Method and coil for winding a film onto a tube

Abstract

A method for winding a film (1) around a winding tube (2,3) to form a coil (4) and unwinding the film (1) from the winding tube (2,3), the film (1) comprising a carrier material for an electrode film, an electrode film having at least one active material or a separator film used as a component of a battery cell, the winding tube (2,3) having a perforated peripheral surface (7) with at least one opening (8). A coil (4) comprising at least the winding tube (2,3) and the film (1) wound around the winding tube (2,3).

Description

[Technical field]

[0001] The present invention relates to a method for winding a film onto a tube and to a coil comprising a tube and a film wound onto said tube. The method and the coil or tube are used in particular for unwinding and winding electrode films, in particular coated and / or uncoated electrode films.

[0002] Batteries, especially lithium-ion batteries, are increasingly being used in motor vehicle drives. These batteries are usually formed from a number of battery cells. Each battery cell has a stack of anode, cathode and separator films, possibly present in the form of layers or material layers. At least a portion of the anode and cathode films are formed as current collectors for conducting the current provided by the battery cell towards consumers arranged outside the battery cell. In the following, the individual elements of the stack are also called electrodes or films.

[0003] The individual films are provided in particular as endless materials, and are optionally coated, for example with active material, and wound up again. The film thus produced is then fed as a wound coil to a process for producing battery cells. In this process, the coil with the optionally coated electrode film is unwound and, for example, cut or separated or divided into individual layers, so that the individual layers can be arranged one on top of the other. The uncoated areas of the coated film can be used as current collectors.

[0004] The coil comprises in particular a so-called tube onto which the film is wound and from which it is later unwound again.

[0005] In view of the increasing automation of the production chain in factories for manufacturing (lithium-ion) battery cells, there is a compelling need to improve the coordination between the individual machines. Such production chains include, in particular, coating processes (i.e. coating, in particular, the carrier material with active material) and stacking (stacking individual layers of films). These processes include, in particular, multiple splicing operations (i.e. bonding processes for joining electrode films together to form an endless material) and cutting operations (for cutting or separating individual layers of the electrode film from the endless material). In particular, it is required that these processes or processes enable a continuous manufacturing process.

[0006] The splicing process is used in particular when unwinding endless material from a coil. When the first film has been fully unwound from the coil, a new second film from a new coil already provided in the machine is automatically spliced ​​to the end of the first film. This connection between the first and second film is called the splice or joint. Subsequently or beforehand, the end of the first film must be separated from the coil or tube, so that the empty tube is disconnected from the process and moved away from the machine. The empty tube can then be replaced by a new coil.

[0007] In particular, the endless material of the first film is wound again onto a (different) winding tube after the process has been carried out, for example after coating the first film. After the splice point has passed through the process (i.e. after coating the film for example), the first film must be separated again from the second film, in particular downstream of the splice point (at a separation point), so that the coil with the first film can be removed from the machine. Following this separation point, the end of the second film is again joined onto a new or empty winding tube, so that defect-free winding can be guaranteed.

[0008] The separation of the endless material, i.e. the production of the separation points, is carried out industrially in particular by cutter or roll cutter cutting and is distinguished by complex automation technology.

[0009] The bonding of the film material to the tube is carried out industrially primarily as an adhesive process and is also distinguished by its complex automation, the challenge here being particularly the application of the adhesive tape to the film or tube.

[0010] A significant disadvantage of these processes, i.e. the generation of separation points and the bonding of the film to the winding tube, is that both complex processes are essentially carried out during fully automated coil changes and therefore in principle constitute a source of defects that significantly reduces the availability of the machine. Furthermore, the separation or cutting process additionally leads to the formation of ablation products, which can lead to contamination of the electrode surface and thus to damage of the composite comprising the electrode film and the separator material.

[0011] The adhesive strips provided to secure or bond the film to the tube subject the film to uneven stresses and, moreover, must be cleaned if the tube is to be reused.

[0012] From CN 108461825 an apparatus for applying adhesive to an electrode film is known.

[0013] From CN 109411831 a device for applying an adhesive strip to an electrode film is known, which describes a vacuum sleeve for fixing the adhesive strip in position.

[0014] From Chinese Utility Model No. 212434693 an apparatus for providing an adhesive film used for producing an electrode film is known.

[0015] The task of the present invention is to at least partially solve the problems described with respect to the prior art, in particular so that the processes for separating the endless material and for joining the endless material to the tube are improved, i.e. in particular so that they are replaced by leaner and simpler and, in addition, more robust technologies, which make it possible to ensure a high degree of automation of the production chain.

[0016] The solution of this problem is provided by a method according to the features of independent claim 1 and a coil according to the features of independent claim 8. Advantageous refinements are the subject of the dependent claims. The features individually recited in the claims can be combined with one another in a technically significant manner and can be supplemented by the details given in the description and / or in the drawings, whereby further embodiments of the invention are shown.

[0017] A method is proposed for winding a film onto a winding tube to form a coil and / or for unwinding the film from the winding tube, the film comprising in particular a carrier material for an electrode film, an electrode film with at least one active material or a separator film, each of which is used as a component of a battery cell. The method comprises the steps of: a) preparing a tube and placing the tube on a shaft; b) providing a film as an endless material, the film having a first end; c) placing the first end on a winding tube; d) winding the film onto a tube to form a coil. The winding tube has a perforated peripheral surface with at least one opening, on which the film is placed in steps c) and d). The winding tube is connected to a vacuum source, by means of which a vacuum is generated in the at least one opening, so that the film is fixed on the peripheral surface at least during step c), and in particular also during step d).

[0018] The above (not definitive) division of the method steps into a) to d) is merely used for the purpose of preferential differentiation and does not impose a sequence and / or relationship. The frequency of the method steps may also vary. It is also possible for the method steps to overlap one another at least partially in time. Quite particularly preferably, steps a) and b) are carried out before steps c) and d). In particular, steps a) and b) are carried out in parallel with one another in time. In particular, step c) is carried out before step d). In particular, steps a) to d) are carried out in the stated order.

[0019] A battery cell includes, among other things, a housing enclosing a volume, and disposed within the volume, at least one electrode film of a first type of electrode (e.g., an anode), an electrode film of a second type of electrode (e.g., a cathode), a separator material disposed therebetween, and an electrolyte, e.g., a liquid or solid electrolyte.

[0020] The battery cells are in particular pouch cells (with a deformable housing made of a pouch film) or prismatic cells (with a shape-invariant housing). The pouch film is a known deformable housing member used as a housing for so-called pouch cells. The pouch film is a composite material, for example comprising plastic and aluminum.

[0021] The battery cells are in particular lithium-ion battery cells or other types of battery cells.

[0022] The individual films of the electrode films are arranged one on top of the other, in particular forming a stack, and the electrode films are each assigned to a different type of electrode, i.e. configured as an anode or a cathode, which are arranged alternately and separated from one another by a separator material.

[0023] A battery cell is a storage device used to store electrical energy, for example in a vehicle. In particular, for example, a vehicle has an electric machine (traction drive) for driving the vehicle. The electric machine can be driven by the electrical energy stored in the battery cell.

[0024] The method is particularly directed to the winding and unwinding of films, where the film wound onto a tube is referred to together with the tube as a coil.

[0025] The winding tube has a perforated circumferential surface with at least one opening. This circumferential surface is in particular cylindrical or hollow cylindrical. The winding tube is in particular designed to be suitable for placement on a shaft, i.e. has connection dimensions or connection geometries suitable for connection to a shaft. The shaft is in particular used for placement and / or (optionally additionally) for driving, i.e. for rotating the winding tube, so that, for example, the rotation of the shaft causes the winding tube to rotate. As a result of the placement on the shaft, the film can be wound onto the winding tube or unwound from the winding tube.

[0026] The shaft is in particular a component of the device which has at least a negative pressure source. The negative pressure source may be connected to the shaft and / or the winding tube, for example, via a suitable connection, so that at least one opening is subject to a negative pressure generated or provided by the negative pressure source (negative pressure relative to the surroundings of the device). The connection may be made, for example, via a rotary coupling, so that a stationary negative pressure source can be connected to the rotating shaft and / or the rotating winding tube.

[0027] The shaft can, for example, be designed as a sleeve with a perforated surface as well. These perforations serve, in particular, only to transmit the underpressure from the underpressure source to the circumferential surface. Alternatively, the shaft can be designed with a closed circumferential surface. The winding tube can, for example, have a connection piece on the end side for the underpressure source. The circumferential surface is arranged at a distance from the shaft, so that the underpressure of the underpressure source can be provided to the at least one opening via a (cylindrical) gap between the circumferential surface and the shaft.

[0028] The negative pressure is used in particular to fix the film to the peripheral surface, where "fixing" means in particular that a pressing force or an attraction force is provided which presses the film against the peripheral surface.

[0029] The films include, in particular, the carrier material of an electrode film, an electrode film with at least one active material or a separator film, each of which is used as a component of a battery cell, and the carrier material includes, in particular, a metallic material, for example a material or alloy containing copper or aluminum.

[0030] The film does not in particular comprise any adhesive components that would allow it to adhere to the circumference of the tube.

[0031] According to step a), in particular the provision of a winding tube and the arrangement of said winding tube on a shaft are carried out, said winding tube being able, for example, to be fitted onto said shaft.

[0032] According to step b), in particular a film is provided as an endless material. The film has a first end. The first end is placed on the circumference and fixed there by means of a vacuum, after which the film is wound up. In particular, the film extends through at least one revolution of the winding tube, in particular through several layers of film, up to a second end of the film. The second end can be formed, for example, by a separation point.

[0033] According to step c), in particular the first end is placed on the winding tube. This can be done, for example, by a feed channel which guides the film towards the winding tube. In this case, the film is applied via the first end to the peripheral surface and is sucked onto the peripheral surface via at least one opening. During the placement, the winding tube can be stationary or can be rotated. The film can be applied to the peripheral surface or can be continuously fed towards the winding tube. The placement also includes in particular the winding of the film, at least in the case where the film is in contact with the peripheral surface over an angular range of 0° to 360° along the circumferential direction, in particular at least 15° and at most 345°.

[0034] In particular, during step c), a negative pressure is applied to the opening at least partially / possibly constantly during this step c), so that the film is brought into contact with the peripheral surface via the negative pressure and in particular fixed there.

[0035] According to step d), in particular the film is wound onto a winding tube to form a coil, which in particular includes winding the film in contact with the circumferential surface over an angular range of more than 0°, in particular more than 15°, preferably more than 345° or even 360° along the circumferential direction.

[0036] The negative pressure can also be switched off again during step d), in particular if at least the film is arranged on the winding tube in at least one layer and is therefore fixed on the circumferential surface via the layers themselves which overlap one another in the circumferential direction.

[0037] In particular, no adhesive material is applied to the circumferential surface of the winding tube during steps c) and d), so that the film adheres to the circumferential surface solely due to the negative pressure.

[0038] The method makes it possible to avoid the use of adhesive materials, such as adhesive tapes, which have been used up to now to fix the film on the winding tube. Accordingly, the separation of the film is also unnecessary, which makes it possible to avoid this method step and the associated risk of contamination of the used apparatus or workpieces, for example by ablation. This makes it possible, in particular, to realize a fully automated winding of the film. In this case, method steps that would otherwise be necessary, such as the separation or cutting of the film and the fastening of the film to the winding tube, can be omitted.

[0039] This means that the otherwise necessary cutting of the film, ie separation of the film from the circumferentially arranged first end, is omitted, whereby material losses can be avoided.

[0040] Furthermore, contamination of the tube with adhesive material can be avoided: a cleaning step of the tube which would otherwise be necessary is no longer necessary.

[0041] By applying negative pressure, in particular a reproducible suction force can be generated that can be adapted to the film material used, whereas with previously used adhesive materials it was only difficult to reproduce the adhesion to the film.

[0042] Furthermore, it is easy to replace the reel and to wind and unwind the film as a whole. No need to cut the sheet No adhesion at the beginning of the winding process No adhesive residue on the tube or no need to remove adhesive residue from the tube, no influence of the first winding (i.e. the inner layer of the film of the formed coil) on the wall thickness in the area of ​​the adhesive tape placed on the winding tube occurs; The cleaning process of the tube is eliminated. Material savings can be realized, especially when active materials are expensive, · Significant material savings due to reduced waste from eliminating the cutting and gluing process; and / or Eliminates the need to use a cutting system to separate the film, which also avoids wear on this cutting system and saves on consumable materials That is why.

[0043] The winding tube in particular has an axis of rotation extending along the axial direction.

[0044] In particular, the circumferential surface has a plurality of openings, which are arranged at least in a distributed manner along the circumferential direction, in particular distributed in a distributed manner along the circumferential direction over the entire circumferential surface.

[0045] Alternatively or additionally, the openings are arranged distributed along the axial direction.

[0046] In particular, the openings are shaped at least partially differently from one another: they can be shaped, for example, as slits or as circles or ellipses.

[0047] In particular, the at least one opening is arranged exclusively in a region of the circumferential surface that extends over an angular range of less than 270°, in particular less than 180°, along the circumferential direction. This allows the film to be arranged, for example, on the circumferential surface in step c), where the film overlaps the at least one opening. This allows for improved adhesion of the film, since all or at least most of the openings are covered by the film. For example, if the entire circumferential surface is perforated along the circumferential direction, the negative pressure may be reduced through the openings that are not covered by the film, and thus sufficient adhesion may not be guaranteed.

[0048] In particular, the winding tube has a plurality of openings on the circumferential surface, the openings being arranged in at least one row extending along the axial direction, in particular the openings of a row being arranged in alignment with one another along the axial direction, in particular the openings of a row being arranged offset with one another along the axial direction (not aligned, but along the circumferential direction).

[0049] In particular, the size of the at least one opening and the negative pressure applied to the at least one opening are adjusted to match the deformation strength of the film, thereby avoiding at least plastic deformation of the film due to adhesion of the film through the at least one opening.

[0050] In particular, when the film is wound onto the tube, the fixing of the film on the circumference is carried out without adhesive means, i.e. without the use of adhesive means.

[0051] In particular, when the film is unwound, this film is completely unwound from the tube in one continuous process, the tube being immediately without adhesive means immediately after unwound, i.e. in particular no separation step is carried out, in which the first end, which is arranged directly on the periphery, is separated from the remainder of the film, i.e. in particular the film is not consistently separated between the first end and the second end, but the entire film is unwound from the tube up to the second end.

[0052] In particular, the film is unwound from the first tube and wound onto the second tube, during which the film is processed, for example trimmed or coated or dried or calendered. In particular, the film is unwound from the first tube including the first end, which is in direct contact with the circumferential surface of the first tube, and wound onto the second tube including the first end. That is to say, in particular, no separation step is performed, in which the first end, which is located directly on the circumferential surface of the first tube, is separated from the remaining part of the film. That is to say, in particular, the entire film is unwound from the first tube up to the first end and is preferably also wound onto the second tube. That is to say, the film is not separated between the first end and the second end.

[0053] Furthermore, a coil is proposed, which comprises at least a winding tube and a film wound on the winding tube, the film comprising a carrier material of an electrode film, an electrode film with at least one active material or a separator film, each of which can be or will be used as a component of a battery cell, the winding tube having a perforated peripheral surface in contact with the wound film, the perforated peripheral surface having at least one opening.

[0054] Coils or tubes and / or films are particularly used in the described methods. A tube is used to wind the film onto the tube to form a coil and to unwind the film from the tube or coil.

[0055] The winding tube in particular has an axis of rotation extending along the axial direction.

[0056] In particular, the circumferential surface has a plurality of openings, which are arranged at least in a distributed manner along the circumferential direction, in particular distributed in a distributed manner along the circumferential direction over the entire circumferential surface.

[0057] Alternatively or additionally, the openings are arranged distributed along the axial direction.

[0058] In particular, the openings are shaped at least partially differently from one another: they can be shaped, for example, as slits or as circles or ellipses.

[0059] In particular, the at least one opening is arranged exclusively in a region of the circumferential surface that extends over an angular range of less than 270°, in particular less than 180°, along the circumferential direction. This allows the film to be arranged, for example, on the circumferential surface in step c), where the film overlaps the at least one opening. This allows for improved adhesion of the film, since all or at least most of the openings are covered by the film. For example, if the entire circumferential surface is perforated along the circumferential direction, the negative pressure may be reduced through the openings that are not covered by the film, and as a result sufficient adhesion may not be guaranteed.

[0060] In particular, the winding tube has a plurality of openings on its circumferential surface, the openings being arranged in at least one row extending along the axial direction, in particular the openings of one row being arranged in alignment with one another along the axial direction.

[0061] In particular, the size of the at least one opening and the negative pressure applied to the at least one opening are adjusted to match the deformation strength of the film, thereby avoiding at least plastic deformation of the film due to adhesion of the film through the at least one opening.

[0062] Furthermore, an apparatus is proposed which comprises at least a shaft, a winding tube which can be arranged on the shaft and a vacuum source. The vacuum source can be connected to the shaft and / or the winding tube, for example, via a suitable connection or coupling. The apparatus is particularly designed to be suitable for carrying out the method.

[0063] The method can in particular be implemented by a system for data processing, for example a control device, which system comprises means suitably equipped, configured or programmed for carrying out the steps of the method or means for implementing the method. feeding the film onto the tube; - Applying the film to the tube; Regulating the negative pressure; Adjusting the rotation of the shaft or tube; Sending films may at least be carried out.

[0064] The device comprises, inter alia, a system for processing data.

[0065] The means of the system comprise, for example, a processor, a memory in which instructions to be executed by the processor are stored, and data lines or transmission devices enabling the transmission of instructions, measurements, data or the like between the described elements.

[0066] Furthermore, a computer program is proposed comprising instructions which, when the program is executed by a computer, cause the computer to carry out the above-mentioned method or steps of the above-mentioned method.

[0067] Further proposed is a computer readable storage medium comprising instructions which, when executed by a computer, cause said computer to perform the above mentioned method or steps of the above mentioned method.

[0068] Furthermore, a battery cell is proposed, which comprises at least a housing and a stack of electrode films arranged in the housing and produced in particular by the described method and / or the described winding tube.

[0069] Furthermore, a motor vehicle is proposed which comprises at least a traction drive and a battery with at least one described battery cell, the traction drive being able to be supplied with energy by the at least one battery cell.

[0070] Descriptions directed to methods may be transferred to, among other things, coils, devices, battery cells, vehicles, systems for data processing, and computer-implemented methods (ie, computers or processors, computer-readable storage media), and vice versa.

[0071] The use of the indefinite articles ("ein", "eine", "einer" and "eines"), in particular in the claims and in the description which reproduces the claims, does not mean a numeral per se and therefore means that an accordingly introduced concept or element is present at least once, but may in particular also be present several times.

[0072] For the sake of clarity, the numerals used herein ("first", "second", ...) are used (only) to preferentially distinguish between a plurality of similar objects, sizes or processes, and do not necessarily establish a relationship and / or order between these objects, sizes or processes in particular. If a relationship and / or order is required, this will be obvious to one of skill in the art upon inspection of the features explicitly described herein or specifically illustrated. To the extent that components may appear multiple times ("at least one"), a description of one of these components applies equally to all or some of the multiple components, although this is not required.

[0073] The present invention and related technologies will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the described embodiments. In particular, unless otherwise specified, it is possible to extract some aspects of the actual objects shown in the drawings and combine them with other elements and findings based on this specification. It should be noted that the drawings and especially the scales of the drawings are merely approximate. [Brief description of the drawings]

[0074] [Figure 1] FIG. 2 shows an apparatus with a first winding tube and a second winding tube. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a diagram showing a part of the apparatus shown in FIG.

[0075] Fig. 1 shows an apparatus 16 having a first winding tube 2 and a second winding tube 3. Fig. 2 shows a perspective view of the winding tubes 2 and 3. Fig. 3 shows a part of the apparatus 16 shown in Fig. 1. Figs. 1 to 3 will be described together below.

[0076] The device 16 comprises two winding tubes 2, 3, each arranged on a shaft 5, and a vacuum source 9 for each winding tube 2, 3. This vacuum source 9 is connected to the winding tubes 2, 3 via suitable connections or couplings (see FIG. 3). Furthermore, a control device 21 is provided for regulating the device 16.

[0077] The second winding tube 3 is used to wind up the film 1 and form a coil 4 together with the second winding tube 3. The first winding tube 2 is used to unwind the film 1 from the first winding tube 2. The film 1 includes a carrier material for an electrode film, an electrode film with at least one active material, or a separator film, which is used as a component of a battery cell. The winding tubes 2, 3 each have a perforated peripheral surface 7 with a number of openings 8 in contact with the film 1 to be wound.

[0078] Each winding tube 2, 3 has an axis of rotation 12 extending along an axial direction 11. The peripheral surface 7 has a plurality of openings 8. These openings 8 may be distributed along the peripheral direction 10, in particular distributed along the peripheral direction 10 over the entire peripheral surface 7 (not shown).

[0079] The openings 8 are arranged distributed along the axial direction 11 in FIGS.

[0080] The opening 8 is formed as a slit in each of FIGS.

[0081] FIG. 2 shows that the openings 8 are arranged exclusively in a region 17 of the circumferential surface 7, which extends over an angular range of approximately 10° along the circumferential direction 10. This allows the film 1 to be arranged, for example, on the circumferential surface 7 in step c), whereby the film 1 overlaps the openings 8. This allows for improved adhesion of the film 1, since all or at least most of the openings 8 are covered by the film 1. If, for example, the entire circumferential surface 7 were perforated along the circumferential direction 10, the negative pressure would be reduced via the openings 8 that are not covered by the film 1, so that sufficient adhesion would not be guaranteed.

[0082] According to Fig. 2, the winding tube 2, 3 has a number of openings 8 on the circumferential surface 7. The openings 8 are arranged in a row 14 extending along the axial direction 11. The openings 8 of the row 14 are aligned with one another along the axial direction 11.

[0083] The size 13 of each opening 8 and the negative pressure applied to each opening 8 are adjusted to match the deformation strength of the film 1, thereby avoiding at least plastic deformation of the film 1 due to adhesion of the film 1 through each opening 8.

[0084] The method described concerns the winding (onto the second tube 3 shown in FIG. 1) and unwinding (from the first tube 2 shown in FIG. 1) of a film, where the film 1 wound on the tubes 2, 3 together with the tubes 2, 3 is called a coil 4.

[0085] The winding tubes 2, 3 have a perforated circumferential surface 7 with openings 8. The circumferential surface 7 is formed as a hollow cylinder. The winding tubes 2, 3 are formed in such a way that they are suitable for being arranged on a shaft 5, i.e. they have suitable connection dimensions or connection geometry for connection with the shaft 5. The shaft 5 serves for the arrangement (first winding tube 2) or additionally for driving (second winding tube 3), i.e. for the rotation of the winding tubes. As a result of the arrangement on the shaft 5, the film 1 can be wound onto the second winding tube 3 and unwound from the first winding tube 2.

[0086] The shaft is formed with a closed circumferential surface 7. The winding tubes 2, 3 have end-side connection pieces 18 for a vacuum source 9. The circumferential surface 7 is arranged at a distance from the shaft 5, so that the vacuum of the vacuum source 9 can be applied to the openings 8 via a (cylindrical) gap 19 between the circumferential surface 7 and the shaft 5 (see FIG. 3). In FIG. 3, the gap 19 is formed inside the material of the winding tubes 2, 3.

[0087] The negative pressure is used to fix the film 1 in place on the peripheral surface 7. By "fixing in place" it is meant that an adhesive force is provided that causes the film 1 to adhere to the peripheral surface 7.

[0088] The film 1 does not have any adhesive components that allow it to be attached to the circumferential surface 7 of the tube 2,3.

[0089] According to step a), the provision of the winding tube 2, 3 and the arrangement of said winding tube 2, 3 on the shaft 5 are carried out.

[0090] According to step b), a film 1 is provided as an endless material. The film 1 has a first end 6. The first end 6 is placed on a peripheral surface 7 and fixed there by means of negative pressure, after which the film 1 is wound up (see FIG. 1 with the first end 6 on a second winding tube 3). The film 1 extends through at least one or more layers of the film 1 up to a second end 15 of the film 1, which in FIG. 1 is in contact with the peripheral surface 7 of the first winding tube 2.

[0091] According to step c), the first end 6 is placed on the second winding tube 3. This can be done, for example, by a feed channel 20, which guides the film 1 towards the second winding tube 3. In this case, the film 1 is applied via the first end 6 against the circumferential surface 7 and is sucked thereon via the opening 8. During the placement, the winding tube 2, 3 can be stationary or can be rotated. The film 1 can be applied against the circumferential surface 7 or can be continuously fed towards the winding tube 2, 3. The placement also includes in particular a winding of the film 1, in which at least the film 1 is in contact with the circumferential surface 7 over an angular range of 0° to 360° along the circumferential direction 10, in particular at least 15° and at most 345°.

[0092] In particular, during step c), a negative pressure is at least partially / permanently applied to the opening 8 during this step c), whereby the film 1 is brought into contact with the peripheral surface 7 via the negative pressure and fixed there.

[0093] According to step d), in particular the film 1 is wound up on a second winding tube 3 to form a coil 4 .

[0094] When the film 1 is unwound, it is completely unwound from the first tube 2 in one continuous process. In this case, the first tube 2 is without adhesive means immediately after unwound, i.e. no separation step is carried out in which the second end 15, which is located directly on the circumferential surface 7 of the first tube 2, is separated from the rest of the film 1. This means that the film 1 is not consistently separated between the first end 6 and the second end 15, but the entire film 1 is unwound from the first tube 2 up to the second end 15.

[0095] According to Fig. 1, a film 1 is unwound from a first winding tube 2 and wound onto a second winding tube 3, during which the film 1 is processed, for example trimmed or coated or dried or calendered (only diagrammatically shown). The film 1 has one first end 6, which is in direct contact with the circumferential surface 7 of the second winding tube 3. The other second end 15 of the film 1 is in direct contact with the circumferential surface 7 of the first winding tube 2. The film 1 is unwound from the first winding tube 2 including the second end 15, which is in direct contact with the circumferential surface 7 of the first winding tube 2, and wound onto the second winding tube 3 including the second end 15. This means that no separation step is performed, in which the second end 15, which is located directly on the circumferential surface 7 of the first winding tube 2, is separated from the remainder of the film 1. That is, starting from the first end 6, which in Figure 1 is already in direct contact with the second winding tube 3, the entire film 1 is unwound from the first winding tube 2 up to the second end 15 and wound onto the second winding tube 3. The film 1 is therefore not separated between the first end 6 and the second end 15. [Explanation of symbols]

[0096] 1. Film 2. First winding tube 3. Second winding tube 4 Coils 5-axis 6 First End 7 Peripheral surface 8 aperture 9. Negative Pressure Source 10 Circumferential direction 11 Axial direction 12 Rotation axis 13 Size 14 columns 15 Second end 16 Equipment 17 Some areas 18 Connection piece 19 Gap 20 Supply route 21 Control device

Claims

1. A method for winding a film (1) around a winding tube (2, 3) to form a coil (4) and unwinding said film (1) from said winding tube (2, 3), said film (1) comprising a carrier material for an electrode film, an electrode film with at least one active material or a separator film used as a component of a battery cell, said method comprising the steps of: a) preparing said winding tubes (2, 3) and placing said winding tubes (2, 3) on a shaft (5); b) providing said film (1) as an endless material having a first end (6); c) placing said first end (6) on said winding tube (2, 3); d) winding said film (1) around said tube (2, 3) to form said coil (4); The method includes at least 4. The method according to claim 3, wherein the winding tube (2, 3) has a perforated peripheral surface (7) with at least one opening (8) in which the film (1) is placed during steps c) and d), and the winding tube (2, 3) is connected to a vacuum source (9) via which a vacuum is generated in the at least one opening (8), whereby the film (1) is fixed in position on the peripheral surface (7) by means of said vacuum, at least during step c).

2. 2. The method according to claim 1, wherein the peripheral surface (7) has a plurality of openings (8) which are arranged distributed at least along a circumferential direction (10), or the winding tube (2, 3) has a rotation axis (12) extending along an axial direction (11) and the openings (8) are arranged distributed along the axial direction (11).

3. 3. The method according to claim 2, wherein the openings (8) are at least partially shaped differently from one another.

4. 4. The method according to claim 1, wherein the size (13) of the at least one opening (8) and the negative pressure applied to the at least one opening (8) are adjusted to a deformation strength of the film (1), thereby avoiding at least plastic deformation of the film (1) due to suction of the film (1) through the at least one opening (8).

5. 5. The method according to claim 1, wherein the film (1) is fixed on the peripheral surface (7) during winding without adhesive means.

6. 6. The method according to claim 1, wherein during unwinding, the film (1) is completely unwound from the tube (2, 3) in one continuous process, the tube (2, 3) being free of adhesive means immediately after unwinding.

7. 7. The method according to claim 1, further comprising unwinding the film (1) from a first winding tube (2) and winding the film (1) onto a second winding tube (3), during which the film (1) is processed, and wherein the film (1) is unwound from the first winding tube (2) at the first end (6) and wound onto the second winding tube (3) at the first end (6).

8. 1. A coil (4), comprising at least a winding tube (2, 3) and a film (1) wound on the winding tube (2, 3), the film (1) comprising a carrier material for an electrode film, an electrode film having at least one active material, or a separator film usable as a component of a battery cell, the winding tube (2, 3) having a perforated peripheral surface (7) in contact with the wound film (1), the perforated peripheral surface having at least one opening (8).

9. 9. The coil (4) according to claim 8, wherein the circumferential surface (7) has a plurality of openings (8) which are arranged distributed at least along a circumferential direction (10), or the winding tube (2, 3) has a rotation axis (12) extending along an axial direction (11) and the openings (8) are arranged distributed along the axial direction (11).

10. The coil (4) according to claim 9, wherein the openings (8) are at least partially shaped differently from one another.

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