Copper pouch film for secondary battery

Abstract

The present invention relates to a copper pouch film for a secondary battery, the pouch film comprising: a copper layer; an outer resin layer formed on a first surface of the copper layer; and an inner resin layer formed on a second surface of the copper layer, wherein a surface treatment layer is formed on one side surface of the copper layer.

Description

Copper pouch film for secondary batteries

[0001] The present invention relates to a copper pouch film for secondary batteries.

[0002] Lithium-ion secondary batteries, due to their superior energy density and output characteristics, are widely used in devices and components such as mobile phones, laptops, tablets, power tools, and electric vehicles. They are particularly prevalent in mobile phones and other mobile devices, which require miniaturization and lightweight design. Traditionally, aluminum alloys have been used as packaging materials for these batteries due to their lightweight, formability, and economical advantages.

[0003] Recently, secondary batteries have seen explosive growth in use and application, from IT devices to key power supplies for electric vehicles, thanks to their diverse advantages, including high energy density and superior output. Pouch films, used as external battery materials, encapsulate the electrodes and electrolyte of these secondary batteries. They must meet demanding specifications, including interlayer adhesion between metal thin films and polymers, thermal fusion strength, electrolyte resistance, airtightness, moisture permeability, and formability.

[0004] Pouch films are largely composed of an outer layer, a metal barrier layer, and an inner sealant layer. The metal barrier layer requires barrier properties against water vapor and other gases, electrolyte resistance, and formability. The barrier layer typically uses a metal, such as aluminum (Al) or an aluminum alloy. While aluminum is currently the most commonly used, the development of new materials continues to be required.

[0005] This pouch film for secondary batteries protects a battery composed of the electrode assembly and an electrolyte introduced into the interior through a subsequent process, and in order to protect it from external impact, an outer resin layer using a polymer resin or the like is formed on the aluminum thin film, and an inner resin layer using a polyolefin or the like is formed on the other side of the aluminum thin film.

[0006] However, secondary batteries using the above aluminum pouch film are experiencing difficulties in use in environments such as electric vehicles where large-capacity batteries are adopted for various reasons. Typically, electric vehicles initially require a range of about 100-200 km, but current requirements call for a range of about 500 km or more. Accordingly, the capacity of each battery cell installed in an electric vehicle is also increasing simultaneously. In vehicles exposed to various environments, heat is generated both by external heat and by the charging and discharging of large-capacity batteries. This abnormal thermal runaway phenomenon is called thermal runaway in secondary batteries.

[0007] Thermal runaway in secondary batteries occurs under abnormal circumstances. This occurs when heat generated within the battery increases rapidly, rapidly raising its temperature. This causes rapid chemical reactions within the battery, releasing heat and gases, which can ultimately lead to explosion and fire. Thermal runaway can occur for a variety of reasons. The most common causes include overcharging, overdischarging, overcurrent, internal short circuits, and high temperatures. These abnormal conditions accelerate reactions within the battery, causing heat accumulation and a rapid increase in reaction rate, resulting in thermal runaway. Thermal runaway severely compromises battery safety and can lead to fire and explosion, resulting in personal injury and property damage. Therefore, it is crucial to consider safety during battery design and manufacturing to prevent such situations. Furthermore, it is crucial to proactively design the battery to prevent abnormal conditions, such as abnormal and uncontrollable temperature surges and propagation, both internally and externally.

[0008] Therefore, in order to solve the above problems, technology for a pouch film using copper, which has excellent thermal conductivity and formability, instead of aluminum is being studied.

[0009] (Patent Document 1) Republic of Korea Publication No. 10-2001-7010231 (November 15, 2001), "Polymer Battery Packaging Material and Manufacturing Method Thereof"

[0010] The present invention aims to provide a copper pouch film for a secondary battery that not only has excellent corrosion resistance and chemical resistance even when the battery is exposed to physical or chemical shock or stress from the outside, but also effectively dissipates heat generated inside the pouch.

[0011] To achieve the above purpose,

[0012] The present invention comprises a copper layer;

[0013] An outer resin layer formed on the first surface of the copper layer;

[0014] It includes an inner resin layer formed on the second surface of the copper layer;

[0015] The above copper layer provides a copper pouch film for a secondary battery including a surface treatment.

[0016] The copper pouch film for a secondary battery of the present invention not only has excellent corrosion resistance and chemical resistance even when the battery is exposed to physical or chemical shock or stress from the outside, but also has the advantage of effectively transmitting heat generated during charging and discharging of the pouch to the outside, thereby preventing thermal runaway.

[0017] Hereinafter, the present invention will be described in more detail.

[0018]

[0019] The present invention comprises a copper layer;

[0020] An outer resin layer formed on the first surface of the copper layer;

[0021] It includes an inner resin layer formed on the second surface of the copper layer;

[0022] The present invention relates to a copper pouch film for a secondary battery, comprising a surface treatment layer on one side of the copper layer.

[0023]

[0024] Hereinafter, each component of the copper pouch film for secondary batteries of the present invention will be described in detail.

[0025]

[0026] copper layer

[0027] In the copper pouch film for secondary batteries of the present invention, any type of copper steel constituting the copper layer can be used without any special restrictions as long as it is copper used in the relevant industry.

[0028] The copper layer included in the copper pouch film for secondary batteries of the present invention can function as a barrier layer of the pouch film.

[0029] Accordingly, the copper layer may preferably have a thickness of 20 to 60 μm, and the total thickness of the pouch film including the copper layer may have a range of 110 to 160 μm.

[0030] When the thickness of the copper layer is 60㎛ or more, the rolling process is easy, but the formability is significantly reduced, making it difficult to apply as a battery outer shell. From this perspective, the thickness of the copper layer for the outer shell is preferably 20 to 60㎛. The formability is almost at the same level when it exceeds 40㎛ and up to 60㎛, but on the other hand, the rolling process is very difficult for foils less than 20㎛, and the rapid increase in manufacturing cost makes it difficult to apply them to mass production.

[0031] The thickness of the copper layer of the present invention can be appropriately set according to the weight, strength, processing depth, etc. required as a battery outer covering material. From the viewpoint of reducing the weight of the battery outer covering material, a thinner plate thickness is preferable. However, as the plate thickness is made thinner, the strength and processability decrease, and furthermore, the manufacturing cost increases. From the viewpoint of securing strength as a battery outer covering material, the plate thickness is preferably 40 to 60 μm.

[0032] The density of the above copper layer is 8.0 to 9.5 g / cm 3 It is desirable that the mechanical properties be a yield strength of 50 to 200 MPa and a tensile strength of 100 to 300 MPa. And the elongation is preferably 5 to 30%. As for thermal properties, the thermal conductivity is preferably 100 to 500 w / mK. As for physicochemical properties, the surface energy is preferably 0.5 to 3 J / m 2 It is desirable that.

[0033]

[0034] External resin layer

[0035] In the copper pouch film for secondary batteries of the present invention, since the outer resin layer corresponds to a portion that directly contacts hardware, it is preferable that it be a resin having insulating properties. Accordingly, the resin used for the outer resin layer may include a polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, or polycarbonate, or may include a polyamide resin, a polyimide resin, or a copolymer of polyamide and polyimide, and preferably may include a copolymer of polyamide and polyimide.

[0036] Specific examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), copolymerized polyesters, and polycarbonate (PC). Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymerized polyesters with ethylene terephthalate as the main repeating unit, and copolymerized polyesters with butylene terephthalate as the main repeating unit. In addition, as a copolymer polyester having ethylene terephthalate as a main repeating unit, specifically, a copolymer polyester having ethylene terephthalate as a main repeating unit and polymerizing with ethylene isophthalate, polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decanedicarboxylate), etc. can be mentioned.

[0037] In addition, as copolymer polyesters with butylene terephthalate as the main repeating unit, specifically, copolymer polyesters 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. can be mentioned. These polyesters may be used singly or in combination of two or more types.

[0038] As polyamide resins, specifically, 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 copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid; polyamides containing aromatics such as polymethaxyleneadipamide (MXD6); alicyclic polyamides such as polyaminomethylcyclohexyladipamide (PACM6); Also, examples thereof include polyamides copolymerized with a lactam component or an isocyanate component such as 4,4'-diphenylmethane-diisocyanate, polyesteramide copolymers or polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyester or polyalkylene ether glycol; and copolymers thereof. These polyamides may be used singly or in combination of two or more.

[0039]

[0040] Internal resin layer

[0041] In the stainless steel pouch film for secondary batteries of the present invention, the inner resin layer may be formed of a polyolefin such as polyethylene (PE) or polypropylene (PP), or a copolymer thereof. The inner resin layer is not particularly limited thereto, and may be formed of a resin layer selected from the group consisting of polyolefins such as polyethylene, polypropylene, and polybutylene, as well as ethylene copolymers, propylene copolymers, polyesters, polyamides, polycarbonates, fluorine-based resins, silicone-based resins, acrylic-based resins, ethylene-propylene-diene-monomer rubber (EPDM), and mixtures thereof. Preferably, a polyolefin-based resin layer or a mixed resin layer of polybutadiene and polyolefin may be used.

[0042] 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; polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); terpolymers of ethylene-butene-propylene; and the like. Among these polyolefins, polyethylene and polypropylene are preferable.

[0043] When polyolefin such as polyethylene or polypropylene or a copolymer thereof is used for the inner resin layer, it is preferable because it not only has the properties required as a secondary battery packaging material such as good heat sealability, moisture resistance, and heat resistance, but also has good processability such as lamination. The thickness of the inner resin layer is preferably 20 to 100 μm, and more preferably 30 to 80 μm, taking into account the formability, insulation, and electrolyte resistance. If the above range is not satisfied, problems such as poor formability, insulation, and electrolyte resistance may occur.

[0044]

[0045] adhesive layer

[0046]

[0047] *The copper pouch film for a secondary battery of the present invention may have a first adhesive layer laminated between a copper layer and an outer resin layer, and a second adhesive layer laminated between the copper layer and the inner resin layer.

[0048]

[0049] First adhesive layer

[0050] The first adhesive layer is a layer that enhances the adhesion between the copper layer and the outer resin layer. The first adhesive layer is formed by an adhesive resin capable of bonding the outer resin layer and the copper layer. The adhesive resin used to form the first adhesive layer may be a two-component curing adhesive resin or a one-component curing adhesive resin. Furthermore, there are no particular limitations on the bonding mechanism of the adhesive resin used to form the first adhesive layer, and any of a chemical reaction type, a solvent volatilization type, a heat melting type, a heat pressure type, etc. may be used.

[0051] Specific examples of the resin component of the adhesive resin that can be used to form the first adhesive layer include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolymerized polyester; polyether adhesives; polyurethane adhesives; epoxy resins; phenolic resins; polyamide resins such as nylon 6, nylon 66, nylon 12, and copolymerized polyamide; polyolefin resins such as polyolefin, acid-modified polyolefin, and metal-modified polyolefin; polyvinyl acetate resins; cellulose adhesives; (meth)acrylic resins; polyimide resins; amino resins such as urea resin and melamine resin; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; silicone resins; and fluorinated ethylene propylene copolymers. This adhesive resin component may be used alone, or two or more types may be used in combination.

[0052] The combination form of the above two or more types of adhesive resin components is not particularly limited, and examples thereof include a mixed resin of polyamide and acid-modified polyolefin, a mixed resin of polyamide and metal-modified polyolefin, a mixed resin of polyamide and polyester, a mixed resin of polyester and acid-modified polyolefin, and a mixed resin of polyester and metal-modified polyolefin. Among these, from the viewpoint of excellent ductility, durability under high-humidity conditions, suppression of response, suppression of deterioration during heat sealing, etc., and suppression of deterioration in the lamination strength between the substrate layer and the metal layer, and effective suppression of delamination, preferable examples include a polyurethane-based two-component curable adhesive resin; a blend resin of polyamide, polyester, or these with a modified polyolefin.

[0053] In addition, examples of known adhesive materials include polyurethane adhesives containing a subject matter including a polyol such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol, and a curing agent including a bifunctional or higher isocyanate compound. By allowing the curing agent to act on the subject matter, a polyurethane resin is formed.

[0054] First, polyols can be mentioned as components of the adhesive. Examples of polyol compounds used in urethane-type adhesives include polyester polyols, polyester polyurethane polyols, polyether polyols, and polyether polyurethane polyols. The hydroxyl equivalent and weight-average molecular weight of these polyol compounds are not particularly limited as long as they ultimately satisfy the above properties in relation to the isocyanate-based compound to be combined. For example, the hydroxyl equivalent (units / mol) can be 0.5 to 2.5, preferably 0.7 to 1.9, and the weight-average molecular weight can be 500 to 120,000, preferably 1,000 to 80,000. Among these polyol compounds, polyester polyols, polyester polyurethane polyols, and polyether polyurethane polyols can be mentioned preferably. These polyol compounds may be used alone, or two or more may be used in combination.

[0055] As the above polyester polyol, it is possible to use a material obtained by reacting at least one polybasic acid with at least one diol. Examples of the polybasic acid 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. Examples of the diol include aliphatic diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methyl pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and dodecanediol; alicyclic diols such as cyclohexanediol and hydrogenated xylylene glycol; and aromatic diols such as xylylene glycol.

[0056] In addition, as a polyester polyol, examples thereof include a polyester urethane polyol in which the hydroxyl groups at both terminals of the polyester polyol are extended using a single isocyanate compound or an adduct, biuret, or isocyanurate compound containing at least one isocyanate compound. Examples of the isocyanate compounds include 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, and the like.

[0057] As the above acrylic polyol, a copolymer containing poly(meth)acrylic acid as a main component can be mentioned. As the copolymer, hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc., alkyl (meth)acrylate monomers having methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group as the alkyl group, or (meth)acrylamide, N-alkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide (alkyl groups including methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.), N-alkoxy (meth)acrylamide, N,N-dialkoxy Examples of materials copolymerized with amide group-containing monomers such as (meth)acrylamide (as an alkoxy group, a methoxy group, an ethoxy group, a butoxy group, an isobutoxy group, etc.), N-methylol (meth)acrylamide, N-phenyl (meth)acrylamide, glycidyl group-containing monomers such as glycidyl (meth)acrylate, allyl glycidyl ether, silane-containing monomers such as (meth)acryloxypropyl trimethoxysilane, (meth)acryloxypropyl triethoxysilane, and isocyanate group-containing monomers such as (meth)acryloxypropyl isocyanate are examples. As the carbonate polyol, a material obtained by reacting a carbonate compound with a diol can be used. As the carbonate compound, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, etc. can be used. As the above diol, aliphatic diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, and dodecanediol, alicyclic diols such as cyclohexanediol and hydrogenated xylylene glycol, and aromatic diols such as xylylene glycol can be used.

[0058] In addition, it is possible to use a polycarbonate urethane polyol in which the terminal hydroxyl group of the above-described carbonate polyol is extended by the above-described isocyanate compound.

[0059] Next, isocyanate can be mentioned as a component of the above adhesive.

[0060] Isocyanate compounds used in the above urethane-type adhesive include, for example, polyisocyanates, adducts thereof, isocyanurate-modified forms thereof, carbodiimide-modified forms thereof, allophanate-modified forms thereof, and biuret-modified forms thereof. Specific examples of the polyisocyanates include aromatic diisocyanates such as diphenylmethane diisocyanate (MDI), polyphenylmethane diisocyanate (polymeric MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), bis(4-isocyanatecyclohexyl)methane (H12MDI), isophorone diisocyanate (IPDI), 1,5-naphthalene diisocyanate (1,5-NDI), 3,3'-dimethyl-4,4'-diphenylene diisocyanate (TODI), and xylene diisocyanate (XDI); Aliphatic diisocyanates such as tramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and isophorone diisocyanate; alicyclic diisocyanates such as 4,4'-methylenebis(cyclohexylisocyanate) and isophorone diisocyanate; and the like. Specific examples of the adduct include those obtained by adding trimethylolpropane, glycol, and the like to the polyisocyanate. Among these isocyanate compounds, preferred are polyisocyanates and adducts thereof; more preferred are aromatic diisocyanates, adducts thereof, and isocyanurate-modified products thereof; more preferred are MDI, polymeric MDI, TDI, adducts thereof, and isocyanurate-modified products thereof; and particularly preferred are adducts of MDI, adducts of TDI, polymeric MDI, and isocyanurate-modified products of TDI. These isocyanate compounds may be used alone, or two or more may be used in combination.

[0061] As the bifunctional or higher isocyanate compound used as the above-mentioned curing agent, it is possible to use the type of isocyanate compound used as the chain extender, and repeatedly, a single isocyanate compound selected from 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., or at least one selected from the above-mentioned isocyanate compounds. Examples include adducts, biuret compounds, and isocyanurates containing isocyanate compounds.

[0062] The amount of the above-mentioned hardener is preferably 1 to 100 parts by weight, more preferably 5 to 50 parts by weight, per 100 parts by weight of the main agent. If it is less than 1 part by weight, there is a concern that performance such as adhesion or electrolyte resistance may not be achieved. If it is more than 100 parts by weight, there is a concern that excessive isocyanate groups will exist, which may affect the adhesive film quality or hardness due to the residual unreacted substances.

[0063] In addition, it is also possible to blend a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, etc. into the above polyurethane adhesive to promote adhesion.

[0064] The above 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, etc. are examples. The above oxazoline compounds include monooxazoline compounds such as 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, and 2,4-diphenyl-2-oxazoline, and dioxazoline compounds such as 2,2'-(1,3-phenylene)-bis(2-oxazoline), 2,2'-(1,2-ethylene)-bis(2-oxazoline), 2,2'-(1,4-butylene)-bis(2-oxazoline), and 2,2'-(1,4-phenylene)-bis(2-oxazoline).

[0065] Examples of the above epoxy compounds include diglycidyl ethers of aliphatic diols such as 1,6-hexanediol, neopentyl glycol, and polyalkylene glycol; polyglycidyl ethers of aliphatic polyols such as sorbitol, sorbitan, polyglycerol, pentaerythritol, diglycerol, glycerol, and trimethylolpropane; polyglycidyl ethers of alicyclic polyols such as cyclohexane dimethanol; diglycidyl esters or polyglycidyl esters of aliphatic and aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, trimellitic acid, adipic acid, and sebacic acid; resorcinol, bis-(p-hydroxyphenyl)methane, 2,2-bis-(p-hydroxyphenyl)propane, tris-(p-hydroxyphenyl)methane; Examples thereof include diglycidyl ethers or polyglycidyl ethers of polyhydric phenols such as 1,1,2,2-tetrakis(p-hydroxyphenyl)ethane, N-glycidyl derivatives of amines such as N,N'-diglycidylaniline, N,N,N-diglycidyltoluidine, N,N,N',N'-tetraglycidyl-bis-(p-aminophenyl)methane, triglycidyl derivatives of aminophenols, triglycidyltris(2-hydroxyethyl)isocyanurate, triglycidyl isocyanurate, orthocresol-type epoxy, and phenol novolac-type epoxy resin.

[0066] The above-mentioned phosphorus compounds include tris(2,4-di-t-butylphenyl)phosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylenephosphonite, 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, Examples include tris(nonylphenyl)phosphite and 4,4'-isopropylidene bis(phenyl-dialkylphosphite).

[0067] As the above silane coupling agent, it is possible to use various silane coupling agents such as vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyl trimethoxysilane, γ-aminopropyltriethoxysilane, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane.

[0068] As an adhesive used for forming a first adhesive layer that satisfies the properties of the stainless steel pouch film for secondary batteries of the present invention, preferably, a urethane-type adhesive comprising at least one polyol compound selected from the group consisting of polyester polyol, polyester polyurethane polyol, polyether polyol, and polyether polyurethane polyol, and at least one isocyanate-based compound selected from the group consisting of aromatic diisocyanates, adducts thereof, and isocyanurate-modified forms thereof; more preferably, a urethane-type adhesive comprising at least one polyol compound selected from the group consisting of polyester polyol, polyester polyurethane polyol, polyether polyol, and polyether polyurethane polyol, and at least one isocyanate-based compound selected from the group consisting of MDI, polymeric MDI, TDI, adducts thereof, and isocyanurate-modified forms thereof.

[0069] In addition, in an adhesive containing a polyol compound (subject) and an isocyanate-based compound (curing agent), the ratio thereof is appropriately set depending on the above-mentioned physical properties to be provided in the adhesive layer, but for example, the ratio of the isocyanate group of the isocyanate-based compound per 1 mol of hydroxyl groups of the polyol compound is 1 to 30 mol, preferably 3 to 20 mol.

[0070] The thickness of the first adhesive layer is preferably 2 to 10 μm, more preferably 3 to 5 μm, taking into account the adhesiveness with the outer resin layer and the thickness after molding. If the thickness is less than 2 μm, the adhesiveness is poor, and if it exceeds 10 μm, problems such as cracking may occur.

[0071]

[0072] Second adhesive layer

[0073] The above second adhesive layer is a layer that increases the adhesion between the inner resin layer and the copper layer.

[0074] In the copper pouch film for secondary batteries of the present invention, polyurethane, acid-modified polyolefin resin, epoxy, or the like can be used as the second adhesive layer. A specific example of the second adhesive layer is maleic anhydride polypropylene (MAHPP).

[0075] 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, ethylene-vinyl acetate copolymer, ionomers, polypropylene, maleic anhydride-modified polypropylene, ethylene-propylene copolymer, and propylene-1-butene-ethylene copolymer, and preferably, it may include at least one olefin resin selected from the group consisting of polypropylene, ethylene-propylene copolymer, and propylene-1-butene-ethylene copolymer.

[0076] The acid-modified polyolefin used in forming the second adhesive layer is a polymer modified by graft polymerization of polyolefin with an unsaturated carboxylic acid, for example. Specific examples of the acid-modified polyolefin include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); terpolymers of ethylene-butene-propylene, and the like. Among these polyolefins, from the viewpoint of heat resistance, preferably, polyolefins having at least propylene as a constituent monomer, and more preferably, terpolymers of ethylene-butene-propylene and random copolymers of propylene-ethylene are mentioned. Unsaturated carboxylic acids used for modification include, for example, maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride. Among these unsaturated carboxylic acids, maleic acid and maleic anhydride are preferable. Acid-modified polyolefins may be used singly or in combination of two or more.

[0077] The second adhesive layer is preferably 2 to 10 µm thick, more preferably 3 to 5 µm, taking into account adhesion to the inner layer and thickness after molding. If the thickness is less than 2 µm, adhesion is poor, and if it exceeds 5 µm, problems such as cracking may occur.

[0078] When laminating the inner resin layer and the copper layer on the second adhesive layer, there is no special limitation, but it is preferable to laminate using a dry lamination method, a heat lamination method, or an extrusion lamination method.

[0079]

[0080] Surface treatment layer

[0081] In the copper pouch film for secondary batteries of the present invention, a surface treatment layer may be provided on at least one side of the copper layer. In particular, the surface treatment layer may be formed between the copper layer and the inner resin layer, i.e., on the second surface of the copper layer. The surface treatment layer may be treated with at least one of corona treatment and chromate treatment. The corona treatment may be performed at 500 to 15,000 W / cm. 2 It can be processed at a speed of 20 to 60 M / min with an energy density of . After corona treatment, chromate treatment can be performed. Specifically, trivalent chromate can be applied at 1 to 5 g / m using a gravure roll on the corona-treated surface. 2 After applying at a concentration of , it can be dried at 60 to 150°C. The above corona treatment and chromate treatment can be repeated two or more times.

[0082]

[0083] Method for manufacturing copper pouch film for secondary batteries

[0084] The copper pouch film for secondary batteries of the present invention is

[0085] a) Step of preparing a copper layer;

[0086] b) a step of forming an outer resin layer on the first surface of the copper layer; and

[0087] c) It can be manufactured by a method including a step of forming an internal resin layer on the second surface of the copper layer.

[0088] The copper layer of step a) above can be corona treated and chromate treated.

[0089]

[0090] a) Step for preparing a copper layer

[0091] The above copper layer may be the same as the copper layer described above.

[0092] The copper layer of the above step a) can be treated with at least one of corona treatment and chromate treatment. The corona treatment is performed at 500 to 15,000 W / cm 2 It can be processed at a speed of 20 to 60 M / min with an energy density of . After corona treatment, chromate treatment can be performed. Specifically, trivalent chromate can be applied at 1 to 5 g / m using a gravure roll on the corona-treated surface. 2 After applying at a concentration of , it can be dried at 60 to 150°C. The above corona treatment and chromate treatment can be repeated two or more times.

[0093]

[0094] b) A step of forming an outer resin layer on the first surface of the copper layer.

[0095] In the step of forming an outer resin layer on the first surface of the copper layer of the copper pouch film for secondary batteries of the present invention, the nylon or polyethylene terephthalate is laminated using a dry lamination method or an extrusion lamination method to form the outer resin layer. When laminating the outer resin layer, the thickness of the laminated outer resin layer is preferably 10 to 30 ㎛, and particularly preferably 12 to 25 ㎛. If the above range is not satisfied, that is, if it is less than 10 ㎛, the physical properties deteriorate and it is easily torn, and if it exceeds 30 ㎛, there is a problem that the formability deteriorates.

[0096]

[0097] c) A step of forming an internal resin layer on the second surface of the copper layer.

[0098] In the step of bonding an inner resin layer to the second surface of the copper layer of the copper pouch film for secondary batteries of the present invention, polyurethane, acid-modified polyolefin resin, epoxy, or the like can be used as the second adhesive layer bonding the copper layer and the inner resin layer, and a specific example is maleic anhydride polypropylene (MAHPP).

[0099] The second adhesive layer is preferably 2 to 30 ㎛ in thickness, taking into account adhesion to the inner resin layer and thickness after molding, and more preferably 3 to 15 ㎛. If the above range is not satisfied, when it is less than 2 ㎛, adhesion is poor, and when it exceeds 30 ㎛, problems such as cracking may occur.

[0100] When laminating the above-mentioned internal resin layer on a copper layer, there is no special limitation, but preferably, the internal resin layer can be laminated using a dry lamination method or an extrusion lamination method.

[0101] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also not included in the scope of the present invention.

[0102]

[0103] Manufacturing example 1.

[0104] After preparing a 35㎛ thick copper film, one side was surface treated. At this time, the surface treatment was performed at 1000W / cm 2 Corona treatment (Vetaphone, Corona-Plus Unit) was performed at a speed of 40 M / min with an energy density of . Afterwards, trivalent chromate (Ipsi Chemical, NR-X) was applied to the corona-treated surface using a gravure roll at a density of 3 g / m 2 After applying at a concentration of , it was dried at 90 degrees.

[0105]

[0106] Manufacturing example 2.

[0107] After preparing a 35㎛ thick copper film, one side was surface treated. At this time, the surface treatment was performed at 1000W / cm 2The corona treatment was performed at a speed of 40 M / min with an energy density of . Afterwards, 3g / m of trivalent chromate was applied to the corona-treated surface using a gravure roll. 2 After applying the film at a concentration of 1000 W / cm, it was dried at 90 degrees. Afterwards, the dried film was heated at 1000 W / cm 2 It was corona treated again at a speed of 40 M / min with an energy density of .

[0108]

[0109] Manufacturing example 3.

[0110] After preparing a 35㎛ thick copper film, one side was surface treated. At this time, the surface treatment was performed at 1000W / cm 2 The corona treatment was performed at a speed of 40 M / min with an energy density of . Afterwards, 3g / m of trivalent chromate was applied to the corona-treated surface using a gravure roll. 2 After applying the film at a concentration of 1000 W / cm, it was dried at 90 degrees. Afterwards, the dried film was heated at 1000 W / cm 2 The corona treatment was performed at a speed of 40 M / min with an energy density of . Trivalent chromate was applied to the corona-treated surface using a gravure roll at a density of 3 g / m 2 After applying at a concentration of , it was dried at 90 degrees.

[0111]

[0112] Comparative manufacturing example 1.

[0113] An aluminum layer was used instead of a copper layer.

[0114]

[0115] Comparative Manufacturing Example 2

[0116] A 35 μm thick copper film was prepared without any treatment.

[0117]

[0118] Comparative manufacturing example 3

[0119] A 35 μm thick copper film was prepared by only performing corona surface treatment.

[0120]

[0121] Comparative Manufacturing Example 4

[0122] A 35 μm thick copper film was prepared by only performing a trivalent chromate surface treatment.

[0123]

[0124] Copper pouch film manufacturing example

[0125] A barrier layer having a thickness of 35 μm was prepared by surface-treating the copper layer and aluminum layer manufactured in the manufacturing example and comparative example.

[0126] In order to laminate an external resin layer on the first surface of the barrier layer, a 3 ㎛ thick polyurethane adhesive resin was applied using a gravure roll method, and then a 15 ㎛ thick polyamide was dry laminated to laminate a polyamide film on the barrier layer.

[0127] Afterwards, in order to laminate an inner resin layer on the second surface of the barrier layer that was surface-treated in the manufacturing example, a maleic anhydride modified polyolefin adhesive was applied to a thickness of 3 ㎛, and then a 30 ㎛ thick cast polypropylene was dry laminated to laminate the polypropylene on the copper layer to manufacture a pouch film for a secondary battery.

[0128] The pouch film using the barrier layer of Manufacturing Example 1 was designated as Example 1, the pouch film using the barrier layer of Manufacturing Example 2 was designated as Example 2, the pouch film using the barrier layer of Manufacturing Example 3 was designated as Example 3, the pouch film using the barrier layer of Comparative Manufacturing Example 1 was designated as Comparative Example 1, and the pouch film using the barrier layer of Comparative Manufacturing Example 2 was designated as Comparative Example 2.

[0129]

[0130] Experimental Example 1. Formability Evaluation

[0131] To measure the formability of pouch films, a mold measuring 3.5 x 6.2 cm in length and width was used, and a stopper for adjustment was used to measure the formability in 1 mm increments. After forming, the sample was placed in a darkroom and a light was shined on the inner surface to observe whether light leaked out, and the presence of cracks or micro-holes was observed to measure the limit forming depth.

[0132] Experimental Example 2. Evaluation of internal electrolyte solution

[0133] The electrolyte resistance of the copper pouch film for secondary batteries of the above example and the aluminum pouch film for secondary batteries of Comparative Example 1 were evaluated.

[0134] Each of the above pouch films was cut to 2.5X10cm, placed in a test container with LiPF6 standard electrolyte, sealed, and heated to 85℃. After 24 hours, the pouch film was collected and the interfacial adhesive strength (N / 15mm) was measured using a universal testing machine according to ASTM D882 standards using UTM equipment for peeling between films.

[0135]

[0136] Experimental Example 3. Adhesion Evaluation

[0137] The adhesive strength of the copper pouch film for secondary batteries of the above example and the aluminum pouch film for secondary batteries of Comparative Example 1 was evaluated. Each pouch film was cut into 2.5X10cm and the interfacial adhesive strength (N / 15mm) was measured using UTM equipment according to the ASTM D882 standard.

[0138]

[0139] Experimental Example 4. Heat Transfer Evaluation

[0140] The thermal conductivity (W / mK) of the copper pouch film for secondary batteries of the above example and the aluminum pouch film for secondary batteries of Comparative Example 1 was measured according to the method specified in ASTM E1461.

[0141]

[0142] Experimental Example 5. Surface Roughness Evaluation

[0143] The surface roughness of the copper pouch film for secondary batteries of the above example and the aluminum pouch film for secondary batteries of the comparative example was evaluated using an AFM (Atomic Forced Microscope) in contact mode, and the arithmetic mean roughness (nm) was evaluated for a unit length of 5 um.

[0144] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Average roughness (Ra, nm) 3 1 2 8 1 8 2 3 1 5 1 0 5

[0145] Classification Formability (mm) Electrolyte resistance (N / 15mm) Adhesion (N / 15mm) Heat transfer (W / mK) Example 11015 - 1720.559 Example 21117 - 1923.367 Example 31320 - 2527.282 Comparative Example 1812 - 1517 - 2043 Comparative Example 2811 - 1420.50 Comparative Example 3912 - 1520.053 Comparative Example 4913 - 1620.255

[0146] It can be seen that the copper pouch film for secondary batteries of the present invention has excellent formability, electrolyte resistance, adhesive strength, and heat transfer properties by using copper foil as a metal layer.

Claims

1. Copper layer; An outer resin layer formed on the first surface of the copper layer; It includes an inner resin layer formed on the second surface of the copper layer; A copper pouch film for a secondary battery, comprising a surface treatment layer on one side of the copper layer.

2. In paragraph 1, A copper pouch film for a secondary battery, characterized in that the surface treatment layer is corona surface treated.

3. In paragraph 1, A copper pouch film for a secondary battery, characterized in that the surface treatment layer is surface-treated with trivalent chromate.

4. In paragraph 1, A copper pouch film for a secondary battery, characterized in that the surface treatment layer is formed between a copper layer and an inner resin layer. 5.a) Step of preparing a copper layer; b) a step of forming an outer resin layer on the first surface of the copper layer; and c) a step of forming an internal resin layer on the second surface of the copper layer; A method for manufacturing a copper pouch film for a secondary battery, characterized in that the copper layer of step a) above is treated with at least one of corona treatment and chromate treatment.