entering the pressure chamber. The inflow angle of the nozzle is directed away from a geometric center of gravity of the pressure chamber, thereby inducing a rotating flow field. This results in continuous mixing of the ceramic slurry within the pressure chamber, which counteracts coagulation. Furthermore, the rotating flow field results in near-wall velocity gradients within the pressure chamber, which prevents sedimentation on the walls of the pressure chamber or breaks down the sediment layer.

[0036] In other words, it is proposed that the feed line has at least one nozzle via which the coating material, in particular the ceramic slurry and / or the adhesion promoter, can preferably be metered into the pressure chamber and / or which is designed to induce at least one rotating flow field within the pressure chamber.

[0037] The feed line can have at least two nozzles, each having different inflow positions and / or inflow angles to induce the rotating flow field. The at least two nozzles can have two opposing inflow angles and inflow positions on opposite sides of the pressure chamber. The at least two nozzles can be configured to alternately change a direction of rotation of the rotating flow field. For this purpose, the nozzles can be configured to individually control a metered mass flow of the ceramic slurry. Alternatively or additionally, the inlet can have a swirl flap. Preferably, a rotation axis of the rotating flow field can be parallel to a rotation axis of the micro-engraving roller. Furthermore, the pressure chamber can have a flow-guiding wall geometry configured to induce the rotating flow field.

[0038] In other words, it is proposed for the device that the feed line has at least two nozzles, which preferably each have different inflow positions and / or inflow angles, in particular to induce the rotating flow field. It is preferred that the at least one nozzle is configured to induce a rotational axis of the rotating flow field parallel to a rotational axis of the micro-engraving roller.

[0039] The device may comprise a first guide roller and a second guide roller, wherein the first guide roller and the second guide roller are configured to guide the web-shaped carrier material over a circumferential portion of the micro-engraving roller.

[0040] In other words, it is proposed for the device that the device has at least one first guide roller and / or at least one second guide roller, wherein preferably the first guide roller and / or the second guide roller is / are designed to guide the web-shaped carrier material over a circumferential section of the micro-engraving roller.

[0041] This is advantageous for the transfer of the ceramic slurry in the so-called kiss-coating process: The micro-engraving roller is positioned between two guide rollers on the substrate, forming a coating line – the kiss-coating line – between the engraved roller and the web. The overfilling of the engraved roller by excess pressure within the pressure chamber and the resulting full-surface contact of the coating fluid in the area of ​​the kiss-coating line with the web promotes uniform coating of the web-like substrate.

[0042] The peripheral section can have a wrap angle of 0.5° to 40°, preferably 5° to 30°, and preferably 8° to 22°. Thus, even a tangential contact of the carrier material with the micro-engraving roller may be sufficient to ensure transfer of the coating material.

[0043] A diameter of the first and / or second guide roller can be larger than a diameter of the micro-engraving roller, in particular a multiple larger than a diameter of the micro-engraving roller.

[0044] The diameter of the first and / or second guide roller can be smaller than the diameter of the micro-engraving roller. This allows the micro-engraving roller to be positioned with a small gap between the first and second guide rollers. This results in good contact between the material web guided between the first and second guide rollers and the micro-engraving roller. This results in advantages for the transfer of the ceramic slurry metered by the micro-engraving roller to the material web. This allows a narrow kiss coating line to be formed between the engraved roller and the material web at moderate wrap angles.

[0045] The device can further be configured to move the pressure chamber doctor blade horizontally in oscillation relative to a longitudinal axis of the microgravure roller. This allows the solids / agglomerates that have settled on the doctor blades of the pressure chamber doctor blade to be loosened. These solids can then be transported away and filtered out with the circulating fluid.

[0046] The angle of the discharge doctor blade of the pressure chamber doctor blade can be positive or negative (also referred to as dragging or piercing). Depending on the properties of the ceramic slurry, this variability in the doctor blade angle can have a positive effect on the quality of the coating film.

[0047] The pressure chamber doctor blade type can also have a minimized pressure chamber, which has a minimized volume for the ceramic slurry. This minimized volume prevents surfaces for sediment accumulation. The outgoing doctor blade and / or the incoming doctor blade can be designed as negatively angled doctor blades on both sides. Alternatively or in addition to the outlet, the pressure chamber doctor blade can have an overflow body for removing excess ceramic slurry from the pressure chamber.

[0048] It is also preferred for the device that the carrier material, in particular for producing at least one current collector,

[0049] • at least in some areas comprises at least one film, at least one fiber composite, at least one nonwoven, at least one net, optionally at least one smooth, rough and / or perforated net,

[0050] • at least partially comprises at least one electrically conductive polymer, in particular polypyrrole, polyaniline, polythiophene or the like,

[0051] • at least partially comprises at least one filled plastic material, wherein the filling material optionally comprises carbon black, conductive carbon black, graphite and / or metal powder,

[0052] • at least partially comprises at least one metal, at least one metal oxide, silver, copper, tin, aluminum, titanium, chromium and / or nickel, and / or

[0053] • comprises at least one, in particular partially metallic, coating, optionally on at least one film, plastic films and / or another material, at least in some areas.

[0054] It is further proposed that the coating material, in particular the adhesion promoter,

[0055] • at least one polyolefin, in particular at least partially comprising polyisobutenes, ethylene-propylene-diene (monomer) rubber, styrene-butadiene, isoprene polymer, preferably with a molecular weight, in particular of the polymer, between 20,000 and 2,000,000, preferably between 50,000 and 300,000 and / or a proportion of 2 to 25 wt.%, preferably of 3.5 to 15 wt.% of the coating material,

[0056] • at least one polymer binder, in particular based on polyacrylic acid, optionally comprising at least one electrically conductive additive,

[0057] • at least one material based on polyolefins, polyvinyl ethers, polystyrene and / or rubbers, preferably at least partially based on SBR (styrene-butadiene rubber) and / or

[0058] • at least one electrical filler, preferably comprising conductive carbon black, graphite, polypyrrole, and / or polyaniline, in particular in amounts of up to 50% by mass, based on the adhesion promoter.

[0059] Furthermore, an arrangement for producing a separator film is claimed, comprising a device for coating a web-shaped carrier material according to one of the above-mentioned embodiments, a web-shaped carrier material, at least one deflection roller and a dryer, wherein the at least one deflection roller is designed to transfer the web-shaped carrier material from the device for coating the web-shaped carrier material to the dryer.

[0060] In other words, the invention provides an arrangement for producing at least one coated carrier material and / or substrate, in particular at least one separator film and / or current collector, comprising at least one device for coating a web-shaped carrier material, as described here, in particular above, a web-shaped carrier material, and at least one deflection roller, further optionally comprising at least one dryer, wherein the at least one deflection roller is designed to transport the web-shaped carrier material further from the device for coating the web-shaped carrier material, in particular to transfer it to the dryer.

[0061] By using the micro pressure chamber doctor blade, in particular a micro engraving on a roller in combination with a pressure chamber doctor blade, coating irregularities such as the formation of a micro foam, which can lead to pinholes, and / or uneven coatings, which are particularly caused by deposits of components of the coating material or the coating mass in the application unit due to sedimentation / separation and thus uneven transfer to the carrier material or substrate, can be minimized.

[0062] In addition to the aforementioned advantages of using a pressure chamber doctor blade, synergistic effects also arise from the combination of a micro-engraving roller and a pressure chamber doctor blade. In particular, this combination enables synergistic effects such as defect-free filling of the micro-engraving roller and optimized transfer of the coating material to the substrate by the micro-engraving roller, for example, in the production of a separator film or a current collector.

[0063] Furthermore, the invention provides a method for coating a web-shaped carrier material with at least one coating material which is at least partially liquid, comprising the steps

[0064] • Transfer of the coating material to a circumference of a continuously rotating micro-engraving roller and

[0065] • Transferring the coating material over the circumference of the micro-engraving roller to the web-shaped carrier material, characterized in that the coating material is transferred to the micro-engraving roller under excess pressure by means of at least one pressure chamber doctor blade. For the method, it is proposed that the web-shaped carrier material be transported in a feed direction.

[0066] It is preferred for the method that the micro-engraving roller is rotated in a direction opposite to the feed direction.

[0067] It is also proposed for the process that an overpressure of 50 to 800 mbar, preferably 100 to 500 mbar, of the coating material is generated in the pressure chamber.

[0068] It is also preferred that the coating material is dosed into the pressure chamber, in particular by means of at least one pre-run.

[0069] It is further proposed that the coating material is drained from the pressure chamber, preferably by means of at least one drain.

[0070] It is also preferred that the coating material is filtered, optionally by means of at least one filter unit, which is in particular fluidically connected to the pressure chamber doctor blade and / or is preferably arranged upstream of the feed line.

[0071] The method can be characterized in that the coating material can be metered into the pressure chamber, optionally by means of at least one nozzle, in particular one encompassed by the feed line, and / or, optionally by means of the nozzle, at least one rotating flow field is induced within the pressure chamber.

[0072] In the preceding embodiment, it is preferred that the rotating flow field is induced by means of at least two nozzles, preferably encompassed by the feed line, which preferably each have different inflow positions and / or inflow angles. For the two aforementioned embodiments, it is proposed that a rotational axis of the rotating flow field be induced parallel to a rotational axis of the micro-engraving roller, preferably by means of the at least one nozzle.

[0073] It is also proposed for the method that the web-shaped carrier material is guided over a circumferential section of the micro-engraving roller, preferably by means of at least one first guide roller and / or at least one second guide roller.

[0074] Finally, it is preferred for the method that a device as described herein is used.

[0075] Further details and functionalities of the invention are illustrated and explained with reference to the drawings. Herein:

[0076] Figure 1 A: a schematic representation of a device according to the

[0077] State of the art;

[0078] Figure 1 B : a detailed enlargement of the surface of a micro-engraving roller in a device according to the prior art;

[0079] Figure 2 A: a schematic representation of a device according to the invention; and

[0080] Figure 2 B : a detailed enlargement of the surface of a micro-engraving roller in a device according to the invention;

[0081] Figures 3 and 4: Detailed views of two embodiments of the inventive

[0082] Pressure chamber doctor blades.

[0083] Fig. 1 shows a schematic representation of a generic device for coating a web-shaped carrier material 1. The web-shaped carrier material 1 is transported in a feed direction 11 and guided over an engraved roller 2. In this case, a coating material, such as a ceramic slurry 3 or an adhesion promoter, is transferred via a circumference 21 of the engraved roller onto the web-shaped carrier material 1, which serves in particular as a substrate, and thus coated. A rinsing chamber is arranged next to the engraved roller 2. In this rinsing chamber, the coating material, in particular ceramic slurry 3 and / or the adhesion promoter, is metered under atmospheric pressure and finally transferred to the circumference 21 of the engraved roller 2. Such a device has decisive disadvantages for the quality of the final product, in particular in the form of a separator film and / or a current collector, as well as for the economic efficiency of the production process.Firstly, air is entrained into the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter. Secondly, the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, tends to sediment within the rinsing chamber. Thirdly, the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, begins to splash, depending on the rotation speed of the engraved roller, above a certain feed speed of the web. Another problem is that, due to the low thickness of the carrier material, in particular the separator films and / or the current collectors, the scoop volume of the engraved roller 2 is low. As a result, the structures introduced into the circumference 21, for example lines or cups, are also very fine.At moderate carrier material speeds, filling problems of the cells or lines occur in the device known from the state of the art.

[0084] This is illustrated by the detailed enlargement “A” shown in Fig. 1 A. Shown greatly enlarged is a section of the circumference of the gravure roller 21 at a position shortly before the transfer of the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, to the carrier material 1. The coating material, in particular the ceramic slurry 1 and / or the adhesion promoter, was transferred to the surface of the gravure roller 21 in the rinsing chamber. Due to the atmospheric pressure present in the rinsing chamber and the negligible geodetic pressure of the liquid column, even at carrier material speeds of less than 100 m / min, only the cups introduced into the surface are filled with coating material, in particular ceramic slurry 3 and / or adhesion promoter.During the subsequent transfer of the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, to the carrier material 1, the carrier material 1 is coated in patches or with an intermittent thickness. Fig. 2A shows a schematic representation of an apparatus according to the invention. The web-shaped carrier material 1 is transported in a feed direction 11 and guided by a first guide roller 5 and a second guide roller 6 over a circumferential section 22 of a micro-engraving roller 2 in the so-called kiss-coating process. Here, a coating material, in particular a ceramic slurry 3 and / or an adhesion promoter, is transferred over a circumference 21 of the micro-engraving roller onto the web-shaped carrier material 1 and thus coated. For this purpose, the feed direction 11 and a direction of rotation 23 of the micro-engraving roller 2 are opposite.The coated web-like carrier material is then transported further via a rubberized deflection roller 7. Particularly in the case of a separator film, it can be transported to a dryer (not shown), in which the ceramic slurry is processed.

[0085] 3 is dried by evaporation of the solvent. In the case of a current collector, further transport to at least one further processing unit can also take place. For example, drying of the coating material, in particular using convection, thermal radiation, preferably near infrared and / or at least one diode laser, contact heat, and / or air drying, is possible.

[0086] Below the micro-engraving roller 2, the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, is transferred to the circumference 21 of the micro-engraving roller 2 by means of a pressure chamber doctor blade 4 under overpressure. The pressure chamber doctor blade

[0087] 4 is shown here as a cutaway. The pressure chamber doctor blade has a pressure chamber 41, which is adjacent to the micro-engraving roller and sealed from the surroundings of the device. For this purpose, the pressure chamber doctor blade 4 has a pair of doctor blades that seal the pressure chamber 41 across the entire width of the micro-engraving roller in or against the direction of rotation 23, so that an overpressure can be built up within the pressure chamber 41. The coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, is metered into the pressure chamber 41 via a feed line 42.

[0088] Upstream of the inlet, a pressure reservoir 44 is arranged within the pressure chamber doctor blade 4, which suppresses or reduces operational pressure fluctuations within the pressure chamber doctor blade 4. The pressure chamber doctor blade 4 is supplied with the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, via an inlet, in particular with a pump and / or a filter unit (not shown). The pressure chamber 41 further has an outlet 43, which is designed to remove the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, from the pressure chamber 41. A pressure reservoir 44 is also arranged downstream of the outlet. A controlled mass flow of the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, can be removed via an outlet.The overpressure in the pressure chamber can be ensured via a throttle or a controllable valve and / or the pump pressure. As such, a statistical residence time of the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, within the pressure chamber doctor blade 4 can be influenced. In particular, the discharged coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, can be mixed into the inlet and thus recirculated.

[0089] The overpressure in the pressure chamber 41 results in faster filling of the cups of the micro-engraving roller. Analogous to the detailed enlargement shown in Fig. 1A, a detailed enlargement of the surface of a micro-engraving roller of the 2 of the device according to the invention is shown in Fig. 2B. On the downstream side of the pressure chamber, the engraved roller can be easily "overdosed" by adjusting the overpressure. Due to the positive pressure gradient between the pressure chamber 41 and the ambient pressure, additional coating material, in particular ceramic slurry 3 and / or adhesion promoter, flows downstream below the pressure chamber doctor blade 4 and overfills the cups in the surface of the micro-engraving roller 1. This is advantageous for the transfer of the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, in the kiss coating process.

[0090] Due to the overfilling of the gravure roller 2 and the resulting full-surface contact of the coating fluid in the area of ​​the kiss coating line with the carrier material 1, the uniform coating is supported even at carrier material speeds of significantly more than 100 m / min.

[0091] Fig. 3 shows an alternative embodiment of the pressure chamber doctor blade 4. Here, the feed line 42 has a nozzle 421, through which the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, is metered into the pressure chamber. In the nozzle, the coating material, in particular the ceramic slurry and / or the adhesion promoter, is accelerated horizontally along the dashed line at the bottom of the pressure chamber 41. This induces a rotating flow field 422 within the pressure chamber 41. The flow field 422 rotates around a rotation axis 423, which runs parallel to the rotation axis of the micro-engraving roller 2. The rotation of the flow field 422 is wall-guided by a geometry of the pressure chamber 41 and amplified by the rotating surface 21 of the micro-engraving roller 2.The rotating flow field 422 mixes and thus homogenizes the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, within the pressure chamber 41. This actively counteracts sedimentation. Furthermore, the rotating flow field 422 induces strong velocity gradients near the walls of the pressure chamber and thus shear stresses, which suppress the deposition of sediment or break up and remove deposits on the walls.

[0092] Fig. 4 shows another embodiment of the pressure chamber doctor blade 4, which has a minimized pressure chamber 41, which has a minimized volume for the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter. This minimized volume prevents surfaces for the accumulation of sediment and minimizes the introduction of ambient air into the coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, within the pressure chamber. Both the outgoing doctor blade and the incoming doctor blade are designed as negatively angled doctor blades. To further reduce the volume of the pressure chamber 41, the pressure chamber 41 does not have an outlet 43.

[0093] Instead, the excess coating material, in particular the ceramic slurry 3 and / or the adhesion promoter, is removed from the pressure chamber 41 via the incoming doctor blade.

[0094] The features of the invention disclosed in the above description, in the drawings, and in the claims may be essential for the realization of the invention, both individually and in any combination. List of reference symbols:

[0095] Web-shaped carrier material

[0096] Micro engraving roller

[0097] Ceramic slurry

[0098] Pressure chamber doctor blade first guide roller second guide roller

[0099] pulley

[0100] Feed direction

[0101] Scope of the micro-engraving roller

[0102] circumferential section

[0103] Rotation direction of the micro-engraving roller

[0104] pressure chamber

[0105] Lead-up

[0106] Sequence

[0107] pressure reservoir

[0108] nozzle

[0109] Rotating flow field

[0110] Rotation axis of the flow field Wrap angle

Claims

CLAIMS 1. Device for coating a web-shaped carrier material (1) with at least one coating material which is at least partially liquid, the device comprising a continuously rotating micro-engraving roller (2) which is designed to transfer the coating material to the web-shaped carrier material (1) transported in a feed direction (11) via a circumference (21) of the micro-engraving roller (2), characterized in that the device has at least one pressure chamber doctor blade (4) which is designed to transfer the coating material under excess pressure to the circumference (21) of the micro-engraving roller.

2. Device according to claim 1, wherein the at least partially liquid coating material comprises at least one ceramic slurry (3) and / or at least one adhesion promoter.

3. Device according to claim 1 or 2, wherein the feed direction (11) and a direction of rotation of the micro-engraving roller (23) are opposite in a region of at least one coating line, which is formed in particular between the micro-engraving roller (2) and web-shaped carrier material (1).

4. Device according to one of the preceding claims, wherein the pressure chamber doctor blade (4) has at least one pressure chamber (41) which is in particular open to the micro-engraving roller (2) and / or is sealed from the environment of the device.

5. Device according to claim 3, wherein an overpressure of 50 to 800 mbar, preferably 100 to 500 mbar, is present in the pressure chamber (41).

6. Device according to one of the preceding claims, wherein the micro-engraving roller has at least in some regions a diameter between 60 mm and 150 mm.

7. Device according to one of the preceding claims, wherein the pressure chamber (41) has at least one feed line (42) which is particularly designed to meter the coating material, in particular the ceramic slurry (3) and / or the adhesion promoter, at least partially into the pressure chamber (41).

8. Device according to one of the preceding claims, wherein the pressure chamber (41) has at least one outlet (43) via which the coating material, in particular the ceramic slurry (3) and / or the adhesion promoter, is drained from the pressure chamber (41).

9. Device according to claim 7 or 8, wherein the pressure chamber doctor blade (4) upstream of the feed (42) and / or downstream of the discharge (43), in particular in each case, has at least one pressure reservoir (44), which preferably provides an additional volume for the coating material, in particular the ceramic slurry (3) and / or the adhesion promoter, in order to avoid pressure fluctuations in the pressure chamber (41).

10. Device according to one of claims 7 to 9, wherein the device has at least one filter unit, in particular for filtering the coating material, in particular the ceramic slurry (3) and / or the adhesion promoter, which is in particular fluidically connected to the pressure chamber doctor blade (4) and / or is preferably arranged upstream of the feed line (42).

11. Device according to one of claims 8 to 10, wherein the feed (42) has at least one nozzle (421) via which preferably the coating material, in particular the ceramic slurry (3) and / or the adhesion promoter, can be metered into the pressure chamber (41) and / or which is designed to form at least one rotating flow field (422) within the pressure chamber (41).

12. Device according to claim 11, wherein the flow line (42) has at least two nozzles, which preferably each have different inflow positions and / or inflow angles, in particular to induce the rotating flow field (422).

13. Device according to claim 11 or 12, wherein the at least one nozzle (421) is configured to induce a rotation axis (423) of the rotating flow field parallel to a rotation axis of the micro-engraving roller (2).

14. Device according to one of the preceding claims, wherein the device has at least one first guide roller (5) and / or at least one second guide roller (6), wherein preferably the first guide roller (5) and / or the second guide roller (6) is / are designed to guide the web-shaped carrier material (1) over a circumferential section (22) of the micro-engraving roller (2).

15. Device according to claim 14, wherein the peripheral portion (22) has a wrap angle (a) of 0.5° to 40°, preferably 5° to 30°, preferably 8° to 22°.

16. Device according to one of the preceding claims, wherein the carrier material, in particular for producing at least one current collector, • at least in some areas comprises at least one film, at least one fiber composite, at least one nonwoven, at least one net, optionally at least one smooth, rough and / or perforated net, • at least partially comprises at least one electrically conductive polymer, in particular polypyrrole, polyaniline, polythiophene or the like, • at least partially comprises at least one filled plastic material, wherein the filling material optionally comprises carbon black, conductive carbon black, graphite and / or metal powder, • at least partially comprises at least one metal, at least one metal oxide, silver, copper, tin, aluminum, titanium, chromium and / or nickel, and / or • at least partially at least one, in particular partially metallic Coating, optionally on at least one film, comprises plastic films and / or another material.

17. Device according to one of the preceding claims, wherein the coating material, in particular the adhesion promoter, • at least one polyolefin, in particular at least partially comprising polyisobutenes, ethylene-propylene-diene (monomer) rubber, styrene-butadiene, isoprene polymer, preferably with a molecular weight, in particular of the polymer, between 20,000 and 2,000,000, preferably between 50,000 and 300,000 and / or a proportion of 2 to 25 wt.%, preferably of 3.5 to 15 wt.% of the coating material, • at least one polymer binder, in particular based on polyacrylic acid, optionally comprising at least one electrically conductive additive, • at least one material based on polyolefins, polyvinyl ethers, polystyrene and / or rubbers, preferably at least partially based on SBR (styrene-butadiene rubber) and / or • at least one electrical filler, preferably comprising conductive carbon black, graphite, polypyrrole, and / or polyaniline, in particular in amounts of up to 50% by mass, based on the adhesion promoter.

18. Arrangement for producing at least one coated carrier material and / or substrate, in particular at least one separator film and / or current collector, comprising at least one device for coating a web-shaped carrier material (1) according to one of claims 1 to 17, a web-shaped carrier material (1), and at least one deflection roller (7), further optionally comprising at least one dryer, wherein the at least one deflection roller (7) is designed to transport the web-shaped carrier material (1) further from the device for coating the web-shaped carrier material (1), in particular to transfer it to the dryer.

19. A method for coating a web-shaped carrier material (1) with at least one coating material which is at least partially liquid, comprising the steps • Transfer of the coating material to a circumference (21) of a continuously rotating micro-engraving roller and • Transferring the coating material over the circumference (21) of the micro-engraving roller (2) to the web-shaped carrier material (1), characterized in that the coating material is transferred to the micro-engraving roller under excess pressure by means of at least one pressure chamber doctor blade (4).

20. The method according to claim 19, wherein the web-shaped carrier material (1) is transported in a feed direction (11) 21. Method according to one of claims 19 to 20, wherein the micro-engraving roller (23) is rotated in a direction opposite to the feed direction (11).

22. Method according to one of claims 19 to 21, wherein an overpressure of 50 to 800 mbar, preferably 100 to 500 mbar, of the coating material is generated in the pressure chamber (41).

23. Method according to one of claims 19 to 22, wherein the coating material is metered into the pressure chamber (41), in particular by means of at least one pre-run (42).

24. Method according to one of claims 19 to 23, wherein the coating material is drained from the pressure chamber (41), preferably by means of at least one drain (43).

25. Method according to one of claims 19 to 24, wherein the coating material is optionally filtered by means of at least one filter unit, which is in particular fluidically connected to the pressure chamber doctor blade (4) and / or is preferably arranged upstream of the feed line (42).

26. Method according to one of claims 19 to 25, wherein the coating material, optionally by means of at least one nozzle (421), in particular comprised by the pre-run (42), can be metered into the pressure chamber (41) and / or, optionally by means of the nozzle (421), at least one rotating flow field (422) is induced within the pressure chamber (41).

27. The method according to claim 26, wherein the rotating flow field (422) is induced by means of at least two nozzles, preferably comprised by the flow section (42), which preferably each have different inflow positions and / or inflow angles.

28. The method according to claim 26 or 27, wherein, preferably by means of the at least one nozzle (421), a rotation axis (423) of the rotating flow field is induced parallel to a rotation axis of the micro-engraving roller (2).

29. Method according to one of claims 19 to 28, wherein the web-shaped carrier material (1) is guided over a circumferential section (22) of the micro-engraving roller (2), preferably by means of at least one first guide roller (5) and / or at least one second guide roller (6).

30. Method according to one of claims 19 to 29, wherein a device according to one of claims 1 to 17 is used.

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