Method for applying a coating and coating device

Abstract

The invention relates to a method for applying a coating (18a, 18b) by means of a coating device (10), in which a film of the coating (18a, 18b) is applied to a substrate in the form of a film element (14) by means of a slot nozzle (16) while the film element (14) is moved by a roller device (12). According to the invention, at least one distance (E1, E2, E3) between a first reference point on the slot nozzle (16) and a second reference point on a surface (14a) of the film element (14) oriented towards an outlet opening (20) of the slot nozzle (16) is continuously measured and / or monitored. The invention further relates to such a coating device (10).

Description

[0001] The invention relates to a method for applying a coating according to the preamble of claim 1. The invention further relates to a coating device.

[0002] A process known as slot-die coating is disclosed in US patent 9,212,089 B2. In this process, a layer of slurry (also called electrode paste) is applied to a conductive foil. The conductive foil is moved by rollers while the slurry layer is applied to the foil surface through a narrow slot / die (the slot die). According to the prior art, this process is used in the production of electrical energy storage devices or batteries, particularly lithium-ion batteries, to produce uniform electrode coatings.

[0003] The object of the invention is to further develop a method for applying a coating and to provide a corresponding coating device in such a way that a particularly uniform and high-quality coating can be applied.

[0004] This problem is solved by means of a method with the features of claim 1 and by means of a coating device according to the invention. Advantageous embodiments of the coating device according to the invention are to be regarded as advantageous embodiments of the method according to the invention, wherein the means of the coating device are used to carry out the method steps. Furthermore, advantageous developments of the invention are described by the dependent claims, the following description, and the figures.

[0005] A first aspect of the invention relates to a method for applying a coating using a coating device, in which a film of the coating is applied to a substrate in the form of a foil element (or film) by means of a slot die, while the foil element is moved by a roller device. The roller device can be arranged in conjunction with the coating device or, as a separate component, perform only the movement of the foil element. The coating device can be used, in particular, in the manufacture of electrodes for lithium-ion batteries or other components where a uniform layer thickness is an important requirement.

[0006] To achieve the object of the invention, it is provided that at least one distance between a first reference point on the slot nozzle, particularly in the immediate vicinity of the exit opening, especially at the exit opening itself, for example at a nozzle lip of the slot nozzle, and a second reference point on a surface of the film element or substrate surface oriented towards the exit opening, is continuously measured and / or monitored. In other words, the distance between the first reference point on the slot nozzle and the second reference point on the surface of the film element is to be continuously measured and / or monitored. The measurement and / or monitoring is performed "in-situ," i.e., in real time, so that measurement and / or monitoring during the coating process can be directly integrated into the production process and carried out without interruption.

[0007] When applying the coating to the film element, specific reference points are recorded to determine the distance between the slot nozzle and the film surface. This distance is continuously measured, and a control system can be used to maintain this distance by translationally adjusting the slot nozzle relative to the roller or the film element. This ensures that the coating is applied evenly. The continuously measured actual values ​​of the distance between the slot nozzle and the film surface are constantly compared with predefined target values. In case of deviations, the system adjusts the position of the slot nozzle to ensure the alignment of the target and actual values ​​and thus a uniform coating.The regulation also includes a multitude of parameters and adjustments, not only the translational adjustment of the slot nozzle relative to the film element, but also the speeds of the roller, the pressure of the exiting coating material and other factors.

[0008] It is particularly preferred that at least two points or more points can be detected. In particular, a gap is measured starting from two pairs of reference points, so that the detected distances represent the gap measured relative to the surface of the film element and / or relative to the surface of a roller of the roller assembly. By detecting two pairs of reference points, not only the distance but also the orientation of the slot nozzle relative to the roller can be measured. This enables precise control of the parallelism between the slot nozzle and the roller, which is particularly necessary for the uniform distribution of the coating on the film element.These measurements thus enable precise monitoring and, for example, control of the coating process by ensuring that the gap between the slot nozzle and the film element is kept constant in order to provide a uniform coating thickness of the applied coating.

[0009] A constant coating thickness, such as that achieved by maintaining a constant gap, is technically necessary to ensure the functional properties of the final product and to meet all specifications. In the manufacture of products like batteries, a uniform coating thickness ensures that the electrical and mechanical properties of the coated material remain within specified tolerances. Fluctuations in the coating thickness can lead, for example, to an inhomogeneous distribution of electric fields, variable light transmission or reflection, and mechanical stresses in the material. These effects can negatively impact the final product; therefore, according to the invention, the coating thickness is applied with particularly high precision and consistency to meet the specified technical requirements and / or specifications.

[0010] The coating device is therefore designed in such a way as to enable a particularly high-quality application of the coating, in particular by continuously measuring and monitoring the gap between an outlet opening of the slot nozzle and the surface of the film element oriented towards the outlet opening. This also enables corresponding control of the coating thickness.

[0011] Preferably, the slot nozzle comprises a base element formed from two superimposed base element parts. These base element parts are abutted along a mutually aligned side, creating a gap. The edges or nozzle lips of the abutting base element parts are preferably tapered. These nozzle lips contain lips that together form the elongated outlet opening, which is essentially horizontally oriented. According to the invention, the slot nozzle is designed to enable a uniform distribution of the coating over, for example, the entire width of the film element. The slot nozzle and the coating device comprise all the necessary components that control the material flow from the storage container to the application onto the substrate.

[0012] The coating material, such as the electrode paste mentioned earlier in the prior art, is first fed from a storage container (tank) via a conveying or piping system by means of a pump into a feed line. This feed line transports the coating material into a central distribution chamber or cavity within the base element or within one of the base element parts of the slot nozzle. The distribution chamber is designed to distribute the material evenly across the entire width of the slot nozzle to apply a particularly homogeneous coating. From the distribution chamber, the material then travels through a further conveying or piping system to the outlet opening of the slot nozzle. This outlet opening is typically designed as a narrow slot with a width of approximately 0.05 mm to 1 mm, depending on the coating thickness requirements and the material being processed.The nozzle opening allows for the controlled dispensing of the coating material, ensuring a uniform coating thickness is applied to the film element. The slot nozzle is designed or provided so that the gap between the nozzle opening and the surface of the film element or the substrate surface can be adjusted and monitored. The nozzle opening of the slot nozzle is also adjustable, allowing the width to be adapted to different requirements. This enables more precise control of the coating thickness and material flow.

[0013] After the coating is applied, a drying phase takes place, during which the film element is guided into a drying chamber, for example, by means of a roller device. In this drying chamber, the solvent is evaporated by controlled heating, resulting in a uniform and stable coating. The temperature and dwell time of the film element in the drying chamber are set so that the solvent evaporates without affecting the coating or the substrate. The drying temperatures can vary depending on the material of the film element and the coating, but they typically range from 50 °C to 150 °C. In some applications, particularly with sensitive coatings or substrates, infrared or UV drying can also be used to accelerate the drying process and ensure a uniform layer thickness.

[0014] The coating device is also designed to first apply a coating to one side of the film and then a coating to the opposite side. However, this creates the problem that the already dried coating on the first side forms an uneven or wavy surface for the film during the rolling process. These irregularities can impair the second coating and lead to deformations. The method according to the invention therefore also measures the unevenness on the film element caused by the first layer, such as the wavy shape. These measurements are used to make targeted adjustments and prevent deformations during the coating process of the second layer. In case of deviations between target and actual values, an automatic control system is used that adjusts the coating process in real time to reduce deformations.If, for example, this automatic control did not occur, there would not only be deformations due to the inaccuracy of the second coating, but also increased deformations caused by the inaccuracy of the first layer already applied.

[0015] In summary, the method proposes applying the coating to the film element using a slot nozzle while the film element is moved or rotated. Crucially, the distance between the slot nozzle's exit opening and the film surface is continuously measured to ensure a uniform coating thickness, for example, through a control system and parameter adjustments.

[0016] In an advantageous embodiment of the invention, at least one distance is continuously measured during the application process by means of at least one sensor device. This sensor device acquires real-time data on the distance between the nozzle opening of the slot nozzle and the surface of the film element. The acquired data is continuously transmitted to an electronic computing device, which is, for example, located in the immediate vicinity of the coating device. The electronic computing device processes the incoming data and thus calculates the current gap between the slot nozzle and the substrate or the film element from the distance between the reference points.This information is used to adjust the material flow and the position of the slot die relative to the roller, the film element, or the film surface in real time (in-situ) to ensure a uniform coating thickness. Continuous data acquisition and processing allow for immediate intervention in case of any deviations in the gap. A variety of different sensor devices can be combined and used to enable even more precise measurement and / or control of the coating process.

[0017] In a further advantageous embodiment of the invention, the at least one sensor device is adjusted during application. The at least one sensor device or devices preferably comprise adjustment mechanisms that allow them to dynamically change their position in order to detect a plurality of reference points at the exit opening and / or on the surface of the film element. This adjustability means, for example, that only one sensor device needs to be arranged to detect multiple pairs of reference points. By detecting multiple pairs of reference points, more precise information about the gap can be obtained. The data from these various reference points are continuously transmitted to an electronic computer, which processes, analyzes, and compares this information.This comparison allows potential irregularities in the coating to be detected early and corrected by adjusting process parameters, such as the position of the slot nozzle or the speed of the roller device.

[0018] In a further advantageous embodiment of the invention, the slot nozzle is positioned relative to the roller assembly and depending on the measured distance. For this purpose, the slot nozzle is provided with its own adjustment device. This adjustment device makes it possible to adapt or adjust the position of the slot nozzle in order to flexibly adjust the gap between the slot nozzle and the film element as well as the distance between the reference points. This adjustment device can, for example, be motorized and at least semi-automatic and controlled by a control system that, for example, accesses the continuously acquired measurement data from the sensor devices.In case of deviations in the measured distance, the control system can automatically adjust the position of the slot nozzle using the aforementioned control system to correct the gap width and thus maintain a constant layer thickness. The gap width can also be changed according to specifications to apply different layer thicknesses or materials with variable viscosity. Furthermore, this adaptability allows for a response to changes in the process environment or the substrate.

[0019] In a further advantageous embodiment of the invention, the slot nozzle is adjusted relative to the roller assembly and depending on the measured distance during application. This previously mentioned adjustment allows for continuous adaptation of the slot nozzle's position to more accurately control the gap width and thus the layer thickness of the applied coating. This dynamic adjustment allows for responses to variations in the distance between the nozzle and the substrate, thereby enabling a uniform coating. The previously mentioned deformations and waveforms that can occur during the coating of two layers make continuous adjustment during application particularly advantageous, as they help to improve the quality of the second layer and minimize undesirable surface deformations.

[0020] In a further advantageous embodiment of the invention, the data from at least one sensor device are aggregated to determine the distance. The sensor devices continuously acquire measured values, which are transmitted in real time to a central electronic computing unit. The electronic computing unit processes this data by aggregation, in which individual measurement points are combined and analyzed to obtain or calculate an accurate or consolidated measurement of the distance between the slot nozzle and the substrate surface. This data aggregation makes it possible, for example, to minimize noise or measurement deviations and to calculate reliable average values ​​that can be used to control the coating process.The aggregated data is thus used as the basis for the dynamic adjustment of the slot nozzle (or roller device), ensuring a constant gap width and therefore a uniform layer thickness. Furthermore, the aggregation of the sensor data results in a uniform distance, higher measurement accuracy, and improved control by the control system.

[0021] In a further advantageous embodiment of the invention, setting data from external components is acquired, and adjustments are implemented based on this data. The external components can provide information from various sources, including databases or systems accessible via telecommunications networks. This external setting data can, for example, relate to material properties of the coating, such as changes in viscosity, temperature dependencies, or adjustments to the width parameters of the slot die. This data can be acquired in real time via a networked infrastructure and transmitted to the central control unit of the coating device. The proposed integration of this external data into the coating process enables dynamic updates and adjustments.For example, current material properties or production specifications stored in a central database can be automatically retrieved and integrated into the control logic of the device.

[0022] In a further advantageous embodiment of the invention, the at least one sensor device is designed as a light band micrometer. The light band micrometer is a measuring instrument used in particular for the precise determination of distances, thicknesses, or positions. Such a light band micrometer operates on the principle of shadow or light quantity measurement and thus detects the size and position of the object to be measured; however, it is also possible to check the contours of workpieces. In particular, it is provided that a shadow casting method is used to detect the changing distance of the reference points. A high-luminosity LED usually serves as the light source in a transmitter of the light band micrometer. This LED is located at the focal point of a collimator to align the divergent light beams of the light source.The collimated light strikes a receiver and the objects being measured perpendicularly, in this case, the slot nozzle and the surface of the foil element. Due to the arrangement below the roller and the slot nozzle, parallel light is emitted through the gap. The light band micrometer is positioned at the edges of the foil element, or rather, the reference points are placed at these edges where there is no coating. Otherwise, the coating would prevent the light from passing from the transmitter to the receiver along the gap. A light-gathering element in the receiver, located on the opposite side of the objects being measured, i.e., above the roller and the slot nozzle, determines the distance between the objects using the shadows cast by the roller and slot nozzle and the detected light. In other words, a thin band of light is projected through the gap.This light band is detected by a detector / light-receiving element, and the position and width of the shadow image or the reflected light line are analyzed to acquire measurement values. In the present invention, the light band micrometer can thus be used to measure or monitor in-situ the distance between the slot nozzle and the surface of the film element. The data acquired thereby enables continuous control and adjustment of the slot nozzle to ensure that the gap to the surface of the film element or substrate surface remains constant and that a uniform coating is applied.

[0023] In a further advantageous embodiment of the invention, at least one sensor device is designed as a chromatic confocal sensor device. A chromatic confocal sensor device utilizes a measurement technique that is used to determine distances and layer thicknesses.

[0024] The method utilizes the ability of lenses to focus light of different wavelengths with varying focal lengths to measure the distance between reference points. This creates a specific color coding known as chromatic coding. The principle of the chromatic confocal measurement method is based on this coding. Light from a polychromatic light source is split into its spectral colors by a lens or lens system with a known chromatic aberration, directed towards the object being measured, namely the surface of the foil element. Depending on the distance to the sensor or the first reference point on the sensor, only a specific color / wavelength is reflected and detected with high intensity. The distance to the measured object can then be determined based on this color / wavelength.The measurement spot, i.e., the area of ​​the object's surface (the surface of the foil element) detected by chromatic confocal sensors or detection devices, is so small that even roughness measurements are possible with this method. In other words, the principle is based on chromatic aberration, where light of different wavelengths is refracted to varying degrees when it enters the lens system. In a chromatic confocal sensor device, a broad light spectrum (for example, generated by a white light source) is focused onto the surface of the object being measured (here, the surface of the foil element). Depending on the distance of the surface from the sensor device, different wavelengths of light are focused to varying degrees, with only one specific wavelength striking the surface precisely and being reflected back.This reflected wavelength is detected by a detector, and the corresponding wavelength is used to determine the precise distance between the sensor and the surface. In the described invention, the light module, white light source, or light beam outlet of the chromatic confocal sensor device is fixedly positioned on the slot nozzle, particularly below the substrate. The second reference point is thus placed on the surface of the film located below the slot nozzle and therefore not yet coated. For this purpose, the roller rotates accordingly, moving the already coated film away, particularly upwards, and bringing the uncoated film into position below for coating. This positioning enables the distance to the surface of the film element to be continuously measured while the substrate moves through the roller device.The first reference point can be located at the chromatic confocal sensor device, and the second reference point on the surface of the film element that has not yet been coated. Since the sensor device is fixed at one point, the distance to the surface can be measured. Using geometric calculations, the gap, or the exact distance between the slot nozzle and the substrate surface, can be calculated from these measurements.

[0025] In a further advantageous embodiment of the invention, the at least one sensor device is designed as a capacitive sensor device. Capacitive sensors typically use changes in electrical capacitance to measure distances or positions. They consist of two electrodes that generate an electric field. When an object, such as the film element, moves into or out of this field, the capacitance between the electrodes changes. This change in capacitance is measured by the sensor device, and the distance to the substrate surface is detected or converted. In the present invention, the capacitive sensor device is used to continuously measure or monitor the distance between the slot nozzle and the surface of the film element or the substrate surface.

[0026] Overall, all measurement data enable precise control of the position of the slot nozzle relative to the substrate surface, thereby regulating the gap width and consequently the layer thickness of the applied coating.

[0027] Another aspect of the invention relates to a coating device for applying a coating to a substrate in the form of a film element. The coating device comprises a roller device through which the film element can be moved, and a slot nozzle through which a film of the coating can be applied to the film element while the film element is moved through the roller device. The coating device is designed such that the distance between a first reference point at the outlet opening of the slot nozzle and a second reference point on a surface of the film element oriented towards the outlet opening can be continuously measured and / or monitored by means of sensor devices. The coating device thus comprises all components necessary for carrying out the method according to the invention.This includes the roller device for moving the film element, the slot nozzle for applying the coating, and sensor devices for continuous in-situ measurement and monitoring of the distances between the relevant reference points. Furthermore, the coating device comprises an electronic computing unit that processes and controls the acquired data. Appropriate software enables the implementation of adjustments and the adaptation of the coating parameters.

[0028] Further features of the invention will become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures alone, are not only usable in the combinations specified, but also in other combinations or on their own.

[0029] The invention will now be explained in more detail with reference to a preferred embodiment and the drawings. The drawings show: Fig. 1 a cross-sectional view of a possible embodiment of a simple coating device with a sensor device for measuring the coating gap; Fig. 2 a schematic perspective view of the coating device for operating a method for applying a coating to a substrate; and Fig. 3 a cross-section of the coating device, showing the sensor devices in their function and geometric arrangement.

[0030] In the figures, identical and functionally equivalent elements are provided with the same reference symbols.

[0031] Fig. Figure 1 shows a cross-sectional view of a coating device 10, which is used to apply a coating 18a made of a coating material 18 to a substrate in the form of a foil element 14.

[0032] The coating device 10 comprises a roller device 12 that sets the film element 14 in continuous motion. Opposite the film element 14, a slot nozzle 16 is arranged, which applies the coating material 18 to the surface 14a of the film element 14. The slot nozzle 16 is fixedly attached to a base element 22, which holds the slot nozzle 16 in position relative to the roller device 12. The slot nozzle 16 includes, among other things, a base element 22, which is formed from two superimposed base element parts 22a, 22b. These base element parts 22a, 22b are abutted at a mutually aligned side, creating a passage for the coating material 18. The edges or nozzle lips 23a, 23b of the abutting base element parts 22a, 22b are preferably tapered.These upper nozzle lips 23a and lower nozzle lip 23b together form the elongated outlet opening 20, which is essentially horizontally oriented. According to the invention, the slot nozzle 16 is designed to enable a uniform distribution of the coating 18a over a region spanning the entire width of the film element 14. The slot nozzle 16 and the coating device 10 comprise all the necessary components that control the material flow from a storage container 19a to the application onto the substrate or film element 14.

[0033] The coating material 18 is first conveyed from the storage container 19a via a conveying system 16a, for example by means of a pump and a supply line, to the outlet opening 20 of the slot nozzle 16. The coating material 18 is transported into a central distribution chamber 19c (cavity shown) of the slot nozzle 16. The distribution chamber 19c is designed to distribute the coating material 18 evenly across the entire width of the outlet opening 20 of the slot nozzle 16 in order to apply a particularly homogeneous coating 18a of the coating material 18. The coating material 18 is thus guided through a channel 19d with a channel thickness D to the outlet opening 20 of the slot nozzle 16 and applied to the film element 14 through the outlet opening 20.

[0034] This involves Fig. Figure 1 shows an exemplary sensor device 26, which is used to detect a gap 17, or a coating gap, with a gap width S, or a nozzle distance to a surface 14a of the film element 14 or the substrate film. This gap width S is to be detected in order to enable at least semi-automatic adjustment of the gap 17 for the most even and uniform coating thickness B possible during application. The sensor device 26 shown here is merely an example and is designed as a camera that monitors the gap 17. Further possible sensor devices 26 are explained in more detail in the following figures. It is particularly intended to use a combination of different sensor devices 26.Furthermore, it is also possible that all sensor devices 26a, 26b, 26c can be manually adjusted by a user of the coating device 10, for example also by using reference objects, thickness gauges and / or known adjustments.

[0035] The gap 17, or gap width S, is to be measured from a distance between a first reference point on the slot nozzle 16 and a second reference point on a surface 14a of the foil element 14 oriented towards the outlet opening 20. This distance can either be measured directly or, if the reference points are located at other positions, determined by corresponding calculations and / or geometries.

[0036] The coating device 10 also includes a drying chamber 36, which is shown as a box because it is used in a process step (not shown) after the coating 18a has been applied. In this step, the film or film element 14 is conveyed into the drying chamber 36. After the coating material 18 has been applied, the film element 14 is guided through the drying chamber 36, where the solvent from the coating 18a is evaporated by controlled heating. This results in a stable and uniform coating 18a on the substrate. The film element 14 can then be turned over and guided again along the slot nozzle 12 by means of the roller device 12 to apply a new coating 18a to another side, and thus to a second surface 14b of the film element 14.

[0037] In Fig. Figure 1 shows in particular that a gap width S of the gap 17 between the outlet opening 20 of the slot nozzle 16 and the surface 14a of the film element 14 indirectly corresponds to a resulting layer thickness B of the applied coating. Here, not only the geometric dimensions are important for the layer thickness B, but also other parameters, such as properties of the coating material 18, movement speeds of the roller device 12, the channel thickness D, and also irregularities on the film element 14.

[0038] Through a process described in the following Fig. 2 and Fig. 3. By adjusting the gap width S as shown, the layer thickness B can be fine-tuned according to the specific requirements of the production process.

[0039] In particular, it shows Fig. 1 Furthermore, that the coating device 10 can be configured such that the foil element 14 can be coated on both sides, with a second coating 18b being arranged on the second surface 14b. At the in Fig. The second surface 14b shown in Figure 1 has already been coated with the second coating 18b of the coating material 18.

[0040] This cross-sectional view illustrates the basic operating principle of the coating device 10 in the prior art, in which uniform material distribution and drying are achieved. In contrast to the prior art, however, the use of additional sensor devices 26 for continuous measurement and monitoring is provided and shown. This allows a control system to be applied to enable adjustment of the gap width S and thus to apply a homogeneous coating 18a.

[0041] Fig. Figure 2 shows a perspective view of a coating device 10. The coating device 10 consists of several essential components that enable the application of a coating 11 to a substrate in the form of a foil element 14.

[0042] The roller device 12 moves the film element 14 in a continuous process under the slot nozzle 16, which is positioned to apply the coating material 18 evenly to the surface 14a of the film element 14. However, the outer edge regions 14c, 14d of the film element 14 are left uncoated; that is, no coating 18 is applied to these edge regions 14c, 14d. The slot nozzle 16 has the outlet opening 20 through which the coating material 18 is applied to the film element 14 in a controlled film.

[0043] The basic element 22 includes an adjustment device 24. This adjustment device 24 enables the adjustment or adjustment direction 34 of the position of the slot nozzle 16 relative to the roller device 12, thereby enabling in particular a flexible adjustment of a gap width S and thus of the coating thickness B of the applied coating material 18.

[0044] The coating device 10 can also be designed such that the coating material 18 can be applied not only across the entire surface but also in one or more tracks to the substrate in the form of the film element 14. This can be achieved by arranging several slot nozzles 16 or by using at least one shim in the slot nozzle 16. This allows the coating pattern to be adapted so that single- or multi-track coatings 18a can be applied as required. This is particularly advantageous in applications where different areas of the substrate require specific coatings 18, where the coating process is to be scaled up by using wider substrates, or where material savings are to be achieved through targeted material application.

[0045] In particular, three sensor devices 26a, 26b, 26c can be used in the coating device 10 to enable combined in-situ monitoring and control of the coating process. The first sensor device 26a can be configured as a light band micrometer, which enables measurement of the gap width and layer thickness by projecting a light band. The second sensor device 26b can be configured as a capacitive sensor device, which is sensitive to small changes in distance and thus ensures / enables the stability of the coating. The third sensor device 26c can be a chromatic confocal sensor device. The combined application of these three sensor devices 26a, 26b, 26c enables comprehensive and accurate acquisition of all relevant parameters, leading in particular to improved accuracy and reliability of the entire coating process.

[0046] The measured data are transmitted in real time to an electronic computing unit 32. This electronic computing unit 32 is equipped with a control system and / or software that processes the measurement data of all sensor devices 26a, 26b, 26c and controls the adjustment mechanisms to adapt the slot nozzle 16 relative to the roller device 12 according to the current process requirements.

[0047] The drying chamber 36 is arranged at the coating device 10, through which the film element 14 is guided after the coating process. In this drying chamber 36, the solvent from the applied coating material 18 is evaporated by controlled heating to provide a uniform coating 18a on the substrate.

[0048] Accordingly, the coating device 10 is designed to apply a precise and uniform coating 18a to the substrate in the form of the film element 14. By combining the use of the roller device 12 for moving the film element 14, the use of the slot nozzle 16 for controlled application of the coating material 18, and the use of the sensor devices 26a, 26b, 26c for continuously monitoring the distance between the slot nozzle 16 and the substrate surface, the coating device 10 enables a consistent coating thickness B.

[0049] The in Fig. The first sensor device 26a shown in Figure 1 is a light band micrometer, which is adjustable in the adjustment direction 35, and thus in particular horizontally and relative to the roller device 12 and thus relative to the film element 14. Accordingly, the first sensor device 26a is also adjustable along the width of the slot nozzle 16. Furthermore, the first sensor device 26a is coupled, for example, to the base element 22 or connected to the coating device 10 by means of an electromechanical coupling 30. These adjustment options make it possible to measure the gap at different points (reference points). In particular, it is intended that such a light band micrometer is directed at the film elements 14 where a coating 18a is not provided (edge ​​regions 14c, 14d), since otherwise the light from a transmitter would not reach the receiver of the light band micrometer.

[0050] The integrated electronic computing unit 32 processes the sensor data in real time and controls the adjustment device 24 to adjust the slot nozzle 16 as needed. Additionally, the applied coating can be stabilized by controlled evaporation of the solvent using the drying chamber 36. The coating device 10 is thus capable of producing precise coatings 18a that surpass the state of the art and meet the specific requirements of modern production processes.

[0051] A further potential improvement could be the introduction of an adaptive control system and / or regulation system that increases the processing speed and sensitivity of the adjustment device 24 to respond to rapid changes in material properties or environmental conditions. The possibility of equipping or arranging the adjustment device 24 with controllable and / or precise actuators that allow for finer adjustment of the slot nozzle position could also further improve the coating accuracy.

[0052] Furthermore, the software could be extended with a learning component that analyzes historical data from previous coating processes to optimize the current process flow and identify and correct potential sources of error early on. Finally, learning models and AI-controlled adjustment mechanisms / autonomous adjustment systems could also be incorporated.

[0053] Fig. Figure 3 shows a cross-section of the coating device 10, through which the sensor devices 26a, 26b, 26c and their function and geometric arrangement are shown.

[0054] The first sensor device 26a, depicted as a light band micrometer, is located vertically Z above the roller device 12. Specifically, a shadow casting method is used to detect the changing distance between the reference points. This changing distance indicates that the contour of the surface 14a of the film element 14 is not uniformly flat; these irregularities can lead to poor coating results. The first reference point at the slot nozzle 16 remains unchanged, while the contour of the film element 14 may be altered, for example, by bubble formation. Therefore, this change is to be detected by measuring the distance between the reference points. A high-intensity LED typically serves as the light source in a transmitter 40 of the light band micrometer. This LED is located at the focal point of a collimator to align the divergent light beams L of the light source.The collimated light L strikes the measuring objects perpendicularly, here slot nozzle 16 and surface 14a of the foil element 14. The light L that passes through the slit 17 strikes a receiver 42.

[0055] Here, the light band micrometer is positioned at the edge regions (edge ​​regions 14c, 14d) of the foil element 14, or rather, the reference points are set at these edge regions where no coating 18a is provided, since otherwise, due to the coating 18a, the light L would not pass from transmitter 40 to receiver 42 along the gap 17. A light receiving element in the receiver 42 on the opposite side of the objects being measured, or above the roller device 12 and the slot nozzle 16, can determine the distance between the objects by means of the object shadows produced by the roller device 12 and the slot nozzle 16, and by means of the detected light L. In other words, a thin band of light is projected through the gap 17.This light band is detected by a detector / light-receiving element / receiver 42, and the position and width of the shadow image or the reflected light line are analyzed to acquire measured values. In the present invention, the light band micrometer can thus be used to measure or monitor in-situ the distance between the slot nozzle 16 and the surface 14a of the film element 14. The data acquired thereby enable continuous control and adjustment of the slot nozzle 16 to ensure that the gap 17 to the surface 14a of the film element 14 or substrate surface remains constant and that a uniform coating 18a is applied.

[0056] In other words, this means that one reference point can be located at a lens of the sensor device 26a at the exit point of the light beam L, and the other reference point is positioned on the coating 18a itself. By measuring the distance between these two reference points, the distance between the slot nozzle 16 and the coating 18a is determined via geometric calculations. This calculation is based on the measured data of the sensor device 26a and thus takes into account the positions of the slot nozzle and the sensor device 26a relative to the surface 14a of the film element 14.

[0057] Alternatively, the second reference point can also be placed on the surface 14a of the foil element 14.

[0058] The first sensor device 26a is also adjustable, in particular along the width of the slot nozzle 16, and is coupled to the base element 22 or connected to the coating device 10 by means of the electromechanical coupling 30. This adjustability makes it possible to move the first sensor device 26a over different areas of the film element 14 in order to detect several pairs of reference points as well as a gap width S.

[0059] The second sensor device 26b is designed as a capacitive sensor device 26b and is used to measure the distance between the slot nozzle 16 and the surface 14a of the film element 14, and thus the gap 17. One reference point is located on the capacitive sensor device 26b itself, while the other reference point lies on the surface 14a of the film element 14. The capacitive sensor device 26b measures the changes in capacitance that occur when the film element 14 moves under the slot nozzle 16. These changes are used to determine the exact distance between the capacitive sensor device 26b and the surface 14a on the film element 14, or the substrate surface.

[0060] The third sensor device 26c is designed as a chromatic confocal sensor device and, like the second sensor device 26b, is used to measure the distance between the slot nozzle 16 and the surface 14a of the film element 14. One reference point is located on the third sensor device 26c itself, while the other reference point is positioned on the surface 14a of the film element 14. In the chromatic confocal sensor device, the light from a polychromatic light source is split into its spectral colors by means of a lens or lens system known for its chromatic aberration and projected as a narrow band of light onto the surface 14a of the film element 14.Depending on the distance between the measuring surface and the sensor, or the actual sensor device 26c, or a corresponding detection device, or a first reference point on the sensor, only a specific color is reflected with high intensity and detected by the sensor. By analyzing this reflected light, the sensor device 26c can precisely determine the distance, and thus the gap 17, between the first reference point or the lens through which the light stripe emerges and the substrate or the second reference point.

[0061] The second sensor device 26b and the third sensor device 26c can also be adjusted relative to the base element 22 and the slot nozzle 16, respectively. In particular, these sensor devices 26b and 26c can be positioned along the longitudinal direction of the slot nozzle 16. This adjustability makes it possible to align the sensor devices 26b and 26c along the width of the film element 14 to ensure complete and uniform monitoring of the coating parameters. Specifically, the second sensor device 26b and the third sensor device 26c are fixed to the slot nozzle and arranged in their respective corresponding cavities.

[0062] The determined distances and thus the gap 17 are forwarded to the electronic computing device 32, which then makes the necessary adjustments to precisely control the gap width and thus the layer thickness of the coating and to ensure a uniform application.

[0063] Fig.Figure 3 further shows that the slot nozzle 16 with the base element 22 is adjustable relative to the roller assembly 12 via an adjustment device 24. This adjustment device 24 allows the position of the slot nozzle 16 to be adjusted with respect to, or relative to, the film element 14 in order to precisely control the gap width S and thus the coating thickness B of the applied coating 18a. Alternatively, the position of the roller assembly 12 can also be adjusted by a separate adjustment device to vary the distance (distance between reference points) to the slot nozzle 16. This flexibility in positioning allows for fine-tuning of the coating process, so that optimal coating quality can be achieved.

[0064] In the illustrated geometric arrangement of the sensor devices 26a, 26b, and 26c, they are positioned relative to the surface 14a of the foil element 14 such that they can measure different distances. The first sensor device 26a detects a distance E1, the second sensor device 26b measures a distance E2, and the third sensor device 26c determines a distance E3 to the surface 14a. These measurement data can either be compared with each other to determine a general distance, or they can be used for detailed analyses where differences in the distances E1, E2, and E3 are relevant.

[0065] The first reference points for distances E1 and E2 are arranged on the same vertical plane (in the vertical direction Z and aligned with the elongated extension of the outlet opening 20 of the slot nozzle 16) relative to the surface 14a, thus creating a consistent measurement basis. Distance E3, on the other hand, is positioned slightly further back but can also be located on this plane if necessary. The sensor devices 26b and 26c are arranged offset so that their respective first reference points also lie on this plane, ensuring that all first reference points are on a common plane and thus provide a uniform measurement reference. This precise arrangement makes it possible to minimize systematic measurement deviations and increase the accuracy of the sensor data.

[0066] In summary, the invention proposes a concept for in situ sensor comparisons during the coating of substrates. Reference symbol list 10 Coating device 12 roller device 14 foil element 14a Surface 14b surface 14c border area 14d edge area 16 slot nozzles 16a Funding system 17 gaps 18 Coating material 18a Coating (of the surface 14a) 18b Coating (of surface 14b) 19a Storage container 19b Supply line 19c Distribution chamber Channel 19d 20 Exit opening 22 Basic element 22a Basic element part 22b Basic element part 23a Upper nozzle lip 23b Lower nozzle lip 24 Adjustment device 26 Sensor device 26a Sensor device (light band micrometer) 26b Sensor device (capacitive sensor device) 26c Sensor device (chromatic confocal sensor device) 30 coupling 32 electronic computing equipment 34 Adjustment direction 35 Adjustment direction 36 drying chamber 40 channels 42 recipients B Coating thickness S gap width Channel thickness E1, E2, E3 distances Z vertical direction QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 9 212 089 B2

[0002]

Claims

[1] Method for applying a coating (18a, 18b) by means of a coating device (10) in which a film of the coating (18a, 18b) is applied to a substrate in the form of a film element (14) by means of a slot nozzle (16) while the film element (14) is moved by a roller device (12), characterized by , that at least a distance (E1, E2, E3) between a first reference point at the slot nozzle (16) and a second reference point on a surface (14a) of the foil element (14) oriented towards an outlet opening (20) of the slot nozzle (16) is continuously measured and / or monitored. [2] Method according to claim 1, characterized by , that at least one distance is continuously measured during application by means of at least one sensor device (26). [3] Method according to claim 2, characterized by , that at least one sensor device (26) is moved during application. [4] Method according to one of the preceding claims 2 or 3, characterized by , that the slot nozzle (16) is positioned relative to the roller device (12) and / or depending on the measured distance (E1, E2, E3). [5] Method according to any one of the preceding claims 2 to 4, characterized by , that the slot nozzle (16) is adjusted relative to the roller device (12) and / or depending on the measured distance (E1, E2, E3) during application. [6] Method according to any one of the preceding claims 2 to 5, characterized by , that the data from at least one sensor device (26) are combined by data aggregation to determine the distance (E1, E2, E3). [7] Method according to any one of the preceding claims 2 to 6, characterized by , that setting data from external components is collected and adjustments are implemented depending on the setting data. [8] Method according to any one of the preceding claims 2 to 7, characterized by , that at least one sensor device (26) is designed as a chromatic confocal sensor device. [9] Method according to any one of the preceding claims 2 to 8, characterized by , that at least one sensor device (26) is designed as a light band micrometer. [10] Method according to any one of the preceding claims 2 to 9, characterized by , that at least one sensor device (26) is designed as a capacitive sensor device. [11] Coating device (10) for applying a coating (18a, 18b) to a substrate in the form of a film element (14), comprising a roller device (12) through which the film element (14) can be moved, and a slot nozzle (16) through which a film of the coating (18a, 18b) can be applied to the film element (14) while the film element (14) is moved through the roller device (12), characterized by, that a distance (E1, E2, E3) between a first reference point at an outlet opening (20) of the slot nozzle (16) and a second reference point on a surface (14a) of the foil element (14) oriented towards the outlet opening (20) is continuously measurable and / or monitorable.

Images