KR20150077637A - Process for Preparation of Battery Cell Having Structure for Coating Electrical Insulating Material on End of Sealing Part Bended - Google Patents

Abstract

The present invention relates to a method for manufacturing a battery cell. More specifically, the present invention relates to a method for manufacturing a battery cell which includes an anode, a cathode and a separator interposed between the anode and the cathode. The method includes a step (a) of forming a sealing part on the outer surface of a receiving part by thermal melting after the electrode assembly is installed to the receiving part of a battery case; a process (b) of bending upwards the receiving part of at least one sealing part of the sealing parts; and a process (c) of adding an electric insulating material to the sealing part bent in the process (b) by an injection needle and hardening it. In the process (c), the electric insulating material is added in a range of 0.2 mm to 1.0 mm, which is a distance between the injection needle and the end of the bent sealing part.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a battery cell having an electrically insulating material on a bent end of a sealing part,

The present invention relates to a method of manufacturing a battery cell to which an electrically insulating material is added on a bent end of a sealing part.

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, And a battery case 20 that houses the leads 60 and 70 and the electrode assembly 30. The upper and lower portions of the electrode leads 60 and 70 are sealed with the battery case 20 At the same time, an insulating film 80 is attached to ensure an electrically insulated state.

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.

Also, the pouch-shaped battery may be exposed to a dielectric breakdown due to the metal layer being exposed at the end of the laminate sheet, which is a battery case.

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, when the outer periphery of a heat-sealed portion is insulated by using a PET label or a tape, peeling of the label or tape may occur, and defects such as bubbles or wrinkles may occur.

Thus, recently, a pouch-shaped battery has been disclosed in which the sealing performance is improved by applying a sealing adjuvant to the outside of the heat-sealed portion. However, it is not easy to apply a sealing adjuvant having a predetermined viscosity and fluidity to the outside of a thin vertical cross-section of the heat-sealed portion. In the process of curing after coating, the sealing adjuvant flows down to the bottom, There is a problem that can be reduced. As a result, the technique is not suitable for actual mass production processes.

Therefore, there is a high need for a technique that improves the sealing performance of a heat-sealed portion and prevents an insulation breakdown phenomenon in a pouch-shaped battery while solving the above problems.

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

The inventors of the present application have conducted intensive research and various experiments. As described later, when an electrically insulating material is added to the folded sealing portion of the battery case under specific conditions, the electrically insulating material is folded It is possible to improve the sealing ability of the battery and effectively solve the problem of the dielectric breakdown phenomenon caused by the exposure of the metal layer of the battery case, .

According to an aspect of the present invention, there is provided a method of manufacturing a battery cell,

A method for manufacturing a battery cell comprising an anode, a cathode, and an electrode assembly including a separator interposed between the anode and the cathode,

(a) a step of attaching the electrode assembly to a receiving portion of a battery case and then forming a sealing portion on the outer circumferential surface of the receiving portion by thermal fusion;

(b) upwardly bending at least one sealing portion of the sealing portions toward the battery case receiving portion; And

(c) adding an electrically insulating material to the sealing portion bent in the step (b) by using an injection needle and curing the electrically insulating material;

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In the step (c), the electrically insulating material is added in a range of 0.2 mm to 1.0 mm between the end of the bent sealing part and the injection needle.

The inventors of the present application have confirmed that the coating state is influenced by the position of the injection needle in the process of applying the electrically insulating material having a predetermined viscosity and fluidity to the bent sealing portion and then curing, To prevent the insulating material from flowing down to the outer side of the outer side, or to insulate the sealing part of the sealing part by insufficiently applying the insulating material.

As a result of intensive researches, it has been found that, as in the manufacturing method of the present invention, the end portion of the bent sealing portion and the injection needle are positioned to have a specific gap, and an electrically insulating material is injected and cured to form an outer appearance of the battery case It has been confirmed that an electrically insulating material can be easily and stably applied to a battery cell in a position or amount in a folded sealing part.

In one specific example, the distance between the end of the bent sealing portion and the injection needle may be 0.2 mm to 1.0 mm as described above, and more specifically, 0.4 mm to 0.6 mm.

If the distance is less than 0.2 mm, the electrically insulating material having a predetermined viscosity may be discharged from the injection needle in a large amount at one time and overflowed onto the outer wall of the bent end portion of the sealing portion, , The application time is long and the amount of the material from the injection needle is constant, but there is an amount that can not be applied on the end of the bent sealing portion, so that application may not be completed, which is not preferable.

In order to more accurately and stably apply the electrically insulating material, it is preferable that an end height of the folded sealing portion is less than a thickness of a receiving portion of the battery case when the sealing portion of the battery case is bent.

In the case where the end portion of the bent sealing portion is bent to be positioned higher than the battery case receiving portion, there is no both sides of the electrically insulating material which are to become the supporting body before the curing after the application. Therefore, And it is difficult to ensure excellent sealing property and insulation property.

Specifically, the height of the end portion of the bent sealing portion may be 40% to 90% of the thickness of the battery case, more specifically, 60% to 80%.

In order to maintain the gap with the injection needle, the storage portion of the battery case and the injection needle are located close to each other, so that the storage portion may be damaged. If it is bent to be positioned at a height exceeding 90%, the coating thickness of the electrically insulating material becomes thin, which may cause problems in sealing property and insulating property.

When the sealing portion of the battery case is bent, the bending phenomenon is not limited. The end portion of the bent sealing portion may be bent so as to be spaced apart from the outer surface of the receiving portion of the battery case by a predetermined distance. But it is preferable to be bent so as to be closely contacted for stable application without flowing down of the electrically insulating material.

In one specific example, the electrically insulating material added to the folded sealing portion may be added in a structure that applies the end portion of the bent sealing portion. In this case, in order to prevent the overflow due to excessive application, And may be added at a height of 45% to 95% of the thickness of the battery compartment of the battery case.

If the coating thickness is less than 45% of the thickness of the storage portion, the coating thickness of the electrically insulating material applied from the end of the folded sealing portion may be thin, The coating can be performed more than necessary, which is inefficient, and the overflow phenomenon may occur, which is not preferable.

Further, in order to effectively prevent the electrically insulating material from flowing down and to stably apply the insulating material, an insulating material is added in a state where the internal angle formed by the injection needle and the side surface of the battery cell is 90 degrees or less in the step (c) And the interior angle may be in the range of 45 degrees to 85 degrees.

If the thickness is less than 45 degrees but less than 45 degrees, it is difficult to coat the end portion of the bending sealing portion, and if it exceeds 85, the outer surface of the battery case of the battery case does not support the electrical insulating material from flowing down I do not.

In one example, the injection needle is positioned perpendicular to the paper surface, and the battery cell has a structure in which the internal angle between the side surface of the battery cell and the injection needle is 90 degrees or less, The injection needle is inclined with respect to the ground so that the internal angle of the injection needle with the side surface of the battery cell is less than 90 degrees, .

In the case where an electrically insulating material is added in a state where the angle of the injection needle and the side surface of the battery cell is 90 degrees or less, the end portion of the storage portion of the battery case and the bent portion of the sealing portion may serve as a support to prevent the insulating material from flowing down together Therefore, it is possible to more effectively prevent the degradation of the sealing property and the breakdown of the insulation caused by the falling phenomenon.

The folded sealing portion to which the insulating material is applied may be a double side sealing portion adjacent to the sealing portion where the electrode terminal of the battery cell is located. In the sealing portion where the electrode terminal is located, The protective circuit board can be mounted in a direction in which the protection circuit board is seated. In this case, the electrically insulating material may be further added to the space between the protection circuit board and the outer surface of the housing part.

In one specific example, the electrically insulating material may be an optical or thermosetting material exhibiting a high intermolecular bonding force due to cross-linking by a chemical reaction by light or heat, and the photo- Or may be an ultraviolet (UV) curable material that undergoes crosslinking.

Examples of the ultraviolet curable material include unsaturated polyester-based materials and polyacrylate-based materials such as polyester acrylate, epoxy acrylate, and urethane acrylate, but are not limited thereto.

The ultraviolet ray-curable material may be a material having a hydrophilic functional group. In this case, the ultraviolet ray-curable material collects moisture introduced into the inside of the battery, thereby enhancing the sealability of the battery case and suppressing the penetration of moisture .

The ultraviolet curable material may also be added in the form of an oligomer having a predetermined viscosity, or a polymer having a small molecular weight, and then cured with UV. In this case, the viscosity may be in the range of 18,000 mPa · s to 35,000 mPa · s, and more specifically, 24,000 mPa · s to 29,000 mPa · s.

A general UV-curable material is a liquid material having a low viscosity, which is composed of a monomer and an oligomer. Since the material is injected into an oligomer having a viscosity in the above range or a polymer having a small molecular weight, It is easy to apply and there is almost no flow even after application, so that an optimum sealing property improving effect can be obtained.

In some cases, the ultraviolet curable material may be added to the site in a state where a predetermined thickener is added as a monomer.

As mentioned above, the ultraviolet ray-curable material composed of a monomer is a liquid material having a low viscosity. Therefore, a thickener such as carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyvinylacrylate, or the like, which can increase the viscosity of such a substance, It is possible to obtain an effect that the application is facilitated and the sealing property is improved.

The ultraviolet ray-curable material having such a viscosity can be cured by UV irradiation in a range of 3 to 20 seconds after being added to the sealing portion.

In one specific example, the electrode assembly is not particularly limited as long as it has a structure in which a plurality of electrode tabs are connected to form an anode and a cathode. Specifically, a folding structure, a stacking structure, and a stacking / have. 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 present invention also provides a battery cell manufactured by the above manufacturing method.

Specifically, the battery cell includes an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, the electrode assembly being mounted on a storage portion of the battery case;

Sealing portions are formed on the outer circumferential surface of the housing portion by thermal fusion;

At least one sealing portion of the sealing portions is bent upward toward the receiving portion of the battery case;

An electrically insulating material is added to an end portion of the bending sealing portion and no electrically insulating material is present between the remaining portion of the bending sealing portion excluding the end portion and the receiving portion.

This is because the electrically insulating material has a predetermined viscosity and is added under certain conditions as described above and the receiving portion of the battery case and the bent sealing portion serve as a support to prevent the insulating material from flowing down together, The electrical insulating material is stably added to the upper portion of the bending sealing portion, but does not flow down between the remaining portion of the bending sealing portion and the receiving portion.

On the other hand, the battery cell according to the present invention is preferably used for a pouch-type secondary battery in which an electrode assembly is built in a pouch-shaped battery case of a laminate sheet including a metal layer and a resin layer, for example, an aluminum laminate sheet A lithium ion secondary battery in which a lithium-containing electrolyte is impregnated in an electrode assembly, a lithium secondary battery such as a so-called lithium ion polymer battery in which an electrode assembly is impregnated with a lithium-containing electrolyte in the form of a gel Can be preferably applied.

Generally, the lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte solution 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 nonaqueous 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, sulfates and the like 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 battery pack including at least one battery cell, wherein the battery pack is used as a power source.

Specific examples of the device include, but are not limited to, a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, or a netbook.

As described above, the method of manufacturing a battery cell according to the present invention is a method of manufacturing a battery cell, in which an electrically insulating material is added to a folded sealing portion of a battery case under specific conditions, The sealing performance of the battery can be improved and the problem of the insulation breakdown phenomenon caused by the exposure of the metal layer of the battery case can be effectively solved.

1 is an exploded perspective view of a general structure of a conventional pouch-shaped battery;
2 is a schematic view illustrating a process of bending a sealing portion according to an embodiment of the present invention;
3 is a schematic view illustrating a process in which the battery cell of FIG. 2 is mounted and fixed to a jig;
4 is a schematic view showing a state where the battery cell opened in the jig of FIG. 3 is inclined at a predetermined angle;
5 is a schematic view showing a process in which an electrically insulating material is added to an end portion of a sealing portion by enlarging a dotted line portion in FIG. 4;
6 is a schematic view showing a process of curing an electrically insulating material added to an end portion of a sealing portion;
7 is a schematic view of a battery cell according to an embodiment of the present invention.

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.

2 to 6 are schematic views illustrating a specific process of a method of manufacturing a battery cell according to an embodiment of the present invention.

2, the battery cell 100 includes an electrode assembly (not shown) having a positive electrode / separator / negative electrode structure in a battery compartment 112 of a battery case, And 132 are formed in the direction of the outer circumferential surface of the housing part 112 in the process of heat fusion. The two side sealing portions 131 and 132 of the battery cell 100 are respectively bent at the adjacent portions to the storage portion 112 and closely contacted with the side wall 113 of the storage portion 112.

3, the battery cell 100 is mounted and fixed to the jig 160 having the indentation 163 of a size corresponding to that of the battery cell 100. Thereafter, as shown in FIG. 4, The battery cell 100 mounted on the jig 160 is tilted at a predetermined angle A. [

Here, the size of the indent 163 of the jig 160 may vary according to the size of the battery cell 100.

Next, an electrically insulating material is added to the folded two-side sealing portions 131 and 132. The dotted line portion of FIG. 4 is enlarged to be described in detail in FIG. Referring to FIG. 5, an electrically insulating material 150 is added using an injection needle 200 to be applied to the end 134 of the bending sealing portion 132.

At this time, the electrically insulating material 150 is added in the range of the distance L between the end portion 134 of the bending sealing portion 132 and the injection needle 200 in the range of 0.2 mm to 1.0 mm, To 0.6 mm.

The electrically insulating material 150 is added in such a state that the internal angle A 'formed by the injection needle 200 and the side surface of the battery cell or the outside surface 113 of the battery case receiving portion 112 is 90 degrees or less. Specifically, the injection needle 200 is positioned perpendicular to the paper, and the battery cell has an internal angle A 'formed by the outer side surface 113 of the battery case receiving portion 112 and the injection needle 200 of 90 degrees or less As shown in Fig. Therefore, the internal angle A 'formed by the injection needle 200 and the outer side surface 113 of the battery case receiving portion 112 is determined by the inclination angle A of the battery cell 100 mounted on the jig 160 same.

In the case where the electrically insulating material 150 is added in a state where the internal angle A 'formed by the injection needle 200 and the outer side surface 113 of the battery case housing part 112 is 90 degrees or less, The outer side surface 113 of the lead portion 112 and the end portion 134 of the bent sealing portion 132 may have a shape similar to the V shape as shown in FIG. 5 to serve as a support to prevent the insulating material 150 from flowing down It is possible to more effectively prevent the lowering of the sealability and the breakdown of the insulation caused by the falling phenomenon.

5, after the electrically insulating material 150 is applied on the end portion 134 of the bending sealing portion 132, the ultraviolet ray 300 is applied to the electrically insulating material 150 as shown in FIG. 6 The end portion 134 of the bending sealing portion 132 is insulated and bonded to the outer side wall 113 of the battery case housing portion 112.

FIG. 7 schematically shows a battery cell 100 according to one embodiment of the present invention thus manufactured.

7, the battery cell 100 has an electrode assembly (not shown) having a positive electrode / separator / negative electrode structure mounted on the housing portion 112 of the battery case, and on both outer surfaces of the housing portion 112, The sealing portions 131 and 132 are formed by upwardly bending the sealing portions 131 and 132 in the direction of the receiving portion of the battery case and the electrical insulating material 150 is attached to the end portions 133 and 134 of the bending sealing portions 131 and 132 .

At this time, the height H ₁ of the end portions 133 and 134 of the bending sealing portions 131 and 132 is positioned at 40% to 90% of the thickness T of the storage portion 112 of the battery case, The height H _{2 at} which the electrically insulating material 150 is added is 45% to 95% of the thickness T of the battery case receiving portion 112.

The electrically insulating material 150 does not flow between the remaining portions except for the end portions 133 and 134 of the bending sealing portions 131 and 132 and the outer side surface 113 of the accommodating portion 112, Only the remaining portions of the bent sealing portions 131 and 132 excluding the end portions 133 and 134 and the remaining portions of the battery case 131 and 132 are accurately and stably added only on the end portions 133 and 134 of the sealing portions 131 and 132, There is no electrically insulating material 150 between the lead 112 and the outer surface 113.

This is because the electrically insulating material 150 has a predetermined viscosity and is added under specific conditions as described with reference to the drawings, as well as the storage portion 112 and the bent sealing portions 131 and 132 of the battery case The electrically insulating material 150 is stably added on the end portions 133 and 134 of the bending sealing portions 131 and 132 while the bushing sealing portions 131 and 132 are formed on the end portions of the bending sealing portions 131 and 132, And 132 and the outer side surface 113 of the battery case receiving portion 112, as shown in FIG.

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 (29)

A method for manufacturing a battery cell comprising an anode, a cathode, and an electrode assembly including a separator interposed between the anode and the cathode,
(a) a step of attaching the electrode assembly to a receiving portion of a battery case and then forming a sealing portion on the outer circumferential surface of the receiving portion by thermal fusion;
(b) upwardly bending at least one sealing portion of the sealing portions toward the battery case receiving portion; And
(c) adding an electrically insulating material to the sealing portion bent in the step (b) by using an injection needle and curing the electrically insulating material;
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Wherein the electrically insulating material is added in a range of 0.2 mm to 1.0 mm between the end of the bent sealing part and the injection needle. The method of claim 1, wherein a distance between the end of the bent sealing part and the injection needle is 0.4 mm to 0.6 mm. The method of manufacturing a battery cell according to claim 1, wherein a height of an end portion of the bent sealing portion is equal to or less than a thickness of the accommodating portion of the battery case. [4] The method of claim 3, wherein a height of the end portion of the bent sealing portion is 40% to 90% of a thickness of the battery case. The method according to claim 1, wherein the end of the sealing part bent in step (b) is bent to be spaced from the outer surface of the housing part of the battery case by a predetermined distance. The method as claimed in claim 1, wherein the end portion of the sealing portion bent in the step (b) is bent so as to be in close contact with the outer surface of the receiving portion of the battery case. The method as claimed in claim 1, wherein the electrically insulating material is added at a height equal to or less than the thickness of the battery case. [8] The method of claim 7, wherein the electrically insulating material is added at a height of 45% to 95% of the thickness of the battery case. The method as claimed in claim 1, wherein the electrically insulating material is applied to the end portion of the bent sealing portion. The method of claim 1, wherein in step (c), an insulating material is added to the injection needle in a state where an internal angle of the injection needle with the side surface of the battery cell is less than 90 degrees. The method of manufacturing a battery cell according to claim 10, wherein the internal angle is 45 degrees to 85 degrees. 11. The battery cell according to claim 10, wherein the injection needle is vertically disposed with respect to the paper, and the battery cell is disposed to be inclined with respect to the paper surface so that an internal angle between the side surface of the battery cell and the injection needle is 90 degrees or less. ≪ / RTI > 11. The battery cell according to claim 10, wherein the battery cell is disposed such that the side surface thereof is perpendicular to the paper surface, and the injection needle is inclined with respect to the paper surface so that an internal angle of the injection needle with the side surface of the battery cell is 90 degrees or less. Gt; The method as claimed in claim 1, wherein the folded sealing portions are both side sealing portions adjacent to a sealing portion where the electrode terminals of the battery cell are located. 15. The method as claimed in claim 14, wherein a protective circuit board is mounted on the sealing portion where the electrode terminals of the sealing portions are located, in a direction to be seated on the outer surface of the battery case receiving portion. 16. The method of claim 15, wherein an electrically insulating material is further added to the space between the protection circuit board and the outer surface of the receiving part. The method of claim 1, wherein the electrically insulating material is an optical or thermosetting material. 18. The method of claim 17, wherein the photocurable material is an ultraviolet (UV) curable material and is irradiated with ultraviolet (UV) light to cure the photocurable material. 19. The method of claim 18, wherein the ultraviolet curable material is a material having a hydrophilic functional group. 19. The method of claim 18, wherein the ultraviolet curable material is an unsaturated polyester-based material or a polyacrylate-based material. 19. The method of claim 18, wherein the ultraviolet curable material is added in the form of an oligomer having a predetermined viscosity or a polymer having a small molecular weight and then cured by UV. The method of claim 21, wherein the viscosity is from 18,000 mPa · s to 35,000 mPa · s. 19. The method of claim 18, wherein the ultraviolet curable material is cured by being irradiated with UV light in a range of 3 to 20 seconds. A battery cell characterized by being manufactured by the method according to any one of claims 1 to 23. The battery cell of claim 24, wherein the battery cell comprises: an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode;
Sealing portions are formed on the outer circumferential surface of the housing portion by thermal fusion;
At least one sealing portion of the sealing portions is bent upward toward the receiving portion of the battery case;
Wherein an electrically insulating material is added to an end portion of the bending sealing portion and no electrically insulating material exists between the remaining portion of the bending sealing portion excluding the end portion and the receiving portion. The battery cell according to claim 24, wherein the battery cell is a lithium secondary battery. A battery pack comprising at least one battery cell according to claim 24. 29. A device according to claim 27, wherein the battery pack is used as a power source. 29. The device of claim 28, wherein the device is a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad or a netbook.

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