A processing device for aluminum-plastic film of soft-pack battery

Abstract

A processing device for an aluminum-plastic film of a soft-pack battery, which is used to laminate a protective film on an aluminum foil. The processing device has at least one film laminating roller group. The film laminating roller group consists of one lower roller and two upper rollers. Among them, the axes of the two upper rollers are arranged in a V-shape, and the axes of the two upper rollers and the axis of the lower roller are arranged in a space-crossed manner. The roller surface of the lower roller is a cylindrical surface, and the roller surface of the upper roller is a concave surface. After the roller surface of the upper roller contacts the roller surface of the lower roller, the contact line is a continuous straight line. During the lamination process of the present invention, the protective film is in a tensioned state in the direction perpendicular to the midline, preventing the protective film from generating wrinkles in the rolling direction and causing the occurrence of longitudinal lamination phenomenon. At the same time, the protective film located at the midline part contacts and laminates with the aluminum foil first, and the protective film located at both side parts contacts and laminates with the aluminum foil last, squeezing the air in the lamination area from the middle part to both side parts, eliminating the generation of bubble phenomenon.

Description

Technical Field

[0001] The present invention relates to the field of aluminum processing, and particularly to a processing device for aluminum-plastic film of soft-pack batteries. Background Art

[0002] The aluminum-plastic film for soft-pack lithium batteries is formed by laminating aluminum foil, with an inner protective film and an outer protective film laminated on the inner and outer sides of the aluminum foil respectively. The aluminum-plastic film is mainly used to isolate water and oxygen and protect the electrolyte from the influence of external moisture. Since accidents such as lithium battery fires are mostly caused by short circuits of the aluminum-plastic film, the quality requirements for the aluminum-plastic film are very high, especially the lamination quality of the inner and outer protective films on the aluminum foil.

[0003] The existing lamination of aluminum-plastic film is carried out on a laminating machine. The laminating machine has multiple pairs of laminating rollers and tension rollers. The laminating rollers can laminate the inner protective film (generally polyethylene film) or the outer protective film (generally nylon film or PET film) on the aluminum foil (generally 8021 aluminum foil) by means of rolling, and the tension rollers are used to tension the aluminum foil, the inner and outer protective films, so that the aluminum foil, the inner and outer protective films are in a longitudinally tensioned state. Usually, the thickness of the inner and outer protective films is 0.02 - 0.06 mm.

[0004] The current problems are as follows: First, since the thickness of the inner and outer protective films is very thin, and the flexibility and stretchability are much greater than those of the aluminum foil, the inner and outer protective films are prone to generate wrinkles in the rolling direction and overlap on the aluminum foil, resulting in the occurrence of longitudinal overlapping. If the aluminum foil, the inner and outer protective films are not longitudinally tensioned, the occurrence of transverse overlapping is likely to occur. Second, the existing laminating rollers roll the aluminum foil and the protective film in parallel, and the air in the composite area cannot be completely extruded, easily resulting in the occurrence of bubble phenomenon. For the aluminum-plastic film of soft-pack lithium batteries, both the overlapping phenomenon and the bubble phenomenon are not allowed to occur. If they occur, the whole section needs to be cut off, which seriously affects the yield of the aluminum-plastic film. Summary of the Invention

[0005] In order to overcome the deficiencies in the background art, the present invention discloses a processing device for aluminum-plastic film of soft-pack batteries, and its purpose is to prevent the occurrence of overlapping phenomenon and bubble phenomenon and improve the yield of the aluminum-plastic film.

[0006] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0007] A processing device for aluminum-plastic film of soft-pack batteries, which is used to laminate a protective film on aluminum foil. The processing device has at least one laminating roller group; the laminating roller group consists of one lower roller and two upper rollers. Among them, the axes of the two upper rollers are arranged in a V-shaped manner, and the axes of the two upper rollers and the axis of the lower roller are set to intersect in space; the roller surface of the lower roller is a cylindrical surface, and the roller surface of the upper roller is a concave surface. After the roller surface of the upper roller contacts the roller surface of the lower roller, the contact line is a continuous straight line.

[0008] Further improving the technical solution, the processing equipment further includes a coiler, a double-pressure roller set and a tension roller.

[0009] Further improving the technical solution, the lower roller is a driving roller, and the two upper rollers are driven rollers. The driving roller drives the driven rollers to rotate through friction.

[0010] Further improving the technical solution, the lower roller rotates in the opposite direction to the two upper rollers, and the linear velocity of the roller surface of the lower roller is between the highest linear velocity and the lowest linear velocity of the roller surfaces of the upper rollers.

[0011] A processing method for an upper roller uses a rod milling cutter with the same roller diameter as the lower roller to mill the upper roller blank; during milling, the upper roller blank is rotated around its axis, and the axis of the upper roller blank is arranged to intersect the axis of the rod milling cutter in space.

[0012] Due to the adoption of the above technical solution, compared with the background technology, the present invention has the following beneficial effects:

[0013] During the compounding process of the present invention, taking the midline as the boundary, two opposite lateral forces F are generated on both sides of the protective film by the two upper rollers. The lateral force F can keep the protective film in a taut state in the direction perpendicular to the midline. The beneficial effect of this lateral tension is to prevent the protective film from wrinkling in the rolling direction and causing longitudinal lamination.

[0014] At the same time, the protective film at the midline part first contacts and compounds with the aluminum foil, and the protective film at both side parts finally contacts and compounds with the aluminum foil. This plays the role of "expelling bubbles", squeezing the air in the compounding area from the middle part to both side parts, and extruding the possible bubbles from both side parts to eliminate the generation of bubbles. Description of the Drawings

[0015] Figure 1 Shows the overall structural schematic diagram of the present processing equipment.

[0016] Figure 2 Shows the structural schematic diagram of the film laminating roller set.

[0017] Figure 3 Shows the working principle diagram of the film laminating roller set.

[0018] In the figure: 1. Aluminum foil reel; 2. Protective film reel; 3. Tension roller; 4. Double-pressure roller set; 5. Coiler; 6. Film laminating roller set; 61. Upper roller; 62. Lower roller; 63. Contact line; 64. Midline; 7. Glue coating roller; 8. Aluminum foil; 9. Protective film. Detailed Embodiments

[0019] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention. It should be noted that in the description of the present invention, the terms "front", "rear", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. It should also be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0020] A processing device for a soft-pack battery aluminum-plastic film is used to laminate an inner protective film or an outer protective film on an aluminum foil 8. In this processing device, the lamination methods of the inner protective film and the outer protective film are the same.

[0021] As Figure 1 shown, the processing device is sequentially provided with an aluminum foil reel 1, a protective film reel 2, a tension roller 3, a glue coating roller 7, a film laminating roller group 6, a double-pressing roller group 4, and a coiler 5 from right to left. The following specifically describes its structure and functions.

[0022] An aluminum foil 8 is wound around the aluminum foil reel 1, and the thickness of the aluminum foil 8 is 0.08 mm. A protective film 9 is wound around the protective film reel 2, and the thickness of the protective film 9 is 0.03 mm. The aluminum foil 8 and the protective film 9 enter the film laminating roller group 6 after being tensioned by the tension roller 3 respectively for lamination. Among them, the protective film 9 comes into rolling contact with the glue coating roller 7 before entering the film laminating roller group 6 to coat adhesive on the surface of the protective film 9. After the laminated aluminum foil 8 and the protective film 9 are laminated by the film laminating roller group 6, they enter the double-pressing roller group 4 for double pressing, and finally are wound up by the coiler 5.

[0023] To prevent the occurrence of longitudinal lamination and bubble phenomena, as Figure 2As shown in the figure, the film laminating roller group 6 is composed of a lower roller 62 and two upper rollers 61. Among them, the axes of the two upper rollers 61 are arranged in a V-shape, and the axes of the two upper rollers 61 intersect the axis of the lower roller 62 in space. The roller surface of the lower roller 62 is a cylindrical surface, and the roller surface of the upper roller 61 is a concave surface. After the roller surfaces of the upper roller 61 and the lower roller 62 come into contact, the contact line 63 is a continuous straight line. During lamination, the aluminum foil 8 is coated on the roller surface of the lower roller 62, and the protective film 9 is coated on the roller surfaces of the two upper rollers 61. The function of the film laminating roller group 6 is to laminate the protective film 9 on the aluminum foil 8. During the lamination process, on the one hand, it is necessary to prevent the generation of bubbles, and on the other hand, it is necessary to prevent the occurrence of overlapping and pressing phenomena. The function of the double pressing roller group 4 is to double press the laminated aluminum-plastic film to ensure the thickness and bonding performance of the lamination. The function of the coiler 5 is to generate tension on the aluminum-plastic film and wind up the aluminum-plastic film.

[0024] In one of the embodiments, the lower roller 62 is a driving roller, and the two upper rollers 61 can be driven rollers. The driving roller drives the driven rollers to rotate through friction. In another embodiment, the lower roller 62 and the two upper rollers 61 are both driving rollers. The lower roller 62 and the two upper rollers 61 rotate in opposite directions, and the linear velocity of the roller surface of the lower roller 62 is between the highest linear velocity and the lowest linear velocity of the roller surface of the upper roller 61.

[0025] As Figure 3 shown, since the roller surface of the lower roller 62 is a cylindrical surface and the lower roller 62 is perpendicular to the lamination direction, the linear velocity V1 of each part of the roller surface of the lower roller 62 is the same. Furthermore, since the axes of the two upper rollers 61 intersect the axis of the lower roller 62 in space and the roller surface of the upper roller 61 is a concave surface, the linear velocity V2 of each part of the roller surface of the upper roller 61 is different. Among them, the linear velocity of the middle part of the concave surface is the smallest, and the linear velocity of the two side parts of the concave surface is the largest. The change in linear velocity must have a force effect. Therefore, during the lamination process, taking the center line 64 as the boundary, the two upper rollers 61 generate lateral forces F in opposite directions on both sides of the protective film 9. This lateral force F can keep the protective film 9 in a taut state in the direction perpendicular to the center line 64. The beneficial effect of this lateral tension is to prevent the protective film 9 from wrinkling in the rolling direction and causing the occurrence of longitudinal overlapping and pressing phenomena.

[0026] Figure 3 The right side in the figure shows the distribution diagram of the tension T along the width direction of the protective film. Since the axes of the two upper rollers 61 intersect the axis of the lower roller 62 in space, on the right side of the contact line 63, the distance R from each part of the right roller surface of the upper roller 61 to the contact line 63 is different, and this distance R gradually decreases from the center line 64 of the protective film 9 to the edge of the protective film 9. Refer to Figure 1 and Figure 2It can be seen that the smaller the distance R is, the smaller the wrapping angle of the upper roller 61's roller surface on the protective film 9 at that position, and thus the smaller the tension T generated on the protective film 9 at that position; the larger the distance R is, the larger the wrapping angle of the upper roller 61's roller surface on the protective film 9 at that position, and thus the larger the tension T generated on the protective film 9 at that position. Then, by superimposing the linear velocity V2 of each roller surface of the upper roller 61, the distribution diagram of the tension T along the width direction of the protective film is obtained. From the distribution diagram of the tension T, it can be seen that the tensions generated at both sides of the protective film 9 are smaller, while the tension generated at the middle part of the protective film 9 is the largest, and the tension T gradually decreases from the middle line 64 of the protective film 9 to the edges of the protective film 9. The beneficial effect of this is that during lamination, the actual contact line 63 between the protective film 9 and the aluminum foil 8 also approaches the distribution diagram of the tension T. The protective film 9 at the middle line 64 position first contacts and laminates with the aluminum foil 8, and the protective film 9 at both sides finally contacts and laminates with the aluminum foil 8, which plays the role of "expelling bubbles", squeezing the air in the lamination area from the middle part to both sides, and squeezing out the possible bubbles from both sides to eliminate the generation of bubbles. It should be noted that the conclusion that the protective film 9 at the middle line 64 position first contacts and laminates with the aluminum foil 8, and the protective film 9 at both sides finally contacts and laminates with the aluminum foil 8 can also be explained geometrically. At the middle line 64 position, the distance R from the right roller surface of the upper roller 61 to the contact line 63 is the largest, the wrapping angle of the upper roller 61's roller surface on the protective film 9 is the largest, the included angle between the protective film 9 and the aluminum foil 8 at this position is the smallest, and the protective film 9 first contacts and laminates with the aluminum foil 8. On the contrary, at both side positions, the distance R from the right roller surface of the upper roller 61 to the contact line 63 is the smallest, the wrapping angle of the upper roller 61's roller surface on the protective film 9 is the smallest, the included angle between the protective film 9 and the aluminum foil 8 at this position is the largest, and the protective film 9 finally contacts and laminates with the aluminum foil 8.

[0027] Since the roller surface of the upper roller 61 has a special concave structure, in order to facilitate the manufacturing of the upper roller 61, the present invention also discloses a processing method for the concave surface of the upper roller 61, and the specific steps are as follows:

[0028] On a milling machine, a rod milling cutter with the same roller diameter as the lower roller 62 is used to mill the blank of the upper roller 61. During milling, the blank of the upper roller 61 is rotated around its axis, and the axis of the blank of the upper roller 61 and the axis of the rod milling cutter are arranged in a spatial intersection, and the angle of this spatial intersection is the same as the spatial intersection angle between the axis of the upper roller 61 and the axis of the lower roller 62. Such a processing method can easily obtain the required concave surface.

[0029] As can be seen from the above, the present invention can prevent the occurrence of laminating phenomenon and bubble phenomenon, and improve the yield rate of the aluminum-plastic film.

[0030] The parts not described in detail are prior arts. Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A processing device for the aluminum-plastic film of a soft-pack battery, which is used to compound a protective film on an aluminum foil, and is characterized in that: The processing equipment has at least one film laminating roller group; the film laminating roller group is composed of one lower roller and two upper rollers. Among them, the axes of the two upper rollers are arranged in a V shape, and the axes of the two upper rollers and the axis of the lower roller are arranged in a space intersection; the roller surface of the lower roller is a cylindrical surface, and the roller surface of the upper roller is a concave surface. After the roller surface of the upper roller contacts the roller surface of the lower roller, the contact line is a continuous straight line.

2. The processing device for the aluminum-plastic film of a soft-pack battery according to claim 1, characterized in that: The processing equipment also has a coiler, a double pressing roller group and a tension roller.

3. The processing device for the aluminum-plastic film of a soft-pack battery according to claim 1, characterized in that: The lower roller is a driving roller, and the two upper rollers are driven rollers. The driving roller drives the driven rollers to rotate through friction.

4. The processing device for the aluminum-plastic film of a soft-pack battery according to claim 1, characterized in that: The lower roller rotates in the opposite direction to the two upper rollers, and the linear velocity of the roller surface of the lower roller is between the highest linear velocity and the lowest linear velocity of the roller surface of the upper rollers.

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