DE102023200980A1 - Method and device for producing a dry film - Google Patents

Abstract

The invention relates to a method for producing a dry film (4) from dry film material (6), wherein a solvent-free dry film material (6) for forming the dry film (4) is fed into a roller gap (16) formed between a first roller (12) and a second roller (14), wherein the dry film (4) formed is cut to size, and wherein material residues (48) from the formation of the dry film and/or the cutting of the dry film (4) are fed to a device (8) for producing the solvent-free dry film material (6). The invention further relates to a device (2) for carrying out the method.

Description

The invention relates to a device and a method for producing a dry film from solvent-free dry film material.

To produce a dry film, as shown in the WO 2018/210723 A1 It is known that a dry film material is conveyed between two rollers of a roller device using a powder conveyor. These rollers introduce pressure and/or shear forces into the dry film material so that the dry film is formed.

It is advisable to trim the dry film at its side edges in order to achieve a sufficiently high quality of the film edges. The cut-off coating edge is typically disposed of as waste.

The invention is based on the object of specifying a particularly suitable method and/or a particularly suitable device for producing a dry film. In particular, the formation of unused material waste should be avoided as far as possible.

With regard to the method, the object is achieved according to the invention by the features of claim 1. With regard to the device, the object is achieved according to the invention by the features of claim 6. Advantageous embodiments and further developments are the subject of the subclaims. The statements in connection with the device also apply mutatis mutandis to the method and vice versa.

The method serves to produce a dry film. The dry film produced is expediently used as a layer, in particular as a layer with active material, for an anode or for a cathode of a lithium-ion battery. For this purpose, the dry film is or will be applied to a substrate.

According to the method, in a first step to form the dry film, solvent-free dry film material is conveyed into a roller gap, which first roller gap is formed between a first roller and a second roller. In this case, a pressing and/or shearing force is generated on the dry film material using the first and second rollers, so that the particles of the dry film material bond with one another and/or so that the dry film deposits on one of the two rollers.

For example, the first and second rollers have different rotational speeds, i.e. different numbers of revolutions. This facilitates roller-supported further conveyance of the dry film, particularly on the roller with the higher rotational speed.

For example, additional rollers and/or pairs of rollers are provided to compact and/or convey the dry film formed.

The dry film material is expediently a granular material, also referred to as granulate, for example a powder or a powder mixture. The dry film material suitably comprises a (dry) active material, a (dry) binder and/or a (dry) conductive agent. In other words, the dry film material comprises a mixture of undissolved active material particles, undissolved binder particles and/or undissolved conductive agent particles.

In a second step of the process, the dry film formed in the roller gap is cut to size. In particular, the dry film is cut off in its edge areas. In other words, the ends of the dry film are cut off in or against a direction, also referred to below as the axial direction, along the axes of the first and second rollers. Consequently, a straight edge of the dry film and/or an edge with a uniform thickness in the longitudinal direction of the dry film and/or a dry film with a predetermined, in particular constant, width (extension in the axial direction) is realized. In addition or alternatively to this, an area of the dry film that does not meet a predetermined criterion is cut off during cutting. Such an area is also referred to as a "not OK area" or "not OK area". For example, a minimum requirement for the homogeneity of the dry film and/or a maximum thickness fluctuation of the dry film is used as a criterion. Such a not OK area arises, for example, when starting up the production process.

In a further, third step of the method, material residues from the formation of the dry film and/or the cutting of the dry film are fed, in particular automatically, to a device for producing the solvent-free dry film material. Material residues from the formation of the dry film are in particular dry film material, i.e. powder or granulate, which was fed into the roller gap but was not processed into a dry film using the rollers, for example because it was removed as excess powder from the dry film material template, in particular using a doctor blade. Material residues from the cutting of the dry film are in particular the cut-off edge areas, in other words the edge area. cut of the dry film, and/or a not OK area cut off from the dry film.

In summary, the material residues formed during the production of the dry film are returned, in particular directly, to the production process of the dry film material. The material residues are therefore returned to the facility for producing the dry film material, whereby the dry film material, which thus at least partially contains the recycled material residues, is expediently processed again into the dry film. In this way, the formation of unused material waste is particularly advantageously avoided or at least reduced.

Here and in the following, the facility for producing the dry film material is also referred to as the production facility.

According to an expedient development of the method, the rate of supply of the material residues to the device for producing the solvent-free dry film material is and/or will be set. For example, the supply is set or regulated in such a way that the (supply) rate is constant over time. The (supply) rate is understood here to mean an amount of material residues per unit of time.

Preferably, the rate is set such that the proportion of dry film material produced from the returned material residues corresponds to a predetermined target proportion of the total amount of dry film material produced using the production device. For example, the feed rate is set such that this proportion of dry film material from the material residues is between 0.1% and 50%.

In a suitable embodiment of the method, the material residues are fed to an extruder, in particular a twin-screw extruder, of the production facility. The extruder serves in particular to pretreat the starting material fed to it and/or to activate a binder of the starting material. According to this embodiment, the material residues and preferably further starting material, in particular a powdered mixture of the binder, the conductive agent and the active material, are fed to the extruder.

Alternatively or additionally, the material residues are fed to a finishing unit of the production facility according to a suitable design. The finishing unit (finishing device) serves in particular to deagglomerate material fed to it and/or, preferably in accordance with a predetermined particle or granulate size of the dry film material, to reduce it, in particular to cut it and/or to grind it. The extrudate is expediently comminuted and then fed to the finishing device. In this case, the material residues are preferably fed to the finishing unit together with the, in particular comminuted, extrudate.

In summary, the production device preferably comprises an extruder for pretreating the starting material fed to the extruder, as well as a finishing unit which refines the extrudate, in particular the dried and pre-cut extrudate, in particular reduces its size. This makes it possible to feed the material residues from the formation of the dry film and/or the cutting of the dry film to the extruder and/or the finishing device, so that dry film material is again produced from these for the formation of the dry film.

According to a suitable embodiment, the material residues are crushed before being fed to the production device. In this way, mixing of the material residues and the extrudate in the finishing device or of the material residues and the starting material, in particular in powder form, in the extruder is facilitated.

For example, the material residues, possibly shredded, are stored before being fed to the production facility. Preferably, however, the material residues are fed directly to the production facility, i.e. without external intermediate storage.

A further aspect of the invention relates to a device for producing a dry film from (solvent-free) dry film material. The device is intended and set up to carry out the method in one of the variants shown above. For this purpose, the device has the device for producing the dry film material. The device also comprises a device for forming the dry film from the dry film material, this device comprising the first and the second roller, and the roller gap is formed between the first and the second roller.

Conveniently, the device comprises a conveyor device which serves to convey the dry film material into the roller gap.

The device further comprises a cutting device for cutting the dry film formed by the rollers, in particular for cutting off the lateral edges of the dry film, i.e. for trimming the dry film with a cutting edge perpendicular to the axial direction. For example, the cutting device comprises a squeezing or roller knife. In particular, the dry film is cut on one of the rollers using the squeezing or roller knife. The device expediently also comprises a cutting and/or removal device, which comprises, for example, a scraper or a doctor blade. In this way, the not OK areas in particular can be cut off and removed from the dry film using the cutting and/or removal device.

The device further comprises a return device (feed device) for feeding, preferably automatically, the material residues from the formation of the dry film and/or cutting of the dry film to the production device. The return device is therefore used in particular to return powder or granulate residues from the dry film production and/or the edge trimming and/or the cut-off defective areas to the production device.

As explained in connection with the method, it is advantageously possible with the aid of such a device to reuse the material residues for the production of the dry film material, so that the formation of unused material waste is avoided or at least reduced.

According to an expedient embodiment, the return device has a shredding unit for shredding the material residues. For example, the shredding unit comprises a cutting unit and/or a grinding unit.

As already described in connection with the method, the production device comprises the finishing unit and/or the extruder according to an expedient embodiment. The material residues can be fed to the extruder and/or the finishing unit using the return device. The return device is therefore designed in such a way that when the return device is in operation, the material residues are fed to the extruder and/or the finishing unit.

In a suitable embodiment, the return device is designed for pneumatic conveying of the material residues. The return device therefore comprises a suction device for removing the material residues from the device for forming the dry film and/or for conveying the material residues to the production device.

As an alternative to pneumatic conveying of the material residues, the return device includes a collecting container for receiving the material residues. Material residues are preferably collected in the collecting container and then fed to the production device. In summary, the material residues are fed to the production device in batches.

• 1 schematisch eine Vorrichtung zur Herstellung eines Trockenfilms aus Trockenfilmmaterials, wobei die Vorrichtung eine Einrichtung zur Herstellung des Trockenfilmmaterials sowie eine Einrichtung zur Bildung des Trockenfilms aus dem Trockenfilmmaterial umfasst,
• 2 schematisch in einer Seitenansicht die Einrichtung zur Bildung des Trockenfilms aus dem Trockenfilmmaterial, wobei diese ein Walzenpaar umfasst, anhand dessen das Trockenfilmmaterial zum Trockenfilm verarbeitet wird,
• 3 schematisch in einer Draufsicht auf deren Unterseite die Einrichtung zur Bildung des Trockenfilms aus dem Trockenfilmmaterial, und
• 4 anhand eines Flussdiagramms ein Verfahren zur Herstellung des Trockenfilms aus dem Trockenfilmmaterial.

In the following, embodiments of the invention are explained in more detail with reference to a drawing. In the drawing:

• 1 schematically shows an apparatus for producing a dry film from dry film material, the apparatus comprising a device for producing the dry film material and a device for forming the dry film from the dry film material,
• 2 schematically shows in a side view the device for forming the dry film from the dry film material, which comprises a pair of rollers by means of which the dry film material is processed into the dry film,
• 3 schematically in a plan view of the underside of the device for forming the dry film from the dry film material, and
• 4 A process for producing the dry film from the dry film material using a flow chart.

Corresponding parts and sizes are always provided with the same reference symbols in all figures.

In the 1 A device 2 for producing a dry film 4 from dry film material 6, in particular in powder or granular form, is shown schematically. The device 2 comprises a (production) device 8 for producing the dry film material 6.

The dry film material 6 produced by the production device 8 is fed to a device 10 for forming the dry film 4. The device 10 for forming the dry film 4 is in the 2 and 3 shown in more detail. This comprises a first pair of rollers with a first roller 12 and a second roller 14, wherein a (first) roller gap 16 is formed between the first and the second roller 14. The device 2 further comprises a conveyor device 18, which in the 2 shown schematically and designed, for example, as a material conveyor, which in particular comprises a hopper. The conveyor device 18 is designed to convey the dry film material 6 produced by the production device 8 into the first roller gap 16, where it is processed into the (first) dry film 4 by the first and second rollers 12, 14.

As continued in the 2 and 3 As can be seen, the device 10 for forming the dry film 4 comprises a second pair of rollers with a third roller 20 and a fourth roller 22. The axes A of the rollers 12, 14, 20 and 22 are preferably arranged parallel to one another and in a common plane. A (second) roller gap 24 is formed between the third roller 20 and the fourth roller 22. A further conveyor device 18 is provided for conveying dry film material 6, in particular dry film material 6 produced using the production device 8, into the second roller gap 24, where it is processed into a second dry film 26 using the third roller 20 and the fourth roller 22.

The first dry film 4 is conveyed, roller-supported, on the second roller 14 into a third roller gap 28, which is formed between the second roller 14 and the third roller 20 adjacent to it. In addition, the second dry film 26 is conveyed, roller-supported, on the third roller 20 into the third roller gap 28. A feed device 30 of the device 2, shown here as a guide roller by way of example, is designed to feed a substrate 32, in particular a film-like substrate, into the third roller gap 28 between the first dry film 4 and the second dry film 26. In the third roller gap 28, the first dry film 4 and the second dry film 26 are laminated onto the substrate 32 to form an electrode 34.

The device 10 further comprises crushing knives as a cutting device 36. Two of the crushing knives are arranged on the second roller 14 in such a way that they are spaced apart in the axial direction, i.e. in a direction parallel to the axis A of the second roller, and laterally cut off the dry film supported on the second roller 14. The edge trim 38 formed in this way is in the 3 indicated by a broken line.

Analogously, two further crushing knives of the cutting device 36 are arranged on the third roller 20 in such a way that they are arranged at a distance in the axial direction, i.e. in a direction parallel to the axis A of the second roller 20, and that they laterally cut off the second dry film 26 supported on the third roller 20. The edge trim 38 formed in this way is in the 3 also indicated by a broken line.

Squeegees 40 of the device 10 are provided to remove the respective edge trimming 38 from the second roller 14 or from the third roller 20. For this purpose, the squeegees 40 are arranged with respect to the 2 arranged in the direction of rotation shown by arrows between the respective crushing knife and the third roller gap 28.

The device further comprises a doctor blade 42 for the second roller 14 and for the third roller 20. These serve to remove and/or cut off an area of the dry film 4 from the second roller 14 or an area of the second dry film 26 from the third roller 20 that does not meet a predetermined quality criterion. Such an area, also referred to as a "not-okay area", arises in particular when the device 10 is started up to form the dry film 4.

In the area of the doctor blades 40, 42, a suction device 44 of a return device 46 of the device 2 is arranged. In other words, the return device 46 is intended and set up to remove the material residues 48 from the cutting of the dry film or the second dry film 26 from the device 10. The return device 46 is therefore set up to suck up the edge trimmings and/or the "not-in-order area" of the dry film 4 and/or the second dry film 26 as material residues 46.

According to an alternative not shown in more detail, a collecting container for the material residues 48 is arranged in the area of each of the doctor blades 40, 42.

During the production of the dry film 4, the dry film material 6, which is in particular solvent-free, is conveyed, in particular poured, into the roller gap 16. This accumulates in the roller gap 16 in front of its narrowest point. A material jam thus forms in the roller gap 16. In the edge area of this so-called dry film material feed, i.e. at its axial ends, a further suction device 44 of the return device (or, according to a variant not shown in more detail, a collecting container) is arranged, which removes excess dry film material 6 from the device 10.

In summary, the device 2 has the return device 46, by means of which the material residues from the cutting and/or the excess dry film material 6 are removed as material residues 48 from the formation of the dry film 4 from the device 10 and fed (returned) to the production device 8. The material residues 48 are conveyed pneumatically.

Optionally, the return device 46 has a cutting mechanism or a grinding mechanism as a shredding unit 50, by means of which the material residues 48 can be shredded. If necessary, the return unit is provided and set up to possibly shredded material residues 48 to the production facility 8.

Like in the 1 As can be seen, the production device comprises an extruder 52, which is designed in particular as a twin-screw extruder, and a finishing unit 58.

The extruder 52 is designed and configured to pretreat a mixture 54, in particular in powder form, of a binder, an active material and a conductive agent as starting material and/or to activate the binder and process it into an extrudate 56. For example, the preferably comminuted material residues 48 are additionally fed to the extruder 52 on the input side as starting material. In this case, the mixture 54 and the material residues 48 are mixed using the extruder 52 and processed into the extrudate 56.

The extrudate 56 is preferably hardened, in particular cooled, and/or comminuted. If necessary, the extrudate 56 is fed to the finishing unit 58. This serves to further reduce and/or grind the possibly cooled and comminuted extrudate 56 to form the dry film material 6. For example, in addition to the extrudate 56, the material residues 48 are fed to the finishing unit 58 and comminuted using these. In this case, both the extrudate and the material residues 48 are comminuted using the finishing unit 58 to form the dry film material 6.

For example, part of the material residues 48 are fed to the extruder 52 and the remaining material residues 48 are fed to the finishing unit 58. Preferably, the material residues 48 are fed only to the extruder 52 or the finishing unit 58. In summary, the material residues 48 can be fed to the extruder 52 and/or the finishing unit 58 using the return device 46.

In summary, the material residues are recycled due to their return from the device 10 for forming the dry film 4 to the production device 8. Thus, the formation of unused material waste is avoided or at least reduced by the material residues 48.

In the 4 A method for producing the dry film 4 by means of the device 2 is shown in a flow chart.

In a first step I, the solvent-free dry film material 6, produced in particular using the production device 8, is conveyed into the (first) roller gap 16 formed between the first roller 12 and the second roller 14. There, the dry film material 6 is processed into the (first) dry film 4 using the two rollers 12, 14.

Optionally, solvent-free dry film material 6, preferably also produced using the production device 8, is conveyed in an analogous manner into the (second) roller gap 24 formed between the third roller 20 and the fourth roller 22. There, the dry film material 6 is processed into the (second) dry film 26 using the two rollers 20, 22. Further optionally, the dry film 4 and the second dry film 26 are conveyed into the third roller gap 28, where the dry film 4 and the second dry film 26 are laminated onto one side of the substrate 32.

In a subsequent second step II, the first dry film 4 and, if applicable, the second dry film 26 are cut using the cutting device 36. In this process, the side edges of the first dry film 4 and the second dry film 4 are cut off.

In a third step III, the material residues 48 from the formation of the first dry film 4 and/or the cutting of the first dry film 4 and optionally the material residues 48 from the formation of the second dry film 26 and/or the cutting of the second dry film 26 are removed from the device 10 for forming the dry film 4 using the return device 46. Optionally, the material residues 48 are shredded. The material residues 48, or the shredded material residues 48, are then fed to the production device 8, i.e. the device 8 for producing the solvent-free dry film material 6, using the return device 46.

In this case, the material residues 48 are fed to the finishing unit 58 and/or the extruder 52 of the production device HE. Optionally and preferably, the material residues 48 are fed to the extruder 52 or the finishing unit 58 in such a way that the rate of supply of the material residues is set. The rate is expediently set or regulated in accordance with a target rate.

The invention is not limited to the embodiments described above. Rather, other variants of the invention can be derived from this by a person skilled in the art within the scope of the claims without departing from the subject matter of the invention. In particular, all individual features described in connection with the embodiments and/or in the claims can also be combined with one another in other ways without departing from the subject matter of the invention.

List of reference symbols

2

contraption

4

Dry film

6

Dry film material

8th

Dry film material production facility/production facility

10

Dry film forming device

12

First roller

14

Second roller

16

(first) roller gap

18

Conveyor system

20

Third roller

22

Fourth roller

24

(second) roller gap

26

second dry film

28

(third) roller gap

30

Feeding device

32

Substrat

34

electrode

36

Cutting device/ roller knife

38

Edge trimming

40

Squeegee

42

Squeegee

44

Extraction

46

Return device

48

Material residue

50

Shredding unit

52

Extruders

54

mixture

56

Extrudate

58

Finishing unit

A

Axis of the roller

I

Formation of the dry film from dry film material

II

Cutting the dry film

III

Supply of material residues to the manufacturing facility

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. 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

• WO 2018210723 A1 [0002]

Claims (9)

Method for producing a dry film (4) from dry film material (6), - wherein, to form the dry film (4), solvent-free dry film material (6) is fed into a roller gap (16) formed between a first roller (12) and a second roller (14), - wherein the dry film (4) formed is cut to size, and - wherein material residues (48) from the formation of the dry film (4) and/or the cutting of the dry film (4) are fed to a device (8) for producing the solvent-free dry film material (6). Procedure according to Claim 1 , characterized in that the rate of supply of the material residues (48) to the device (8), in particular constant over time, is and/or is set. Procedure according to Claim 1 or 2 , characterized in that the material residues (48) are fed to a finishing unit (58) of the device (8) for producing the solvent-free dry film material (6). Procedure according to one of the Claims 1 until 3 , characterized in that the material residues (48) are fed to an extruder (52) of the device (8) for producing the solvent-free dry film material (6). Method according to one of the Claims 1 until 4 , characterized in that the material residues (48) are crushed before being fed to the device (8). Device (2) for producing a dry film (4) from dry film material (6) according to the method according to one of the Claims 1 until 5 , comprising - a device (8) for producing the dry film material (6), - a first roller (12) and a second roller (14), wherein a roller gap (16) for forming the dry film (4) is formed between the first roller (12) and the second roller (14), - a cutting device (36) for cutting the dry film (4) formed, and - a return device (46) for feeding material residues (48) from the formation of the dry film (4) and/or from cutting the dry film (4) to the device (8) for producing the dry film material (6). Device (2) according to Claim 6 , characterized in that the return device (46) has a comminution unit (50) for comminuting the material residues. Device (2) according to Claim 6 or 7 , characterized in that the device (8) for producing the dry film material (6) comprises an extruder (52) and/or a finishing unit (58), wherein the material residues (48) can be fed to the extruder (52) and/or the finishing unit (58) by means of the return device (46). Device (2) according to one of the Claims 6 until 8th , characterized in that the return device (46) is arranged for the pneumatic conveying of the material residues (48).

Images