KR20240002226A - Aluminium pouch film for the secondary battery and the manufacturing method thereof - Google Patents

Abstract

The present invention relates to an aluminum layer; an internal resin layer laminated on the first surface of the aluminum layer; an external resin layer laminated on the second surface of the aluminum layer; An outermost layer laminated on one side of the outer resin layer; and a heat dissipation layer laminated on one surface of the outermost layer, wherein the heat dissipation layer includes a pattern composed of concave portions and convex portions. The present invention relates to an aluminum pouch film for secondary batteries and a method of manufacturing the same.

Description

Aluminum pouch film for secondary batteries and manufacturing method thereof {ALUMINIUM POUCH FILM FOR THE SECONDARY BATTERY AND THE MANUFACTURING METHOD THEREOF}

The present invention relates to an aluminum pouch film for secondary batteries and a manufacturing method thereof, and more specifically, to an aluminum pouch film for secondary batteries with improved heat dissipation characteristics compared to conventionally used pouch films, and a manufacturing method thereof.

Secondary batteries, which are electrochemical devices recently used to supply power to various electronic and electrical products, usually refer to lithium secondary batteries, which are batteries that have a polymer electrolyte and generate current through the movement of lithium ions. A pouch film made by laminating polymer and metal is used as an exterior packaging material to protect secondary batteries. This pouch film for secondary batteries protects the battery cells, which are composed of the electrode assembly and the electrolyte filled inside through subsequent processes, and is composed of an aluminum thin film interposed in order to stably maintain the electrochemical properties of the cell. In order to protect the battery cell from external shock, polyethylene terephthalate (PET) resin, nylon film, etc. are formed as an external resin layer on the aluminum thin film.

That is, the pouch film generally consists of an outer layer, a metal barrier layer, and an inner layer. Typically, the outer layer or outermost layer is made of nylon or a mixed material of nylon and polyethylene terephthalate (PET), oriented polypropylene (OPP), polyethylene, etc. The required properties of this outer layer or outermost layer include heat resistance, pinhole resistance, chemical resistance, moldability, and insulation.

The metal barrier layer requires formability as well as barrier properties against water vapor and other gases. In this respect, moldable metals such as aluminum (Al), iron (Fe), copper (Cu), and nickel (Ni) are used in the barrier layer, and aluminum is currently used the most.

The inner layer requires electrolyte resistance and insulation resistance in that it is a layer in contact with an electrolyte solution along with thermal adhesiveness and moldability, and polypropylene (PP) and polyethylene (PE) are generally used.

Meanwhile, in recent years, various electronic products such as laptops and mobile phones are progressing at a remarkable pace in terms of performance and miniaturization. With the increase in performance and miniaturization of electronic products, the battery components built therein are becoming larger in capacity and highly integrated, and as a result, electronic products are generating a lot of heat.

In particular, the application field of lithium-ion batteries is expanding from small-sized to medium-to-large vehicles such as automobiles, and the problem of heat generation due to the larger size and higher performance of pouch-type batteries used in electric vehicles (EV) and energy storage systems (ESS) is increasingly emerging. It's a situation. Heat generated from the battery can shorten the lifespan of the product, cause breakdown or malfunction, and in severe cases, it can cause explosion or fire. For example, in NCM-based lithium-ion batteries, it is predicted that thermal runaway will occur within 35-50 minutes if the surface temperature is increased at a rate of 4-7°C/min.

As the outer layer of the existing pouch film is coated with a polymer material with low thermal conductivity, there is a problem in that it is difficult to effectively cool the overall temperature of the battery. In order to overcome this, research is needed on the outer layer that ensures stability in use by controlling the surface temperature of the pouch-type secondary battery or releasing internal heat.

Republic of Korea Patent Publication No. 10-2001-7010231 (November 15, 2001), “Packaging materials for polymer batteries and manufacturing method thereof”

The present invention is intended to solve the above problems, and has the heat dissipation function of a pouch-type secondary battery, and can increase the stability of use against the risk of fire or explosion by maintaining the temperature of the battery surface even against internal and external heat sources. The purpose is to provide an aluminum pouch film for secondary batteries and a method for manufacturing the same.

According to a first aspect of the present invention, an aluminum layer; an internal resin layer laminated on the first surface of the aluminum layer; an external resin layer laminated on the second surface of the aluminum layer; An outermost layer laminated on one side of the outer resin layer; and a heat dissipation layer laminated on one surface of the outermost layer, wherein the heat dissipation layer includes a pattern composed of concave portions and convex portions.

In addition, the heat dissipation layer provides an aluminum pouch film for secondary batteries including a pattern consisting of concave portions and convex portions on one or both sides in the direction in which the heat dissipation layer is adhered to the outermost layer.

In addition, an aluminum pouch film for a secondary battery is provided wherein the ratio of the height (a) of the convex portions and the separation distance (b) between the convex portions is 1:1 to 1:10.

In addition, an aluminum pouch film for secondary batteries is provided in which the height of the convex portion is 1% to 80% based on the thickness of the heat dissipation layer.

In addition, when the heat dissipation layer includes a pattern consisting of concave portions and convex portions on both sides, an aluminum pouch film for secondary batteries is provided in which the positions of the convex portions face each other symmetrically.

In addition, the pattern provides an aluminum pouch film for secondary batteries in which any one of a triangular shape, a square shape, a semicircular shape, an elliptical shape, and a polygonal shape is selected in cross-section.

In addition, the pattern is selected from the group consisting of a stripe pattern, a lattice pattern, a honeycomb pattern, a cross pattern, a dot pattern, a diamond pattern, and a diagonal pattern on a plane. Provided is an aluminum pouch film for secondary batteries containing one or more types.

In addition, the heat dissipation layer provides an aluminum pouch film for secondary batteries in which any one is selected from the group consisting of iron (Fe)-based alloy, aluminum (Al)-based alloy, and copper (Cu)-based alloy.

The aluminum pouch film for secondary batteries according to the present invention can maintain or reduce the temperature of the surface of the pouch-type secondary battery despite internal and external heat sources due to the heat dissipation layer including various patterns.

In addition, by using the aluminum pouch film for secondary batteries according to the present invention, the use stability of pouch-type secondary batteries against fire or explosion can be increased and the resulting social costs can be reduced.

1 to 3 show the structure of an aluminum pouch film for secondary batteries according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the implementation examples described herein. Additionally, in the drawings, the same reference numbers refer to the same components, and the size or thickness of each component may be exaggerated for convenience of explanation.

In this specification, when a member is said to be located “on” another member, this includes not only the case where a member is in contact with another member, but also the case where another member exists between the two members.

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

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

The present invention provides an aluminum pouch film for secondary batteries.

Figure 1 shows the structure of an aluminum pouch film for secondary batteries according to an embodiment of the present invention.

Hereinafter, each configuration of the aluminum pouch film for secondary batteries of the present invention will be described in detail.

Aluminum layer (10)

In the film for secondary battery packaging of the present invention, the material of the metal thin film used as a barrier layer to prevent penetration of oxygen or moisture, etc. from the outside, is preferably aluminum or an aluminum alloy. Aluminum alloys include alloys made by adding various metals and non-metals to pure aluminum or stainless steel alloys. The aluminum layer is preferably made of soft aluminum foil, and more preferably, aluminum foil containing iron is used to provide formability to the aluminum foil. Since the aluminum foil series with high purity has excellent processability, aluminum alloy foil of the 1000 or 8000 series is preferable. Additionally, the aluminum substrate optionally includes silicon, boron, germanium, arsenic, antimony, copper, magnesium, manganese, zinc, lithium, iron, chromium, vanadium, titanium, bismuth, potassium, tin, lead, zirconium, nickel, cobalt and It may be an alloy containing elements selected from the group consisting of combinations thereof. In the aluminum foil containing iron, it may preferably contain 0.1 to 9.0 mass%, and more preferably 0.5 to 2.0 mass%, based on 100 mass% of the total aluminum foil. If the iron content of the aluminum foil is less than 0.1% by mass, the ductility of the aluminum layer decreases, and if the iron content of the aluminum foil exceeds 9.0% by mass, the problem of poor formability occurs. The surface of the aluminum foil used in the aluminum layer can be etched or degreased to improve adhesion to the internal resin layer, but this can be omitted to reduce process speed. The aluminum layer is intended to prevent gas and water vapor from penetrating into the interior of the battery from the outside, and it is necessary for the aluminum thin film to be free of pinholes and processability (pouching, embossing). The thickness is preferably 10 to 100 ㎛, more preferably 30 to 50 ㎛, considering processability, oxygen and moisture barrier properties, etc. If the above range is not satisfied, if it is less than 10 ㎛, it is easily torn and electrolytic resistance and insulation properties are poor, and if it exceeds 50 ㎛, there is a problem of poor formability.

Internal resin layer (20)

In the aluminum pouch film for secondary batteries of the present invention, polyolefins such as polyethylene (PE) or polypropylene (PP) or copolymers thereof can be used as the inner resin layer. The inner resin layer is not particularly limited thereto, and may include, in addition to polyolefins such as polyethylene, polypropylene, and polybutylene, ethylene copolymer, propylene copolymer, polyester, polyamide, polycarbonate, fluorine, silicone, acrylic, It consists of a resin layer selected from the group consisting of ethylene-propylene-diene-monomer rubber (EPDM) and mixtures thereof. Preferably, a polyolefin-based resin layer or a mixed resin layer of polybutadiene and polyolefin can be used.

Specific examples of the polyolefin used above include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; Polypropylenes such as homopolypropylene, block copolymers of polypropylene (for example, block copolymers of propylene and ethylene), and random copolymers of polypropylene (for example, random copolymers of propylene and ethylene); terpolymer of ethylene-butene-propylene; etc. can be mentioned. Among these polyolefins, polyethylene and polypropylene are preferred.

When polyolefins such as polyethylene or polypropylene or copolymers thereof are used in the inner resin layer, not only do they have the physical properties required for packaging materials for secondary batteries, such as good heat sealing, moisture resistance, and heat resistance, but they also have good processability such as lamination. Therefore, it is desirable. The thickness of the polymer layer of the internal resin layer is preferably 20 to 100 ㎛, more preferably 30 to 80 ㎛, considering moldability, insulation, and electrolyte resistance. If the above range is not satisfied, problems such as poor formability, insulation, and electrolyte resistance may occur.

Outer resin layer (30) and outermost layer (40)

In the aluminum pouch film for secondary batteries of the present invention, the outer resin layer or outermost layer corresponds to the area in direct contact with the hardware, so it is preferably a resin with insulating properties. Therefore, the resin used as the outer resin layer is polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolyester, polycarbonate, or polyamide resin. It is desirable to do so.

Polyester resins specifically include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), copolymerized polyester, polycarbonate (PC), etc. can be mentioned. In addition, as polyester, specifically, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyester with ethylene terephthalate as the main repeating unit. , copolymerized polyester with butylene terephthalate as the main repeating unit, and the like. In addition, copolymerized polyester with ethylene terephthalate as the main repeating unit, specifically, copolymer polyester polymerized with ethylene isophthalate with ethylene terephthalate as the main repeating unit, polyethylene (terephthalate/isophthalate), Polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate), polyethylene (terephthalate/sodium sulfoisophthalate) decanedicarboxylate) and the like. In addition, copolymerized polyester with butylene terephthalate as the main repeating unit, specifically, copolymer polyester with butylene terephthalate as the main repeating unit and polymerized with butylene isophthalate, polybutylene (terephthalate) / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate, etc. The above polyester may be used alone or in combination of two or more types.

Polyamide resins specifically include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; Hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid and T represents terephthalic acid) containing structural units derived from terephthalic acid and/or isophthalic acid. , polyamide containing aromatics such as polymethoxylene adipamide (MXD6); Alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); In addition, polyamides that are copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane-diisocyanate, and polyesteramide copolymers or polyethers that are copolymers of copolymerized polyamide and polyester or polyalkylene ether glycol. esteramide copolymer; These copolymers, etc. can be mentioned. The above polyamides may be used individually or in combination of two or more types.

In the outer resin layer as described above, it is particularly desirable to use a nylon film as a packaging film for secondary batteries. The nylon film not only has excellent bursting strength, pinhole resistance, and gas barrier properties, but also has excellent heat resistance, cold resistance, and mechanical strength, so it is mainly used as a packaging film. Specific examples of the nylon film include polyamide resins, such as nylon 6, nylon 66, copolymers of nylon 6 and nylon 66, nylon 610, and polymethoxysilene amidipamide (MXD6). When laminating the outer resin layer, the thickness of the laminated outer resin layer is preferably 10 to 30 ㎛ or more, and particularly preferably 12 to 25 ㎛. If the above range is not satisfied, if it is less than 10 ㎛, the physical properties are poor and easily torn, and if it exceeds 30 ㎛, there is a problem in that the moldability is poor.

Heat dissipation layer (50)

The heat dissipation layer 50 of the aluminum pouch film for secondary batteries according to the present invention emits heat sources inside or outside the battery, maintaining or reducing the surface temperature of the pouch-type secondary battery, thereby increasing the safety of the secondary battery from the risk of fire and explosion. and can improve the problem of surface temperature control of secondary batteries.

Figure 2 shows various patterns of the heat dissipation layer of an aluminum pouch film for secondary batteries according to an embodiment of the present invention.

The heat dissipation layer according to an embodiment of the present invention may include a specific pattern on one side. The specific pattern is a nano-scale fine pattern, and the surface on which the pattern is formed has a larger surface area than when it is flat, so it is more effective in dissipating heat.

The specific pattern is capable of fine structural shapes ranging from 0.01 μm to 10 mm. The pattern forming method may be formed using screen printing, photolithography, nanotransfer printing (NTP), etc., but is not limited thereto.

The heat dissipation layer 50 may include a pattern consisting of concave portions and convex portions.

When viewed in cross section (a cross section cut perpendicular to the longitudinal direction of the pattern), the pattern included in the heat dissipation layer 50 may be formed as any one of the group consisting of a triangular shape, a square shape, a semicircular shape, an elliptical shape, and a polygonal shape. there is. Accordingly, the pattern may have continuous irregularities such as triangular, square, semicircular, oval, or polygonal cross sections along the length direction.

In addition, the pattern included in the heat dissipation layer 50 is, when viewed in plan, a stripe pattern, a lattice pattern, a honeycomb pattern, a cross pattern, a dot pattern, and a diamond pattern. It may be formed as a pattern, a diagonal pattern, or a combination thereof.

The pattern included in the heat dissipation layer 50 may be formed by repeating concave portions and convex portions. Areas with higher relative heights are convex portions, and areas with lower relative heights are concave portions. Additionally, a first area where the depth from the highest point of the pattern is less than a predetermined value may be defined as a convex part, and a second area where the depth from the highest point of the pattern is greater than a predetermined value may be defined as a concave part.

The ratio of the height (a) of the convex portion and the separation distance (b) between the convex portions (i.e., the width of the concave portion) may be 1:1 to 1:10. Specifically, the ratio of the height (a) of the convex portions and the separation distance (b) between the convex portions is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7. , 1:8, 1:9 or 1:10. When a pattern is formed in which the ratio of the height (a) of the convex parts and the distance (b) between the convex parts satisfies the range of 1:4 to 1:6, thermal dissipation is most effective.

The height of the convex portion may be 1% to 80% based on the thickness of the heat dissipation layer. Specifically, the height of the convex portion is 1% or more, 5% or more, 10% or more, 15% or more, 20% or more, 25% or more, or 80% or less, 75% or less, or 70% or less, based on the thickness of the heat dissipation layer. It may be 65% or less, 60% or less, 55% or less, and 50% or less.

The heat dissipation layer 50 may have a pattern formed on one or both sides in the direction in which it is adhered to the outermost layer. Since the surface on which the pattern is formed has a larger surface area than the flat surface, it is efficient in absorbing or dissipating heat generated inside and outside the battery.

Additionally, when a pattern consisting of concave portions and convex portions is formed on both sides of the heat dissipation layer 50 in the direction in which it is adhered to the outermost layer, the convex portions may be structured so that the positions of the convex portions face each other symmetrically. When the positions of the convex portions are in the same direction on both sides of the heat dissipation layer, it is more effective in absorbing or emitting heat generated inside and outside the battery.

The heat dissipation layer 50 may be selected from the group consisting of iron (Fe)-based alloy, aluminum (Al)-based alloy, and copper (Cu)-based alloy.

The thickness of the heat dissipation layer 50 may be 1 to 40 ㎛. Specifically, the thickness of the heat dissipation layer is 1 ㎛ or more, 2 ㎛ or more, 3 ㎛ or more, 4 ㎛ or more, 5 ㎛ or more, 6 ㎛ or more, 7 ㎛ or more, 8 ㎛ or more, 9 ㎛ or more, 10 ㎛ or more, or It may be 40 ㎛ or less, 39 ㎛ or less, 38 ㎛ or less, 37 ㎛ or less, 36 ㎛ or less, 35 ㎛ or less, 34 ㎛ or less, 33 ㎛ or less, 32 ㎛ or less, 31 ㎛ or less, and 30 ㎛ or less.

First adhesive layer (100)

As shown in Figure 3, the first adhesive layer 100 is a layer that increases adhesion between the internal resin layer 20 and the aluminum foil layer 10.

In the aluminum pouch film for secondary batteries of the present invention, polyurethane, acid-modified polyolefin resin, or epoxy can be used as the first adhesive layer. A specific example of the first adhesive may be maleic anhydride polypropylene (MAHPP).

Examples of the heat-adhesive olefin resin include polyethylene, ethylene-α-olefin copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid ester copolymer, Examples include ethylene-vinyl acetate copolymer, ionomers, polypropylene, maleic anhydride modified polypropylene, ethylene-propylene copolymer, and propylene-1-butene-ethylene copolymer, with polypropylene and ethylene being preferred. -It may contain at least one type of olefin resin selected from the group consisting of propylene copolymer and propylene-1-butene-ethylene copolymer.

The acid-modified polyolefin used to form the first adhesive layer is a polymer modified by graft polymerization of polyolefin with an unsaturated carboxylic acid. Specific examples of acid-modified polyolefin include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; Crystalline or amorphous copolymers such as homo polypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene), etc. polypropylene; and terpolymers of ethylene-butene-propylene. Among these polyolefins, from the viewpoint of heat resistance, polyolefins having at least propylene as a constituent monomer are preferred, and more preferably, terpolymers of ethylene-butene-propylene and random copolymers of propylene-ethylene are used. Examples of unsaturated carboxylic acids used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic acid anhydride. Among these unsaturated carboxylic acids, maleic acid and maleic anhydride are preferred. Acid-modified polyolefin may be used individually, or may be used in combination of two or more types.

The first adhesive layer is preferably 2 to 10 ㎛, more preferably 3 to 5 ㎛, considering adhesiveness with the internal resin layer and thickness after molding. If the above range is not met, if it is less than 2 ㎛, adhesiveness may be poor, and if it exceeds 5 ㎛, problems such as cracks may occur.

When laminating the internal resin layer 20 and the aluminum layer 10 on the first adhesive layer 100, there is no particular limitation, but preferably they are laminated using a dry lamination method, a heat lamination method, or an extrusion lamination method. You can.

Second adhesive layer (200)

The second adhesive layer is a layer that increases adhesion between the external resin layer 30 and the aluminum foil layer 10. The adhesive layer is formed of an adhesive resin capable of bonding the base material layer and the metal layer. The adhesive resin used to form the adhesive layer may be a two-component curing type adhesive resin, or may be a one-component curing type adhesive resin. Additionally, the bonding mechanism of the adhesive resin used to form the adhesive layer is not particularly limited, and may be any of the chemical reaction type, solvent volatilization type, heat melt type, and heat pressure type.

Resin components of the adhesive resin that can be used to form the adhesive layer specifically include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolyester, etc. polyester resin; polyether adhesive; polyurethane-based adhesive; Epoxy resin; Phenolic resin-based resin; Polyamide resins such as nylon 6, nylon 66, nylon 12, and copolyamide; Polyolefin-based resins such as polyolefin, acid-modified polyolefin, and metal-modified polyolefin; polyvinyl acetate-based resin; Cellulose-based adhesive; (meth)acrylic resin; polyimide resin; Amino resins such as urea resin and melamine resin; Rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; Silicone-based resin; and fluorinated ethylene propylene copolymer. These adhesive resin components may be used individually, or two or more types may be used in combination.

There is no particular limitation on the form of combination of two or more types of adhesive resin components, but examples of the adhesive resin component include a mixed resin of polyamide and acid-modified polyolefin, a mixed resin of polyamide and metal-modified polyolefin, and polyamide. and polyester, a mixed resin of polyester and acid-modified polyolefin, and a mixed resin of polyester and metal-modified polyolefin. Among these, it is excellent in malleability, durability and anti-fading action under high humidity conditions, anti-deterioration action during heat sealing, etc., and effectively suppresses the occurrence of delamination by suppressing a decrease in the lamination strength between the base material layer and the metal layer. , preferably a polyurethane-based two-component curable adhesive resin; Examples include polyamide, polyester, and blended resins of these and modified polyolefin.

The second adhesive layer is a layer that increases adhesion between the base layer and the aluminum thin layer.

The second adhesive layer can be formed using a material known as an adhesive used for laminating a resin film and aluminum foil. Examples of the adhesive include polyurethane-based adhesives containing a base material containing polyols such as polyester polyol, polyether polyol, acrylic polyol, and carbonate polyol, and a curing agent containing a bifunctional or higher isocyanate compound. . A polyurethane-based resin is formed by causing the curing agent to act on the main body.

First, polyol may be mentioned as a component of the adhesive.

Examples of polyol compounds used in urethane-type adhesives include polyester polyol, polyester polyurethane polyol, polyether polyol, and polyether polyurethane polyol. The hydroxyl equivalent and weight average molecular weight of these polyol compounds are not particularly limited as long as they ultimately satisfy the above physical properties in relation to the isocyanate-based compound to be combined, but are preferably, for example, 0.5 to 2.5 as the hydroxyl equivalent (piece/mol). Examples include 0.7 to 1.9, and the weight average molecular weight is 500 to 120,000, preferably 1,000 to 80,000. Among these polyol compounds, polyester polyol, polyester polyurethane polyol, and polyether polyurethane polyol are preferred. These polyol compounds may be used individually, or may be used in combination of two or more types.

As the polyester polyol, it is possible to use a material obtained by reacting at least one type of polybasic acid with at least one type of diol. Polybasic acids include aliphatic dibasic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and brassylic acid, and aromatic dibasic acids such as isophthalic acid, terephthalic acid, and naphthalene dicarboxylic acid. Dibasic acids, such as kiacic acid, can be mentioned. Examples of diols include aliphatic diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methyl pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and dodecanediol, cyclohexanediol, and hydrogenated diols. Alicyclic diols such as silylene glycol, aromatic diols such as xylylene glycol, etc. are mentioned.

In addition, as a polyester polyol, the hydroxyl groups at both ends of the polyester polyol are chain-extended using a single isocyanate compound or an adduct body, biuret body, or isocyanurate body containing at least one isocyanate compound. Ester urethane polyol, etc. can be mentioned. Isocyanate compounds include, for example, 2,4- or 2,6-tolylene diisocyanate, xylylene isocyanate, 4,4'-diphenylmethane diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate , isopropylidene dicyclohexyl-4,4'-diisocyanate, etc.

Examples of acrylic polyol include copolymers containing poly(meth)acrylic acid as a main component. The copolymer includes hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate, and includes methyl, ethyl, n-propyl, and i-propyl groups as alkyl groups. , n-butyl group, i-butyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group alkyl (meth)acrylate monomer, or (meth)acrylamide, N-alkyl (meth)acryl Amide, N,N-dialkyl (meth)acrylamide (alkyl groups include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, 2-ethylhexyl group) actual group, cyclohexyl group, etc.), N-alkoxy (meth)acrylamide, N,N-dialkoxy (meth)acrylamide (alkoxy groups include methoxy group, ethoxy group, butoxy group, isobutoxy group, etc.), N- Amide group-containing monomers such as methylol (meth)acrylamide and N-phenyl (meth)acryl amide, glycidyl group-containing monomers such as glycidyl (meth)acrylate and allyl glycidyl ether, (meth)acryloxy Examples include materials obtained by copolymerizing silane-containing monomers such as propyl trimethoxysilane and (meth)acryloxypropyl triethoxysilane, and isocyanate group-containing monomers such as (meth)acryloxypropyl isocyanate.

As the carbonate polyol, it is possible to use a material obtained by reacting a carbonate compound with a diol. As the carbonate compound, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, etc. can be used. Examples of the diol include aliphatic diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and dodecanediol, cyclohexanediol, and hydrogenated diols. Alicyclic diols such as silylene glycol, aromatic diols such as xylylene glycol, etc. can be used.

Additionally, it is possible to use a polycarbonate urethane polyol in which the terminal hydroxyl group of the carbonate polyol is chain-extended with the above-mentioned isocyanate compound.

Next, isocyanate may be mentioned as a component of the adhesive.

Isocyanate-based compounds used in the urethane-type adhesive include, for example, polyisocyanate, its adduct form, its isocyanurate-modified form, its carbodiimide-modified form, its allophanate-modified form, its biuret-modified form, etc. can be mentioned. Specifically, the polyisocyanate includes diphenylmethane diisocyanate (MDI), polyphenylmethane diisocyanate (polymeric MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and bis(4-isocyanatecyclohexyl). ) Methane (H12MDI), isophorone diisocyanate (IPDI), 1,5-naphthalene diisocyanate (1,5-NDI), 3,3'-dimethyl-4,4'-diphenylene diisocyanate (TODI), xylene Aromatic diisocyanates such as diisocyanate (XDI); Aliphatic diisocyanates such as trimethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and isophorone diisocyanate; and alicyclic diisocyanates such as 4,4'-methylenebis(cyclohexylisocyanate) and isophorone diisocyanate. Specific examples of the adduct include those obtained by adding trimethylolpropane, glycol, etc. to the polyisocyanate. Among these isocyanate-based compounds, polyisocyanate and its adduct body are preferred; More preferably aromatic diisocyanate, its adduct form, and its isocyanurate modified form; More preferably, MDI, polymeric MDI, TDI, adduct forms thereof, and isocyanurate modified forms thereof; Particularly preferable examples include the adduct form of MDI, the adduct form of TDI, polymeric MDI, and the isocyanurate modified form of TDI. These isocyanate-based compounds may be used individually or in combination of two or more types.

As the bifunctional or higher isocyanate compound used as the curing agent, it is possible to use isocyanate compounds of the type used as the chain extender, and although repeated, 2,4- or 2,6-tolylene diisocyanate, xylylene isocyanate, 4 ,4'-diphenylmethane diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate , methylcyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, or a single isocyanate compound selected from the above. An adduct form, a biuret form, and an isocyanurate form containing at least one type of isocyanate compound selected from isocyanate compounds can be mentioned.

The amount of the curing agent to be added is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass, per 100 parts by mass of the main agent. If it is less than 1 part by mass, there is a risk that performance may not be achieved in terms of adhesion and electrolyte resistance. If it is more than 100 parts by mass, excess isocyanate groups will be present, and there is a risk that residual unreacted substances may affect the adhesive film quality or hardness.

It is also possible to mix a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, etc. into the polyurethane adhesive to promote adhesion.

Examples of carbodiimide compounds include N,N'-di-o-toluyl carbodiimide, N,N'-diphenyl carbodiimide, N,N'-di-2,6-dimethylphenyl carbodiimide, N ,N'-bis(2,6-diisopropylphenyl)carbodiimide, N,N'-dioctyldecyl carbodiimide, N-triyl-N'-cyclohexyl carbodiimide, N,N'- di-2,2-di-t-butylphenyl carbodiimide, N-triyl-N'-phenyl carbodiimide, N,N'-di-p-nitrophenyl carbodiimide, N,N'-di -p-aminophenyl carbodiimide, N,N'-di-p-hydroxyphenyl carbodiimide, N,N'-di-cyclohexyl carbodiimide and N,N'-di-p-toluyl carbodiimide. Bodiimide, etc. can be mentioned.

Examples of oxazoline compounds include 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, and 2,4-diphenyl-2-oxazoline. Monooxazoline compounds such as 2,2'-(1,3-phenylene)-bis(2-oxazoline), 2,2'-(1,2-ethylene)-bis(2-oxazoline), Dioxazoline compounds such as 2,2'-(1,4-butylene)-bis(2-oxazoline) and 2,2'-(1,4-phenylene)-bis(2-oxazoline) I can hear it.

Examples of epoxy compounds include 1,6-hexanediol, neopentyl glycol, diglycidyl ethers of aliphatic diols such as polyalkylene glycol, sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, and trimethylolpropane. Polyglycidyl ethers of aliphatic polyols such as polyglycidyl ethers of alicyclic polyols such as cyclohexane dimethanol, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, trimellitic acid, adipic acid, sebacic acid, etc. Diglycidyl ester or polyglycidyl ester of aliphatic or aromatic polyhydric carboxylic acid, resorcinol, bis-(p-hydroxyphenyl)methane, 2,2-bis-(p-hydroxyphenyl)propane , diglycidyl ether or polyglycidyl ether of polyhydric phenol such as tris-(p-hydroxyphenyl)methane, 1,1,2,2-tetrakis(p-hydroxyphenyl)ethane, N,N N- of amines such as '-diglycidylaniline, N,N,N-diglycidyltoluidine, N,N,N',N'-tetraglycidyl-bis-(p-aminophenyl)methane, etc. Glycidyl derivatives, triglycidyl derivatives of aminophenol, triglycidyltris(2-hydroxyethyl)isocyanurate, triglycidyl isocyanurate, ortho cresol type epoxy, phenol novolac type epoxy resin, etc. can be mentioned.

Examples of phosphorus-based compounds include tris(2,4-di-t-butylphenyl)phosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene phosphonite, and bis(2). ,4-di-t-butylphenyl)pentaerythritol-di-phosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol-di-phosphite, 2,2-methylene bis (4,6-di-t-butylphenyl)octyl phosphite, 4,4'-butylidene-bis(3-methyl-6-t-butylphenyl-di-tridecyl)phosphite, 1,1, 3-tris(2-methyl-4-ditridecyl phosphite-5-t-butyl-phenyl)butane, tris(mixed mono- and di-nonylphenyl)phosphite, tris(nonylphenyl)phosphite, 4, 4'-isopropylidene bis(phenyl-dialkyl phosphite), etc. can be mentioned.

As silane coupling agents, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, and γ-glycidoxypropyltrimethoxysilane. , γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyl trimethoxy It is possible to use various silane coupling agents such as silane, γ-aminopropyltriethoxysilane, and N-β(aminoethyl)-γ-aminopropyltrimethoxysilane.

The adhesive used to form an adhesive layer that satisfies the physical properties of the packaging film for secondary batteries of the present invention is preferably at least selected from the group consisting of polyester polyol, polyester polyurethane polyol, polyether polyol, and polyether polyurethane polyol. A urethane type adhesive containing one type of polyol compound and at least one type of isocyanate-based compound selected from the group consisting of aromatic diisocyanate, its adduct, and its isocyanurate modified product; More preferably, at least one polyol compound selected from the group consisting of polyester polyol, polyester polyurethane polyol, polyether polyol and polyether polyurethane polyol, MDI, polymeric MDI, TDI, and adducts thereof and a urethane type adhesive containing at least one type of isocyanate-based compound selected from the group consisting of isocyanurate modified products thereof.

In addition, in the adhesive containing a polyol compound (main agent) and an isocyanate-based compound (curing agent), the ratio thereof is appropriately set depending on the physical properties to be provided in the adhesive layer, but for example, per mole of hydroxyl group of the polyol compound, The ratio of isocyanate groups in the isocyanate-based compound is 1 to 30 mol, preferably 3 to 20 mol.

The second adhesive layer is preferably 2 to 10 ㎛, more preferably 3 to 5 ㎛, considering adhesiveness with the external resin layer and thickness after molding. If the above range is not met, if it is less than 2 ㎛, adhesiveness may be poor, and if it exceeds 10 ㎛, problems such as cracks may occur.

Third adhesive layer (300)

As shown in Figure 3, the third adhesive layer 300 is a layer that increases adhesion between the outer resin layer 30 and the outermost layer 40.

In the aluminum pouch film for secondary batteries of the present invention, it may contain the same components as the second adhesive layer 200, and is the same as described for the second adhesive layer.

The third adhesive layer is preferably 2 to 10 ㎛, more preferably 3 to 5 ㎛, considering adhesiveness with the external resin layer and thickness after molding. If the above range is not met, if it is less than 2 ㎛, adhesiveness may be poor, and if it exceeds 5 ㎛, problems such as cracks may occur.

When laminating the outer resin layer 30 and the outermost layer 40 on the third adhesive layer 300, there is no particular limitation, but preferably they are laminated using a dry lamination method, a heat lamination method, or an extrusion lamination method. You can.

Manufacturing method of aluminum pouch film for secondary batteries

The present invention includes the steps of a) manufacturing an aluminum layer, b) adhering the inner resin layer to the first surface of the aluminum layer, c) forming an outer resin layer on the second surface of the aluminum layer, d) ) It provides a method of manufacturing an aluminum pouch film for a secondary battery, comprising the steps of adhering an outermost layer to one side of the outer resin layer, and e) adhering a heat dissipation layer to one side of the outermost layer.

a) manufacturing the aluminum layer

Preferably, soft aluminum foil can be used as the aluminum layer of the aluminum pouch film for secondary batteries of the present invention, and more preferably, aluminum foil containing iron is used to further provide pinhole resistance and ductility during cold forming. There is a number. In the aluminum foil containing iron, the iron content may preferably include 0.1 to 9.0 mass%, and more preferably 0.5 to 2.0 mass%, based on 100 mass% of the total aluminum foil. there is. If the iron content relative to 100 mass% of the total aluminum foil is less than 0.1 mass%, the ductility of the aluminum layer is reduced, and if it is contained in excess of 9.0 mass%, there is a problem of poor formability.

The thickness of the aluminum layer is preferably 10 to 100 ㎛, more preferably 30 to 50 ㎛, considering pinhole resistance, processability, oxygen and moisture barrier properties, etc. If the above range is not satisfied, if it is less than 10㎛, it is easily torn and the electrolyte resistance and insulation properties are poor, and if it exceeds 100㎛, there is a problem that the formability is poor.

As the aluminum foil used in the aluminum layer, untreated aluminum foil may be used, but it is more preferable to use degreased aluminum foil from the viewpoint of imparting electrolyte resistance and electrolyte resistance, etc. Degreasing treatment methods include wet type and dry type treatment methods.

Examples of wet type degreasing treatment include acid degreasing and alkaline degreasing. Examples of acids used for acid degreasing include inorganic acids such as sulfuric acid, acetic acid, phosphoric acid, and hydrofluoric acid. These acids may be used individually or in combination of two or more types. Additionally, in order to improve the etching effect of the aluminum foil, various metal salts may be mixed, if necessary. Examples of alkalis used for alkaline degreasing include strong alkalis such as sodium hydroxide, and those mixed with weak alkalis or surfactants can also be used.

An example of a dry type degreasing treatment is a method of performing degreasing treatment in a process of annealing aluminum at a high temperature.

b) adhering the inner resin layer to the first surface of the aluminum layer

In the step of adhering the inner resin layer to the first surface of the aluminum layer of the aluminum pouch film for secondary batteries of the present invention, the first adhesive layer for bonding the aluminum layer and the inner resin layer is polyurethane, acid-modified polyolefin resin, or epoxy. etc. can be used, and specific examples include maleic anhydride polypropylene (MAHPP).

The first adhesive layer is preferably 2 to 30 ㎛, more preferably 3 to 15 ㎛, considering adhesion to the internal resin layer and thickness after molding. If the above range is not met, if it is less than 2㎛, adhesiveness may be poor, and if it exceeds 30㎛, problems such as cracks may occur.

When laminating the inner resin layer to the aluminum layer, there is no particular limitation, but preferably, the inner resin layer can be laminated using a dry lamination method or an extrusion lamination method.

c) forming an external resin layer on the second surface of the aluminum layer

In the step of forming an external resin layer on the second surface of the aluminum layer of the aluminum pouch film for secondary batteries of the present invention, a second adhesive layer is applied to the aluminum layer prepared in step a). At this time, the thickness of the second adhesive layer applied is preferably 2 to 10 ㎛, more preferably 3 to 5 ㎛, considering the adhesiveness with the external resin layer and the thickness after molding. If the above range is not satisfied, if it is less than 2㎛, adhesiveness may be poor, and if it exceeds 10㎛, problems such as cracks may occur.

The outer resin layer is laminated on the second adhesive layer applied in this way and then laminated using a dry lamination method or an extrusion lamination method to form the outer resin layer. Since the outer resin layer corresponds to the area in direct contact with the hardware, it is preferable that it is a resin with insulating properties. Therefore, as the resin used as the outer resin layer, it is better to use polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, and polycarbonate, or use nylon film. It is preferable, and it is especially preferable to use a nylon film. The nylon film not only has excellent bursting strength, pinhole resistance, and gas barrier properties, but also has excellent heat resistance, cold resistance, and mechanical strength, so it is mainly used as a packaging film. Specific examples of the nylon film include polyamide resins such as nylon 6, nylon 66, copolymers of nylon 6 and nylon 66, nylon 610, and polymethoxylinene amidipamide (MXD6).

When laminating the outer resin layer, the thickness of the laminated outer resin layer is preferably 10 to 30 μm or more, and particularly preferably 12 to 25 μm. If the above range is not satisfied, if it is less than 10㎛, the physical properties are poor and easily torn, and if it exceeds 30㎛, there is a problem in that the moldability is poor.

When laminating the outer resin layer, there is no particular limitation, but preferably, the outer resin layer can be laminated using a dry lamination method or an extrusion lamination method.

d) Adhering the outermost layer to one side of the outer resin layer

In the step of adhering the outermost layer to one surface of the outer resin layer of the aluminum pouch film for secondary batteries of the present invention, the third adhesive layer for bonding the outer resin layer and the outermost layer includes the same components as the second adhesive layer 200. It may include, and is as described in the second adhesive layer above.

Additionally, the outermost layer may contain the same components as the resin used in the outer resin layer in step c), and the thickness and lamination method may also be the same.

e) forming a heat dissipation layer on one side of the outermost layer

In the step of forming a heat dissipation layer on one surface of the outermost layer of the aluminum pouch film for secondary batteries of the present invention, the step of manufacturing heat dissipation layers of various patterns may be further included.

The heat dissipation layer may include a pattern consisting of concave portions and convex portions. As a method of forming the pattern, the pattern can be formed using screen printing, photolithography, nanotransfer printing (NTP), etc.

Additionally, the pattern forming method of the printing technique may include contact printing and non-contact printing. The contact printing method includes gravure printing, flexo printing, offset printing, etc., and the non-contact printing method includes spray printing, inkjet printing, slot die printing, solution sharing printing, etc. .

In the photolithography process, after cleaning the substrate, materials are deposited using techniques such as electron beam evaporation (e-beam evaporation) and physical vapor deposition (PVD). Afterwards, a photo resist (PR) is coated on the substrate, and an exposure process is performed by applying light to each part through a mask. Thereafter, the treated substrate is developed using a special solution to form a pattern on the heat dissipation layer.

In addition, the nanotransfer printing process coats a polymer material (poly(methyl methacrylate), etc.) on the mold, peels it off with an adhesive film (polyimide, etc.), and then deposits a PVD functional material. Afterwards, the pattern can be formed using an isotropic or anisotropic deposition method.

Example: Preparation of pouch film

[Example 1]

In order to laminate an external resin layer on the second surface of a 40 ㎛ thick aluminum foil (produced by Dongil Aluminum Co.), a 4 µm thick polyurethane adhesive resin (produced by Toyo Ink Co., Ltd.) was applied using a gravure roll method, A 25 ㎛ thick nylon 6 film (manufactured by Hyosung) was dry laminated and the nylon film was laminated on the aluminum layer. Afterwards, in order to laminate the internal resin layer on the first surface of the aluminum foil, a maleic anhydride modified polyolefin adhesive (manufactured by Toyo Ink) was applied to a thickness of 4 ㎛, and then cast polypropylene (manufactured by Sammin Chemical Industry) with a thickness of 40 ㎛ was applied. product) was laminated with polypropylene on aluminum using a dry lamination method.

In order to form an outermost layer on one side of the outer resin layer, a 15 ㎛ thick polyethylene terephthalate (PET) film was prepared, and then PET was laminated on the outer resin layer.

In order to form a heat dissipation layer on one side of the outermost layer, a heat dissipation layer including a dot pattern was manufactured, and then a heat dissipation layer with a thickness of 20 μm was laminated on the outermost layer to prepare a pouch film. The heat dissipation layer was manufactured to have convex portions using a patterning stamp with a dot pattern on one side, and the height of the convex portions of the heat dissipation layer was 10 ㎛.

[Example 2]

A pouch film was manufactured in the same manner as Example 1, except that the height of the convex portion of the heat dissipation layer was 5 μm.

[Comparative Example 1]

A pouch film was manufactured in the same manner as Example 1, except that it included the heat dissipation layer.

[Experimental example]

The cooling efficiency of the battery using the pouch film prepared in Examples 1 and 2 and Comparative Example 1 was measured. The cooling efficiency was measured when a battery with a surface temperature of 85°C was cooled to 25°C by spraying 25°C air at 1 m/sec, and the results are shown in Table 1 below.

division Example 1 Example 2 Comparative Example 1 surface area 145% 125% 100% surface temperature 85℃ 85℃ 85℃ Evaluation conditions 25℃, 1m/sec, air 25℃, 1m/sec, air 25℃, 1m/sec, air Cooling efficiency 30% 10% 0%

As shown in Table 1, it was confirmed that the pouch film of Example 1, which had a high convex portion of the heat dissipation layer, had superior cooling efficiency compared to the pouch film of Example 2. In addition, it was confirmed that the cooling efficiency of the pouch films of Examples 1 and 2 including the convex portion of the heat dissipation layer was superior to that of Comparative Example 1 which did not include the heat dissipation layer.

10: Aluminum layer
20: Internal resin layer
30: External resin layer
40: outermost layer
50: heat dissipation layer

Claims (8)

aluminum layer;
an internal resin layer laminated on the first surface of the aluminum layer;
an external resin layer laminated on the second surface of the aluminum layer;
An outermost layer laminated on one side of the outer resin layer; and
It includes a heat dissipation layer laminated on one side of the outermost layer,
An aluminum pouch film for a secondary battery, wherein the heat dissipation layer includes a pattern consisting of concave portions and convex portions. According to paragraph 1,
An aluminum pouch film for a secondary battery, wherein the heat dissipation layer includes a pattern consisting of concave portions and convex portions on one or both sides in the direction in which the heat dissipation layer is adhered to the outermost layer. According to paragraph 1,
An aluminum pouch film for a secondary battery, wherein the ratio of the height (a) of the convex portions and the separation distance (b) between the convex portions is 1:1 to 1:10. According to paragraph 1,
An aluminum pouch film for a secondary battery, wherein the height of the convex portion is 1% to 80% based on the thickness of the heat dissipation layer. According to paragraph 2,
When the heat dissipation layer includes a pattern consisting of concave portions and convex portions on both sides, the aluminum pouch film for secondary batteries has a structure in which the positions of the convex portions face each other symmetrically. According to paragraph 1,
The aluminum pouch film for secondary batteries, wherein the pattern is selected from the group consisting of a triangular shape, a square shape, a semicircular shape, an elliptical shape, and a polygonal shape in cross-section. According to paragraph 1,
The pattern is one selected from the group consisting of a stripe pattern, a lattice pattern, a honeycomb pattern, a cross pattern, a dot pattern, a diamond pattern, and a diagonal pattern on a plane. An aluminum pouch film for secondary batteries, which includes the above. According to paragraph 1,
The heat dissipation layer is an aluminum pouch film for a secondary battery, wherein any one is selected from the group consisting of iron (Fe)-based alloy, aluminum (Al)-based alloy, and copper (Cu)-based alloy.