CN114228124A

CN114228124A - Membrane presss from both sides and is used for preparing membrane stretching device of lithium ion battery diaphragm including it

Info

Publication number: CN114228124A
Application number: CN202110881351.8A
Authority: CN
Inventors: 申邰容
Original assignee: Tcms Co ltd
Current assignee: Tcms Co ltd
Priority date: 2020-09-09
Filing date: 2021-08-02
Publication date: 2022-03-25
Also published as: KR102199603B1

Abstract

The invention provides a film clamp which can stably hold two side parts of a film in a film stretching process for preparing a lithium ion battery diaphragm. The film clamp of the invention enables the swing unit not to be directly combined with the spring, but enables the inner side surface of the swing unit to be contacted with the middle end of the spring to receive elastic force, thereby preventing the spring from being broken due to the repetition of the film holding and holding releasing actions of the swing unit, and improving the efficiency of the film stretching process.

Description

Membrane presss from both sides and is used for preparing membrane stretching device of lithium ion battery diaphragm including it

Technical Field

The present invention relates to a film holder capable of stably holding both side portions of a film in a film stretching process for producing a lithium ion battery separator, which is one of secondary battery core members, and a film stretching apparatus including the same.

Background

Microporous membranes are widely used in various fields such as medical dialysis, environmental filtration, food purification, and the like. Recently, a fine porous film is widely used as a lithium ion battery separator of a lithium secondary battery (a lithium ion battery, a lithium polymer battery, or the like). In particular, when a fine porous film is used in a lithium polymer battery, it functions as a separator of a lithium ion battery of an anode and a cathode and a medium for ion conduction, that is, an electrolyte.

As described above, a microporous film used as a lithium ion battery separator and an electrolyte of a battery can be realized by using a polyolefin resin. The polyolefin resin includes polyethylene and polypropylene, and is expected to improve not only tensile strength, rigidity and impact strength but also ion permeability when used as a lithium ion battery separator for a lithium secondary battery due to its high degree of crystallization.

A method for producing a lithium ion battery separator using a microporous film of a polyolefin resin can be produced using a raw material film. Methods for producing lithium ion battery separators using raw material membranes are roughly classified into a stretching method (MCS: 1Phase), a thermally induced Phase separation method (TIPS: 2Phase), and a Phase inversion method (Phase inversion: 3 Phase). Among them, a dry preparation method of an MSS system using only a polymer as a raw material and drawing (stretching) without using a solvent is mainly used.

The conventional dry production method produces a lithium ion battery separator having fine pores formed therein by axially stretching a raw material film using a stretching device. The lithium ion battery separator preparation method by uniaxial stretching has an advantage of being able to improve the tensile strength in the Machine Direction (MD) while having the most economical efficiency because it can realize mass production in a simple production process, but has a problem of reducing the strength in the width direction (TD), that is, the strength in the direction perpendicular to the stretching direction, and thus reduces the stability of the lithium ion battery separator.

In order to solve the above problems, a production method has been proposed in which a raw material film is stretched twice or more by a stretching device. The preparation method of the lithium ion battery diaphragm can improve the mechanical strength of the lithium ion battery diaphragm and meet the high porosity characteristic inside the lithium ion battery diaphragm.

The film stretching apparatus used in the above-described process for producing a lithium ion battery separator uses a plurality of film holders for holding and fixing both side portions of a raw material film. The number of the film clips may vary depending on the size of the stretching device, but a maximum of 2500 film clips are arranged in one stretching device to hold and fix both side portions of the raw film.

Recently, the raw material film tends to be thinner and larger in area. Therefore, when the stretching process is performed by the conventional stretching apparatus, a phenomenon in which the raw material film is separated from the film nip occurs, and a problem occurs in that the quality and yield of the lithium ion battery separator are reduced.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a film holder capable of stably holding both side portions of a film in a film stretching process for producing a lithium ion battery separator, and a film stretching apparatus including the same.

The film clamp of one embodiment of the present invention holds the side ends of the film to move in one direction along the guide rail. Such a membrane clip comprises: a body unit including a side wall, a placement portion formed to protrude from a lower end of a front surface of the side wall and configured to place a side end of the film, and a pair of coupling portions formed to protrude from both sides of an upper end of the front surface of the side wall so as to be aligned with the placement portion; a connecting unit combined with the lower part of the placing part; a swing unit rotatably coupled to one end of the coupling portion, a lower end of the swing unit contacting an upper surface of a side end of the film placed on the placing portion; and a spring, both ends of which are combined with the inner side of the combining part, and the middle end of which is contacted with the inner side of the swinging unit.

Wherein the swing unit controls the swing to be in contact with or not in contact with the upper surface of the side end of the film by the elastic force of the spring. The present invention is characterized in that a plurality of protrusions in a zigzag form are formed on a bottom surface of a lower end portion of the swing unit.

The present invention is characterized in that the connection unit is shaped like 'Contraband' to shield the front. The connecting unit comprises a pair of first oil-proof parts which are respectively formed by extending from two sides of the front surface of the connecting unit.

The film clamp also comprises a chain unit which is combined at the inner side of the connecting unit and connects the adjacent pair of connecting units. The chain unit includes: a pair of hollow rolls arranged side by side with each other; chain combining pins respectively inserted into the hollow rollers; and an oilless bearing disposed between the hollow roller and the chain coupling pin.

The film clamp further includes a first transfer unit coupled to a rear surface of the side wall of the body unit to contact the guide rail, and the film clamp is moved along the guide rail by unidirectional rotation. The first transfer unit includes: a first transfer roller combined with the upper end of the back of the side wall and contacting with the upper end of the guide rail; and a second transfer roller combined with the lower end of the back of the side wall and contacting with the front of the guide rail.

And a second transfer unit coupled to a rear surface of the connection unit and contacting the guide rail, and moving the film holder along the guide rail by unidirectional rotation.

The film stretching device of an embodiment of the present invention stretches a film for producing a lithium ion battery separator in the width direction. The film stretching device includes a first guide rail and a second guide rail, which are respectively disposed on both sides of a film being conveyed in one direction, and are provided with a plurality of film holders. The film clamp holds both side ends of the film and moves in the film conveying direction along the first guide rail and the second guide rail.

According to the film clip of the present invention, the swing unit for gripping the film is not directly coupled to the spring, but the inner side surface thereof is brought into contact with the middle end of the spring to receive the elastic force, thereby preventing the spring from being broken due to repetition of the film gripping and releasing operations of the swing unit, and improving the efficiency of the film stretching process.

Further, the film clamp has a plurality of protrusions formed on the bottom surface of the swing unit to be in line contact with the upper surface of the film, thereby improving the holding force and fixing force between the bottom surface of the swing unit and the film.

Further, the oil-proof portions are formed on both side ends of the front surface of the connecting unit and both side ends of the side wall of the main body unit so as to extend a predetermined length, respectively, thereby preventing foreign matter from penetrating from the outside in the direction of the film held by the swing unit and reducing the fraction defective in the film stretching process.

Further, the film clip can disperse the load applied in the process of gripping and moving the film to the body unit and the connection unit, respectively, thereby preventing the film clip from being broken or the gripping of the film from being released due to the load applied in the process of moving the film clip.

Drawings

Fig. 1 is a diagram showing a stretching device of a lithium ion battery separator including a membrane cartridge according to an embodiment of the present invention.

Fig. 2 is a view showing the film clip in fig. 1.

Fig. 3 is a view showing an exploded perspective view of the film clip in fig. 2.

Fig. 4 is a rear view of fig. 2.

Fig. 5 is a view showing the body portion in fig. 2.

Fig. 6 is a view showing the swing portion in fig. 2.

Fig. 7 is a view showing the chain unit in fig. 3.

Description of reference numerals

100: film stretching device 10: raw material film

110: first guide rail 120: second guide rail

130 a: first rotating roller 130 b: second rotating roll

200: the film clip 210: body unit

220: the swing unit 230: connection unit

240: spring 260: first transfer unit

265: second transfer unit 270: chain unit

Detailed Description

Terms used in the present specification and the scope of the claims are general terms selected in consideration of functions in various embodiments of the present invention. However, such terms may be different due to the intention of those skilled in the art to which the present invention pertains or due to legal or technical explanations and the advent of new technologies. Also, some terms may be terms arbitrarily selected by the applicant. Such terms may be interpreted as defined in the present specification, and may be interpreted based on the entire contents of the present specification and general technical knowledge in the technical field to which the present invention pertains, unless otherwise specified.

In addition, the same reference numerals or symbols in the drawings described in the present specification denote components or elements that actually perform the same functions. For ease of illustration and understanding, the same reference numbers or symbols are used in the description even in different embodiments. That is, even if the constituent elements denoted by the same reference numerals are shown in a plurality of drawings, it is not intended that the plurality of drawings show the same embodiment.

In the present specification and the scope of the claims, terms including ordinal numbers such as "first" and "second" may be used to distinguish the respective constituent elements. These ordinal numbers are used to distinguish the same structural elements or similar structural elements, but should not be construed as being limited in meaning by the terms in which they are used. For example, the components combined with the above ordinal numbers should not be construed as being limited to the order of use or arrangement by the numbers. The ordinal numbers may be used in place of each other as needed.

In this specification, the singular expressions include the plural expressions unless the context clearly dictates otherwise. In the present application, terms such as "including" or "constituted by … …" refer to the presence of the features, numerals, steps, actions, structural elements, components, or combinations thereof described in the specification, and should not be construed as excluding the presence or addition possibility of one or more other features, numerals, steps, actions, structural elements, components, or combinations thereof.

In addition, in the embodiments of the present invention, when a certain portion is connected to another portion, the case of direct connection is included, and the case of indirect connection through another medium is also included. Note that unless otherwise specified, the inclusion of a certain component in a certain part does not mean that another component is excluded, but means that another component may be included.

Hereinafter, a film cartridge and a lithium ion battery separator stretching apparatus including the same according to an embodiment of the present invention will be described in detail with reference to the drawings.

Referring to fig. 1, the film stretching apparatus 100 for manufacturing a lithium ion battery separator of the present embodiment can stretch a raw material film 10 drawn and supplied from the outside, for example, from a film roll (not shown), in a width direction (Y-axis direction) perpendicular to a conveying direction (X-axis direction) thereof.

The film stretching apparatus 100 can move the film holders 200 in the conveyance direction of the raw material film 10 by holding both side portions of the raw material film 10 by the plurality of film holders 200. In this case, the raw film 10 may be stretched in the width direction by gradually increasing the pitch between the opposing film clips 200 among the plurality of film clips 200.

The film stretching apparatus 100 may include a first guide rail 110 and a second guide rail 120 disposed on both sides of the raw material film 10 along the conveyance section of the raw material film 10. Further, a plurality of film clips 200 may be disposed on the first rail 110 and the second rail 120, respectively.

The conveyance section of the raw film 10 in the film stretching apparatus 100, i.e., the section from one side to the other side of the first guide rail 110 and the second guide rail 120, may be divided into a plurality of process sections.

For example, the conveyance section from the side of the first guide rail 110 and the second guide rail 120, in other words, from the side of drawing the raw material film 10, may be divided into a preheating section a1 for preheating the raw material film 10, a first stretching section a2 for performing the first stretching step, a second stretching section A3 for performing the second stretching step, a holding section a4 for holding the second stretched state, and a curing section a5 for curing the stretched raw material film 10.

The film stretching apparatus 100 may further include a start-gripping section (not shown) for gripping the raw film 10 by the plurality of film clips 200 before the preheating section a1, and may further include a release-gripping section (not shown) for releasing the gripping state of the plurality of film clips 200 gripping the stretched film after the curing section a 5.

The plurality of film holders 200 can reciprocate along the first guide rail 110 and the second guide rail 120 in the conveyance section of the raw material film 10. For example, the plurality of film holders 200 may be moved from the position of the grip start section of the film stretching apparatus 100 to the grip release section along the first guide rail 110 and the second guide rail 120. The plurality of film holders 200 can be moved from the release section of the film stretching apparatus 100 to a position along the first guide rail 110 and the second guide rail 120 to the start section. That is, the first guide rail 110 and the second guide rail 120 may be provided in an annular shape that can reciprocate the plurality of film holders 200 on both sides of the film stretching device 100.

On the other hand, a plurality of film holders 200 may be provided with chains (not shown) connected at predetermined intervals and moving along the first guide rail 110 and the second guide rail 120. Further, a first rotating roller 130a and a second rotating roller 130b connected to a chain provided in each film gripper 200 may be provided at the front end of the gripping start section and the rear end of the gripping release section of the film stretching apparatus 100, respectively.

The first rotating roller 130a and the second rotating roller 130b may be rotated in one direction, respectively. The respective chains of the plurality of film clips 200 are moved in one direction by the rotation of the rotating roller, so that the film clips 200 can be moved cyclically at a predetermined speed along the first guide rail 110 and the second guide rail 120.

Further, in the holding start section of the film stretching apparatus 100, holding start portions (not shown) for causing the plurality of film holders 200 to hold the side ends of the raw film 10 may be arranged. Further, in the release section, a release section (not shown) may be disposed to release the state of the side end of the raw material film 10 being held by each of the plurality of film holders 200.

Therefore, the raw film 10 can be held by the plurality of film holders 200 in the holding start section, and stretched to a predetermined width while being conveyed along the conveyance section of the film stretching apparatus 100 and passing through the preheating section a1, the first stretching section a2, the second stretching section A3, the holding section a4, and the curing section a 5.

The stretched raw material film 10 can be continuously moved for the subsequent process after releasing the holding state from the plurality of film holders 200 in the holding release region. The plurality of film holders 200 can be moved again to the gripping start section along the first guide rail 110 and the second guide rail 120 by the rotation of the first rotating roller 130a and the second rotating roller 130b after releasing the state of gripping the raw film 10.

The raw material film 10 whose side ends are gripped by the plurality of film grippers 200 in the gripping start section can be conveyed to the preheating section a1 of the film stretching apparatus 100 in accordance with the movement of the film grippers 200. A predetermined heating unit (not shown) may be disposed in the preheating section a 1. Thereby, the raw material film 10 which is held by the plurality of film holders 200 and moves to the preheating section a1 can be preheated to a predetermined temperature. By the above-described preheating, rapid stretching can be realized in the subsequent stretching step of the raw material film 10, and uniform tension can be imparted to the raw material film 10 in the width direction.

The first guide rail 110 and the second guide rail 120 corresponding to the preheating section a1 may be arranged parallel to the conveyance direction of the raw material film 10. Thus, the width of the film passing through the preheating section a1 by the movement of the plurality of film holders 200, for example, the first width W0 may be the same as the width of the raw material film 10 initially supplied to the film stretching apparatus 100.

The film passing through the preheating zone a1 can be conveyed to the first stretching zone a2 of the film stretching apparatus 100 by the movement of the film holder 200. In the first stretching section a2, the first guide rail 110 and the second guide rail 120 may be disposed at a predetermined angle with respect to the film conveyance direction.

For example, the first guide rail 110 and the second guide rail 120 may be disposed outward at a first stretching angle θ 1 with respect to the film conveyance direction, and the distance between the first guide rail 110 and the second guide rail 120 may increase toward the rear end of the first stretching section a 2.

In this way, the distance between the film clips 200 facing each other among the plurality of film clips 200 moving along the first guide rail 110 and the second guide rail 120, respectively, can be increased. Therefore, the raw material film 10 preheated to the predetermined temperature in the preheating zone a1 can be stretched for the first time in the width direction intersecting the conveying direction by the plurality of film holders 200 moving in the first stretching zone a 2. Wherein the second width W1 of the film passing through the first stretching interval a2 may be wider than the first width W0 of the film passing through the preheating interval a 1.

The film that has passed through the first stretching section a2 and has been stretched for the first time can be transported to the second stretching section A3 of the film stretching apparatus 100 by the movement of the film holder 200. In the second stretching section a3, the first guide rail 110 and the second guide rail 120 may be arranged at predetermined angles with respect to the transport direction of the first stretched film, and may be arranged outward at a second stretching angle θ 2, for example.

Accordingly, in the second stretch section a3, the distance between the first rail 110 and the second rail 120 may be increased toward the rear end thereof, and thus the distance between the film clips 200 facing each other may be increased. Wherein the second stretching angle θ 2 may be greater than the first stretching angle θ 1.

Accordingly, the film once stretched to the second width W1 in the width direction by the first stretching section a2 may be twice stretched to the third width W2 wider than the second width W1 in the width direction while passing through the second stretching section A3.

The stretching angles, the widths of the first stretching section a2 and the second stretching section A3, and the moving speed of the film clip 200 can be adjusted by the optimum values set by a control unit (not shown). It is apparent that other embodiments of the present invention may modify the set values by an operator at the time of the stretching process of the raw material film 10.

Also, the first stretch zone a2 and the second stretch zone A3 may have the same zone width, or the second stretch zone A3 may have a relatively large zone width.

In order to further improve the stretching efficiency of the raw material film 10, the first stretching section a2 and the second stretching section A3 may further include a heating unit (not shown) for maintaining the conveyed film at a constant temperature.

On the other hand, the film stretching apparatus 100 of the present embodiment has been described by taking an example including two stretching sections, but the present invention is not limited thereto. For example, the film stretching apparatus 100 may further include three or more stretching sections to stretch the raw material film 10 three or more times.

In the holding section a4 and the curing section a5 of the film stretching apparatus 100, the first guide rail 110 and the second guide rail 120 may be arranged parallel to the film conveyance direction. Thus, the film passed through the second stretching section A3 and stretched for the second time can be conveyed while maintaining the stretched width while passing through the holding section a4 and the curing section a 5.

In the curing zone a5, a curing mechanism (not shown) for performing thermosetting and cold curing may be disposed to return the film stretched for the second time to a normal temperature state. The curing means can prevent the stretched film from being deformed by gradually curing the second stretched film conveyed through the holding section a 4.

The film stretched for the second time in the curing zone a5 passes through the grip releasing zone, and in this way, the plurality of film clips 200 can release the grip of the film. The plurality of film clips 200 may move along the first guide rail 110 and the second guide rail 120 to return to the gripping start section. The stretched film released from the plurality of film clips 200 can be wound around a winding roll (not shown) or the like and moved for a subsequent process.

As described above, the film stretching apparatus 100 for manufacturing a lithium ion battery separator according to the present embodiment can stretch the raw material film 10 to manufacture a lithium ion battery separator by moving the film holders 200 along the first guide rail 110 and the second guide rail 120 in a state where both side portions of the raw material film 10 are held and fixed by the plurality of film holders 200. In this case, in order to improve the efficiency of the film stretching process and the production yield, the raw film 10 should be held and fixed by the film holder 200 accurately and stably. Accordingly, in order to accurately hold and fix the membrane, the present invention proposes a membrane holder 200 having a new structure, which will be described in detail below.

Fig. 2 is a view showing the film clip of fig. 1, fig. 3 is a view showing an exploded perspective view of the film clip of fig. 2, and fig. 4 is a rear view of fig. 2.

Fig. 5 is a view showing the main body portion in fig. 2, and fig. 6 is a view showing the swing portion in fig. 2. Fig. 7 is a view showing a chain unit incorporated in the connecting unit in fig. 3.

Hereinafter, a film clip 200 according to an embodiment of the present invention will be described in detail with reference to the drawings. For convenience of description, in the present embodiment, only the film clip 200 coupled to the first guide rail 110 is described, and it is apparent that the film clip coupled to the second guide rail 120 also has the same structure.

Referring to fig. 2 to 7, the film clip 200 of the present embodiment may be configured such that the body unit 210, the connection unit 230, and the swing unit 220 are coupled to each other.

The film clip 200 can be moved in one direction along the first guide rail 110 by coupling the rear face to the first guide rail 110. In this case, one or more transfer units may be provided between the rear surface of the film clamp 200 and the first guide rail 110, and for example, the film clamp 200 may be smoothly moved along the first guide rail 110 by providing the first transfer unit 260 and the second transfer unit 265.

The body unit 210 of the membrane cartridge 200 may include a sidewall 211, a placing portion 213, and a coupling portion 212. Further, coupling holes for coupling the swing unit 220, the connection unit 230, and the first transfer unit 260, respectively, may be formed in the body unit 210, and for example, first to third coupling holes 212a to 211b may be formed.

The placing portion 213 of the body unit 210 may be formed to protrude from the lower end of the side wall 211 toward the front direction, for example, toward the film direction facing the rear surface connected to the first guide rail 110. One side end of the film may be placed on the above-mentioned placing portion 213.

The coupling portions 212 of the body unit 210 may protrude from the upper ends of the sidewalls 211 in a front direction to form a pair. The pair of coupling portions 212 may be formed to face each other. The pair of coupling portions 212 may be formed in parallel with the placement portion 213.

One end of the coupling portion 212 may be coupled with the swing unit 220. For this, a first coupling hole 212a into which the rotation shaft 253 can be inserted may be formed at one end of the coupling portion 212. Also, an insertion hole 222a may be formed in the swing unit 220 to be positioned on the same line as the first coupling hole 212 a. Thus, the pivot shaft 253 of the first coupling hole 212a on one side of the coupling portion 212 is fixed in the first coupling hole 212a on the other side of the coupling portion 212 through the insertion hole 222a of the swing unit 220, and the swing unit 220 can be coupled to the inside of one end of the coupling portion 212. In this case, the swing unit 220 can be coupled to the coupling portion 212 to swing by a predetermined angle through the rotation shaft 253.

Further, a spring 240 may be coupled to an inner side of the coupling portion 212. The spring 240 may be positioned between a portion combined with the swing unit 220 and the sidewall.

Both ends of the spring 240 may be coupled to the inner sides of the coupling parts 212, respectively. A protrusion 245 protruding a predetermined degree may be formed at the middle end of the spring 240 to contact the inner surface of the swing unit 220. The protrusion 245 of the spring 240 may protrude in a U-shape to contact an inner side surface of the swing unit 220, so as to provide a predetermined elastic force to the swing unit 220.

A first transfer unit 260 formed of one or more transfer rollers may be coupled to the rear of the side wall 211. The first transfer unit 260 may be disposed between the body unit 210 and the first guide rail 110 to move the body unit 210, that is, to move the film clip 200 along the first guide rail 110.

The first transfer unit 260 may include: a first transfer roller 261 coupled to the rear surface of the side wall 211 in a parallel manner, and contacting the upper end of the first guide rail 110; and a second transfer roller 263 vertically combined with the rear surface of the side wall 211 to contact the front surface of the first guide rail 110.

The first transfer roller 261 may be coupled by being inserted into a coupling hole (not shown) formed in the rear surface of the side wall 211, and the second transfer roller 263 may be coupled by being inserted into a second coupling hole 211a formed in the rear surface of the side wall 211.

The first transfer roller 261 and the second transfer roller 263 are configured to be in contact with the first guide rail 110 and to be rotated in one direction in accordance with the movement of the chain unit 270, which will be described later. Thereby, the film clamp 200 can move along the first guide rail 110.

The swing unit 220 may be rotatably coupled to an inner side of one end of the coupling portion 212 by a rotation shaft 253. The swing unit 220 may be integrally formed of: an upper end 221 formed to be higher than the upper end of the body unit 210 and exposed; a middle end portion 222 coupled to the coupling portion 212; and a lower end portion 223 adjacent to one surface of the placing portion 213 and holding the film.

The upper end 221 of the swing unit 220 may be pressed in one direction by the grip start portion and the grip release portion of the film stretching apparatus 100. The inner side of the swing unit 220 receives an elastic force provided by the spring 240 in accordance with the pressurization of the upper end 221, so that the lower end 223 can grip or release the film placed on the placing part 213 of the body unit 210.

For example, when the film clamp 200 moves along the first guide rail 110 and enters the grip start section of the film stretching device 100, the grip start portion may press the upper end portion 221 of the swing unit 220 in the first direction, for example, may press in the front direction of the body unit 210. Accordingly, the lower end 223 of the swing unit 220 may be disposed to be inclined at a predetermined angle with respect to one surface of the placement portion 213 of the main unit 210, thereby forming an open state, i.e., a state spaced apart from one surface of the placement portion 213.

In this state, when one side end of the film is placed on the placing portion 213, the holding start portion can release the pressing of the upper end portion 221 of the swing unit 220. Then, the swing unit 220 can be restored to the original state by the elastic force of the spring 240 contacting the inside thereof, for example, the lower end portion 223 is in a closed state vertically disposed on one surface of the placing portion 213 to contact the upper surface of the film. Thereby, the film can be fixed by its upper surface being gripped by the lower end 223 of the swing unit 220.

In this case, as shown in fig. 6, a contact portion 225 composed of a plurality of protrusions protruding in a zigzag shape may be formed at the bottom surface of the lower end portion 223 of the swing unit 220. The bottom surface of the lower end portion 223 can be in line contact with the upper surface of the film through the contact portion 225, whereby the holding force and the fixing force of the film can be increased by the swing unit 220.

In a state where the film is gripped by the swing unit 220, the film clamp 200 can move along the first guide rail 110 and enter the grip release section of the film stretching apparatus 100. In this case, the film may be in a state of being stretched in the axial direction through the preheating zone a1, the first stretching zone a2, the second stretching zone A3, and the curing zone a5 of the stretching device 100.

The grip release portion may press the upper end portion 221 of the swing unit 220 of the film clamp 200 entering the grip release section in the first direction. Accordingly, the lower end 223 of the swing unit 220 can be disposed to be inclined at a predetermined angle with respect to one surface of the placement portion 213 of the main unit 210, thereby forming an open state. Thus, the stretched film is released from the fixation of the side ends thereof, and the roll is moved on a winding roll for use in the subsequent step.

In addition, the film clamp 200 may be returned to the clamping start section along the first guide rail 110 again in a state where the upper end 221 of the swing unit 220 is pressed by the clamping release portion. In this case, the grip releasing portion may release the pressurization of the upper end portion 221 of the swing unit 220 when the film clip 200 is separated from the grip releasing section. Then, the swing unit 220 is restored to the original state by the elastic force of the spring 240 contacting the inner side thereof, and can move along the first guide rail 110 to the grip start section.

As described above, the swing unit 220 of the present embodiment controls the swing thereof as the grip start portion and the grip release portion pressurize and release the upper end portion, so as to be in the open state and the closed state by the elastic force of the spring 240. The upper surface of the side end of the film placed on the placing section 213 can be gripped and fixed or released by the swing control of the swing unit 220. On the other hand, a second insertion hole 222a for inserting the aforementioned rotation shaft 253 may be formed at the middle end portion 222 of the swing unit 220. The second insertion hole 222a may be formed to be aligned with the first coupling hole 212a formed in the coupling portion 212 of the body unit 210.

The swing unit 220 swings the middle end portion 222 via the rotation shaft 253 in accordance with the pressurization and release of the upper end portion 221, thereby allowing the lower end portion 223 to be opened and closed.

The connection unit 230 may be coupled to a lower portion of the placement part 213 of the body unit 210. Then, a connection coupling pin inserted for coupling with the connection unit 230 may be formed at the body unit 210, for example, a third coupling hole 211b inserted with the first coupling pin 251 may be formed. The connection unit 230 is coupled to a lower portion of the placement part 213 of the body unit 210 by a first coupling pin 251 inserted through the third coupling hole 211b of the body unit 210.

The connection unit 230 may be formed in a shape of "Contraband" to shield the front of the lower portion of the placement part 213. Further, a chain unit 270 connected to the first rotating roller 130a or the second rotating roller 130b of the film stretching device 100 and moving may be coupled to the inside of the connection unit 230, for example, in a space between the front surface of the connection unit 230 and the front surface of the first guide rail 110. The chain unit 270 may be coupled to the inside of the connection unit 230 by a chain coupling pin coupled from the upper portion of the connection unit 230, for example, by a second coupling pin 255.

The chain unit 270 may be coupled to two at the inner side of the connection unit 230. In this case, the chain units 270 are not connected to each other, but the connecting unit 230 may be coupled to the connecting unit 230 of another adjacent film clip 200.

Referring to fig. 3 and 7, the chain unit 270 may include an upper cover 271, a lower cover 272, and a pair of hollow type rollers 273 and bearings 275 therebetween.

Openings for inserting the pair of second coupling pins 255 may be formed at the upper cover 271 and the lower cover 272, respectively. The second coupling pins 255 of the adjacent two film clips 200 are inserted into the respective openings of the upper cover 271 and the lower cover 272, respectively.

That is, one chain unit 270 may be coupled to the connection units 230 of two adjacent film clips 200 by two second coupling pins 255, respectively. Thus, two chain units 270 are coupled to the coupling unit 230 of one film clamp 200, and in this way, one film clamp 200 can be coupled to two adjacent film clamps 200 by the chain units 270.

The second coupling pin 255 may be inserted through an upper opening of the coupling unit 230, and fixed to a lower surface of the coupling unit 230 after passing through an opening of the upper cover 271 of the chain unit 270, an inner side of the roller 273, and an opening of the lower cover 272, respectively.

Here, the bearing 275 may be disposed between the second coupling pin 255 and the inner surface of the roller 273. The bearing 275 can prevent abrasion by friction between the second coupling pin 255 and the roller 273. The bearing 275 may be an oilless bearing having a plurality of holes 275a formed in an outer circumferential surface thereof, but is not limited thereto.

The chain unit 270 coupled to the coupling unit 230 is in contact with the first rotating roller 130a and the second rotating roller 130b of the film stretching apparatus 100, and can move by the rotation thereof. The film clip 200 can be moved along the first guide rail 110 by the movement of the chain unit 270 described above.

That is, a plurality of film clips 200 may be provided to the first guide rail 110 by being connected to each other by the respective chain units 270. As the first and second

rotating rollers

130a and 130b of the first guide rail 110 rotate in one direction, the chain unit 270 of the film clip 200 located at the relevant position is connected to the first and second

rotating rollers

130a and 130b and rotates, and can pull the other film clip 200 connected thereto to move. As the above process is repeated, the plurality of film clips 200 may move on the first guide rail 110 in one direction.

On the other hand, the aforementioned chain unit 270 may be coupled to the inner side of the connection unit 230 so as not to contact the first guide rail 110. Accordingly, in the film clamp 200 of the present embodiment, transfer rollers may be coupled to the top and back surfaces of the connection unit 230, respectively, for smooth movement, and for example, a second transfer unit 265 including a third transfer roller 266 and a fourth transfer roller 267 may be coupled thereto.

The third transfer roller 266 of the second transfer unit 265 may be coupled to an upper surface of the connection unit 230. The third transfer roller 266 may be coupled to the upper surface of the link unit 230 in the same direction as the second transfer roller 263 of the first transfer unit 260, that is, in contact with the front surface of the first guide rail 110 in the vertical direction.

The fourth transfer roller 267 of the second transfer unit 265 may be coupled to the rear surface of the connection unit 230. The fourth transfer roller 267 may contact the front of the first rail 110 in a perpendicular manner by being disposed side by side with the third transfer roller 266.

That is, the first transfer unit 260 and the second transfer unit 265 contacting the first guide rail 110 are coupled to the body unit 210 and the connection unit 230, respectively, and rotate in one direction on the first guide rail 110 according to the movement of the chain unit 270, so that the film clip 200 can move in one direction along the first guide rail 110.

As shown in fig. 2 and 3, an oil-proof portion extending from both side ends of the connecting unit 230 by a predetermined length may be formed on the front portion of the connecting unit, and for example, a first oil-proof portion 235 may be formed. The first oil prevention part 235 may prevent impurities from penetrating forward from the chain unit 270 or the first guide rail 110 coupled to the inside of the coupling unit 230, for example, impurities such as lubricating oil from penetrating in a direction of the film.

The first oil proof portion 235 may extend from both front side end portions of the connecting unit 230, and the end thereof may correspond to about 1/2 of the width of the chain unit 270. Then, the ends of the first oil prevention parts 235 formed at the front faces of the respective connecting units 230 of the two film clips 200 coupled and adjacent by the chain unit 270 are brought into contact with each other, so that the front faces of the connecting units 230 can be completely shielded.

As shown in fig. 2 and 5, a second oil-proof portion 215 similar to the first oil-proof portion 235 may be formed at both side ends of the side wall 211 of the body unit 210. The second oil-proof portion 215 may be formed to extend from both side ends of the side wall 211 by a predetermined length, and may prevent impurities such as lubricating oil from penetrating from the first rail 110 in a direction of the film.

On the other hand, the film clip 200 of the present embodiment can appropriately distribute the loads respectively applied to the body unit 210 and the connection unit 230, so that it is possible to prevent the release of the gripping of the film or the breakage of the film clip 200 due to the load in the process of gripping and moving the film.

That is, the film holder 200 includes transfer units, i.e., the first transfer unit 260 and the second transfer unit 265, each including one or more transfer rollers that contact the first guide rail 110, in the body unit 210 and the connection unit 230, and the load applied to the chain unit 270 may be dispersed to the body unit 210 and the connection unit 230 by the first rotating roller 130a and the second rotating roller 130b of the film stretching device 100. This can prevent the film clip 200 from being damaged or released from holding the film during the movement.

Also, the film clip 200 can achieve easy coupling or separation between the body unit 210 and the connection unit 230, and thus, the film clip 200 can be easily coupled or separated with the first guide rail 110.

As described above, the swing unit 220 of the film holder 200 according to the present embodiment for gripping the film is not directly contacted with the spring 240, but the inner side surface thereof is contacted with the middle end of the spring 240 to apply the elastic force, thereby preventing the spring 240 from being broken due to the repetition of the film gripping and releasing operations of the swing unit 220, and improving the efficiency of the film stretching process.

Further, the film clip 200 has a plurality of protrusions formed on the bottom surface of the swing unit 220 to be in line contact with the upper surface of the film, so that the holding force and the fixing force between the bottom surface of the swing unit 220 and the film can be improved.

Further, the film clips 200 are formed by extending the oil-proof portions by a predetermined length at both front side ends of the connection unit 230 and both side ends of the side walls of the main body unit 210, respectively, thereby preventing the permeation of foreign substances from the outside in the direction of gripping the film by the swing unit 220, and reducing the fraction defective in the film stretching process.

Meanwhile, the film clamp 200 of the present embodiment can disperse the load applied during the process of holding and moving the film to the body unit 210 and the connection unit 230, respectively, so that it can prevent the film clamp 200 from being broken or released from holding the film during the moving process.

While the embodiments of the present invention have been described, those skilled in the art to which the present invention pertains can make various modifications and alterations to the present invention by addition, alteration, deletion, or addition of structural elements without departing from the scope of the invention as set forth in the claims, and these modifications and alterations should also be construed as falling within the scope of the invention.

Also, the aforementioned terms are defined in consideration of their functions in the present invention, and may be different according to the intention or the custom of the user or the operator. Accordingly, these terms should be determined based on the contents throughout the present specification.

Claims

1. A film clamp, moving in one direction along a guide rail by holding the side end of a film,

the method comprises the following steps:

a body unit including a side wall, a placement portion formed to protrude from a lower end of a front surface of the side wall and configured to place a side end of the film, and a pair of coupling portions formed to protrude from both sides of an upper end of the front surface of the side wall so as to be aligned with the placement portion;

a connecting unit combined with the lower part of the placing part;

a swing unit rotatably coupled to one end of the coupling portion, a lower end of the swing unit contacting an upper surface of a side end of the film placed on the placing portion; and

a spring with two ends combined with the inner side of the combining part and a middle end contacted with the inner side of the swinging unit,

the swing unit controls the swing by the elastic force of the spring to contact or not contact the upper surface of the side end of the film.

2. The film holder according to claim 1, wherein a plurality of protrusions are formed in a zigzag pattern on a bottom surface of a lower end portion of the swing unit.

3. The film clip of claim 1, wherein said connecting element is shaped like "Contraband" to shield the front.

4. The membrane clip of claim 1, further comprising a pair of first oil-proof portions extending from each of the two sides of the front surface of the connecting unit.

5. The film clamp of claim 1, further comprising a chain unit coupled to an inner side of the connection unit to connect a pair of adjacent connection units.

6. The film clamp of claim 5, wherein said chain unit comprises:

a pair of hollow rolls arranged side by side with each other;

chain combining pins respectively inserted into the hollow rollers; and

and an oilless bearing disposed between the hollow roller and the chain coupling pin.

7. The film clamp of claim 1, further comprising a first transfer unit coupled to a rear surface of the side wall of the body unit to contact the guide rail, and configured to move the film clamp along the guide rail by unidirectional rotation.

8. The film clamp of claim 7, wherein the first transfer unit comprises:

a first transfer roller combined with the upper end of the back of the side wall and contacting with the upper end of the guide rail; and

and a second transfer roller combined with the lower end of the back of the side wall and contacting with the front of the guide rail.

9. The film clamp according to claim 1, further comprising a second transfer unit having one or more transfer rollers, wherein the second transfer unit is coupled to at least one of an upper surface and a rear surface of the connection unit to contact the guide rail, and moves the film clamp along the guide rail by unidirectional rotation.

10. A film stretching device for stretching a film for preparing a lithium ion battery separator in a width direction,

the method comprises the following steps:

the membrane clip of any one of claims 1 to 9; and

a first guide rail and a second guide rail respectively arranged at both sides of the film and provided with a plurality of film clips,

the film clamp holds both side ends of the film and moves in the film conveying direction along the first guide rail and the second guide rail.