Method for wrapping battery cells in film by means of a film-wrapping device

Abstract

The invention relates to a method for wrapping battery cells in film by means of a film-wrapping device. The invention also relates to a battery cell which is obtained or obtainable according to said method and is coated with an adhesive film.

Description

[0001] tesa Societas Europaea Norderstedt

[0002] Method for coating battery cells using a foiling device

[0003] The present invention relates to a method for coating battery cells with a film coating device. The present invention further relates to a battery cell coated with an adhesive film, obtained or obtainable according to this method.

[0004] For hybrid and pure electric vehicles, the stability and safety of the vehicle batteries are of crucial importance. The reliability of the insulating part of the battery cell's casing is a key factor influencing the battery cell's stability and safety.

[0005] As is well known, the operating environment of a car is demanding, with high temperatures, high humidity, strong vibrations, heavy impacts, etc. In such a harsh environment, the stability and reliability of the insulating part of the battery cell is of great importance to prevent breakage and connection failures that could cause a battery short circuit.

[0006] For vehicle battery cells, a currently used insulation method consists of wrapping a battery cell with an adhesive film for insulation.

[0007] The process of laminating a prismatic cell on all six typical side surfaces is currently carried out by rolling and / or folding tunnels.

[0008] For applying film to large surfaces, state-of-the-art technology uses rollers that are usually longer than the cell.

[0009] The short sides of the cell are either covered with foil using long rolls, or by gradually folding the adhesive foil over folding blocks that have different angles to the cell.

[0010] CN 216750017 U describes a battery film coating device and a film coating system and belongs to the technical field of lithium battery manufacturing equipment. The battery film coating device includes a drive mechanism suitable for moving a battery that is to undergo film coating. KR 101935557 B1 relates to a device for automatically applying insulating tape to a battery cell, which is attached to a battery for vehicles.More precisely, the device comprises: a bottom roller section that rolls the insulating tape horizontally and applies it to the bottom of a battery cell located on the opposite side from the side with a terminal formed thereon; a long-side roller section that rolls the insulating tape vertically and applies it to both long sides of the battery cell; a short-side roller section that rolls the tape horizontally and applies it to both short sides of the battery cell; and a corner roller section that rolls the corner insulating tape, which extends and projects from the bottom of the battery cell, vertically to both short sides.

[0011] It is therefore desirable to provide methods for coating battery cells that avoid or largely avoid the disadvantages described above. In particular, the methods of the present invention should enable the automation of applying the adhesive film to the battery cell, which is coated with the adhesive film.

[0012] This problem is addressed by a method for coating battery cells using a coating device, and by a battery cell obtained or obtainable by said method, with the features of the independent claims. Advantageous embodiments, which can be implemented individually or in combination, are described in the dependent claims.

[0013] Therefore, the present invention relates to a method for coating battery cells using a coating device. The method comprises the steps described in more detail below. These steps are carried out in the order stated.

[0014] Therefore, the present invention relates to a method for coating battery cells using a coating device, comprising

[0015] (i) a winding unit for a single-sided adhesive film, preferably covered with a liner

[0016] The adhesive film typically comprises or consists of a carrier film onto which an adhesive, preferably a pressure-sensitive adhesive, is applied on one side. A liner may be laminated onto the adhesive to protect it; this liner must be removed before bonding to the battery cell.

[0017] The unwinding unit has a receiving device for the adhesive film wound into a roll. (ii) preferably a winding spool for the liner

[0018] Before applying the adhesive film to the battery cell, the liner must be removed. To prevent the liner from interfering with the subsequent process, it is recommended to wind it onto a spool, which is replaced periodically once its capacity is exhausted. Alternatively, the liner can be removed directly. Preferably, a drive mechanism is used to rotate the spool, thus winding the liner onto the spool.

[0019] (iii) a clamping device with a cutting unit in which the adhesive film can be cut to the desired length

[0020] After unwinding, the adhesive film must be cut into appropriate lengths, the size of which depends on the size of the battery cell to be encased. To cut the film, it is held in place, for example, by a clamp that presses it against a flat base plate. The film can then be cut transversely using a cutting unit, such as a standard cutting blade.

[0021] (iv) a gripping unit

[0022] The gripping unit grasps the free end of the adhesive film created after the previous cutting process and pulls it into the film application device up to the starting position.

[0023] (v) a first roller unit comprising, in particular, four rollers arranged in pairs opposite each other, wherein the lower roller of each pair is arranged below the adhesive film and the upper roller of each pair is arranged above the adhesive film, wherein one pair of rollers is arranged in close proximity to the cutting unit and one pair of rollers is arranged in close proximity to the gripping unit

[0024] The first roller unit serves to fix and hold under tension the adhesive film that has been pulled into the film application unit by the gripper. For this purpose, the rollers of the roller pairs are first moved apart, so that the gripper unit moves from its rest position towards the cutting unit, grasps the free end of the adhesive film, and moves back towards its rest position, thereby pulling the adhesive film into the film application unit. After reaching the rest position, the roller pairs move towards each other, so that the adhesive film is clamped between the upper and lower rollers of each pair.

[0025] (vi) a fixing unit by means of which the battery cell to be foiled, which is introduced into the foiling device and has a front wall Si and a rear wall S2 opposite each other, two opposite side walls S3 and S4 connecting the front wall S1 and the rear wall S2, a bottom U and a top O, is placed with the bottom U on the adhesive foil and held upright. The fixing unit can in the simplest case be a frame whose cross-sectional area is almost equal to the cross-sectional area of ​​the battery cell, so that the battery cell is fixed almost immovably.

[0026] (vii) a second roller unit comprising in particular two rollers located below the clamped adhesive film in contact with the adhesive film and whose axes are movable in a plane parallel to the underside U of the battery cell in order to start the process of hammering in the battery cell

[0027] The second roller unit performs several tasks. First, the rollers are moved back and forth so that the adhesive film is pressed onto the underside U of the battery cell, initiating the process of wrapping the battery cell. When the battery cell is subsequently conveyed into the roller tunnel provided in the wrapping unit (described in detail later), the rollers are positioned so that one roller presses the adhesive film onto the front wall Si and the other roller presses the adhesive film onto the rear wall S2, while the battery cell is conveyed between the rollers towards the roller tunnel.

[0028] (viii) a stamp which pushes the battery cell through the fixing unit, through the second roller unit into the roller tunnel.

[0029] The punch rests on the top O of the battery cell and pushes the battery cell through the fixing unit in which the battery cell is fixed, the roller unit.

[0030] (ix) a roller tunnel comprising the following functional elements:

[0031] • a doctor blade unit consisting of two doctor blades

[0032] The squeegees are arranged so that, as the battery cell passes by, the adhesive film is folded over the edge that connects the underside U with the two opposite side walls S3 and S4, and pressed onto the side walls S3 and S4.

[0033] • a multitude of guide rollers arranged in such a way that they make contact with the battery cell and guide the battery cell precisely aligned through the roller tunnel

[0034] The guide rollers are arranged such that, after the battery cell is inserted into the roller tunnel, several, preferably at least two, rollers make contact with the front wall S1 and several, preferably at least two, make contact with the rear wall S2. In this way, the battery cell is guided precisely through the roller tunnel in a straight line without the rollers being able to change its orientation.

[0035] • four folding roller blocks, each consisting of at least four rollers arranged one below the other and

[0036] Each folding roller block serves to fold the adhesive film over the edge located between the front wall S1 and the two side walls S3 and S4, or between the rear wall S2 and the two side walls S3 and S4, and to press the film onto the side walls S3 and S4. Each folding roller block preferably has the same arrangement of folding rollers, which is explained below using the edge located between the front wall S1 and side wall S3 as an example. The axis of the uppermost folding roller in the folding roller block is aligned parallel to the edge located between the front wall S1 and side wall S3 (the angle between the axis and side wall S3 is 90°), with the uppermost folding roller touching the edge. This contact is not direct; rather, there is still adhesive film to be folded between the folding roller and the edge.The axis of the folding roller below is tilted by an angle of, for example, 20° towards the side wall S3 (the angle between the axis and the side wall S3 is 70°), the axis of the folding roller below is preferably tilted by twice the angle, i.e., for example, 40° (the angle between the axis and the side wall S3 is 50°), wherein this folding roller also touches the edge, the axis of the folding roller below is preferably tilted by three times the angle, i.e., for example, 60° (the angle between the axis and the side wall S3 is 30°), wherein this folding roller also touches the edge, and the axis of the folding roller below is preferably tilted by four times the angle, i.e., for example, 80° (the angle between the axis and the side wall S3 is 10°), wherein this folding roller also touches the edge.In this way, the adhesive film located between the folding rollers and the edge is folded over the edge, so that, with the described arrangement of the folding rollers, the piece of film has an angle of 10° to the side surface S3. It should be mentioned again at this point that the folding rollers do not directly touch the edge, but rather the adhesive film is present between each folding roller and the edge, which is folded around the edge by the fan-like arrangement of the folding roller axes.

[0037] • another doctor blade unit consisting of two doctor blades

[0038] The squeegees are arranged so that when the battery cell passes by, the two pieces of adhesive film, which have been bent by a folding roll block over the two edges between front wall S1 and side wall S3 and between rear wall S2 and side wall S3 or the two edges between front wall S1 and side wall S4 and between rear wall S2 and side wall S4, are pressed onto the side wall S3 or side wall S4.

[0039] (x) A folding slide unit for folding the film onto the top surface S1 of the battery cell. A folding slide unit is provided after the roller tunnel. The battery cell is conveyed out of the roller tunnel until the top surface O of the battery cell is located in the folding slide unit. By means of two folding slides located at the edge between the top surface O and the side wall S3, and between the top surface O and the side wall S4, the protruding pieces of adhesive film are folded over the two edges and pressed onto the top surface O. Furthermore, two additional folding slides are provided at the edges between the front wall S1 and the top surface O, and between the rear wall S2 and the top surface O, with which the protruding pieces of adhesive film are folded over the two edges and pressed onto the top surface O.

[0040] Part of the method according to the invention comprises in detail the following individual steps:

[0041] (a) Providing a battery cell comprising at least one front wall Si and a rear wall S2 opposite each other, two opposite side walls S3 and S4 connecting the front wall S1 and the rear wall S2, a bottom U and a top O;

[0042] (b) Providing an adhesive film, wherein the adhesive film comprises at least one preferably pressure-sensitive cross-linked adhesive layer and at least one carrier;

[0043] (c) Bringing the adhesive film according to (ii) into contact with the at least one bottom U of the battery cell according to (i), comprising bonding the adhesive layer of the adhesive film and the at least one bottom U of the battery cell;

[0044] (d) In bringing the adhesive film into contact with the front wall S1 and the rear wall S2, comprising bonding the adhesive layer of the adhesive film to the front wall S1 and the rear wall S2,

[0045] (e) Bringing the adhesive film into contact with the two side walls S3 and S4, comprising bonding the adhesive layer of the adhesive film to the two side walls S3 and S4;

[0046] (f) In bringing the adhesive film into contact with the top surface O, comprising bonding the adhesive layer of the adhesive film to the top surface O of the battery cell.

[0047] Preferably, the battery cells are cuboid in shape with six sides. However, other body shapes can also be coated with the adhesive film according to the inventive method.

[0048] Preferably, the front wall S1 and the rear wall S2 comprise the two surfaces Fi and F2, wherein the side wall S1 comprises the surface Fi and the side wall S2 comprises the surface F2. Preferably, the surface Fi and the surface F2 are of the same size.

[0049] Preferably, the two opposing side walls S3 and S4 comprise two surfaces F3 and F4, wherein side wall S3 comprises surface F3 and side wall S4 comprises surface F4. Preferably, surface F3 and surface F4 are the same size. Preferably, surfaces F1 and F2 are larger than surfaces F3 and F4.

[0050] Preferably, the underside U is located opposite the top side O. Preferably, the underside U and the top side O each have two surfaces Fu and Fo, wherein the underside U comprises surface Fu and the top side O comprises surface Fo. Preferably, surface Fu and surface Fo are the same size. Preferably, the top side O includes battery contacts. According to a variant of the invention, side walls S3 and S4 each have a battery contact.

[0051] Preferably, the cut-to-length adhesive film has a width b and a length I.

[0052] Preferably in step (iii) the width b of the adhesive film extends beyond the underside U of the battery cell by area Abi.

[0053] Preferably in step (iv) the length I of the adhesive film extends by area Ah beyond the top surface O of the battery cell.

[0054] Preferably in step (iv) the width b of the adhesive film extends beyond area Ab2 beyond the at least two opposite side walls S1 and S2 of the battery cell, wherein Ab2 < Abi.

[0055] Preferably in step (iv) the width b of the adhesive film extends beyond the underside U of the battery cell by area Aba, where Aba < Aba < Abi.

[0056] The adhesive film typically comprises or consists of a carrier film onto which a preferably pressure-sensitive adhesive compound is applied on one side.

[0057] Preferably, the support comprises an insulating support, preferably an electrically insulating support, more preferably an electrically insulating support with a specific volume resistance of >10 15 Preferably >10 16 That, further preferred >10 17 This is determined according to DIN EN 62631-3-1 (VDE 0307-3-1): 2017-01.

[0058] Preferably, the support comprises one or more materials selected from the group consisting of polyimide, polybenzimidazole, polyamide-imide, polyetherimide, polyacetal, polyphenylene sulfide, polyetheretherketone, polytetrafluoroethylene, polyamide 6, ultra-high molecular weight polyethylene, polypropylene, vinyl chloride resin, polystyrene, polyethylene terephthalate, acrylonitrile butadiene styrene, polycarbonate, polyvinyl chloride, ethylene vinyl acetate and polyester, further preferably from the group consisting of polypropylene, polyethylene terephthalate, polycarbonate and polyvinyl chloride, and further preferably from the group consisting of polypropylene and polyethylene terephthalate.

[0059] There are generally no particular restrictions regarding the thickness of the support. Preferably, the support has a thickness in the range of 20 to 100 pm, more preferably in the range of 30 to 90 pm, and even more preferably in the range of 40 to 75 pm.

[0060] There are generally no particular restrictions regarding the thickness of the adhesive layer. Preferably, the cross-linked adhesive layer has a thickness in the range of 10 to 150 pm, more preferably in the range of 10 to 100 pm, and even more preferably in the range of 20 to 60 pm.

[0061] Preferably, the adhesive layer comprises a pressure-sensitive adhesive compound, which may additionally be cross-linked. An adhesive compound that is exemplary in forming an adhesive film which can be applied according to the method of the invention is disclosed in EP 4 345 992 A2.

[0062] Adhesive tapes coated with adhesive on one or both sides are typically wound into a roll in the form of an Archimedean spiral at the end of the manufacturing process. To prevent the adhesive from sticking to the backing in single-sided tapes, the tape is applied to a release liner (also known as a liner material) before winding. This release liner is wound together with the tape. Such liners are known to those skilled in the art as release liners or simply liners. Besides covering single- or double-sided adhesive tapes, liners are also used to cover labels.

[0063] A liner (release paper, release film) is not a component of an adhesive tape or label, but merely an aid in their manufacture, storage, or further processing by die-cutting. Furthermore, unlike an adhesive tape backing, a liner is not permanently bonded to an adhesive layer.

[0064] The invention also relates to a sheathed battery cell, obtainable or obtained by the inventive method.

[0065] The present invention, as described above, is further described by the following set of embodiments and combinations of embodiments, the combinations arising from the corresponding dependencies and cross-references. It should be noted in particular that in those places where a range of embodiments is mentioned—such as in connection with an expression like “method according to one of embodiments 1 to 5”—each individual embodiment within that range is explicitly disclosed to the person skilled in the art, and that this expression is understood by the person skilled in the art as synonymous with the expression “method according to one of embodiments 1, 2, 3, 4 and 5”.Furthermore, it should be explicitly pointed out that the following set of embodiments does not constitute the set of patent claims determining the scope of protection, but rather a suitably structured part of the description that focuses on general and preferred aspects of the present invention.

[0066] Description of the characters

[0067] Further details and features of the present invention will become apparent from the description of the figures and exemplary embodiments. The respective features can be implemented individually or in combination with one another. The invention is not limited to the exemplary embodiments. The exemplary embodiments are shown schematically in the figures. Identical reference numerals in the individual figures denote identical or functionally equivalent elements, or elements that correspond to one another with respect to their functions. The figures are described collectively.

[0068] Figure 1a shows a battery cell 110 comprising a bottom surface U 111, a front surface (hereinafter also referred to as the front) Si 112 and a rear surface (hereinafter also referred to as the back) S2 opposite the front surface, two opposite side surfaces S3 and S4 113, the top surface O 114 and two battery contacts 115 on the top surface 114. Figure 1b shows another variant of a battery cell 110 comprising a bottom surface U 111, a front surface S1 112 and a rear surface S2 opposite the front surface, two opposite side surfaces S3 and S4 113, each with a battery contact 115, and a top surface O 114.

[0069] The adhesive film, comprising at least one adhesive layer and at least one carrier, covers the front wall S1 and the rear wall S2, the underside U and the top side O in one piece, with the ends of the adhesive film overlapping and adhering to each other. The adhesive film is wider than the front and rear walls S1 and S2, the underside U and the top side O, so that the adhesive film has an overhang on the two opposite side walls S3 and S4, each of which has a battery contact. The individual sections forming the overhang on the front and rear walls S1 and S2, on the underside U and on the top side O are folded over and adhered to the respective side walls S3 and S4.

[0070] Figure 2 shows the method for encasing a battery cell 110 according to Figure 1a. In particular, Figure 2 shows an embodiment of a method for encasing a battery cell 110.

[0071] Step (i) 130 shows the provision of a battery cell 110, wherein the battery cell comprises at least one front wall S1 and one rear wall S2 opposite each other, at least two opposite side walls S3 and S4, at least one bottom U and at least one top O.

[0072] Step (ii) 132 shows the provision of an adhesive film 116 with a width b 118 and a length I 117.

[0073] Step (iii) 134 shows bringing the adhesive film 116 into contact with the at least one underside U of the battery cell 116, comprising bonding the adhesive layer of the adhesive film 116 and the at least one underside U 111 of the battery cell, wherein the width b 118 of the adhesive film 116 extends beyond the underside U 111 of the battery cell 110 by area Abi 119.

[0074] Step (iv) 136 shows bringing the adhesive film 116 into contact with the front wall S1 and the rear wall S2 112, comprising bonding the adhesive layer of the adhesive film 116 to the front wall Si and the rear wall S2 112, wherein the width b 118 of the adhesive film extends by area Ab2 121 beyond the front wall S1 and the rear wall S2 112 of the battery cell 110 and wherein the length I 117 extends by area Ah 120 beyond the top surface O 114 of the battery cell 110.

[0075] Steps (v) 138 and (vi) 140 show bringing the adhesive film 116 into contact with the at least two side walls S3 and S4 113, comprising bonding the adhesive layer of the adhesive film 116 to the at least two side walls S3 and S4 113, wherein the width b 118 of the adhesive film 116 extends beyond the underside of the battery cell 110 by area Abs 122, wherein Ab3122 is bonded to the at least two side walls S3 and S4 113 and wherein Ab2 121 is bonded to the at least two side walls S3 and S4 113, comprising bonding the adhesive layer of the adhesive film 116 to the at least two side walls S3 and S4 113, forming area AI2 124.

[0076] Step (vi) 140 shows bringing the adhesive film 116 into contact with the at least one top surface O 114, comprising bonding the adhesive layer of the adhesive film 116 and the at least one top surface O 114 of the battery cell 110, wherein AI2 124 is bonded to the top surface O 114 of the battery cell 110 to form surface AI3 125 and wherein AI3 125 is bonded to the top surface O 114 of the battery cell 110, comprising bonding the adhesive layer of the adhesive film 116 and the at least one top surface O 114.

[0077] Furthermore, Figure 2 shows an embodiment of a sheathed battery cell 150.

[0078] Figure 3 shows the entire film wrapping device 1. All assemblies ((i) to (x)) are integrated into the film wrapping device 1, although not all assemblies are shown in detail in Figure 3.

[0079] Figure 4 shows a winding unit 10 for a roll 11 of a single-sided adhesive film, preferably coated with a liner. The adhesive film typically comprises or consists of a carrier film onto which an adhesive, preferably a pressure-sensitive adhesive, is applied on one side.

[0080] The winding spool 12 is used to wind up the liner.

[0081] Figure 5 shows the clamping device 21 with a cutting unit 22 in which the adhesive film can be cut to the desired length.

[0082] After unwinding, the adhesive film must be cut into appropriate lengths, the length of which is determined by the size of the battery cell 110 to be encased. For cutting, the adhesive film is fixed in the clamping device 21, for example by a movable hold-down device 211, which presses the adhesive film onto a smooth base plate 212. The adhesive film can be cut transversely using the cutting unit 22, in the form of a conventional, particularly pneumatically actuated, cutting blade. The clamping device 21 for holding the film has two positions. In the closed position, the adhesive film is fixed; in the open position, the adhesive film is free. The hold-down device 211 of the clamping device 21 has several fingers arranged in a comb-like manner. Corresponding comb-like fingers are also provided on the base plate, so that when the hold-down device 211 is lowered, the fingers overlap and the adhesive film is clamped between them.

[0083] During the cutting process, the knife of the cutting unit 22 cuts through the film behind the fingers, so that the film between the fingers is freely accessible.

[0084] Opposite the clamping device 21, a movable gripping unit 23 is provided, which can be guided towards the clamping device 21 via the guide 24, which consists of two rods. The gripping unit 23 consists of an upper plate and a lower plate, which can be moved towards each other. The upper and lower plates also have fingers arranged in a comb-like pattern, the fingers being offset relative to the fingers of the clamping device 21, so that the comb of the gripping unit 23 can be moved into the comb of the clamping device 21.

[0085] The gripping unit 23, in its open position (upper and lower plates are separated), is moved from its rest position towards the clamping device 21 until the fingers of the gripping unit 23 engage in the gaps between the fingers of the clamping device 21. Then, the upper and lower plates of the gripping unit 23 move towards each other until they clamp the free end of the adhesive film (not shown here) created after the previous cutting process, and the gripping unit 23 is closed. The clamping device 21 is then opened. The gripping unit 23, with the adhesive film now clamped, returns to its rest position, thereby drawing the adhesive film into the film applicator 1. Once the gripping unit 23, along with the adhesive film, has reached its rest position, the clamping device 21 closes again, so that the film is clamped under tension between the clamping device 21 and the gripping unit 23.

[0086] Figures 6a to 6d show, each at a different angle, the first roller unit 31 consisting of four rollers 311, 312, 313, 314, which are opposite each other in pairs, the fixing unit 41 and the second roller unit 51 consisting of two rollers 511, 512.

[0087] The first roller unit 31 also serves to fix and hold under tension the adhesive film drawn into the film applicator 1 by the gripping unit 23. The first roller unit 31 has two pairs of rollers, each consisting of two rollers 311, 312 and 313, 314. The lower roller 312, 314 of each pair is positioned below the adhesive film (not shown here), and the upper roller 311, 313 of each pair is positioned above the adhesive film. The left pair of rollers is located close to the cutting unit 21, and the right pair of rollers is located close to the gripping unit 23.

[0088] The gripping unit 23 is moved from its rest position towards the clamping device 21 by the open roller pairs, grips the adhesive film, and is moved back to its rest position with the adhesive film, so that the adhesive film is drawn into the film application device 1. After reaching the rest position, the rollers 311, 312 and 313, 314 of the roller pairs move towards each other, so that the adhesive film is clamped between the upper and lower roller of each roller pair.

[0089] Figure 6a shows the roller pairs in the open position, figures 6b, 6c and 6d in the closed position, whereby the adhesive film is clamped in the roller pairs and thus kept under tension.

[0090] Between the pairs of rollers is the fixing unit 41, by means of which the battery cell 110, which is to be coated and inserted into the coating device 1, is placed with its underside U on the adhesive film and held upright. Figures 6b to 6d show how the battery cell 110 is fixed. The battery cell 110 can be inserted manually into the fixing unit 41, or alternatively, it can be placed automatically in the fixing unit 41 by a suitable mechanical device. The fixing unit 41 consists in particular of an open frame 411, the cross-sectional area of ​​which is almost equal to the cross-sectional area of ​​the battery cell 110 and which encloses the battery cell 110.

[0091] Figure 7 shows how, by means of a stamp 412 which rests on the top surface O of the battery cell, the battery cell 110 can be pushed in a vertical direction into the foiling device 1.

[0092] Furthermore, Figures 6a to 6d show a second roller unit 51 consisting of two rollers 511 and 512. The two rollers 511 and 512 are located below the clamped adhesive film and are in contact with the adhesive film. Their axes are movable in a plane parallel to the underside U of the battery cell 110 in order to initiate the process of hammering in the battery cell 110.

[0093] This state corresponds to step (iii) 134 in Figure 2.

[0094] In the starting position, both rollers 511 and 512 lie side by side below the fixing device 41 (Figure 6a), so that the battery cell 110, inserted into the fixing device 41, rests with its underside U directly on the adhesive film above the rollers 511 and 512. To start the film application process, the rollers 511 and 512 are moved apart so that the adhesive film is pressed onto the underside U of the battery cell 110 (Figure 6b).

[0095] After the adhesive film is pressed onto the underside U of the battery cell 110, it is cut in the cutting unit 22. The cut piece of adhesive film is held in position and under tension by the two pairs of rollers of the first roller unit 31. The clamping device 21 and the gripping unit 23 open, releasing the ends of the cut piece of adhesive film.

[0096] The battery cell 110 is then pressed by the punch 412 towards the roller tunnel 61 provided in the film application device 1, which will be described in detail later; in other words, downwards in Figure 7. Prior to this, the rollers 511 and 512 are positioned so that one roller 511 presses the adhesive film onto the front wall Si and the other roller presses the adhesive film onto the rear wall S2, while the battery cell is pressed between the rollers 511 and 512 towards the roller tunnel. In Figures 6c and 6d, the two rollers 511 and 512 are spaced apart to a distance corresponding to the depth of the battery cell 110 (i.e., the width of the side walls S3 and S4).

[0097] This state corresponds to step (iv) 136 in Figure 2.

[0098] Figures 8a and 8b show the front view (Figure 8a) and the rear view (Figure 8b) of the roller tunnel 61. The roller tunnel 61 comprises several functional elements that are attached to a frame 611 forming the roller tunnel 61.

[0099] To guide the battery cell 110 precisely through the roller tunnel 61, a plurality of guide rollers 62 are provided, arranged so that they make contact with the battery cell 110 and guide the battery cell 110 through the roller tunnel 61 in precise alignment. The guide rollers 62 consist of a central axle 621, which has a rotatable sleeve 622 at its end. The sleeves 622 are in contact with the front wall S1 and the rear wall S2, respectively, as the battery cell 110 is guided past them. The sleeves 622 are preferably made of a hard but sufficiently flexible plastic such as polyurethane. This makes it possible to compensate for slight variations in the dimensions of the battery cells 110 with respect to depth by allowing the sleeves 622 to be slightly compressed. This ensures that a slightly deeper battery cell 110 is not compressed and damaged.

[0100] At the beginning of the roller tunnel 61 there is a first squeegee unit 63 consisting of two squeegees 631, 632.

[0101] The squeegees 631, 632 are arranged such that when the battery cell 110 passes by, the adhesive film is folded over the edge that connects the underside U with the two opposite side walls S3 and S4 and pressed onto the side walls S3 and S4.

[0102] Following the first doctor blade unit 63, a total of four folding roller blocks 64, 65, 66, 67 are arranged, each folding roller block 64, 65, 66, 67 preferably consisting of the six rollers arranged one below the other shown here. Two folding roller blocks 64, 65 and 66, 67 are positioned opposite each other.

[0103] Each folding roll block 64, 65, 66, 67 serves to fold the adhesive film over the edge located between the front wall Si and the two side walls S3 and S4, or between the rear wall S2 and the two side walls S3 and S4, and to press it towards the side walls S3 and S4.

[0104] The upper, parallel folding roller blocks 64, 65 fold the cut piece of adhesive film over the two edges on the front wall S1 onto the side walls S3 and S4. The two folding roller blocks 66, 67 below fold the cut piece of adhesive film over the two edges on the rear wall S2 onto the side walls S3 and S4.

[0105] Each folding roll block 64, 65, 66, 67 has the same arrangement of folding rolls. The arrangement is explained below using folding roll block 64 as an example. Folding roll block 64 has a total of six folding rolls 641, 642, 643, 644, 645, 646. The axis of the uppermost folding roll 641 in folding roll block 64 is aligned parallel to the edge located between the front wall S1 and the side wall S3 (the angle between the axis and the side wall S3 is 90°), with the uppermost folding roll 641 resting against and touching the edge. The axis of the folding roll 642 below it is tilted at an angle of 15° towards the side wall S3 (the angle between the axis and the side wall S3 is 75°). This 642 folding roll also touches the edge.The axis of the folding roller 643 below is tilted by twice the angle, i.e., 30° (the angle between the axis and the side wall S3 is 60°), and this folding roller 643 also touches the edge. The axis of the folding roller 644 below is tilted by three times the angle, i.e., 45° (the angle between the axis and the side wall S3 is 45°), and this folding roller 643 also touches the edge. The axes of the subsequent folding rollers 645 and 646 are each also tilted by 15° (the angle between the axis and the side wall S3 is 30° and 15°, respectively). Both of these folding rollers also touch the edge.

[0106] It should also be mentioned again at this point that the folding rollers 641, 642, 643, 644, 645, 646 do not directly touch the edge, but rather the adhesive film is present between each folding roller 641, 642, 643, 644, 645, 646 and the edge, which is folded around the edge by the fan-like arrangement of the axes of the folding rollers 641, 642, 643, 644, 645, 646.

[0107] This ensures that the adhesive film is bent over the edge, so that, in the described arrangement of the folding rolls 641 , 642, 643 ,644, 645, 646, the piece of film has an angle of 15° to the side surface S3.

[0108] The folding rollers 641, 642, 643, 644, 645, 646 are rotatably mounted and preferably have a surface made of rubber or a solid foam. The number of folding rollers 641, 642, 643, 644, 645, 646 in each folding roller block 64, 65, 66, 67 can vary; preferably, there are four to ten rollers in each folding roller block 64, 65, 66, 67, more preferably five to seven, and particularly preferably six. The offset angle from one folding roller to the next is also variable, preferably, the offset angle from one roller to the next being always the same. The angle between the axis of the lowest folding roller and the side wall can vary; preferably, this angle is between 0° and 20°, and more preferably, between 10° and 15°.

[0109] Following the folding roller blocks 64, 65, 66, 67, a second further doctor blade unit 68 consisting of two doctor blades 681, 682 is connected in the roller tunnel 61.

[0110] The squeegees 681, 682 are arranged such that, as the battery cell 110 passes by, the two adhesive film pieces, which have been bent by a folding roll block 64, 65, 66, 67 over the two edges between the front wall Si and side wall S3 and between the rear wall S2 and side wall S3, or the two edges between the front wall S1 and side wall S4 and between the rear wall S2 and side wall S4, are pressed onto the side wall S3 or side wall S4, respectively. In particular, if the last folding roll in the folding roll block 64, 65, 66, 67 has an angle of 0° with the side walls S3 and S4, i.e., rests on the side walls S3 and S4, the second squeegee unit 68 is not required.

[0111] This state corresponds to step (v) 138 (in Figure 2).

[0112] Figure 8 shows the folding slide unit 71 for folding the film onto the top surface S1 of the battery cell 110. The folding slide unit 71 is connected to the roller tunnel 61. The battery cell 110 is pressed into the folding slide unit 71 by means of the punch 41 through the roller tunnel 61 until the top surface O of the battery cell 110 is positioned exactly within the folding slide unit 71. Two short folding slides 711, 712, located at the edge between the top surface O and the side wall S3 and between the top surface O and side wall S4, fold the protruding pieces of the adhesive film over the two edges and press them onto the top surface O. Furthermore, two long folding slides 713, 714 are provided at the edges between the front wall S1 and the top surface O and between the rear wall S2 and the top surface O. These slides fold the protruding pieces of the adhesive film over the two edges and press them onto the top surface O.

[0113] This state corresponds to step (vi) 140 (in Figure 2).

[0114] Subsequently, battery cell 110 is completely covered with adhesive film on five sides. Only on the top side O are there narrow strips of adhesive film, so that the battery contacts remain freely accessible. Battery cell 110 is pushed out of the film applicator 1 and can be removed as a film-coated battery cell 150. Reference numeral list

[0115] I film wrapping equipment

[0116] 110 battery cells

[0117] 111 Subpage

[0118] 112 Front side Si (and back side S2)

[0119] 113 Side walls S3 and S4

[0120] 114 Top side O

[0121] 115 battery contacts

[0122] 116 adhesive film

[0123] 117 Length I

[0124] 118 width b

[0125] 119 Area Abi

[0126] 120 area Ah

[0127] 121 Area Ab2

[0128] 122 Area Aba

[0129] 124 Area Al2

[0130] 125 Area Ah

[0131] 130 steps (i)

[0132] 132 Step (ii)

[0133] 134 Step (iii)

[0134] Step 136 (iv)

[0135] 138 steps (v)

[0136] 140 steps (vi)

[0137] 150 Encased battery cells

[0138] 10 unwinding units 10

[0139] II roll of a single-sided adhesive film

[0140] 12 winding spool

[0141] 21 Clamping device

[0142] 22 cutting unit

[0143] 23 gripping units

[0144] 24 Guided Tour

[0145] 31 roller unit 31 consisting of four rollers arranged in pairs opposite each other, which

[0146] 41 Fixing unit

[0147] 51 second roller unit 51

[0148] 61 Roller tunnel 62 Guide rollers 62

[0149] 63 first doctor blade unit

[0150] 64, 65, 66, 67 Folding roll block

[0151] 68 second doctor blade unit

[0152] 71 Folding slide unit

[0153] 211 Hold-down devices

[0154] 212 Base plate

[0155] 311, 312, 313, 314 rolls

[0156] 411 Frame

[0157] 412 stamps

[0158] 511, 512 rolls

[0159] 621 Central axis

[0160] 622 sleeve

[0161] 631, 632 squeegee

[0162] 641, 642, 643, 644, 645, 646 Folding rolls

[0163] 681, 682 squeegee

[0164] 711, 712 short folding sliders

[0165] 713, 714 long folding sliders

Claims

Patent claims 1. Method for coating battery cells using a coating device, comprising (i) a winding unit for a single-sided adhesive film, preferably covered with a liner (ii) preferably a winding spool for the liner (iii) a clamping device with a cutting unit in which the adhesive film can be cut to the desired length (iv) a gripping unit that pulls the adhesive film into the film application unit to the starting position (v) a first roller unit comprising, in particular, four rollers arranged in pairs opposite each other, wherein the lower roller of each pair is arranged below the adhesive film and the upper roller of each pair is arranged above the adhesive film, wherein one pair of rollers is arranged in close proximity to the cutting unit and one pair of rollers is arranged in close proximity to the gripping unit (vi) a fixing unit by means of which the battery cell to be foiled, which is inserted into the foiling device and has a front wall Si and a rear wall S2 opposite each other, two opposite side walls S3 and S4 connecting the front wall S1 and the rear wall S2, a bottom U and a top O, is placed with the bottom U on the adhesive foil and held upright (vii) a second roller unit comprising in particular two rollers located below the clamped adhesive film in contact with the adhesive film and whose axes are movable in a plane parallel to the underside U of the battery cell in order to start the process of hammering in the battery cell (viii) a stamp that pushes the battery cell through the fixing unit, through the second roller unit into the roller tunnel (ix) a roller tunnel comprising the following functional elements • a first doctor blade unit consisting of two doctor blades • a multitude of guide rollers arranged in such a way that they make contact with the battery cell and guide the battery cell precisely aligned through the roller tunnel • four folding roller blocks, each consisting of at least four rollers arranged one above the other • preferably a second doctor blade unit consisting of two doctor blades (x) a folding slide unit for folding the adhesive film onto the top side S1 of the battery cell, the method comprising the following steps: (1) Removing the adhesive film from the unwinding unit (2) optionally peeling off the liner in front of the adhesive film, the liner preferably being wound up in the winding unit (3) Pulling the adhesive film through the gripping unit into the film application device (4) Clamping the adhesive film using a first roll unit (5) precise positioning of the battery cell by means of a fixing unit in which the battery cell is fixed into the film wrapping device (6) Press the adhesive film onto the underside of the battery cell using a second roller unit. (7) Cutting the adhesive film to length with the cutting unit (8) Laminating the adhesive film on the front wall Si and the rear wall S2 using the second roller unit of the roller tunnel, by guiding the battery cell through the second roller unit, so that after passing through the roller tunnel the adhesive film is laminated on the front wall S1 and on the rear wall S2. (9) Inserting the battery cell into the roller tunnel, in which the adhesive film is folded over using appropriate functional elements and laminated onto the side walls S3 and S4 of the battery cell. (10) Folding the adhesive film onto the top side O of the battery cell using the folding slider unit and (11) Ejection of the battery cell from the foil wrapping device 2. Method according to claim 1, characterized in that the clamping device has a movable hold-down and a base plate, wherein the hold-down device and the base plate have several fingers that are arranged in a comb-like manner.

3. Method according to claim 1 or 2, characterized in that the gripping unit consists of an upper plate and a lower plate which can be moved towards each other and which have fingers which are arranged in a comb-like manner, wherein the fingers are offset from the fingers of the clamping device, so that the comb of the gripping unit can be moved into the comb of the clamping device.

4. Method according to at least one of claims 1 to 3, characterized in that the first roller unit consists of four rollers arranged in pairs opposite each other.

5. Method according to at least one of the preceding claims, characterized in that the second roller unit consists of two rollers whose axes are movable in a plane and parallel to the underside U of the battery cell.

6. Method according to at least one of the preceding claims, characterized in that each folding roll block has the same arrangement of folding rolls and consists of, in particular, six rolls, wherein the uppermost folding roll is aligned parallel to the edge located between the front wall or rear wall and a side wall and touches the edge, wherein the axes of the folding rolls below are each inclined at a more pronounced angle to the side surface, preferably at the same angle, and wherein the angle is preferably 15°, and wherein the folding rolls each touch the edge.

7. Method according to at least one of the preceding claims, characterized in that the folding slider unit has two short folding sliders and two long folding sliders with which the protruding adhesive film pieces are bent over the edges and pressed onto the top surface O.

8. Method according to at least one of the preceding claims, characterized in that the carrier of the adhesive film is an insulating carrier, preferably an electrically conductive one. insulating carrier, more preferably an electrically insulating carrier with a specific volume resistance of >10 15 Preferably >10 16 That, further preferred >10 17 Qcm, determined according to DIN EN 62631-3-1 (VDE 0307-3-1): 2017-01 , includes.

9. Method according to at least one of the preceding claims, characterized in that the carrier comprises one or more materials selected from the group consisting of polyimide, polybenzimidazole, polyamide-imide, polyetherimide, polyacetal, polyphenylene sulfide, polyetheretherketone, polytetrafluoroethylene, polyamide 6, ultra-high molecular weight polyethylene, polypropylene, vinyl chloride resin, polystyrene, polyethylene terephthalate, acrylonitrile butadiene styrene, polycarbonate, polyvinyl chloride, ethylene vinyl acetate and polyester, preferably from the group consisting of polypropylene, polyethylene terephthalate, polycarbonate and polyvinyl chloride.

10. Method according to at least one of the preceding claims, characterized in that the adhesive layer has a thickness in the range of 10 to 150 pm, preferably in the range of 10 to 100 pm, more preferably in the range of 20 to 60 pm.

11. Encased battery cell, obtainable or obtained by a method according to any one of claims 1 to 10.

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