Patent Application
20250197151
This application claims priority to German Application DE 10 2023 135 403.5, filed Dec. 15, 2023, the entire contents of which is hereby incorporated by reference.
The disclosure relates to a film winding device, a film production system as well as a method for winding a film web.
Film production systems are used to produce a film web from a plastic melt which has specific material properties that can be used for specific purposes. The film production systems comprise at the same time film stretching units comprising longitudinal and/or transverse stretching zones.
The line speed of such film stretching units is increasing continually. In this context, one of the challenges being faced is to wind the finished end product, namely the film web.
Film winding devices are known for this purpose, which wind the film web produced. When winding, it is important to ensure that no folds occur in the film web so that later the individual layers can be separated more easily from each other. This is achieved by means of a film tension as constant as possible when winding.
Depending on the type of film to be produced, particular line parameters must still be adhered to or achieved. The production of extra-thin films or membrane films, such as a battery separator film (BSF), is very demanding. In contrast to films, which for example are made of PET or PP, only low film tension may be applied in the production of extra-thin films such as BSF.
This however results in problems as in the case of low film tensions high dynamics of the film winding device is necessary to compensate for changes in the film tensions. In addition, the setup of known film winding devices is extremely complex as the used rolls and rollers must be aligned to each other precisely.
Thus, there is a need to provide a film winding device, a film production system as well as a method for winding a film web that can ensure film tensions as low as possible and is simple to setup.
A film winding device for winding a film web into a film bale is provided, in particular a film web made of an extra-thin film. The film winding device comprises a winding apparatus and a feed apparatus, wherein the winding apparatus comprises at least one winding core and is configured to wind a film bale onto a winding core. The feed apparatus comprises a feed slide, a contactor and at least one tensioner, wherein the contactor is attached to the feed slide and is located adjacent to the winding core in such a way that the contactor is able to guide the film web to the winding core or to the film bale on the winding core. The tensioner is attached to the feed slide and is located before the contactor in the direction of travel of the film web in such a way that the tensioner is able to set a film tension of the film web. The tensioner comprises a cylinder with a circumferential surface, wherein the cylinder comprises an arc in the cross-section and the circumferential surface comprises at least a micro-porous surface in the region of the arc.
By using a cylinder as tensioner, more dynamic control of the film tension is possible as due to the cylinder and the micro-porous surface, the tensioner must not be set in rotation by the film web and thus only has a low inertia.
For example, the cylinder is at least in part hollow, in particular completely hollow.
For example, the feed apparatus is located before the winding apparatus in the direction of travel of the film web. In particular, the tensioner guides the film web to the contactor.
In one aspect, the feed slide relative to the winding apparatus is moveable linearly towards the winding apparatus and away from the winding apparatus. It is also conceivable that the feed slide is immovable relative to the winding apparatus.
The length of the contactor, in particular the contact roller, and the length of the cylinder correspond at least to the width of the film web. The width of the film web is, for example, between 1.5 m and 15 m, such as 6.2 m, 10.4 m or 12 m.
It is conceivable that the winding apparatus comprises two or more winding cores, wherein the film web is always only guided to one of the cores and a film bale is wound on this core.
By means of the film winding device according to the disclosure, the film production system according to the disclosure as well as the method according to the disclosure, monoaxially or biaxially stretched extra-thin films, in particular battery separator films (BSF), PP capacitor films or PET capacitor films and membranes, such as PTFE E membranes (polytetrafluoroethylene), can be produced and wound.
Thicker films can also be produced by means of the film winding device according to the disclosure, the film production system according to the disclosure as well as the method according to the disclosure.
Extra-thin films are understood to mean, for example, films with a thickness less than 10 μm, in particular less than 5 μm. BSF are also extra-thin films within this meaning.
In particular, the film winding device is a film winding device for winding a battery separator film (BSF) to a film bale.
The film tensions attainable through the film winding device according to the disclosure range from 1 N/m to 200 N/m, in particular range from 5 N/m to 15 N/m.
For example, due to the viscoelastic properties of battery separator films, it is not possible to use a high contact force of a contact roller on the film bales (winding bales) and on the winding core. For example, the contact force ranges from 0 N/m to 100 N/m, in particular ranges from 1 N/m to 10 N/m for winding BSF.
The film winding device can wind, for example, film webs at a speed ranging from 40 m/min to 350 m/min, in particular at a speed of 150 m/min.
The arc is in particular a circular arc. The arc can however also be based on a geometry other than a circle. For example, the arc can have an elliptical shape or a clothoid shape.
In an embodiment, the arc corresponds to an angle of at least 90°, in particular at least 180°, particularly at least 200°, by means of which the winding around the cylinder with the film web is large and thus in doing so the stress on the film web is small.
This also applies to the cylinder of the deflector.
The cross-section of the cylinder of the tensioner and/or the cylinder of the deflector is, for example, a circular sector with circle radii and the arc.
In an embodiment, the micro-porous surface comprises a plurality of openings that have a diameter smaller than 900 μm, in particular smaller than 500 μm, thereby achieving a particularly homogeneous air buffer.
The openings are particularly evenly distributed across the micro-porous surface.
For example, the micro-porous surface extends along at least 80%, particularly at least 90% of the length of the cylinder.
In the circumferential direction, the micro-porous surface extends, for example, along at least 80%, particularly at least 90% of the circumferential length of the arc.
In an embodiment of the disclosure, the feed apparatus comprises at least one deflector that is attached to the feed slide and is located in the direction of travel before the tensioner or in the direction of travel of the film web between the tensioner and the contactor, wherein said at least one deflector comprises a cylinder with a circumferential surface, wherein the cylinder has an arc in the cross-section and the circumferential surface comprises a micro-porous surface at least in the region of the arc. In this way, the travel path of the film web can be selected more freely.
Said at least one deflector is attached, for example, immovably to the feed slide.
For example, the feed apparatus comprises at least two deflectors, wherein one of the deflectors is located in the direction of travel of the film web before the tensioner and another one of the deflectors is located in the direction of travel of the film web between the tensioner and the contactor.
In an embodiment, the cylinder of the tensioner and/or the deflector comprise a compressed-air connection, by means of which compressed air can be introduced into the interior of the cylinder, thereby making it possible to supply the cylinder with compressed air flexibly.
For example, a compressed air source of the film winding device or the film production system is connected to the compressed air connection in such a way that the compressed air source generates overpressure in the interior of the cylinder.
In an embodiment, the thickness of the film web is smaller than 10 μm, in particular smaller than 5 μm. Thus, extra-thin films can also be wound.
To precisely ensure the desired contact pressure, the contactor can comprise a contact roller.
In an embodiment, the contactor comprises at least one adjustment mechanism comprising an adjustment slide and an adjustable slide, wherein the contact roller is attached to the feed slide moveably, in particular moveable linearly, by means of said at least one adjustment mechanism, thereby making it possible to move the contact roller extremely dynamically so that the contact pressure can also be set extremely dynamically.
The direction of travel of the adjustment mechanism is, for example, parallel to the direction of travel of the feed slide and/or the contact roller is attached to the feed slide.
In an embodiment, the tensioner comprises at least one adjustment mechanism comprising an adjustment rail and an adjustment slide, wherein the cylinder is attached the feed slide moveably, in particular moveably linearly, by means of said at least one adjustment mechanism. In this way, the film tension can be set particularly precisely.
The direction of travel of the adjustment mechanism is in particular parallel to the direction of travel of the feed slide.
For example, the adjustment rail and/or the adjustable slide comprise air outlet openings in such a way that an air bearing can be provided for the adjustable slide. In particular, the adjustment rail and/or the adjustable slide are connectable to the compressed air source.
It is conceivable that the adjustment rail and the adjustable slide provide a hydrostatic bearing.
For the further reduction of the mass to be moved, the tensioner and/or the contactor can comprise two of the adjustment mechanisms, wherein the cylinder or the contact roller is attached with each of its end faces in each case to one of the adjustment mechanisms.
For particularly precise setting, said at least one adjustment mechanism can comprise at least one adjusting actuator that is connected to the adjustable slide and is configured to move the adjustable slide linearly.
It is conceivable that the adjustment mechanisms have a common adjustment actuator.
In an embodiment of the disclosure, the feed apparatus comprises at least one feed rail for the feed slides, in particular wherein the feed rail and/or the feed slides comprise air outlet openings in such a way that an air bearing can be provided for the feed slides, thereby making it possible to slide the contactor across a large region in order to take into consideration the increasing film bale on the film core.
The feed rail and/or the feed slide are connected in particular to the compressed air source.
It is conceivable that the feed rail and the feed slide form a hydrostatic bearing.
For particularly precise setting, the feed apparatus comprises at least one feed actuator that is connected to the feed slide and is configured to move the feed slide linearly.
In an embodiment, the film winding device comprises a control device that is designed to control the feed apparatus in such a way that the contactor, in particular the contact roller, bears against the winding core or against the film bale on the winding core with a predefined contact pressure, in particular through control of the feed actuator and/or the adjustment actuator of the contactor, and/or to control the feed apparatus in such a way that the tensioner, in particular the cylinder of the tensioner, applies a specific film tension on the film web, in particular through control of the adjustment actuator of the tensioner. In this way, control of the contact pressure and/or film tension is possible.
The object is also solved by means of a film production system comprising at least one film stretching unit and a film winding device as described previously.
The features and advantages described for the film winding device apply equally to the film production system and vice versa.
Moreover, the object is solved by means of a method for winding a film web, in particular a film web made of battery separator film, by means of a film winding device as previously described and/or a film production system as previously described, in particular wherein the contactor, in particular the contact roller, bears against the winding core or against the film bale on the winding core with a predefined contact pressure, and/or a specific film tension is applied to the film web by means of the tensioner, in particular the cylinder.
The features and advantages discussed for the film winding device and/or the film production system equally apply to the method and vice versa.
Additional features and advantages of the disclosure are found in the following description as well as the attached drawings to which reference is made. In the drawings:
Lists having a plurality of alternatives connected by “and/or”, for example “A, B and/or C” are to be understood to disclose an arbitrary combination of the alternatives, i.e. the lists are to be read as “A and/or B and/or C” or as “at least one of A, B or C”. The same holds true for listings with more than three items.
The film stretching unit 110 is used to produce a plastic film web that is within the scope of this disclosure is simply referred to as the film web 12. For this purpose, the film stretching unit 110 is divided into different zones 110a, 110b, 110c, 110d and 110e. However, not all of these zones 110a, 110b, 110c, 110d and 110e actually need to be present.
In the various zones 110a to 110e, the film web 12 is exposed to different temperatures in order to generate or set certain film properties. The first zone 110a is also termed the preheating zone. The second zone 110b is termed the stretching zone, whereas the third zone 110c is termed the further heating zone. The fourth zone 110d is also termed the neutral zone and the fifth zone 110e is termed the cooling zone. In principle, there may be fewer or additional neutral zones between the individual zones 110a to 110e to ensure a separation of the zones 110a to 110e so that the individual zones 110a to 110e have less impact on each other (the air flows from one zone 110a to 110e into the other). Using the film stretching unit 110, it is possible to produce film webs 12 with a width that is greater than 2 m, 3 m, 4 m, 5 m, 6 m, 7 m, 8 m, 9 m, 10 m, 11 m, 12 m, 13 m or greater than 14 m, but is for example smaller than 15 m, 14 m, 13 m, 12 m, 11 m, 10 m, 9 m, 8 m, 7 m, 6 m, 5 m, 4 m or is smaller than 3 m.
For example, the working width, i.e. the width of the film web 12, of the film stretching unit 110 and the film winding device 10, is equal to 6.2 m, 10.4 m or 12 m.
The film stretching unit 110 comprises an entry area 111, wherein a film to be stretched can be fed to the film stretching unit 110 at its entry area 111. The stretched film web 12 exits at the end of the film stretching unit 110, thus at its exit area 112. The exit area 112 of the film stretching unit 110 is connected to a film entry area 14 of the film winding device 10 according to the disclosure.
As explained initially, different types of film should be wound up differently as only then can it be ensured that the winding is executed without wrinkling and that sufficient air is introduced between the individual layers so that it is possible to unwind the film web 12 without any difficulty in subsequent process steps. The method of winding according to the disclosure also ensures that the film web 12 does not tear.
The film web 12 is, in particular, a film web with a thickness less than 10 μm, in particular less than 5 μm. For example, the film web 12 is made of battery separator film (BSF), but the film web 12 can also be made of another material.
As explained initially, the winding of battery separator films is particularly demanding. Winding can only be executed using low contact force and low film tension.
In
The film winding device 10 comprises a winding apparatus 16 and a feed apparatus 18.
It is also conceivable that the film winding device 10 comprises a compressed air source 20, such as an air compressor. The compressed air source 20 can also be designed as one or more connections to a central compressed air supply, for example a central compressed air supply of the film production system 100.
The film winding device 10 also comprises a control device 22 that controls the feed apparatus 18, the winding apparatus 16 and the compressed air source 20. For example, the control device 22 is designed separately or as part of a control device for the film production system 100.
The feed apparatus 18 is located in the direction of travel of the film web 12 before the winding apparatus 16. The feed apparatus 18 thus receives the film web 12 by means of the film entry area 14 and transfers the film web 12 to the winding apparatus 16.
The winding apparatus 16 comprises at least one winding core 24, in the shown embodiment, there are two winding cores 24.
The winding cores 24 can each rotate here about their central axes; in particular, they are driven.
The winding cores 24 are arranged together on a rotatable base body of the winding apparatus 16, by means of which one of the winding cores 24 can be brought into a winding position (of the two winding cores 2 in
In the shown embodiment, the feed apparatus 18 comprises a feed slide 30, at least one feed rail 32, a feed actuator 34, a contactor 36, a tensioner 38 as well as two deflectors 40.
The contactor 36, the tensioner 38 and the two deflectors 40 are attached to the feed slide 30.
Both deflectors 40 are attached to the feed slide 30 fixedly, thus immovably.
The contactor 36, the tensioner 38 and both deflectors 40 guide the film web 12 to the winding apparatus 16 and are shown isolated in
Starting from the film entry area 14 and following the direction of travel of the film web 12, the film web 12 runs from the film entry area 14 initially to the first one of the deflectors 40 and is deflected there towards the tensioner 38.
At the tensioner 38, the film web 12 is deflected further and then runs to a second deflector 40 that is located between the tensioner 38 and the contactor 36.
At the second deflector 40, the film is directed to the contactor 38 and the contactor feeds the film web 12 to the winding apparatus 16. More specifically, the contactor 36 directs the film web 12 onto the winding core 24 or to a film bale 28 already formed at the winding core 24. The contactor 36 is thus located adjacent to the winding core 24.
The contactor 36 comprises a contact roller 42 as well as an adjustment mechanism 44. The contact roller 42 is attached to the feed slide 30 in a linear moveable manner by means of an adjustment mechanism 44.
The tensioner 38 and both deflectors 40 do not comprise rollers in the shown embodiment, but each have a cylinder 54 that is in each case hollow and not rotatable.
The length of the cylinder 54 of at least the tensioner 38, but also the deflector 40 transverse to the direction of travel of the film web 12 is greater than the width of the film web 12.
For example, the contact roller 42 and the cylinder 54 of the tensioner 38 and the deflectors 40 have the same length in the direction transverse to the direction of travel of the film web 12.
Each of the cylinders 54 has a circumferential surface 56 that is not circular. Provided it is not indicated otherwise, the following embodiments apply in particular to each of the cylinders 54 of the tensioner 38 and the deflectors 40.
The cross-section of the cylinder 54 comprises at least an arc 58, i.e. a section of the circumferential surface 56 that describes an arc. For example, the arc 58 is a circular arc. The arc 58 can have however another shape, such as an elliptical or clothoid shape.
In the shown embodiment, the cross-section of the cylinder 54 is a circular sector with an arc 58 and two circle radii 60 that extend at the end of the arc 58 towards the centre point of the circle.
An angle corresponding to the angle of the arc 58 is enclosed between the circle radii 60.
In the shown embodiment, the angle corresponding to the arc 58 of the cylinder 54 of the tensioner 38 is greater than 180°, in particular greater than 200°.
For example, the angle corresponding to the arc 58 of the cylinder 54 of the first deflector 40 is also greater than 180°, in particular greater than 200°.
The angle corresponding to the arc 58 of the cylinder 54 of the second deflector 40 is smaller than 180°, but greater than 90°.
The circumferential surface 56 is a micro-porous surface 62 in the region of the arc 58 so that the circumferential surface 56 comprises a plurality of openings that extend through the circumferential surface 56. For example, the diameter of the openings is in each case smaller than 900 μm, in particular smaller than 500 μm.
The openings are distributed particularly evenly across the micro-porous surface 62, for example in a grid or a lattice.
For example, the micro-porous surface 62 extends along at least 80%, particularly at least 90% of the length of the cylinder 54, i.e. in the axial direction of the cylinder 54.
In the circumferential direction about the axis of the cylinder 56, the extent of the micro-porous surface 62, for example, is such that it covers at least 80%, in particular at least 90% of the extent of the arc 58 in the circumferential direction.
The circumferential surface 56 of the cylinder 54 is designed in such a way that the porous surface 62 is provided in those sections on which the film web 12 would rest if the film web 12 had been clamped in the feed apparatus 18.
The cylinder 54 also comprises a compressed-air connection 64 that is in fluid contact with the interior of the cylinder 54.
The compressed-air connection 64 is connected to the compressed air source 20 fluidly so that compressed air can be introduced into the interior of the cylinder 54 by means of the compressed-air connection 64 in order to generate overpressure in the cylinder 54.
By introducing compressed air into the cylinder 54, air flows through the openings of the porous surface 62 outwards so that the film web 12 passing the porous surface 62 does not come into contact with the circumferential surface 56 but is moved on an air buffer.
In this way, damages such as scratches or defects on the film web 12 are avoided, thereby increasing the quality of the film web 12 and reducing rejects. In addition, complex alignment of the rollers to each other is not necessary as the air buffer can compensate to a certain extent for any misalignment of the cylinders 54 to each other and to the contact roller 42.
Similarly, the contact roller 42 is also attached to the cylinder 54 of the tensioner 38 by means of at least one adjustment mechanism 44 in a linearly moveable manner in relation to the feed slide 30. In the shown embodiment, two adjustment mechanisms 44 are provided for the attachment to each of the face ends of the cylinder 54 of the tensioner 38.
The contact roller 42 is attached to the feed slide 30 in the same way by means of one or two adjustment mechanisms 44 of the contactor 36.
The adjustment mechanism 44 comprises an adjustment rail 46, an adjustable slide 48 as well as an adjustment actuator 50, wherein the adjustment rail 46 is connected fixedly to the feed rail 32 and the cylinder 54 is attached to the adjustable slide 48.
The adjustable slide 48 is bearing-mounted linearly on the adjustment rail 46 so that the cylinder 54 is moveable linearly in relation to the feed slide 30.
The adjustment mechanism 44 is designed as an air bearing in the shown embodiment. To this end, the adjustment rail 46 and/or the adjustable slide 48 comprises, for example, a plurality of air outlet openings 66 so that an air bearing can be provided between the adjustable slide 48 and the adjustment rail 46. To this end, the adjustable slide 48 or the adjustment rail 46 are connected to the compressed air source 20, for example via a compressed-air connection 52.
It is however conceivable that the adjustment mechanisms 44 provide a hydrostatic bearing.
The cylinder 54 of the tensioner 38 is attached on each of its face ends to one of the adjustable slides 48 of one of the two adjustment mechanisms 44.
The adjustment actuator 50 is connected to the adjustable slide 48 and is configured to move the adjustable slide 48 linearly. The adjustment actuator 50 is, for example, an electric motor or a piezo actuator.
The adjustment actuator 50 is connected to the control device 22 for the transmission of data and/or control commands, for example wirelessly or via a wired connection.
It is conceivable that both adjustment mechanisms 44 have a common adjustment actuator 50.
The designs for the attachment of the cylinder 54 of the tensioner 38 apply in the same way to the contact roller 42 of the contactor 36.
Also the entire feed slide 30, together with the contactor 36, the tensioner 38 and the deflectors 40, is slidable linearly in relation to the winding apparatus 16, namely towards the winding apparatus 16 or away from the winding apparatus 16.
For example, the feed rail 32 and/or the feed slide 30 comprise air outlet openings so that—as described for the adjustment mechanisms 44—an air bearing is provided for the feed slide 30. To this end, the feed rail 32 and the feed slide 30 are connected to the compressed air source 20 fluidly.
It is however conceivable here that the feed rail 32 and the feed slide 30 constitute a hydrostatic bearing.
The feed actuator 34 which can move the feed slide 34 linearly is provided for moving the feed slide 30.
The linear movement of the feed slide 30 runs parallel to the linear movements of the adjustment mechanisms 44.
Just like the adjustment actuator 50, the feed actuator 34 is connected to the control device 22 for the transmission of data and/or control commands, for example wirelessly or via a wired connection.
During the operation of the film winding device 10, the method is executed that is illustrated by means of the double arrows in
The control device 22 is configured in such a way that it can execute the method.
The control device 22 controls the feed actuator 34, the adjustment actuator 50 of the tensioner 38 and/or the adjustment actuator 50 of the contactor 36 in order to move the cylinder 54 of the tensioner 38, the contact roller 42 of the contactor 36 or, by moving the entire feed slide 30, simultaneously the cylinder 54 of the tensioner 38 and the contact roller 42 of the contactor 36 linearly towards the winding apparatus 16 or away from the winding apparatus 16 and thus also to move towards and away from the winding core 24 or film bale 28 situated on it.
The controlling of the actuators 34, 50 occurs in such a way that a specific, in particular a predefined film tension is applied to the film web 12 by means of the cylinder 54 of the tensioner 38. The tensioner 38 therefore applies the specific film tension to the film web 12 and assumes the function that a floating roller fulfils in the state of the art.
In addition, the position of the contact roller 42 of the contactor 36 can be set by the control device 22 in such a way that the contact roller 42 bears against the winding core 24 or against the film bale 28 situated on it with a predefined contact pressure.
Through the use of the cylinder 54 that is, for example, lighter than comparable rollers, the weight of the tensioner 38 and also the feed slide 30, together with assemblies, is reduced, thereby making more dynamic control of the film tension of the film web 12 possible. Moreover, the cylinder 54 does not rotate as the film web 12 is guided on the air buffer. Through friction formed between the film web 12 and a roller, the film web 12 must not therefore first overcome the inertia of the roller in order to set this in rotation. The film tension can thus be set more dynamically and the quality of the film produced is therefore increased further.
In
The film winding device 10 of the second embodiment only comprises one deflector 40, namely the first deflector 40 that is arranged before the tensioner 38 in relation to the direction of travel of the film web 12.
The film web 12 thus runs from the tensioner 38, more specifically from the cylinder 54 of the tensioner 38, to the contactor 36, more specifically the contact roller 42. By dispensing with the second deflector 40, the complexity of the feed apparatus 18 is reduced and the weight is reduced further, thereby making an even more dynamic setting of the contact pressure possible.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2023 135 403.5 | Dec 2023 | DE | national |
