KR102675025B1 - Film for cell pouch and manufacturing method thereof - Google Patents

Abstract

This specification relates to a film for a cell pouch and a method of manufacturing the same. The film for a cell pouch and its manufacturing method according to an embodiment of the present invention maintain the plate shape of the film and also provide excellent mechanical strength and formability.

Description

Film for cell pouch and manufacturing method thereof {FILM FOR CELL POUCH AND MANUFACTURING METHOD THEREOF}

Disclosed herein is a film for a cell pouch and a method for manufacturing the same.

Pouch-type batteries, which are generally used in electric vehicles, have the advantage of being easier to change shape and having higher energy density than cylindrical or prismatic batteries. These cell pouches generally include a first process of surface treating one side of the metal layer, a second process of surface treating the other side of the metal layer, a third process of laminating the outer layer to one side, and a third process of laminating a sealant layer to the other side. It is manufactured through 4 processes in order.

Korean Patent Publication No. 10-2016-0070468 discloses such a process. However, according to this conventional process, the order of coating, drying, and winding is repeated for each process, and in this case, there is a concern that the probability of running loss and process defects occurring during the transfer of the fabric will increase. . In addition, the conventional process is slow and proceeds in a high-temperature atmosphere, so the plate shape of the film is not maintained, resulting in wrinkles. Furthermore, the tension of the driving roll that transports the film is high, which causes a problem of poor formability, which is a major physical property.

Korean Patent Publication No. 10-2016-0070468 Korean Patent Publication No. 10-2022-0031820

An object of one aspect of the present invention is to provide a film for a cell pouch that maintains the plate shape of the film and has excellent mechanical strength and formability, and a method for manufacturing the same.

In one aspect of the present invention, the present invention includes a barrier layer made of metal and surface treated on both sides; Adhesive layers formed on both sides of the barrier layer; and a functional fabric layer formed on both sides of the adhesive layer, and has a tensile strength of 25 kgf/cm ² to 34 kgf/cm ² .

In another aspect, the present invention provides a cell pouch including the film for the cell pouch.

In another aspect, the present invention includes a double-sided surface treatment step of surface treating both sides of a metal fabric forming a barrier layer; A one-side coating step of forming an adhesive layer by applying an adhesive to one side of the surface-treated metal fabric; and a laminating step of laminating functional fabric to one side of the adhesive layer to form a functional fabric layer. It provides a method of manufacturing a film for the cell pouch, including a.

The film for a cell pouch and its manufacturing method according to an embodiment of the present invention maintain the plate shape of the film and also provide excellent mechanical strength and formability.

1 is a diagram schematically showing a cross section of a film according to an embodiment of the present disclosure.
Figure 2 is a schematic diagram of a film manufacturing apparatus for a cell pouch according to an embodiment of the present invention.
Figures 3a and 3b are photographs showing the shape of a film for a cell pouch according to an embodiment of the present invention.
Figures 4a and 4b are photographs showing the shape of the film for a cell pouch according to a comparative example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

The embodiments of the present invention disclosed in the text are illustrative only for illustrative purposes, and the embodiments of the present invention may be implemented in various forms and should not be construed as limited to the embodiments described in the text. . The present invention can make various changes and take various forms, and the embodiments are not intended to limit the present invention to the specific disclosed form, but all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention. It should be understood as including.

In this specification, when a part “includes” a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Throughout the specification, similar parts are given the same reference numerals. Throughout the specification, when a part such as a layer, membrane, region, plate, etc. is said to be “on” or “on” another part, this includes not only the case where it is directly on top of the other part, but also the case where there is another part in between. . Throughout the specification, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. Terms are used only to distinguish one component from another.

In the specification, “cell” refers to a battery, and has the broadest meaning to include all types of batteries such as secondary batteries such as lithium ion batteries and lithium polymer batteries, and portable storage batteries.

In this specification, a “cell pouch” refers to a cell component such as an anode, a cathode, and a separator impregnated with an electrolyte and stored therein. In order to accommodate the cell components, a cell pouch has gas barrier properties, bendability, and resistance. It has the broadest meaning, including all films with a laminated structure that take into account electrolyte properties and thermal adhesiveness, processed into a bag or box shape, etc.

In this specification, “barrier property” refers to the ability to block water vapor from the outside of the battery.

As used herein, “flexibility” refers to the degree of bending of the cell and/or cell pouch. The better the bendability, the easier the cell and/or flexible cell pouch can be bent.

In this specification, “Wave” refers to a wave-like phenomenon that appears in a sample when the sample is spread out on a flat surface.

In this specification, “wrinkle” refers to a stripe-like phenomenon that appears on both sides of the sample in the machine direction (MD).

Film for cell pouch

1 is a diagram schematically showing a cross section of a film according to an embodiment of the present disclosure.

In exemplary embodiments of the present invention, a barrier layer made of metal and surface treated on both sides; Adhesive layers formed on both sides of the barrier layer; and a functional fabric layer formed on both sides of the adhesive layer, and has a tensile strength of 25 kgf/cm ² to 34 kgf/cm ² .

One embodiment of the present disclosure includes a sealant layer 500; An inner adhesive layer 400 laminated on the sealant layer 500; A barrier layer 300 laminated on the inner adhesive layer 400; An external adhesive layer 200 laminated on the barrier layer 300; and an outer layer 100 formed on the outer adhesive layer 200, wherein the barrier layer 300 includes a metal layer 320 and surface treatment layers 310 and 330 uniformly coated on both surfaces of the metal layer 320, respectively. ) can be provided.

In one embodiment, an extruded resin layer may be further formed between the adhesive layer and the functional fabric layer. The extruded resin layer can improve the bendability, adhesiveness, insulation, etc. of the pouch. The extruded resin layer contains an olefin-based resin such as polypropylene-based resin. The extruded resin layer may have a thickness of about 5 to 80 μm. Alternatively, the inner layer of the cell pouch film may be formed of the extruded resin layer and the sealant layer without the inner adhesive layer. In the case where there is no inner adhesive layer as described above, the extruded resin layer may serve as the inner adhesive layer.

In one embodiment, the barrier layer may block the entry and exit of external moisture or air and internally generated gas. The barrier layer is not limited as long as it is a metal having gas barrier properties.　The barrier layer may include one or more selected from metal thin films and metal deposition layers.　 At this time, the metal thin film can be a metal foil, etc., and the metal deposition layer can be a separate plastic film, for example, a film of polyethylene terephthalate (PET), polyethylene (PE), or polypropylene (PP). It can be formed by vacuum deposition.　

In one embodiment, the tensile strength of the film is between 25 kgf/cm ² and 34 kgf/cm ² . The manufacturing process of the film for cell pouches according to the present invention uses a suction roll as a driving roll, so the tension is low, and the drying step is shortened, so the tensile strength of the film is low and the elongation is high. More specifically, the tensile strength of the film is 25 kgf/cm ² or more, 26 kgf/cm ² or more, 27 kgf/cm ² or more, 28 kgf/cm ² or more, 29 kgf/cm ² or more, 30 kgf/cm ² or more. or more, 31 kgf/cm ² or more, 32 kgf/cm ² or more; It may be 34 kgf/cm ² or less, 33 kgf/cm ² or less, and 32 kgf/cm ² or less, but is not limited thereto.

The present invention is not a method of repeating the order of coating, drying, and winding for each process, but a 1 pass 3 coating process in which three or more coating processes can be performed in one facility according to the manufacturing method of the present invention. 3 Coating, 1P3C) In-line method is used. Accordingly, it is possible to reduce the probability of running loss and process defects that occur when transferring fabric. In addition, according to the method of the present invention, the process speed is high, the number of windings is reduced, so the stress applied to the film is reduced, the tension of the driving roll that transports the film is low, so it does not cause a change in the tensile curve of the film, and the drying step is reduced. As it is shortened, the plate shape of the film is maintained, preventing wrinkles from occurring, and it also has excellent mechanical strength and formability.

In one embodiment, the functional fabric layer formed on one side of the adhesive layer is an outer layer made of synthetic resin fabric, and the functional fabric layer formed on the other side of the adhesive layer is a sealant layer made of sealant fabric.

In one embodiment, the sealant layer is an inner layer that is attached by heat after a cell is embedded to provide sealing properties, and may include a sealing resin for thermal bonding.

In one embodiment, the wave height of the film is 3 mm or less. The wave height refers to the height from the floor to the curved portion of the film when the film is placed on a flat floor. The manufacturing process of the film for cell pouches according to the present invention uses a suction roll as a driving roll, so the tension is low and the drying step is shortened, so the plate shape of the film is maintained and wrinkles do not occur. The lower limit of the wave height of the film is not limited. More specifically, the wave height of the film is 0 mm or more, 0.1 mm or more, 0.2 mm or more, 0.3 mm or more, 0.4 mm or more, 0.5 mm or more, 0.6 mm or more, 0.7 mm or more, 0.8 mm or more, 0.9 mm or more, 1 mm or more, 1.1 mm or more, 1.2 mm or more, 1.3 mm or more, 1.4 mm or more, 1.5 mm or more, 1.6 mm or more, 1.7 mm or more, 1.8 mm or more, 1.9 mm or more, 2 mm or more; It may be 3 mm or less, 2.9 mm or less, 2.8 mm or less, 2.7 mm or less, 2.6 mm or less, 2.5 mm or less, 2.4 mm or less, 2.3 mm or less, 2.2 mm or less, 2.1 mm or less, 2 mm or less, but is not limited to these. no.

In one embodiment, the formability of the film is 2.6 mm to 3.5 mm. The formability refers to the critical depth at which the metal layer does not break after being molded to each depth using a test mold when measuring the depth of a specimen cut from a cell pouch film. More specifically, the formability of the film is 2.6 mm or more, 2.7 mm or more, 2.8 mm or more, 2.9 mm or more, 3 mm or more; It may be 3.5 mm or less, 3.4 mm or less, 3.3 mm or less, 3.2 mm or less, 3.1 mm or less, and 3 mm or less, but is not limited thereto.

In one embodiment, the metal constituting the barrier layer, specifically the metal constituting the metal thin film or metal deposition layer, is, for example, aluminum (Al), iron (Fe), copper (Cu), and nickel (Ni). , one or more (single metal or a mixture of single metals) selected from the group consisting of tin (Sn), zinc (Zn), indium (In) and tungsten (W), or an alloy of two or more selected from these. An example is given.　In one embodiment, the metal of the barrier layer is stainless steel (Stainless Use Steel, SUS) or an alloy thereof. The barrier layer requires properties such as moldability as well as barrier properties against water vapor and other gases. In addition, the barrier layer may be surface-treated with phosphoric acid, chromium, etc. for corrosion resistance.

In one embodiment, the outer layer includes one or more resins selected from the group consisting of polyethylene terephthalate (PET) resin and nylon resin. The outer layer requires properties such as heat resistance, pinhole resistance, chemical resistance, wear resistance, moldability, and insulation. The outer layer may be composed of multiple layers.

In one embodiment, the sealant layer comprises at least one polyolefin resin selected from the group consisting of polypropylene, low density polyethylene, linear low density polyethylene, very low density polyethylene, medium density polyethylene, high density polyethylene, polybutene, and ethylene/propylene copolymer. do. The sealant layer requires properties such as heat resistance, cold resistance, heat adhesion, and formability, as well as electrolyte resistance and insulation resistance, since it is a layer in contact with an electrolyte solution. The sealant layer may be composed of multiple layers.

In one embodiment, the surface treatment layer may be a surface treatment layer using phosphoric acid, chromium, zirconium, cerium, lanthanum, etc. to provide corrosion resistance to metal.

In one embodiment, the adhesive layer may include one or more of an epoxy-based adhesive, a polyurethane-based adhesive, a phenolic resin-based adhesive, a polyester-based adhesive, and a polyolefin-based adhesive. As an example, the inner and outer adhesive layers may each have a thickness of 0.5 μm to 10 μm.

In one embodiment, the barrier layer may have a thickness of 5 μm to 100 μm. If the thickness of the barrier layer is less than 5 μm, it is not easy to implement it as a cell pouch for a secondary battery, and if the thickness of the barrier layer exceeds 100 μm, the battery capacity may rapidly decrease in a bendability test of the cell pouch. there is.

In one embodiment, the outer layer may have a thickness of 5 μm to 50 μm.

In one embodiment, the sealant layer may have a thickness of 5 μm to 100 μm.

In one embodiment, an extruded resin layer may be further formed between the inner adhesive layer and the sealant layer. The extruded resin layer can improve the bendability, adhesiveness, insulation, etc. of the pouch. As an example, the extruded resin layer may include an olefin-based resin such as polypropylene-based resin. As another example, the inner layer of the cell pouch film may be formed of the extruded resin layer and the sealant layer without the inner adhesive layer. In the case where there is no inner adhesive layer as described above, the extruded resin layer may serve as the inner adhesive layer. In one embodiment, the extruded resin layer may have a thickness of 5 μm to 80 μm.

cell pouch

The film for cell pouches according to an embodiment of the present invention has excellent gas barrier properties, bendability, electrolyte resistance, and thermal adhesiveness, and is therefore suitable for cell pouch applications.

In other exemplary embodiments of the present invention, a cell pouch is provided including a film for a cell pouch according to an embodiment of the present invention.

Method of manufacturing film for cell pouch

Other exemplary embodiments of the present invention include a double-sided surface treatment step of surface treating both sides of a metal fabric forming a barrier layer; A one-side coating step of forming an adhesive layer by applying an adhesive to one side of the surface-treated metal fabric; and a laminating step of laminating functional fabric to one side of the adhesive layer to form a functional fabric layer. It provides a method of manufacturing a film for the cell pouch, including a.

The present invention is not a method of repeating the order of coating, drying, and winding for each process, but a 1 pass 3 coating process in which three or more coating processes can be performed in one facility according to the manufacturing method of the present invention. 3 Coating, 1P3C) In-line method is used. Accordingly, it is possible to reduce the probability of running loss and process defects that occur when transferring fabric. In addition, according to the method of the present invention, the process speed is high, the number of windings is reduced, so the stress applied to the film is reduced, the tension of the driving roll that transports the film is low, so it does not cause a change in the tensile curve of the film, and the length of the film is reduced. The mechanical strength in direction (MD) and transverse direction (TD) does not change.

The double-sided surface treatment step is a process of surface treating both sides of the metal fabric forming the metal layer by applying first and second coatings. The double-sided surface treatment step includes a double-sided double coater including a first coater and a second coater. This is carried out by coating means.

The double-sided surface treatment step includes a fabric supply process of unwinding and supplying the wound metal fabric; A foreign matter removal process to remove foreign substances present on the surface of the supplied metal fabric; A tension control process that adjusts the tension of the metal fabric from which foreign substances on the surface have been removed; and a double-sided double coating process in which coating is performed on both sides of a metal fabric in which a constant tension is maintained.

The foreign matter removal process may include a first foreign matter removal process in which oil is removed by performing discharge treatment on both surfaces of the metal fabric. In addition, the foreign matter removal process may further include a pinhole inspection process to check whether pinholes are generated on both surfaces of the metal fabric from which oil has been removed. In addition, the foreign matter removal process may further include a secondary foreign matter removal process in which foreign matter occurring on both surfaces of the metal fabric that has undergone the pinhole inspection is removed using a roll method.

One surface of the metal fabric is subjected to primary coating by applying a water-based and solvent-based coating solution using a combination of direct coating and reverse kiss coating (RKC) using a primary coater, thereby Physical properties and changes were also taken into consideration. The other surface of the metal fabric can be subjected to secondary coating by applying a coating solution using RKC and film up/down coating methods. Meanwhile, by adjusting the position of the substrate contact surface, coating roll, and doctor, it is possible to improve coating uniformity and work speed. In particular, by constructing a chamber method (closed piping) for precise control of the coating agent, the viscosity of the coating agent can be adjusted and the entry of foreign substances can be blocked at the source.

A physical property stabilization drying step of stabilizing the physical properties by drying the metal fabric coated on both surfaces in a floating manner between the double-sided surface treatment step and the double-sided coating step of forming an adhesive layer; A cooling step of cooling the dried metal fabric; And it may further include a surface inspection step of inspecting the surface of the cooled metal fabric.

Once the double-sided surface treatment step is completed, the metal fabric with both surfaces coated can be dried using a floating method to stabilize the physical properties. At this time, the drying method can be an air floating method so that the coated substrate can be dried in a non-contact manner in a floating state. Through this, the double-sided coated metal fabric can be dried while minimizing contact with components such as transfer rolls. Thereafter, after cooling the dried metal fabric, the surface of the cooled metal fabric can be inspected.

The one-side coating step of forming the adhesive layer is a process of applying adhesive to one side of the surface-treated metal fabric through two coatings, and is performed by a tertiary coater. It is used for lamination through processes such as drying. Get ready. After applying the adhesive, the adhesive-coated metal fabric is dried to form an adhesive layer, the thickness of the dried adhesive layer is measured, and the surface of the adhesive layer is corona treated to strengthen the adhesive strength.

One embodiment of the method may further include, after the lamination step, an inner adhesive layer coating step of forming an inner adhesive layer by applying an inner adhesive to the other side of the metal fabric to which the outer layer is not laminated. Additionally, one embodiment may further include a drying step after the coating step. One embodiment may further include laminating a sealant layer fabric to the lower portion of the inner adhesive layer.

In one embodiment, the method may include a total of two winding steps or less to prevent the fabric used in each step from being nicked and/or pressed until the outer layer laminating step. Specifically, the metal fabric may be wound a total of two times or less. More specifically, the winding step may include a total of one winding step. In one embodiment, the winding step may be included after the outer adhesive layer coating step and before the outer layer fabric laminating step. For example, the winding step may be performed in step 10 of FIG. 2.

In one embodiment, the lamination step of laminating the outer layer fabric on the top of the outer adhesive layer and the step of lamination of the sealant layer fabric on the bottom of the inner adhesive layer are each a process of laminating the functional fabric to one side of the metal fabric to which the adhesive is applied, The inner side may be laminated with a sealant layer fabric to mainly stabilize the heat resistance and cold resistance of the battery, and the outer side may be laminated with an outer layer fabric for heat resistance, pinhole resistance, and abrasion resistance. In one embodiment, each of the above laminating steps may be laminating pre-prepared outer layer fabric or sealant fabric.

Between the third coating step and the lamination step, an adhesive drying step of drying the metal fabric to which the adhesive is applied to form an adhesive layer; An adhesive layer thickness measuring step of measuring the thickness of the dried adhesive layer; And it may further include an adhesive layer surface treatment step of corona treating the surface of the adhesive layer to strengthen adhesive strength.

After the lamination step, a surface inspection step of inspecting the surfaces of the sealant layer and the outer layer may be further included.

Meanwhile, in the process of transporting each fabric, in order to minimize the occurrence of foreign substances and scratches, both a tendency structure in which the substrate contact roll and shaft are operated separately and a shaft structure in which the guide roll is operated in an integrated manner can be applied. You can. While the general drive method of the guide roll transfers the rotation transmitted from the motor to the shaft-integrated guide roll and drives it at a 1:1 speed, the tension drive method separates the guide roll and the axis to mutually compensate for the rotation speed of the fine rolls. It is structured so that it can be applied to the required section.

On the other hand, the re-winder department and unwinder department (fabric supply department) can be separately configured so that they can be operated separately when a problem occurs in this part of the facility and the operation of the facility occurs. there is.

Additionally, the present disclosure may further include a maturation step as an example. The aging step is a necessary process to improve the reliability of adhesion, electrolyte resistance, and peel strength when manufacturing cell pouches, but the time required is somewhat long, so an optimal aging process is important. In terms of productivity, it is preferable to manufacture the product through only one aging process for the final structure of the cell pouch. Specifically, the method may include one maturing step. More specifically, the method may be to apply an adhesive to one side of the surface-treated metal fabric without a maturing step after the double-sided surface treatment step, and the maturing step may be included after the lamination step of the sealant layer. For example, when a maturing step is included in the double-sided surface treatment step before the lamination step, the film in the intermediate manufacturing step may be exposed to the air for a certain period of time or more, causing desorption of the non-laminated surface treatment agent. For example, if a maturation step is included in the adhesive layer forming step, some reaction of the adhesive layer may proceed and a blocking phenomenon in which the adhesive layer sticks to other layers may occur.

The first intermediate structure of the cell pouch film may be composed of an outer layer/adhesive layer/surface treatment layer/barrier layer/surface treatment layer/adhesive layer, and the second intermediate structure is an outer layer/adhesive layer/surface treatment layer/barrier layer/surface. It may have a structure of processing layers. If it is unavoidable to ripen twice, it is desirable to first ripen with the second intermediate structure and then do the second maturing with the final structure. If primary aging is performed with the first intermediate structure, problems such as problems in the manufacturing process and deterioration of physical properties may occur. More specifically, products that have undergone primary aging with the first intermediate structure may have a partial reaction of the inner adhesive layer (sealant layer side), causing a blocking phenomenon in which the inner adhesive layer sticks to the outer layer. In addition, when forming a sealant layer after primary aging, an additional process to strengthen the adhesive strength of the inner adhesive layer is required, raising concerns about decreased productivity.

Meanwhile, a suction roll can be applied to the tension control section to minimize the occurrence of foreign substances and scratches during fabric transfer, and to prevent foreign substances generated during driving from sticking to the roll and causing appearance defects (dents, scratches, etc.). A contact clean roll can be applied to remove foreign substances.

In one embodiment, the transfer of the film for the cell pouch is performed by a driving roll, and all or part of the driving roll is a suction roll. The suction roll has a plurality of holes to suck air from the surrounding surface. As the holes suck in air, the film is pulled into contact with the surrounding surface of the suction roll.

In one embodiment, the tension applied to the film for the cell pouch by the suction roll is 0.02 kgf/cm ² to 2.5 kgf/cm ² .

In one embodiment, between the double-side surface treatment step and the one-side coating step of forming an adhesive layer, the method further includes a property stabilization drying step of stabilizing the physical properties by drying the metal fabric coated on both surfaces in a floating manner, wherein the adhesive layer Between the step of coating one side and the step of lamination, an adhesive drying step of drying the metal fabric to which the adhesive is applied to form an adhesive layer is further included. The manufacturing process of the film for cell pouches according to the present invention uses a suction roll as a driving roll, so the tension is low, and the drying step is shortened, so the tensile strength of the film is low and the elongation is high, and the plate shape of the film is maintained, causing wrinkles. It also has excellent mechanical strength and formability.

Film manufacturing equipment for cell pouches

Other exemplary embodiments of the present invention include a double-sided surface treatment means including a first coater (3) and a second coater (4) for surface treating both sides of the metal fabric forming the barrier layer; A tertiary coater (7) for applying adhesive to one side of the surface-treated metal fabric; and a laminating portion (9) for laminating functional fabric to one side of the adhesive layer. It provides a film manufacturing apparatus for the cell pouch, including a.

Figure 2 is a schematic diagram of a film manufacturing apparatus for a cell pouch according to an embodiment of the present invention.

The double-sided surface treatment means may include a fabric supply unit (1), a foreign matter removal unit (2), a tension control unit, and a first coater (3) and a second coater (4). The fabric supply unit 1 unwraps and supplies the wound metal fabric. The foreign matter removal means 2 removes foreign substances present on the surface of the supplied metal fabric. The tension control unit adjusts the tension of the metal fabric from which foreign substances on the surface have been removed. The first coater 3 and the second coater 4 perform coating on both sides of the metal fabric while maintaining a constant tension.

The foreign matter removal means 2 may include a first foreign matter removal unit that removes oil by performing discharge treatment on both surfaces of the metal fabric. In addition, it may further include a pinhole inspection unit that checks whether pinholes occur on both surfaces of the metal fabric from which oil has been removed. If there is no abnormality as a result of the confirmation, it may further include a second foreign matter removal unit that removes foreign matter generated on both surfaces of the metal fabric using a roll method.

A property stabilization drying unit 5 may be formed between the double-sided surface treatment means and the tertiary coater 7 to stabilize the physical properties by drying the metal fabric coated on both surfaces by a floating method. At this time, the drying method can be an air floating method so that the coated substrate can be dried in a non-contact manner in a floating state. Through this, the double-sided coated metal fabric can be dried while minimizing contact with components such as transfer rolls. Afterwards, the dried metal fabric can be cooled by the cooling unit 6, and the surface of the cooled metal fabric can be inspected by the surface inspection unit.

An adhesive drying unit (8) between the tertiary coater (7) and the laminating unit (9), which forms an adhesive layer by drying the metal fabric to which the adhesive has been applied; It may further include an adhesive layer measuring unit that measures the thickness of the dried adhesive layer; and an adhesive layer surface treatment unit that corona-treats the surface of the adhesive layer to strengthen the adhesive force.

Following the laminating part 9, a surface inspection part that inspects the surfaces of the sealant layer and the outer layer may be further included.

A film for a cell pouch, such as the second intermediate structure, can be manufactured using the manufacturing device shown in FIG. 1. A fourth coater (not shown) and a drying unit (not shown) that apply adhesive to the other side of the surface-treated metal fabric between the laminating unit (9) and the final winding unit (End, ^2nd Re-wind) in FIG. 1 ), functional layer lamination section (not shown), extrusion section (including co-extrusion) (not shown), etc. may be added as needed.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments so that those skilled in the art can easily practice it. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

{Example}

<Manufacturing example> Manufacture of film for cell pouch

1. Example 1

Both sides of the stainless steel foil metal fabric forming the barrier layer were surface treated with first and second coatings. Next, the metal fabric with both surfaces coated was dried using a floating method to stabilize the physical properties. Next, the dried metal fabric was cooled, and a urethane-based adhesive was applied to one side of the surface-treated metal fabric using a tertiary coater to form an adhesive layer. Next, a previously prepared PET/nylon film was laminated on one side of the adhesive layer to form an outer layer. An adhesive was applied to the other side of the surface-treated metal fabric, and non-stretched polypropylene films were laminated to form a sealant layer, thereby producing a film for a cell pouch and winding it. A suction roll was applied as a driving roll.

2. Example 2

A film according to Example 2 was prepared in the same manner as Example 1, except that a nip roll was used as a driving roll.

3. Comparative Examples 1 and 2

One side of the stainless steel foil metal fabric forming the barrier layer was first coated and surface treated, dried, and then wound. The other side of the stainless steel foil metal fabric forming the barrier layer was surface treated with a second coating, dried, and then wound. A urethane-based adhesive was coated on one side of the stainless steel foil metal fabric with both surfaces treated, dried, and then pre-prepared PET/nylon film was laminated to form an outer layer and wound. Afterwards, the inner layer adhesive was coated and dried, and then the inner layer (silint film) was laminated and wound.

In Comparative Example 1, a suction roll was applied as a driving roll, and in Comparative Example 2, a nip roll was applied as a driving roll.

<Experimental Example 1> Evaluation of tensile strength of film

The tensile strength of the cell pouch film prepared in the manufacturing example was evaluated. More specifically, the film was cut using a specimen cutter to prepare specimens of 130 mm × 15 mm in the longitudinal direction (MD) and transverse direction (TD). The tensile strength of the manufactured specimen was measured using a UTM (manufacturer: INSTRON) universal testing machine in accordance with ASTM D638 under the conditions of a stretching speed of 50 mm/min and a distance between grips of 50 mm.

The results are shown in Table 1.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Tensile Strength (kgf/cm ² ) 27 32 35 37

From Table 1, it can be seen that the film for cell pouches according to the present invention has excellent mechanical strength.

<Experimental Example 2> Evaluation of wave height and wrinkles of film

The shape and wave height of the cell pouch film prepared in the manufacturing example were evaluated. The wave height was measured from the bottom to the curved part of the film when the film was placed on a flat floor (◎: very good, ○: good, △: severe).

The results are shown in Table 2 below.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 wave height (mm) One 2 4 5 wrinkle ◎ ○ △ △

From Table 2, it can be seen that the plate shape is maintained in the case of the film for cell pouch according to the present invention.

<Experimental Example 3> Ratio evaluation of shape, flatness, and waveform of the film

The shape, flatness, and waviness ratio of the cell pouch film prepared in the manufacturing example were evaluated (SPEC <10 mm). The results are shown in Table 3, Figures 3a, 3b, 4a, and 4b below. Figures 3a and 3b are photographs showing the shape of a film for a cell pouch according to an embodiment of the present invention (Examples 1 and 2, respectively). Figures 4a and 4b are photographs showing the shape of the film for a cell pouch according to a comparative example (Comparative Examples 1 and 2, respectively).

Plane/Waveform Example 1 Example 2 Comparative Example 1 Comparative Example 2 1P 2.0 One 13.5 8 2P 1.5 1.5 7 28 3P - 2.5 1.5 7 4P - 2 3.5 -

From Table 3, FIGS. 3A, 3B, 4A, and 4B, it can be seen that the film for cell pouch according to the present invention maintains the plate shape and does not generate wrinkles.

<Experimental Example 4> Evaluation of formability and wrinkles of film

The formability of the cell pouch film prepared in the manufacturing example was evaluated. More specifically, the formability was evaluated by measuring the critical depth at which the metal layer does not break after forming at each depth using a molding machine and a test mold under conditions of 23 ± 2°C and 50 ± 10%. The test mold size was 30 mm × 75 mm, and the film was cut to 150 mm × 200 mm. After molding using the above method, the degree of wrinkles was observed with the naked eye (◎: very good, ○: good, △: severe).

The results are shown in Table 4 below.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Formability (mm) 3.0 2.7 2.5 2.3 wrinkle ◎ ○ △ △

From Table 4, it can be seen that the film for cell pouches according to the present invention has the best formability and wrinkles.

Although exemplary embodiments of the present invention have been described above in relation to the above-mentioned preferred embodiments, various modifications and variations can be made without departing from the gist and scope of the invention. Accordingly, the appended claims will include such modifications and variations as long as they fall within the spirit of the present invention.

1: Fabric supply unit 2: Foreign matter removal means
3: Primary coater 4: Secondary coater
5: Physical property stabilization drying section 6: Cooling section
7: Tertiary coater 8: Adhesive drying unit
9: Laminating part 10: Final winding part
100: outer layer 200: outer adhesive layer
300: barrier layer 310: surface treatment layer
320: Metal layer 330: Surface treatment layer
400: inner adhesive layer 500: sealant layer

Claims (10)

A barrier layer made of stainless steel (Stainless Use Steel, SUS) or its alloy and surface treated on both sides; Adhesive layers formed on both sides of the barrier layer; And a functional fabric layer formed on both sides of the adhesive layer,
The tensile strength is 25 kgf/cm ² to 34 kgf/cm ² ,
Film for cell pouches with a wave height of 3 mm or less. According to paragraph 1,
The functional fabric layer formed on one side of the adhesive layer is an outer layer made of synthetic resin fabric,
A film for a cell pouch, wherein the functional fabric layer formed on the other side of the adhesive layer is a sealant layer made of sealant fabric. According to paragraph 1,
A film for a cell pouch having a moldability of 2.6 mm to 3.5 mm. According to paragraph 2,
The outer layer includes one or more resins selected from the group consisting of polyethylene terephthalate resin and nylon resin,
The sealant layer is a cell pouch comprising at least one polyolefin resin selected from the group consisting of polypropylene, low-density polyethylene, linear low-density polyethylene, very low-density polyethylene, medium-density polyethylene, high-density polyethylene, polybutene, and ethylene/propylene copolymer. film. A cell pouch comprising the cell pouch film of any one of claims 1 to 4. A double-sided surface treatment step of surface treating both sides of the metal fabric forming the barrier layer;
A one-side coating step of forming an adhesive layer by applying an adhesive to one side of the surface-treated metal fabric; and
The method of manufacturing a film for a cell pouch according to any one of claims 1 to 4, comprising a laminating step of laminating functional fabric to one side of the adhesive layer to form a functional fabric layer. According to clause 6,
A method of manufacturing a film for a cell pouch, wherein the transfer of the film for a cell pouch is performed by a driving roll, and all or part of the driving roll is a suction roll. In clause 7,
The tension applied to the film for a cell pouch by the suction roll is 0.02 kgf/cm ² to 2.5 kgf/cm ² , a method of manufacturing a film for a cell pouch. According to clause 6,
Between the double-sided surface treatment step and the one-side coating step for forming an adhesive layer, a physical property stabilization drying step of stabilizing the physical properties by drying the metal fabric coated on both surfaces in a floating manner is further included,
A method of manufacturing a film for a cell pouch further comprising an adhesive drying step of drying a metal fabric to which the adhesive is applied to form an adhesive layer between the one-side coating step and the lamination step of forming the adhesive layer.
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