COATING DEVICE HAVING A STABLE SHEET GUIDANCE

Abstract

A coating device for coating a carrier with a coating is proposed, comprising a transport device for transporting the carrier during the coating process for coating the carrier on at least one side of the carrier and for transportation at least after the application of the paste to one side, and an aligning device. For particularly stable sheet guidance, the transport device comprises a supporting device for the positionally stable supporting of the carrier with regard to the direction perpendicular to the transport surface, in which the carrier lies during transport, and/or perpendicular to the transport direction, which is configured to form a mechanical constraint for the range of movement of the carrier perpendicular to the surface in the direction of the uncoated side of the carrier, in order to counteract a change in the position with regard to the direction perpendicular to the surface.

Claims

1. A coating apparatus for coating at least one side of a carrier with a coating comprising particles which can be oriented in a force field, comprising a transporting apparatus for transporting the carrier during the coating operation for coating the carrier on at least one side of the carrier, and also for transport at least after the application of the coating on one side, wherein an orienting apparatus for orienting particles in the coating is provided, said orienting apparatus generating a force field for orienting the particles, wherein the transporting apparatus comprises a bearing apparatus for the positionally stable mounting of the carrier in relation to the direction perpendicular to the transport surface, in which the carrier lies during transport, and/or perpendicular to the transporting direction, said bearing apparatus being configured to exert a mechanical force on the carrier and to engage at least with an uncoated side of the carrier and/or to form a mechanical constraint for the movement range of the carrier perpendicular to the surface and/or perpendicular to the transporting direction, at least in the direction of the uncoated side of the carrier, in order to counteract a change in position in relation to the direction perpendicular to the surface and/or perpendicular to the transporting direction.

2. The coating apparatus according to claim 1, wherein the bearing apparatus comprises: at least one roller bearing, on which the carrier can rest and which is configured to, in contact with the carrier, co-rotate with the translational movement of the carrier, and/or at least one grinding bearing, on which the carrier can rest and which is configured to, in contact with the carrier, remain rotationally fixed with respect to the translational movement of the carrier, and/or at least one air bearing, for contactless mounting of the carrier, and/or a vacuum bearing for exerting a pressing force perpendicular to the transport surface and/or transporting direction and/or for exerting a pulling force on the carrier parallel to the transporting direction, and/or a liquid cushion as mount, and/or an electromagnetic bearing.

3. The coating apparatus according to claim 1, wherein the bearing apparatus is configured for multi-side mounting of the carrier, which can be arranged on multiple sides of the carrier, wherein the bearing apparatus has at least two bearings situated opposite one another in relation to the transport surface and/or the carrier.

4. The coating apparatus according to claim 1, wherein the bearing apparatus comprises a contactless bearing, in order to engage with the uncoated and/or coated side of the carrier, said contactless bearing being configured as an air bearing.

5. The coating apparatus according to claim 1, wherein on a side of the transport surface on which the uncoated side of the carrier is located, at least two bearings are connected in series in the transporting direction and are arranged in an angled manner relative to one another, in order to permit a curved transport profile of the carrier.

6. The coating apparatus according to claim 1, wherein at least two air bearings, which are connected in series in the transporting direction are provided and a vacuum bearing is arranged between two successive gas bearings, in order to generate a pressing force perpendicular to the transporting direction.

7. The coating apparatus according to claim 2, wherein an opposite air bearing to the at least one air bearing is arranged in relation to the transport surface and/or to the carrier.

8. The coating apparatus according to claim 1, wherein the orienting apparatus is configured to generate a temporally and/or spatially alternating magnetic field using at least one permanent magnet, in order to orient the particles in the paste.

9. The coating apparatus according to claim 1, wherein the bearing apparatus is configured to hold the carrier at a distance of 0-200 mm away from the orienting apparatus.

10. The coating apparatus according to claim 1, wherein the bearing apparatus comprises at least two bearings which are connected in series in the transporting direction and the distance of which is between 1 cm and 8 m.

11. The coating apparatus according to claim 1, wherein the bearing apparatus is configured to guide the carrier on a curved transport path.

12. The coating apparatus according to claim 1, wherein the orienting apparatus has at least two partial orienting elements, which are connected in series in relation to the transporting direction and which are arranged in an angled manner relative to one another along at least a part of the curved transport path.

13. The coating apparatus according to claim 1, wherein the orienting apparatus is configured to be curved along at least a part of the curved transport path, in order to adapt the field distribution of the force field to the profile of the curved transport path.

14. The coating apparatus according to claim 1, wherein the carrier is a foil, and the coating is a paste and/or a dry coating for producing an anode of a lithium ion battery.

15. The coating apparatus according to claim 1, wherein the force field is a spatially and/or temporally alternating magnetic field.

16. The coating apparatus according to claim 2, wherein the grinding bearing is a wire and/or plastics thread which are/is arranged parallel to the transport surface and/or perpendicular to the transporting direction.

17. The coating apparatus according to claim 2, wherein the vacuum bearing is formed by a vacuum pump.

18. The coating apparatus according to claim 2, wherein the electromagnetic bearing is an electrostatic bearing and/or an eddy current bearing.

19. The coating apparatus according to claim 9, wherein the distance is 1 mm-4 mm.

20. The coating apparatus according to claim 10, wherein the distance is between 1 cm-50 cm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Exemplary embodiments of the present invention are illustrated in the drawings and are explained in more detail below with further details and advantages being given.

[0043] FIG. 1 shows differently coated carriers;

[0044] FIG. 2 shows a schematic illustration of a roller bearing in a coating apparatus;

[0045] FIG. 3 shows a schematic illustration of a grinding bearing in a coating apparatus according to the present invention;

[0046] FIG. 4 shows a schematic illustration of an air bearing in a coating apparatus according to the present invention;

[0047] FIG. 5 shows a schematic illustration of a combination of air bearing and vacuum bearing according to the present invention;

[0048] FIG. 6 shows a schematic illustration of a double-sided air bearing according to the present invention;

[0049] FIGS. 7 and 8 each show schematic illustrations of an air bearing with convex foil guidance according to the present invention and with differing embodiments of the permanent magnets generating the force field;

[0050] FIG. 9 shows a schematic illustration of a coating apparatus according to the present invention; and

[0051] FIG. 10 shows an illustration of an air bearing for use according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0052] FIGS. 2-4 each show bearings which act on one side.

[0053] Different types of carriers 1a, 1b, 1c which can be processed or transported by means of a coating apparatus according to the present invention are schematically illustrated in FIG. 1. The carrier 1a essentially consists only of the foil F, without any coating. The carriers 1b, 1c each have one coating B or, respectively, two coatings B1, B2. The coatings B1, B2 can generally also differ from one another. Fundamentally suitable as coating B, B1, B2 is a paste or a dry coating. The further carriers 1 in the following figures can correspondingly be coated or uncoated.

[0054] FIG. 2 shows a detail of a transport path over which a foil F or a carrier 1 is transported in a transporting direction T in order to be coated. The carrier 1 runs over roller bearings 2. Furthermore, in order to orient particles in a coating of the foil of the carrier 1, magnets 3 (not illustrated here) are provided, in the magnetic field of which the particles can be oriented. In order to not disrupt the field lines, the magnets 3 are arranged between the roller bearings 2. The carrier 1 sags to some extent between two adjacent roller bearings 2, with the result that the distance of the carrier 1 from the magnet 3 decreases compared with a fully stretched foil. The roller bearings 2 have a small amount of friction, but also engage only on one side of the carrier 1 in this case. The foil side facing the magnet 3 is therefore the coated side, the opposite side, which is not contacted by the bearing, is coated. This arrangement has the disadvantage that the distance of the carrier 1 from the magnet 3, the distance being crucial for a defined particle orientation, depends very greatly on individual factors such as the current tensile stress on the carrier 1 and can by all means vary from case to case, as a result of which the manufacturing quality is subject to fluctuations.

[0055] The ground 4 is depicted in order to indicate the direction of gravitational force.

[0056] The sagging of the carrier 1 can be reduced by supporting the latter at more locations that lie closer together. However, a prerequisite for this is that the bearings 12 are smaller, in order to not significantly influence the magnetic field through the magnets 3. Such an embodiment can be achieved using grinding bearings in the form of spacers 12 as shown in FIG. 3. Individual wires or plastics threads, which are braced transverse to the transporting direction T and over which the carrier 1 can slide, are sufficient for the grinding bearings 12. The spacers 12 can then also lie between carrier 1 and magnet 3. Even if a certain degree of sagging of the carrier 1 can still be observed here, the distance of the carrier 1 from the magnet 3 is nevertheless approximately constant. During transport of the foil, the grinding bearings may scratch the surface of said foil as a result the friction.

[0057] Friction effects can, by contrast, be reduced or avoided by way of air bearings 22, as is illustrated in FIG. 4. The mounting is in this case effected in a completely contactless manner.

[0058] According to FIGS. 2-4, one-sided mounting is provided. If the foil is deformed, for example, due to distortion during the drying of the applied coating paste, it can also detach locally from a bearing and lift off. This not only makes transport more difficult, but also the distance from the magnet 3 then no longer corresponds to the predetermined distance value, but rather has increased.

[0059] FIGS. 5-8 show bearings which act on two sides.

[0060] A contacting bearing such as a grinding or roller bearing could damage the coating on the foil top side. An air bearing in turn could, as shown in FIG. 6, block access to the upper, coated side, which could, for example, make the drying operation more difficult. In order to be able to allow a force which counteracts the supporting force of the bearing 22 to act on the carrier 1, a vacuum pump 29 in the form of a vacuum bearing which uses suction action to produce a pressing force against the air bearing 22 is provided in a preferred embodiment according to FIG. 4. In this case, the upper, coated side is freely accessible.

[0061] Another option having a two-sided mounting effect similar to in FIG. 5 (air bearing with vacuum bearing) can be achieved by exertion of a pulling force on the carrier 1. Corresponding embodiments with convex guide profile are illustrated in FIGS. 7 and 8. This pulling force is achieved by way of a convex guide profile, which is curved in relation to the transporting direction and away from the air bearings 22, because the carrier 1 in the stretched state has to exert a counterforce counter to the supporting force of the air bearings 22 in order to maintain the convex shape. In addition to the air bearings 22, the magnets 3 also have to be arranged angled relative to one another, as can be seen in FIG. 7, or the magnet is curved and thus generates the corresponding magnetic field with the desired field line profile or the desired field distribution, as is illustrated in FIG. 8. In general, the curvature cannot be selected to be as large as desired and the adaptation of the field line profile to the curvature is also not simple in technical terms, because a comparable field strength should fundamentally prevail at all points across a region of the carrier 1, in particular, transverse to the transporting direction. In the case of an angled magnet arrangement, as emerges from FIG. 7, the carrier 1 also runs in a slightly angled manner at the transition points between two magnets which are arranged angled relative to one another.

[0062] FIG. 9 shows a schematic illustration of a coating apparatus 30 for coating a foil F or a carrier 1. The foil F or the carrier 1 is provided with paste in the application station 31 and subsequently supplied in the transporting direction T to a drying module 32 for drying the paste. The drying module 32 comprises a determined number n of individual stations 32.1, 32.2, . . . , 32.n-1, 32.n, which are connected in series. By means of the return station 33, the carrier 1 returns with a reversal of direction, for example, in order to be coated on the other side.

[0063] FIG. 10 shows the technical implementation of an air bearing 22 for a coating apparatus according to the present invention. The air bearing 22 comprises a fastening plate 23 in the form of a base plate for fitting within the installation. The surface 24 facing the object to be mounted is configured as a porous graphite surface, in order to be able to allow air to pass through and form an air cushion. To this end, air connections 25 are provided on the lateral sections.

LIST OF REFERENCE DESIGNATIONS

[0064] 1, 1a, 1b, 1c Carrier [0065] 2 Roller bearing [0066] 3 Magnet [0067] 4 Ground [0068] 12 Grinding bearing [0069] 22 Gas bearing/air bearing [0070] 23 Fastening plate [0071] 24 Porous graphite surface [0072] 25 Air connections [0073] 29 Vacuum pump/vacuum bearing [0074] 30 Coating apparatus [0075] 31 Application station [0076] 32 Drying module [0077] 32.1, 32.2, . . . ,32.n Individual stations for drying [0078] 33 Return station [0079] B, B1, B2 Coating [0080] F Foil [0081] T Transporting direction