Device for coating sheet-like carrier material with slurry

Abstract

The invention relates to a device for coating a sheet-like carrier material (1) with an electrically conductive or ceramic slurry (3), comprising a continuously rotating micro-gravure roller (2) which is designed to transfer the electrically conductive or ceramic slurry on the circumference (21) of the micro-gravure roller onto the sheet-like carrier material conveyed in a feed direction (11). According to the invention, the device has a pressure chamber blade (4) which is designed to transfer an electrically conductive or ceramic slurry onto the circumference of the micro-gravure roller under positive pressure. The invention also relates to an assembly for producing a diaphragm.

Description

[0001] The present invention relates to the technical field of producing diaphragms and electrode shunts, and in particular to equipment for producing diaphragms and electrode shunts for lithium-ion batteries.

[0002] Separators are used to spatially separate the electrodes in a battery. To this end, they must act as a barrier to electron conduction to prevent short circuits between the electrodes. Furthermore, they must facilitate the transport of ions between the electrodes. For these reasons, separators are typically made of ceramic materials, whose advantageous properties can be achieved by selectively adjusting the porosity during production.

[0003] To increase the specific energy density of batteries, separators must be as thin and lightweight as possible. However, to prevent battery fires or thermal runaway, the film's mechanical strength must be ensured. This places particularly high demands on the manufacturing process and the achievable tolerances of manufacturing equipment.

[0004] Typically, a sheet-like carrier material is coated with a conductive or ceramic slurry. Ceramic slurry is a suspension of a solvent (usually deionized water) and raw ceramic particles. The slurry layer is then transferred to a dryer, where the solvent evaporates. The aforementioned key properties of the separator are already decisively influenced during the coating of the sheet-like carrier material.

[0005] The conductive slurry can be, for example, a carbonaceous slurry, such as a conductive carbon and / or graphite and / or activated carbon slurry for electrode shunts. Like the ceramic slurries used to coat the separators, the conductive adhesion promoters for battery applications are also prone to sedimentation and foaming during application to the current collector. In particular, carbon black, as the main component in the formulation, tends to form chain-like agglomerates. Due to the good affinity of these carbon black agglomerates for air, the microfoam formed is additionally stabilized. Typical resulting coating defects are "pinholes" - microbubbles that have burst after application to the current collector - or uneven, streaky, turbid coatings caused by deposition of coating material components in the application unit due to sedimentation / separation, which leads to uneven transfer to the current collector.

[0006] The equipment that is used to be coated with the traditional coating fluid of for example ink or tackiness agent has the micro-gravure roller of continuous rotation, and this micro-gravure roller is designed to transfer coating fluid on the circumference of micro-gravure roller on the sheet-like carrier material that carries along the feed direction.This type of equipment has been described among EP 0 214 574 A1.In order to transfer coating fluid on the circumference of micro-gravure roller, corresponding equipment has rinsing chamber and scraper, and this scraper forms the application gap along the length of micro-gravure roller and the circumference of micro-gravure roller.Coating fluid is directly quantitatively sent into and applies gap and is transferred to circumference via rinsing chamber. Similar devices are also described in documents DE 100 61710 A1, DE 197 54 684 A1, DE 199 26 956 A1, DE 299 17 981 U1, DE 20 2006 003 265 U1, EP 2 632 605 B1 or WO 2020 / 025349 A1.

[0007] The problem here is that conductive or ceramic slurries differ from conventional coating fluids. Specifically, slurries are multiphase fluids containing solid particles, making them susceptible to sedimentation. Conductive or ceramic raw material particles tend to form deposits on the walls of the equipment, particularly in the rinse chamber and on the doctor blade. As the equipment ages, the flow field within the equipment and the effective width of the application gap change. To maintain precise manufacturing tolerances, operations must be interrupted regularly to thoroughly clean the equipment of these deposits.

[0008] A further problem arises from the introduction of ambient air into the conductive or ceramic slurry, which is inherent in the rinsing chamber. In the systems known from the prior art, this introduction leads to coating defects, such as insufficiently wetted film areas due to microbubbles. If the microbubbles within the conductive or ceramic slurry are transported to the web using a gravure roller, defects can form there because the bubbles displace the coating material. This means that there is no conductive or ceramic slurry at these points, or too little. These defects reduce the protective effect of the conductive or ceramic layer.

[0009] Furthermore, ceramic slurries differ from conventional coating materials in their rheological properties. Consequently, even at moderate rotational speeds of the gravure rollers or low web feed speeds, ceramic slurries are susceptible to spattering. Spattering onto the web leads to coating defects. Furthermore, the surrounding area must be protected from significant contamination through structural measures within the coating facility.

[0010] Conventionally used gravure rollers with diameters between 250 and 400 mm have a radius of curvature that is too large. In the resulting wide coating line formed between the gravure roller and the carrier material, separation processes occur between the ceramic solids and the solvent of the ceramic slurry in the area of ​​the transfer point to the web. This results in an undesirable, streaky coating.

[0011] The object of the present invention is therefore to further develop the apparatus described in the introduction so that it is suitable for coating sheet-like carrier materials with conductive or ceramic slurries. Claim 1 describes a corresponding apparatus. Advantageous embodiments are the subject matter of claims 2 to 14. Claim 15 describes an assembly for producing conductive or ceramic diaphragms or electrode shunts, which assembly comprises a corresponding apparatus.

[0012] Therefore, it is provided that the apparatus comprises a pressure chamber doctor blade designed to transfer the conductive or ceramic slurry to the circumference of a micro-gravure roller.

[0013] When coating sheet-like carrier materials with conductive or ceramic slurries, micro-gravure rollers are distinguished by their relatively small diameter. The small diameter and the associated small radius of curvature counteract unnecessary separation processes. Micro-gravure rollers can have diameters between 60 mm and 150 mm.

[0014] However, the smaller diameter of the micro-gravure roller in conventional systems often has a negative impact on the maximum achievable carrier material speed. Especially at high carrier material speeds, and therefore significantly higher rotational speeds of the micro-gravure roller compared to conventional gravure rollers, low-viscosity conductive or ceramic slurries can easily fall off the gravure roller due to centrifugal forces, resulting in splashing or misting. Pressure chamber blades, on the other hand, eliminate this effect, allowing high carrier material speeds to remain possible. Carrier material speeds of up to 500 m / min are possible.

[0015] The feeding direction and the rotation direction of the micro gravure roller can be opposite.

[0016] Furthermore, the pressure chamber doctor blade may include a pressure chamber that abuts the first circumferential portion of the micro-gravure roller and is sealed from the surroundings of the apparatus. In the pressure chamber, an overpressure at the pressure chamber inlet creates a fluid barrier between the adjacent pressure chamber doctor blade and the micro-gravure roller, minimizing the ingress of air into the pressure chamber. The conductive or ceramic slurry within the pressure chamber is substantially free of microbubbles. The overpressure within the pressure chamber can range from 50 to 800 mbar, in particular from 100 to 500 mbar.

[0017] A further advantage of the overpressure in the pressure chamber is the faster filling of the cells and / or engraving lines of the micro-gravure roller. Since only a very small amount of conductive or ceramic slurry is applied, the cavity volume of the micro-gravure roller is small and the structure of the micro-gravure roller is therefore very fine. The device can be designed to use less than 10 g / m 2 , especially less than 5 g / m 2 The surface of the conductive or ceramic slurry is heavier than the coated carrier material.

[0018] Especially at high coating speeds, this type of system often experiences problems filling the cells and / or engravings of the micro-gravure roller. Overpressure in the pressure chamber helps accelerate the filling of the cups and / or engravings, and thus achieve these coating speeds. Furthermore, these tend to "overfeed" the doctor blade on the discharge side. Due to the positive pressure gradient between the pressure chamber and the ambient pressure, additional coating fluid flows downstream under the doctor blade and overfills the gravure roller in a controlled manner, which has a positive impact on the fluid transfer to the web and, therefore, the coating quality.

[0019] The pressure chamber doctor blade can have a discharge doctor blade and an infeed doctor blade, which seal the pressure chamber against the environment in the direction of rotation of the micro-gravure roller or counter to the direction of rotation of the micro-gravure roller.

[0020] The pressure chamber can have a feed line designed to quantitatively feed the conductive or ceramic slurry into the pressure chamber. The pressure chamber can also have an outlet designed to remove the conductive or ceramic slurry from the pressure chamber. In this way, the statistical residence time of the conductive or ceramic slurry in the device can be precisely adjusted. In this way, the slurry can not only be removed from the pressure chamber via the circumference of the micro-gravure roller, but can also be discharged via the outlet using a controlled material flow. If the residence time is too long, the conductive or ceramic slurry tends to cause the conductive raw material particles or ceramic raw material particles to agglomerate, which gradually changes the particle size distribution. This in turn accelerates sedimentation and also has a significant impact on the porosity of the diaphragm or electrode shunt.

[0021] The pressure chamber scraper can have a pressure reservoir upstream of the feed and / or downstream of the discharge in order to avoid pressure fluctuations in the pressure chamber. This is an additional volume for the conductive or ceramic slurry, which is fluidically connected to the pressure chamber and supports the distribution of the conductive or ceramic slurry over the length of the pressure chamber scraper parallel to the longitudinal axis of the micro-gravure roller. Transient effects, such as fluctuations in the rotational speed of the micro-gravure roller or fluctuations in the material flow provided by the pump, lead to pressure fluctuations in the pressure chamber scraper. The large volume of the conductive or ceramic slurry in the pressure chamber scraper offsets the amplitude of these pressure fluctuations. Therefore, the additional volume provided by the pressure reservoir makes it possible to keep the volume of the pressure chamber small without the pressure fluctuations in the pressure chamber having a negative impact on the porosity or the coating thickness. On the other hand, the small volume of the pressure chamber offsets the sedimentation in the pressure chamber.

[0022] Furthermore, the apparatus may comprise a filter unit for filtering the conductive or ceramic slurry, the filter unit being fluidly connected to the pressure chamber blade and arranged upstream of the inlet.

[0023] In particular, the feed line can include at least one nozzle through which the conductive or ceramic slurry can be metered into the pressure chamber, and the nozzle is configured to induce a rotating flow field within the pressure chamber. Due to the constriction of the flow cross section within the nozzle, the conductive or ceramic slurry is accelerated before entering the pressure chamber. The inflow angle of the nozzle is oriented away from the geometric center of gravity of the pressure chamber, which induces a rotating flow field. This ensures continuous mixing of the conductive or ceramic slurry within the pressure chamber, which counteracts agglomeration. In addition, the rotating flow field causes a near-wall velocity gradient within the pressure chamber, which prevents sedimentation on the pressure chamber wall or degrades the sedimentation layer.

[0024] The feed line may include at least two nozzles, each nozzle having a different inflow position and / or inflow angle to induce a rotating flow field. The at least two nozzles may have two relative inflow angles and inflow positions on opposite sides of the pressure chamber. The at least two nozzles may be configured to alternately change the direction of rotation of the rotating flow field. To this end, the nozzles may be designed to individually control the quantitative feed material flow of the conductive or ceramic slurry. Alternatively or additionally, the inlet may have a vortex baffle. Preferably, the rotation axis of the rotating flow field may be parallel to the rotation axis of the micro-gravure roller. In addition, the pressure chamber may have a guide wall geometry that is designed to induce a rotating flow field.

[0025] The apparatus may include a first guide roller and a second guide roller, wherein the first guide roller and the second guide roller are configured to guide the sheet-form support material past a circumferential portion of the micro-gravure roller.

[0026] This is advantageous for transferring conductive or ceramic slurries in the so-called kiss coating process: A micro-gravure roller is positioned between two guide rollers on the support material, with a coating line – the kiss coating line – forming between the gravure roller and the web. Due to the overpressure in the pressure chamber, the gravure roller is overfilled, and the resulting coating fluid in the kiss coating line region comes into contact with the entire surface of the web, thus supporting uniform coating of the sheet-like support material.

[0027] The circumferential section can have a wrap angle of 5° to 30°, preferably 8° to 22°.

[0028] The diameter of the first and / or second guide roller may be larger than the diameter of the micro gravure roller, in particular several times larger than the diameter of the micro gravure roller.

[0029] The diameter of the first and / or second guide rollers can be smaller than that of the micro-gravure roller. Therefore, the micro-gravure roller can be positioned with a small distance between the first and second guide rollers. This results in good contact between the web guided between the first and second guide rollers and the micro-gravure rollers. This leads to an advantage in transferring the conductive or ceramic slurry, which is metered in by the micro-gravure rollers, to the web. This allows a narrow kiss coating line to be formed between the gravure rollers and the web at a moderate wrap angle.

[0030] The apparatus can be further configured to move the pressure chamber blade horizontally in an oscillating manner relative to the longitudinal axis of the micro-gravure roller. This allows solids / agglomerates that have adhered to the blade of the pressure chamber blade to be removed. These solids can then be transported away by the circulating fluid and filtered out.

[0031] The discharge blade of the pressure chamber doctor blade can be set positively or negatively (also called swept or piercing). Depending on the properties of the conductive or ceramic slurry, this variability in the doctor blade position can have a positive effect on the quality of the coated film.

[0032] Pressure chamber scraper types can further include a minimized pressure chamber with a minimized volume for the conductive or ceramic slurry. The minimized volume avoids surfaces where sedimentation can accumulate. The discharge scraper and / or the infeed scraper can be designed with negative angle scrapers on both sides. Alternatively, or in addition to the outlet, the pressure chamber scraper can also have an overflow for removing excess conductive or ceramic slurry from the pressure chamber.

[0033] Finally, protection is claimed for an assembly for producing a diaphragm or electrode shunt, comprising: an apparatus for coating a sheet-like carrier material according to any of the above-described embodiments, a sheet-like carrier material, at least one deflection roller and a dryer, wherein the at least one deflection roller is designed to transfer the sheet-like carrier material from the apparatus for coating the sheet-like carrier material to the dryer.

[0034] Conductive adhesion promoters can be provided for use in electrodes of batteries, including lithium polymer batteries. The adhesion promoter is intended to ensure that the active anode or cathode material adheres to the corresponding current collector, ie does not become detached during battery operation (charge / discharge).

[0035] Conductive adhesion promoters can be made from Bonderite or LOCTIDE EDAG from Henkel. They can also be made from metal oxides or polyacrylic acid-based polymer binders, optionally with conductive additives. Alternatively, adhesion promoters can be based on polyolefins, polyvinyl ethers, polystyrenes, or styrene-butadiene rubbers.

[0036] The separator or electrode shunt, also called current collector, can preferably be in the form of a foil, fiber, nonwoven, mesh, smooth, rough or perforated.

[0037] The conductive paste may, for example, contain a conductive polymer such as polypyrrole, polyaniline, or polythiophene. Alternatively, the conductive paste may consist of a filled plastic, wherein carbon black, graphite, and / or metal powders are provided as filler materials. Furthermore, the conductive paste may contain metals such as silver, copper, tin, aluminum, titanium, chromium, and / or nickel. Alternatively, the metal may be present as a coating on a plastic film or other material.

[0038] When using conductive pastes, it has surprisingly been shown that, compared to conventional engraving processes, the problem of (micro)foam formation, in particular, is significantly reduced. This is accompanied by a reduction in the resulting coating defects (pinholes), which has a positive effect on the functionality of the applied layer / cell.

[0039] Active anode and cathode materials, along with the current collectors to which they are applied, form the electrodes. Transition metal oxides such as Co(III) oxide, Ni(II) oxide, Mn(IV) oxide, tungstates, molybdates, titanates, ferrates, and / or chromates—all in lithium-containing forms, e.g., LiCoO2, LiNiO2, LiMn2O4—can be used as the cathode active material. Graphite, carbon, soot, and / or fibers can be used as the anode active material.

[0040] An important component of the anode or cathode material is an adhesion promoter. The adhesion promoter generally ensures the adhesion of the above-mentioned materials to the current collector. The adhesion or bonding of the transition metal oxide or carbon is intended to create an adhesion to the current collector that is stable even over a long cycle period of >200 cycles, i.e. does not show any detachment. In addition, the adhesion promoter should be sufficiently stable so that even mechanical stresses such as bending or squeezing pressure do not lead to cracks, detachment or displacement from the current collector. Polymers can be used as adhesion promoters, which are inert to the processes and ion exchange reactions in the battery system and ensure the adhesion of the anode or cathode material to the current collector.

[0041] For example, polyolefins such as polyisobutylene, EPDM rubber, and / or styrene-butadiene (isoprene) polymers are used as adhesion promoters. The molecular weight of the polymer can be between 20,000 and 2,000,000, preferably between 50,000 and 300,000. The amount used is 2 to 25 weight percent (wt.%), preferably 3.5 to 15 weight percent.

[0042] Furthermore, electrical conductivity is an important prerequisite for system effectiveness. It can be provided that the proportion of adhesion promoters in the active anode or cathode material does not exceed 25% based on the solids. For example, this proportion can be 5-15%. Conductive fillers such as conductive carbon black, graphite, polypyrrole, polyaniline, or the like can be provided to increase conductivity. Based on the adhesion promoter, the material can be added in an amount of up to 50% of the material.

[0043] The accompanying drawings are used to illustrate and explain further details and functionality of the present invention. Specifically: Figure 1A shows a schematic diagram of an apparatus according to the prior art; Figure 1B shows a detailed enlarged view of the surface of a micro-gravure roller in an apparatus according to the prior art; Figure 2A A schematic diagram showing an apparatus according to the present invention; and Figure 2B shows a detailed enlarged view of the surface of a micro-gravure roller in an apparatus according to the present invention; Figure 3 and Figure 4 Detailed views of two embodiments of pressure chamber scrapers according to the invention are shown.

[0044] Figure 1 shows a schematic diagram of a common apparatus for coating sheet-like carrier material 1. The sheet-like carrier material 1 is conveyed in a feed direction 11 and directed over a gravure roller 2. In this process, a conductive or ceramic slurry 3 is transferred onto the sheet-like carrier material 1 via the circumference 21 of the gravure roller, thereby coating it. A flushing chamber is located adjacent to the gravure roller 2. In this flushing chamber, the conductive or ceramic slurry is metered in at atmospheric pressure and ultimately transferred to the circumference 21 of the gravure roller 2. This type of apparatus has significant drawbacks for the quality of the final separator and the economic efficiency of the manufacturing process. First, air is introduced into the conductive or ceramic slurry 1. Second, the conductive or ceramic slurry 1 tends to settle within the flushing chamber. Third, depending on the rotational speed of the gravure roller, the conductive or ceramic slurry 1 begins to splatter at a certain feed speed of the web. Another issue is that the cavity volume of the gravure roller 2 is low due to the low thickness of the separator. Consequently, the structures introduced into the circumference 21, such as lines or cells, are also very fine. At moderate carrier material speeds, the devices known from the prior art suffer from problems with filling the cells or lines.

[0045] This is due to Figure 1A The enlarged detail "A" is shown. It shows an enlarged section of the circumference of the gravure roller 21 at a point shortly before the conductive or ceramic slurry 3 is transferred to the carrier material 1. The conductive or ceramic slurry 1 has already been transferred to the surface of the gravure roller 21 in the rinsing chamber. Due to the atmospheric pressure applied to the rinsing chamber and the negligible ground pressure of the liquid column, only the cells inserted into the surface are filled with the conductive or ceramic slurry, even at carrier material speeds below 100 m / min. During the subsequent transfer of the conductive or ceramic slurry 3 to the carrier material 1, the carrier material is applied in patches or with intermittent thicknesses.

[0046] Figure 2AA schematic diagram of the apparatus according to the present invention is shown. A sheet-like carrier material 1 is conveyed 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-gravure roller 2 in a so-called kiss coating process. The conductive or ceramic slurry 3 is transferred to the sheet-like carrier material 1 via the circumference 21 of the gravure roller and thus coated. For this purpose, the feed direction 11 and the direction of rotation 23 of the micro-gravure roller 2 are opposite. The coated sheet-like carrier material is then conveyed via a rubber deflection roller 7 to a dryer (not shown), where the conductive or ceramic slurry 3 is dried by solvent evaporation.

[0047] Beneath the micro-gravure roller 2, the conductive or ceramic slurry 3 is transferred under positive pressure onto the circumference 21 of the micro-gravure roller 2 by a pressure chamber blade 4. The pressure chamber blade 4 is shown here in cross-section. The pressure chamber blade 4 comprises a pressure chamber 41, which is adjacent to the micro-gravure roller 2 and sealed from the surroundings of the system. To this end, the pressure chamber blade 4 comprises a pair of blades that seal the pressure chamber 41 across the entire width of the micro-gravure roller in either the direction of rotation 23 or the counter-direction of rotation 23, allowing a positive pressure to build up within the pressure chamber 41. The conductive or ceramic slurry 3 is metered into the pressure chamber 41 via a feed line 42.

[0048] Upstream of the inlet, a pressure reservoir 44 is arranged in the pressure chamber scraper 4, which suppresses or reduces operating pressure fluctuations in the pressure chamber scraper 4. The pressure chamber scraper 4 is supplied with conductive or ceramic slurry 3 via a feed line having a pump and a filter unit (not shown). The pressure chamber 41 further comprises an outlet 43, which is configured to remove the conductive or ceramic slurry 3 from the pressure chamber 41. The pressure reservoir 44 is also arranged downstream of the outlet. A controlled material flow of the conductive or ceramic slurry 3 can be removed via a drain pipe. The positive pressure in the pressure chamber can be ensured via a throttle valve or a controllable valve and / or a pump pressure. In this way, the statistical residence time of the conductive or ceramic slurry 3 in the pressure chamber scraper 4 can be influenced. In particular, the discharged conductive or ceramic slurry 3 can be mixed into the feed line and thus recirculated.

[0049] The positive pressure in the pressure chamber 41 results in faster filling of the cells of the micro-gravure roller. Figure 1A The details shown are similar to the enlarged view. Figure 2BAn enlarged detail of the surface of the micro-gravure roller 2 of the apparatus according to the present invention is shown. On the downstream side of the pressure chamber, the gravure roller can be easily "overfed" by adjusting the positive pressure. Due to the positive pressure gradient between the pressure chamber 41 and the ambient pressure, additional conductive or ceramic slurry 3 flows downstream under the pressure chamber blade 4 and overfills the cells on the surface of the micro-gravure roller 1. This facilitates the transfer of the conductive or ceramic slurry 3 during the kiss coating process. The overfilling of the gravure roller 2 and the resulting contact of the coating fluid with the entire surface of the carrier material 1 in the kiss coating line area support uniform coating even at carrier material speeds significantly above 100 m / min.

[0050] Figure 3 An alternative embodiment of a pressure chamber scraper 4 is shown. Here, the feed line 42 has a nozzle 421, through which the conductive or ceramic slurry 3 is metered into the pressure chamber. In the nozzle, the conductive or ceramic slurry 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 about an axis of rotation 423, which is parallel to the axis of rotation of the micro-gravure roller 2. The rotation of the flow field 422 is amplified by the wall guidance geometry of the pressure chamber 41 and the rotating surface 21 of the micro-gravure roller 2. The rotating flow field 422 mixes the conductive or ceramic slurry 3 within the pressure chamber 41 and thus homogenizes it. This effectively counteracts sedimentation. In addition, the rotating flow field 422 induces a strong velocity gradient near the pressure chamber wall, and thus induces shear stress, which inhibits the deposition or destruction of sedimentation and removes sedimentation on the wall.

[0051] Figure 4 Another embodiment of a pressure chamber scraper 4 is shown, which has a minimized pressure chamber 41 with a minimized volume for the conductive or ceramic slurry 3. The minimized volume avoids the formation of a surface where sedimentation can accumulate and minimizes the introduction of ambient air into the conductive or ceramic slurry 3 in the pressure chamber. Both the discharge scraper and / or the feed scraper are designed as negative angle scrapers. To further reduce the volume of the pressure chamber 41, the pressure chamber 41 does not have an outlet 43. Instead, excess conductive or ceramic slurry 3 is removed from the pressure chamber 41 via the feed scraper.

[0052] The features of the invention disclosed in the above description, the drawings and the claims may be essential for the implementation of the invention both individually and in any combination.

[0053] List of reference numerals: .

Claims

1. A device for coating a sheet-like carrier material (1) with an electrically conductive or ceramic slurry (3), for example a carbon-containing electrically conductive slurry, for example an electrically conductive slurry containing conductive carbon black and / or graphite and / or activated carbon, comprising a continuously rotating micro-gravure roller (2) designed to transfer the electrically conductive or ceramic slurry (3) on the circumference (21) of the micro-gravure roller (2) onto the sheet-like carrier material (1) being transported in a feed direction (11), characterized in that The apparatus has a pressure chamber blade (4) designed to transfer the conductive or ceramic slurry (3) onto the circumference (21) of the micro-gravure roller (2) under positive pressure.

2. The device according to claim 1, wherein In the region of the coating line formed between the micro-gravure roller (2) and the sheet-like carrier material (1), the feed direction (11) and the rotation direction of the micro-gravure roller (23) are opposite.

3. The apparatus according to any one of the preceding claims, wherein The pressure chamber doctor blade (4) has a pressure chamber (41) which is open to the micro-gravure roller (2) and sealed with respect to the environment of the apparatus.

4. The device according to claim 3, wherein The positive pressure in the pressure chamber (41) is 50 to 800 mbar, preferably 100 to 500 mbar.

5. Apparatus according to any one of the preceding claims, wherein The micro-gravure roller (2) has a diameter between 60 mm and 150 mm.

6. Apparatus according to any one of the preceding claims, wherein The pressure chamber (41) has a feed line (42) designed to meter the conductive or ceramic slurry (3) into the pressure chamber (41).

7. Apparatus according to any one of the preceding claims, wherein The pressure chamber (41) has an outlet (43) through which the conductive or ceramic slurry (3) is discharged from the pressure chamber (41).

8. The apparatus according to claim 6 or 7, wherein: The pressure chamber scraper (4) has a pressure reservoir (44) located upstream of the feed line (42) and / or downstream of the outlet (43), which provides additional volume for the conductive or ceramic slurry (3) to avoid pressure fluctuations in the pressure chamber (41).

9. The apparatus according to any one of claims 6 to 8, wherein The apparatus has a filter unit for filtering the conductive or ceramic slurry (3), which is fluidically connected to the pressure chamber scraper (4) and is preferably arranged upstream of the feed line (42).

10. The apparatus according to any one of claims 7 to 9, wherein The feed line (42) has at least one nozzle (421) through which the conductive or ceramic slurry (3) can be metered into the pressure chamber (41), and the at least one nozzle is designed to induce a rotating flow field (422) in the pressure chamber (41).

11. The apparatus according to claim 10, wherein The feed line (42) has at least two nozzles, each nozzle having a different inflow position and / or inflow angle to induce the rotating flow field (422).

12. The apparatus according to claim 10 or 11, wherein The at least one nozzle (421) is configured to induce a rotation axis (423) of the rotating flow field to be parallel to a rotation axis of the micro-gravure roller (2).

13. Apparatus according to any one of the preceding claims, wherein The device comprises a first guide roller (5) and a second guide roller (6), wherein the first guide roller (5) and the second guide roller (6) are designed to guide the sheet-like carrier material (1) on a circumferential section (22) of the micro-gravure roller (2).

14. The apparatus according to claim 13, wherein The circumferential section (22) has a wrap angle (α) of 5° to 30°, preferably 8° to 22°.

15. An assembly for producing a diaphragm or an electrode shunt, comprising an apparatus for coating a sheet-like carrier material (1) according to any one of claims 1 to 14, a sheet-like carrier material (1), at least one deflection roller (7) and a dryer, wherein: The at least one deflection roller (7) is designed to transfer the sheet-like carrier material (1) from the device for coating the sheet-like carrier material (1) to the dryer.

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