WO2017082669A1

WO2017082669A1 - Pouch-type secondary battery and manufacturing method therefor

Info

Publication number: WO2017082669A1
Application number: PCT/KR2016/012996
Authority: WO
Inventors: 오세운; 황수지; 정희석
Original assignee: 주식회사 엘지화학
Priority date: 2015-11-11
Filing date: 2016-11-11
Publication date: 2017-05-18
Also published as: KR101925982B1; CN207818629U; KR20170055439A

Abstract

The present invention relates to a pouch-type secondary battery and a manufacturing method therefor, the battery allowing metal layers at the edges of laminate sheets in each of an upper pouch and a lower pouch to face each other and be bonded in a heatless manner such that a sealing part is formed, wherein a pouch outer circumference sealing part is formed by the bonding of the metal layers, and thus the present invention has an effect of further lowering or preventing the possibility of moisture permeation from the outside and the possibility of electrolyte leakage from the battery.

Description

Pouch type secondary battery and manufacturing method thereof

This application claims the priority based on Korean Patent Application No. 10-2015-0158303, filed November 11, 2015, all the contents disclosed in the specification of the application is incorporated in this application.

The present invention relates to a pouch type secondary battery and a method of manufacturing the same, and more particularly, a pouch type secondary battery in which a metal layer of an edge portion of a laminate sheet constituting an upper pouch and a lower pouch is joined to each other in a non-heating manner to form a sealing portion. It relates to a manufacturing method.

As the development and demand for mobile devices increases, the demand for secondary batteries as energy sources is increasing rapidly. Among these secondary batteries, many researches have been conducted and commercialized and widely used for lithium secondary batteries with high energy density and discharge voltage. It is used.

Lithium secondary batteries are largely classified into cylindrical batteries, square batteries, pouch-type batteries, and the like according to their appearance, and may be classified into lithium ion batteries, lithium ion polymer batteries, lithium polymer batteries, and the like depending on the type of electrolyte.

Due to the recent trend toward the miniaturization of mobile devices, there is an increasing demand for thinner rectangular batteries and pouch-type batteries. In particular, for pouch-type batteries that are easy to deform, low in manufacturing cost and light in weight. Interest is high.

In general, a pouch-type battery is made of a pouch laminate sheet including an inner resin layer, a metal layer, and an outer resin layer, and includes a storage space in which an electrode assembly and an electrolyte are stored, and a sealing part sealed and sealed around the electrode space. Say. The electrode assembly accommodated in the accommodation space may be a jelly-roll (wound) electrode assembly, a stacked (laminated) electrode assembly, or a composite (stack / folding) electrode assembly.

1 is an exploded perspective view schematically showing the configuration of a general pouch type secondary battery. Referring to FIG. 1, the pouch type secondary battery includes an electrode assembly 10 and a pouch 20 as a basic structure.

Here, the electrode assembly 10 may be composed of a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode to electrically insulate between the positive electrode and the negative electrode, the electrode assembly 10 is formed extending from the positive electrode And a negative electrode tab extending from the negative electrode.

Each of the positive electrode tab and the negative electrode tab may be bonded to the positive electrode lead 11 and the negative electrode lead 12 by a method such as resistance welding, ultrasonic welding, laser welding, and the like. As a function of electrically connecting the secondary battery and the external application device to each other.

The electrode assembly 10 is introduced into the secondary battery pouch 20 together with an electrolyte solution including an electrolyte.

The secondary battery pouch 20 may be divided into an upper case 21 and a lower case 22, and may be referred to as a single cap or a double cap according to a storage space position of the electrode assembly 10. In addition, a portion of the secondary battery pouch sealed around the storage space is referred to as a 'sealing portion', and in particular, an edge portion of the pouch edge portion where the electrode tab and / or the electrode lead is referred to as a 'terrace portion'.

The secondary battery pouch 20 may be formed of a laminate sheet having a metal layer interposed therebetween to protect the electrolyte solution and the electrode assembly 10 introduced therein, and to improve the electrochemical properties of the battery cell and to improve heat dissipation. have. In order to secure insulation between the battery cell and the outside, an outer resin layer coated with an insulating material such as polyethylene terephthalate (PET) resin or nylon (nylon) may be formed on the outside of the metal layer. An inner resin layer including unstretched polypropylene (CPP) or polypropylene (PolyPropylene, PP) may be formed on the lower surface of the upper case 21 and the upper surface of the lower case 22 for adhesion to each other. have. The inner resin layer serves to insulate the upper case 21 and the lower case 22 from the outer circumferential surface, as well as prevent insulation between the metal layer and the electrolyte injected into the pouch 20.

FIG. 2 is an enlarged cross-sectional view of part A and B of FIG. 1. Referring to FIG. 2, the upper case 21 has a predetermined layered structure in the order of the outer resin layer 25, the metal layer 24, and the inner resin layer 23 from above, and the lower case 22 is upward. From the inner resin layer 23, the metal layer 24 and the outer resin layer 25. The upper case 21 and the lower case 22 may be heat-sealed at the outer circumferential surface to form a sealing part. As a method of forming a sealing portion, a bar-type sealing tool as shown in FIG. 3 is used to thermo-compress the portions to be sealed of the upper case 21 and the lower case 22. Methods are known.

On the left side of Fig. 4, a cross-sectional view of each of the laminate sheet 421 of the upper case and the laminate sheet 422 of the lower case before sealing is shown schematically, and the right side of Fig. 4 is a rod-shaped while applying heat and / or pressure. The cross section of the laminate sheet after fusion bonding the laminate sheet of the upper case and the laminate sheet of the lower case with a sealing tool is shown schematically.

On the left side of FIG. 4, the laminate sheet 421 of the upper case includes the outer resin layer 425, the metal layer 422, and the inner resin layer 423 from top to bottom, and the laminate sheet 422 of the lower case. The inner resin layer 423, the metal layer 422, and the outer resin layer 425 are sequentially formed from above. After the sealing tool is applied, the inner resin layer 423 is fused to the surface, and the metal layer 424 and the outer resin layer 425 are laminated around the inner resin layer 423. Comparing the left and right views of FIG. 4, after the sealing tool is applied, the thickness of the laminate sheet for the pouch is generally thin, but the outer resin layer 25, the metal layer 24, and the inner resin layer 23 are still thin. The layered structure is maintained.

On the other hand, the end surface of the inner resin layer constituting the secondary battery pouch is exposed to the outside of the pouch even after the sealing is made. Since the inner resin layer is mainly made of a polymer resin material, despite the fusion of the upper case and the lower case, the penetration of moisture through the cross section of the inner resin layer can easily occur and there is a possibility of electrolyte leakage. Such water permeability and the possibility of electrolyte leakage act as a factor that hinders the life and stability of the battery when the battery is used for a long time.

Therefore, it is necessary to develop a secondary battery pouch capable of suppressing water penetration and preventing electrolyte leakage.

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

An object of the present invention to provide a secondary battery pouch having a sealing portion of a specific structure that can greatly improve the moisture resistance and durability of the secondary battery pouch and a pouch type secondary battery comprising the same.

Another object of the present invention is to provide a method of improving the sealing property of the sealing portion without damaging the pouch laminate film.

According to an aspect of the present invention, in the secondary battery pouch including an upper pouch and a lower pouch formed of a laminate sheet including an outer resin layer, a metal layer and an inner resin layer, the metal layer of each of the laminate sheets of the upper pouch and the lower pouch is There is provided a secondary battery pouch which is joined to face in a non-heating manner to form a sealing portion. At this time, the terrace portion is not included in the sealing portion.

The metal layer may be formed of aluminum.

The pouch sealing portion may be thinner toward the outside.

The inside of the upper pouch and the lower pouch bonded by the metal layer may be surrounded by the inner resin layer.

According to another aspect of the present invention, the pouch type secondary battery, characterized in that the electrode assembly and the electrolyte comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode is accommodated in the above-described secondary battery pouch. Is provided.

The pouch type secondary battery may be a lithium secondary battery.

According to another aspect of the invention, preparing an upper pouch and a lower pouch each formed of a laminate sheet comprising an outer resin layer, a metal layer and an inner resin layer; storing the electrode assembly and the electrolyte in the pouch; And bonding the laminate sheet metal layer in a non-heating manner at the edge of the pouch. The method of manufacturing a pouch for a secondary battery is provided.

At the edge of the pouch except for the terrace portion, the metal layer constituting the laminate sheet may extend outwardly than the inner resin layer.

Before performing the joining of the metal layer, the portion to be sealed in the upper pouch and the lower pouch may be fused by a sealing tool of a bar bar.

The joining may be performed by solid state welding such as friction stir welding and cold press welding.

The sealing tool may be a sealing tool to form a thinner thickness toward the outside of the pouch sealing portion.

In the secondary battery pouch according to the present invention, the metal layers of the upper pouch and the lower pouch are joined at the edge portion in a non-heating manner, thereby forming a pouch sealing portion without damaging the laminate sheet, possibly penetrating moisture from the outside, and possibly leaking the electrolyte of the battery. There is an effect that can be lowered or prevented.

As a result, the battery life is extended and battery safety is improved.

1 is a view schematically showing a conventional pouch type secondary battery.

FIG. 2 is a view schematically showing the structure of a laminate sheet constituting the pouch for the secondary battery of FIG. 1.

FIG. 3 schematically illustrates a conventional embodiment in which a sealing tool is fused to a portion to be sealed in an upper pouch and a lower pouch using a sealing tool.

FIG. 4 is a diagram schematically showing a general embodiment before and after fusion of the laminate sheet of the upper pouch and the laminate sheet of the lower pouch.

5 is a schematic representation of a laminate sheet of an upper pouch and a laminate sheet of a lower pouch, together with a sealing tool applicable thereto, in accordance with an aspect of the present invention.

FIG. 6 is a schematic representation of a laminate sheet of an upper pouch and a laminate sheet of a lower pouch according to another aspect of the present invention, with a sealing tool applicable thereto.

7 is a schematic cross-sectional view of a pouch sealing part for a secondary battery according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

According to one aspect of the present invention, in the secondary battery pouch comprising a top pouch and a bottom pouch formed of a laminate sheet including an outer resin layer, a metal layer and an inner resin layer, each of the upper pouch and the lower pouch to form a pouch outer peripheral surface sealing portion The metal layer of the laminate constituting the laminate is bonded to each other in a non-heating manner, and since the inner resin layer does not exist in the sealing portion and the sealing tool is applied, the metal layer becomes thinner toward the outside of the sealing portion. The upper pouch and the lower pouch may each be in a separate form or one side is connected.

Referring to Figure 7 describes the secondary battery pouch according to an aspect of the present invention, it can be seen that the thickness of the pouch sealing portion becomes thinner toward the outside. In addition, the pouch sealing section end surface is composed of a metal layer or a metal layer and an outer resin layer, and the inner resin layer 723 is present inside the bonded metal layer and is not exposed to the outside. Therefore, a phenomenon in which external moisture penetrates into the battery through the inner resin layer 723 cross section can be prevented, and a phenomenon in which the electrolyte leaks to the outside through the inner resin layer 723 can also be prevented. On the other hand, since the metal layer of the laminate film is in contact with the electrolytic solution, it is preferable to further secure the sealing property of the joined metal layer.

The metal that can be used as the metal layer in the present invention is particularly limited as long as the metal can be used in the art to secure the mechanical strength of the pouch sheathing material, and to prevent gas and moisture from flowing into the secondary battery. It doesn't work. Non-limiting examples of the metal include aluminum. In the case of aluminum, it is possible to secure a mechanical strength of a predetermined level or more, and is light in weight, and is advantageous in improving the electrochemical properties by the electrode assembly and the electrolyte and improving heat dissipation. However, the present invention is not necessarily limited thereto, and various materials other than aluminum may be used as the metal layer. The thickness of the metal layer is not particularly limited, but may be 20 to 100 μm in consideration of weldability and moisture penetration inhibiting ability.

The outer resin layer is made of a material having electrical insulation, and should be provided on the outside of the metal layer to protect the electrode assembly from an external material, and to electrically insulate the electrode assembly and the metal layer from the outside.

Non-limiting examples of materials that can be used as the outer resin layer include polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon , Oriented nylon. It may consist of one or more materials selected from the group consisting of polyesters, polyparaphenylene benzobisoxazoles, polyarylates, teflon, and glass fibers. In addition, the outer resin layer may have a single film structure made of any one material, or may have a composite film structure formed by layering two or more materials, respectively.

The inner resin layer is formed inside the metal layer so that the metal layer and the electrode assembly or the metal layer and the electrolyte can be electrically insulated.

Non-limiting examples of materials that can form the inner resin layer include polyethylene, polypropylene, casted polypropylene (CPP), polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, 1 type, or 2 or more types of mixtures chosen from the group which consists of polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, teflon, and glass fiber. The inner resin layer may have a single film structure made of any one material, or may have a composite film structure formed by forming two or more layers of each material.

One aspect of the method of forming the pouch sealing portion according to the present invention is shown in FIG. 5. In FIG. 5, the laminate sheet of each of the upper and lower pouches comprises an inner resin layer 523, a metal layer 524, and an outer resin layer 525, wherein the metal layer 524 is longer than the inner resin layer. It is formed to extend to. If the bonding between metal layers can be ensured, the length of the metal layer extending outward longer than the inner resin layer is not particularly limited. However, in the pouch terrace portion, it may be desirable to terminate the metal layer and the inner resin layer at the same end to ensure safety. The laminate sheet may be fused by a rod-shaped sealing tool as shown in FIG. 5 as needed. The sealing tool may be applied at, for example, a temperature of 25 to 500 ° C. or a pressure of 1.0 MPa or less, or the temperature range and the pressure range, but is not limited thereto. For example, it can be fused by pressure only at room temperature without a heating process.

Another aspect of the method of forming the pouch sealing according to the invention is shown in FIG. 6. In FIG. 6, the laminate sheet of each of the upper and lower pouches comprises an inner resin layer 623, a metal layer 624, and an outer resin layer 625, with the metal layer and inner resin layer terminated at the same end. . At this time, in the structure in which the inner resin layer is bonded, it is difficult to apply the non-heating bonding. In the present invention, the inner resin layer is pushed into the sealing portion by a sealing tool or the like, so that the upper and lower pouches between the metal layers are separated. To be bonded. To this end, a sealing tool may be applied such that a thinner sealing portion is formed toward the outside of the pouch sealing portion, for example, a seal of the type as disclosed in FIG. The tool can be applied. As described above, the sealing tool may be applied at, for example, a temperature of 25 to 500 ° C. or a pressure of 1.0 MPa or less, or the temperature range and the pressure range, but is not limited thereto.

Subsequently, the upper pouch and the lower pouch edge portion are pressed by a method of joining the metal layer of the laminate sheet in a non-heating manner. In the present specification, the term "bonding in a non-heating manner" refers to a bonding in which materials are strongly compressed with each other at room temperature to induce local pressure welding, and preferably, a solid state welding method such as cold welding and friction stir welding may be used. have. This is because, in the case of joining the metal layer by a method such as resistance welding or ultrasonic welding, the possibility of defects in the weld portion is very high, and the weld portion may be dropped due to the vibration of the external impact. On the other hand, when joining by cold press welding and friction stir welding, the metal layer can be stably joined. In particular, friction stir welding is an environmentally friendly welding that does not emit harmful light or harmful substances during the welding process because heat sources, welding rods, and solvents are unnecessary as compared to other welding. In addition, since dynamic recombination occurs, solidification cracks that may occur in the melt joint can be prevented, and there is almost no deformation, thereby having an excellent mechanical property.

An electrode assembly and an electrolyte including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode may be accommodated in the secondary battery pouch formed of the laminate sheet.

The positive electrode may include a positive electrode active material and a positive electrode current collector, and the negative electrode may include a negative electrode active material and a negative electrode current collector.

The positive electrode may be prepared by applying a mixture of a positive electrode active material, a conductive material, and a binder on a positive electrode current collector, followed by drying. If necessary, a filler may be further added to the mixture.

The positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with a transition metal or more; 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 , V ₂ O ₅ , Cu ₂ V ₂ O _7, and the like; Ni-site-type lithium nickel oxide represented by the formula LiNi ₁ _- _x M _x O ₂ , wherein 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 (wherein M = Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (wherein M = Fe, Co, Lithium manganese composite oxide represented by Ni, Cu or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with alkaline earth metal ions; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ and the like, but are not limited to these.

The positive electrode current collector is generally made to a thickness of 3 to 500 ㎛. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, the surface of stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel Surface treated with carbon, nickel, titanium, silver or the like can be used. The current collector may form fine irregularities on its surface to increase the adhesion of the positive electrode active material, and may be in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric.

The binder is a component that assists in bonding the active material and the conductive material to the current collector, and is generally added in an amount of 1 to 50 wt% based on the total weight of the positive electrode mixture. A high molecular weight polyacrylonitrile-acrylic acid copolymer can be used as such a binder, but is not limited thereto. Other examples include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, Polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluorine rubber, various copolymers and the like.

The conductive material is conductive without causing chemical change in the battery, and may be added in an amount of 1 wt% to 50 wt% based on the total weight of the positive electrode mixture. For example, graphite, such as natural graphite and artificial graphite; Carbon blacks such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive polymers such as polyphenylene derivatives and the like can be used. The positive electrode may optionally include a filler as a component for inhibiting expansion.

The filler is not particularly limited as long as it is a fibrous material that does not cause chemical changes in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, are used.

The negative electrode may be obtained by applying a mixture including a negative electrode active material, a binder, and a conductive material to a current collector, and then drying the solvent.

Examples of the negative electrode active material include carbon and graphite materials such as natural graphite, artificial graphite, expanded graphite, carbon fiber, non-graphitizable carbon, carbon black, carbon nanotube, fullerene, and activated carbon; Metals such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, Pt, Ti which can be alloyed with lithium, and compounds containing these elements; Complex compounds of metals and their compounds with carbon and graphite materials; Lithium-containing nitrides; and the like.

A component for improving the conductivity of the negative electrode active material may further include a conductive material and / or a filler. The conductive material and the filler are the same as described above with respect to the positive electrode.

The negative electrode current collector may be generally made to a thickness of about 3 to 500 ㎛. Such a negative electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, the negative electrode current collector may be formed on a surface of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper, or stainless steel. Surface-treated with carbon, nickel, titanium, silver and the like, aluminum-cadmium alloy and the like can be used. In addition, like the positive electrode current collector, fine concavities and convexities may be formed on the surface to enhance the bonding strength of the negative electrode active material, and may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric.

The separator 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 m, and the thickness is generally 5 to 300 m. As such a separator, For example, Olefin type polymers, such as chemical-resistance and hydrophobic polypropylene; Sheets or non-woven fabrics made of glass fibers or polyethylene, etc. may be used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

The separator is preferably within the weight average molecular weight 1,000 ~ 20,000 range. Outside of the molecular weight range, it may be difficult to secure proper tensile strength and elongation.

The pouch type secondary battery according to the present invention may further include a lithium salt-containing non-aqueous electrolyte, in addition to the positive electrode, the negative electrode, and the separator.

The said lithium salt containing non-aqueous electrolyte consists of a nonaqueous electrolyte and lithium.

As the nonaqueous electrolyte, a nonaqueous electrolyte, an organic solid electrolyte, an inorganic solid electrolyte, or the like may be used.

As said non-aqueous electrolyte, N-methyl- 2-pyrrolidinone, a propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butylo lactone, 1, 2- dimeth, for example Methoxy ethane, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolon, formamide, dimethylformamide, dioxolon, acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester , Trimethoxy methane, dioxorone derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, ethyl propionate and the like An aprotic organic solvent can be used.

Examples of the organic solid electrolytes include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfides, polyvinyl alcohol, polyvinylidene fluoride, Polymers containing ionic dissociating 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, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , and the like, may be used.

The lithium salt is a good material to be dissolved 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, may be used, such as chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate.

In addition, for the purpose of improving charge / discharge characteristics, flame retardancy, etc., for example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphate triamide, etc. Nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxy ethanol, aluminum trichloride, etc. It may be. In some cases, in order to impart nonflammability, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further included, and carbon dioxide gas may be further included to improve high temperature storage characteristics.

The secondary battery according to the present invention may preferably be a lithium secondary battery, and in particular, may be preferably applied to a so-called lithium ion polymer battery in which a lithium-containing electrolyte is impregnated into the electrode assembly in the form of a gel.

In addition, the battery according to the present invention can be preferably used as a unit cell in a small battery pack of a mobile device, as well as a medium-large battery pack of high output large capacity.

In addition, the present invention may provide a device including the battery pack as a power source, specifically, may be a mobile electronic device.

In addition, the battery pack of the present invention may be used as an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device in consideration of mounting efficiency, structural safety, and the like.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

Claims

A pouch type secondary battery comprising an upper pouch and a lower pouch formed of a laminate sheet including an outer resin layer, a metal layer, and an inner resin layer,

A pouch type secondary battery in which a metal layer of a laminate sheet of an upper pouch and a lower pouch is bonded to each other in a non-heating manner to form a sealing part.
The method of claim 1,

A pouch type secondary battery, wherein the metal layer is formed of aluminum.
The method of claim 1,

A pouch type secondary battery characterized in that the thickness of the pouch sealing portion becomes thinner toward the outside.
The method of claim 1,

The inside of the upper pouch and the lower pouch bonded by the metal layer is surrounded by an inner resin layer pouch type secondary battery.
The method of claim 1,

A pouch type secondary battery, characterized in that an electrode assembly comprising an anode, a cathode, and a separator interposed between the anode and the cathode, and an electrolyte.
The method of claim 1,

Pouch type secondary battery, characterized in that the lithium secondary battery.
Preparing an upper pouch and a lower pouch each formed of a laminate sheet including an outer resin layer, a metal layer, and an inner resin layer; Storing the electrode assembly and the electrolyte in the pouch; And face-to-face bonding the laminate sheet metal layer at the edge of the pouch in a non-heating manner.

Method of manufacturing a pouch type secondary battery.
The method of claim 7, wherein

The manufacturing method characterized in that at the edge of the pouch except for the terrace portion, the metal layer constituting the laminate sheet extends further outward than the inner resin layer.
The method of claim 8,

Prior to performing the joining of the metal layer, the sealing portion of the bar bar is welded to the portion to be sealed of the upper pouch and the lower pouch.
The method of claim 7, wherein

And the joining is performed by friction stir welding or cold press welding.
The method of claim 9,

The sealing tool is a manufacturing method characterized in that the sealing tool to form a thinner thickness toward the outside of the pouch sealing portion.
The method of claim 9,

The sealing tool is a manufacturing method, characterized in that applied at a temperature of 25 to 500 ℃, a pressure of 1.0 MPa or less or the temperature range and pressure range.