KR20150037274A - Multilayer Insulating Tape and Battery Cell Comprising the Same - Google Patents

Abstract

The present invention relates to a multilayer insulating tape and a battery cell comprising the same. More particularly, the present invention relates to an insulating tap attached to the outer surface of a battery cell. The multilayer insulating tape includes a bonding layer for attaching an insulating tape to the outer side of the battery case; a primer layer for electrical insulation and preventing the penetration of moisture into the battery cell; and an external coating layer for protecting the outer side of the primer layer. The bonding layer, the primer layer, and the external coating layer are successively stacked.

Description

TECHNICAL FIELD [0001] The present invention relates to a multilayer insulating tape and a battery cell including the multilayer insulating tape.

The present invention relates to a multilayered insulating tape and a battery cell including the same. More particularly, the present invention relates to an insulating tape to be attached to an outer circumferential surface of a battery cell, including an adhesive layer for attaching an insulating tape to an outer surface of a battery case, And a coating layer for protecting the outer surface of the primer layer, wherein the adhesive layer, the primer layer, and the outer coating layer are sequentially laminated. And an insulating tape.

The secondary battery, which has recently been used in an increasing amount, has a high demand for a prismatic secondary battery and a pouch-type secondary battery that can be applied to products such as mobile phones with a thin thickness in terms of the shape of the battery. , Lithium secondary batteries, lithium ion batteries, and the like, which have advantages such as high output stability and output stability.

Also, the secondary battery is classified according to how the electrode assembly having the anode / separator / cathode structure is formed. Typically, the long battery-shaped anodes and cathodes are jelly- A stacked (stacked) electrode assembly in which a plurality of positive electrodes and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator interposed therebetween, a stacked (stacked) electrode assembly in which a predetermined unit of positive and negative electrodes are stacked, A stack / folding type electrode assembly in which a Bi-cell or a full cell stacked in a single state is wound up as a separation film can be given.

Recently, a pouch-shaped battery having a structure in which a stacked or stacked / folded electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet is attracting much attention due to low manufacturing cost, small weight, Its usage is also gradually increasing.

FIG. 1 schematically shows a general structure of a typical conventional pouch-type secondary battery as an exploded perspective view.

1, the pouch type secondary battery 10 includes an electrode assembly 30, electrode taps 40 and 50 extending from the electrode assembly 30, electrodes 40 and 50 welded to the electrode taps 40 and 50, Leads 60 and 70, and a battery case 20 for accommodating the electrode assembly 30. [

The electrode assembly 30 is a power generation element in which an anode and a cathode are sequentially stacked with a separation membrane interposed therebetween. The electrode assembly 30 has a stacked or stacked / folded structure. The electrode tabs 40 and 50 extend from each electrode plate 30 of the electrode assembly 30 and the electrode leads 60 and 70 are connected to a plurality of electrode tabs 40 and 50 extending from each electrode plate, Respectively, and a part of the battery case 20 is exposed to the outside. An insulating film 80 is attached to the upper and lower surfaces of the electrode leads 60 and 70 in order to increase the degree of sealing with the battery case 20 and at the same time to ensure an electrically insulated state.

The battery case 20 is made of an aluminum laminate sheet, provides a space for accommodating the electrode assembly 30, and has a pouch shape as a whole. 1, a plurality of positive electrode tabs 40 and a plurality of negative electrode tabs 50 may be coupled to the electrode leads 60 and 70. In the stacked electrode assembly 30, The inner top is spaced from the electrode assembly 30.

In such a pouch-shaped battery, the electrode assembly is housed in a laminate sheet, and an electrolyte is injected to seal the electrode assembly by thermal fusion or the like. In the step of sealing the electrode assembly, There is a problem in that it is difficult to maintain a complete sealing state even after the heat fusion is performed due to excessive melting phenomenon and / or protrusion of the inner resin layer due to the pressurization, so that penetration of moisture is easy and there is a possibility of leakage of the electrolytic solution.

In addition, in the pouch-shaped battery, the metal layer is exposed at the end portion of the laminate sheet, which is the battery case, so that the insulation breakdown phenomenon may occur, and moisture and the like may permeate through the heat fusion portion at the end portion.

In this connection, the prior art discloses a battery which tries to insulate using a PET label and a tape at the outer periphery of the heat-welded portion. However, conventional PET labels and tapes are composed of a polymer resin layer constituting the outer layer and an adhesive layer formed on the surface facing the battery cell at the time of manufacturing. In the case of the polymer resin layer, the rigidity of the surface is weak, In particular, when a colored print layer is included to form the outer appearance of a battery cell, a problem arises in that the manufacturing process of the insulating tape is complicated and the manufacturing cost is increased.

Therefore, there is a great need for a technique that can fundamentally solve the above problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

An object of the present invention is to provide a battery pack having an adhesive layer for attaching an insulating tape to an outer surface of a battery case attached to an outer circumferential surface of a battery cell, a primer layer for preventing water penetration into the battery cell and electrically insulating the outer surface of the battery case, The battery case may be repeatedly expanded and contracted during the charging and discharging of the battery so that moisture may penetrate into the sealing portion of the battery or the electrolyte may leak out of the battery case, And an insulating tape for manufacturing a battery cell for preventing a dielectric breakdown phenomenon caused by exposure of a metal layer of a battery cell.

It is another object of the present invention to provide an insulating tape for manufacturing a battery cell, which can solve the problems such as simplification of the manufacturing process and cost compared to the conventional insulating tape manufacturing work, improve the yield and ensure a high yield rate and can be easily manufactured.

The insulating tape for manufacturing a battery cell according to the present invention for achieving the above object is an insulating tape attached to an outer circumferential surface of a battery cell,

An adhesive layer for attaching the insulating tape to an outer surface of the battery case;

A primer layer for preventing water penetration into the battery cell and electrically insulating the battery cell; And

An outer coating layer for protecting an outer surface of the primer layer;

And a structure in which the adhesive layer, the primer layer, and the outer coating layer are sequentially laminated.

Therefore, the insulating tape for manufacturing a battery cell according to the present invention comprises an adhesive layer for attaching to an outer surface of a battery case, a primer layer for preventing water penetration into the battery cell and electrically insulating the battery cell, And the outer coating layer are laminated in order to prevent water from penetrating into the sealing portion where the battery body repeatedly expands and shrinks during repetitive charging and discharging of the battery or leakage of electrolyte inside the battery case, It is possible to solve the problems of insulation breakdown caused by the metal layer exposure and to solve the problems such as the simplification of the process and the cost compared with the conventional insulating tape manufacturing operation and to improve the yield and ensure the high yield rate.

In one specific example, the thickness of the adhesive layer is preferably in the range of 18 to 22 micrometers, and the thickness of the primer layer is preferably in the range of 4.5 to 5.5 micrometers in order to exhibit a desired degree of insulation, The thickness of the coating layer can be appropriately selected within a range that does not impair the mechanical strength, handleability of the exterior film, and the like, and is preferably in the range of 20 to 26 micrometers in a specific example.

If the thickness of the adhesive layer, the primer layer, and the outer coating layer is too small, a desired degree of mechanical strength and insulation can not be exhibited. On the contrary, if the thickness is too large, bending along the outer surface of the battery pack is not easy It is not preferable because the adhesion and the bonding force with the outer surface of the battery pack may be lowered on the bent surface.

On the other hand, the adhesive layer is not particularly limited as long as it can be attached without damaging the outer surface of the battery cell. For example, the adhesive layer may be at least one selected from the group consisting of acrylic and ethyl acetate.

The primer layer is not particularly limited as long as it is a colored material having insulating properties, and may be at least one selected from the group consisting of carbon black and black polyolefin resin, and may be a black color primer layer .

In another specific example, the primer layer may further include a curing agent, and the curing agent is not particularly limited as long as it is a substance that improves the adhesive force by controlling the diffusion effect of the primer. Examples of the curing agent include melamine compounds, oxazoline compounds, An aziridine group, an isocyanate compound, an amine compound, and an amide compound.

The outer coating layer may be made of a material having high tensile strength and weatherability to impart durability. As a transparent material for expressing the hue of the inner primer layer, a polyethylene teraphthalate film, an acrylic film and a polyvinyl chloride film , And a transparent PET film can be preferably used.

The present invention also provides a battery cell characterized in that the insulating tape is attached to the outer circumferential surface.

In one specific example, the battery cell has an electrode assembly including an anode, a separator, and a cathode mounted on a battery case, and the electrode assembly may be a folding structure, a stacking structure, or a stacking / .

Details of the stacked / folded structure of the electrode assembly are disclosed in Korean Patent Application Laid-Open Nos. 2001-0082058, 2001-0082059 and 2001-0082060, the contents of which are incorporated herein by reference. As a reference.

The battery cell according to the present invention is characterized in that a laminated sheet including a metal layer and a resin layer, specifically an electrode assembly of a pouch-shaped case of an aluminum laminate sheet, is embedded in the outer peripheral surface of the aluminum laminate sheet by heat- It can be preferably applied to a battery cell.

In another specific example, the battery cell may have a structure in which the outer circumferential surface of the laminated sheet is in a bent state and is in close contact with the outer surface of the receiving portion of the electrode assembly, and the insulating tape is attached while covering the outer circumferential surface.

For reference, a typical lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt.

The positive electrode is prepared, for example, by coating a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode current collector, and then drying the mixture. Optionally, a filler may be further added to the mixture.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ and the like; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode is manufactured by applying and drying a negative electrode active material on a negative electrode collector, and if necessary, the above-described components may be selectively included.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x < Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The non-aqueous electrolyte solution containing a lithium salt is composed of a polar organic electrolyte and a lithium salt. As the electrolytic solution, a non-aqueous liquid electrolytic solution, an organic solid electrolyte, an inorganic solid electrolyte and the like are used.

Examples of the nonaqueous liquid electrolytic solution include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge-discharge characteristics and the flame retardancy, the non-aqueous liquid electrolyte may contain, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like are added It is possible. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

The present invention also provides a device including the battery pack.

Preferred examples of such devices include, but are not limited to, mobile phones, portable computers, smart phones, tablet PCs, smart pads, netbooks, LEVs (Light Electronic Vehicles), electric vehicles, hybrid electric vehicles, plug- Home appliances, and the like, but the present invention is not limited thereto.

The structure of these devices and their fabrication methods are well known in the art, and a detailed description thereof will be omitted herein.

As described above, the insulating tape for manufacturing a battery cell according to the present invention comprises an adhesive layer for adhering to the outer surface of a battery case, a primer layer for preventing water penetration into the battery cell and electrically insulating the outer surface of the battery case, It is possible to prevent water from penetrating into the sealing portion of the battery due to repeated expansion and contraction of the battery body during the charging and discharging of the battery or leakage of the electrolyte inside the battery case, It is possible to prevent the dielectric breakdown phenomenon caused by the metal layer of the case being exposed, simplify the process compared to the conventional insulating tape manufacturing operation, reduce the manufacturing cost, improve the yield and secure a high yield rate.

1 is an exploded perspective view of a general structure of a conventional pouch-shaped battery;
2 is a front view of a battery cell according to one embodiment of the present invention;
FIG. 3 is a front view of a position cell having an insulation tape for manufacturing a battery cell according to an embodiment of the present invention. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

FIG. 2 is a schematic front view of a battery cell according to an embodiment of the present invention. FIG. 3 is a front view of a cell having an insulation tape for manufacturing a battery cell according to an embodiment of the present invention. Are schematically shown.

Referring to FIG. 2, a battery cell according to an exemplary embodiment of the present invention includes an electrode assembly (not shown) Side sealing portions 120 and 130 are vertically bent along the dot-dash lines 111 and 112 in the direction of the receiving portion 140 of the electrode assembly.

Next, referring to FIG. 3, in the state where the two side sealing parts 120 and 130 are vertically bent in the direction of the receiving part 140 of the electrode assembly, the sealing parts 110, 120, (201, 202, 203) are attached to complete the battery cell.

Specifically, the insulating tapes 201, 202, and 203 include an adhesive layer 210 for attaching to the outer surface of the battery cell 100, a black color primer for electrically insulating the battery cell 100 from moisture penetration into the battery cell 100, A transparent PET film 230 for protecting the outer surface of the layer 220 and the black color primer layer 220 and for expressing the hue of the black color primer layer 220 in a sequential manner.

Therefore, the insulating tape for manufacturing a battery cell according to the present invention can prevent moisture penetration into the battery cell by the primer layer and achieve electrical insulation, and the outer coating layer can express the color of the primer layer by using a transparent material Therefore, the step of forming a separate colored print layer is omitted, the operation is simplified, and the production yield of the battery and the efficiency of the manufacturing process are improved.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (18)

An insulating tape attached to an outer circumferential surface of a battery cell,
An adhesive layer for attaching the insulating tape to an outer surface of the battery case;
A primer layer for preventing water penetration into the battery cell and electrically insulating the battery cell; And
An outer coating layer for protecting an outer surface of the primer layer;
Wherein the adhesive layer, the primer layer, and the outer coating layer are sequentially laminated. The method of claim 1, wherein the thickness of the adhesive layer is in the range of 18 to 22 micrometers, the thickness of the primer layer is in the range of 4.5 to 5.5 micrometers, and the thickness of the outer coating layer is in the range of 20 to 26 micrometers Wherein the insulating tape is made of a resin. The insulating tape for manufacturing a battery cell according to claim 1, wherein the adhesive layer comprises at least one selected from the group consisting of acrylic and ethyl acetate. The insulating tape for manufacturing a battery cell according to claim 1, wherein the primer layer is a colored material and comprises at least one selected from the group consisting of carbon black and a black polyolefin resin. The insulating tape for manufacturing a battery cell according to claim 4, wherein the primer layer further comprises a curing agent. The insulating tape for battery cell production according to claim 5, wherein the curing agent is at least one selected from the group consisting of a melamine compound, an oxazoline compound, an aziridine group-containing compound, an isocyanate compound, an amine compound and an amide compound. The insulating tape for manufacturing a battery cell according to claim 1, wherein the primer layer is a black color primer layer. The insulating tape for manufacturing a battery cell according to claim 1, wherein the outer coating layer is a transparent material and is at least one selected from the group consisting of a polyethylene terephthalate film, an acrylic film and a polyvinyl chloride film. The insulating tape for manufacturing a battery cell according to claim 8, wherein the outer coating layer is a transparent PET film. A battery cell characterized in that an insulating tape according to any one of claims 1 to 9 is attached to the outer circumferential surface. 11. The battery pack of claim 10, wherein the battery cell has an electrode assembly including a positive electrode, a separator, and a negative electrode mounted on a battery case, wherein the electrode assembly has a folding structure, a stacking structure, And the battery cell. The battery cell according to claim 10, wherein the battery case comprises a laminate sheet including a resin layer and a metal layer. 13. The battery cell according to claim 12, wherein the laminate sheet is an aluminum laminate sheet. The battery cell according to claim 13, wherein the outer circumferential surface of the laminate sheet is sealed by thermal fusion when the electrode assembly is embedded. 15. The battery cell according to claim 14, wherein the outer circumferential surface of the laminate sheet is in close contact with the outer surface of the receiving portion of the electrode assembly in a bent state, and the insulating tape is attached while surrounding the outer circumferential surface. A battery pack comprising at least one battery cell according to claim 10. A device comprising the battery pack according to claim 16 as a power source. 18. The device of claim 17, wherein the device is selected from the group consisting of a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, ≪ / RTI > device.

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