KR20130124053A - Adhesive tape and secondary battery manufactured using the same - Google Patents

Abstract

The present invention provides an adhesive tape including the winding end part of an electrode assembly body for being attached to outer surface in order to maintain the winding state of the electrode assembly body comprising an adhesive layer contacting the outer surface of the electrode assembly body and a material layer where the adhesive layer is coated wherein the adhesive tape is a roll shape wound in multi-layer structure when being kept and the adhesive layer in the roll shape contacts surface where an adhesive layer is not formed at the material layer of a lower part structure, moreover the adhesive layer of the upper part structure does not damage the material layer of the lower part structure when the adhesive layer of the upper part structure is separated from the surface where the adhesive layer is not formed at the material layer.

Description

Adhesive Tape and Secondary Battery Manufactured Using the Same

The present invention relates to an adhesive tape and a secondary battery using the same, and more particularly, an adhesive tape attached to an outer surface including a winding end of an electrode assembly to maintain a wound state of the electrode assembly, the outer surface of the electrode assembly. And a base layer on which the adhesive layer is applied, wherein the adhesive tape is in the form of a roll wound in a multi-layered structure during storage, and in the roll form, the adhesive layer is an adhesive layer of the base layer of the underlying structure. The adhesive layer of the upper structure has a property of not damaging the substrate layer of the lower structure when the adhesive layer of the upper structure is separated from the surface on which the adhesive layer is not formed. It relates to an adhesive tape.

In general, a secondary battery, unlike a primary battery that cannot be charged, means a battery that can be charged and discharged, and is widely used in electronic devices such as mobile phones, notebook computers, camcorders, or electric vehicles. In particular, the lithium secondary battery has an operating voltage of about 3.6V, and has a capacity of about three times that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for electronic equipment, and has a high energy density per unit weight. The degree is increasing rapidly.

The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate coated with a positive electrode active material and a negative electrode active material are disposed with a separator interposed therebetween, and an exterior member sealingly storing the electrode assembly together with an electrolyte solution.

Meanwhile, according to the shape of a battery case, a lithium secondary battery may be classified into a can type secondary battery in which an electrode assembly is embedded in a metal can and a pouch type battery in which the electrode assembly is embedded in a pouch of an aluminum laminate sheet. In addition, the can-type secondary battery may be further classified into a cylindrical battery and a square battery according to the shape of the metal can.

The electrode assembly is classified into a jelly-roll type wound through a separator between a positive electrode plate and a negative electrode plate, and a stack type sequentially stacked with a separator between a plurality of positive electrode plates and a negative electrode plate of a predetermined size. The stack type electrode assembly is mainly used for a pouch type battery, and the jelly-roll type electrode assembly is mainly used for a can type secondary battery. In particular, the jelly-roll type electrode assembly has been widely used because it is easy to manufacture, high energy density per weight, and easy to store in a can of a cylindrical or rectangular battery.

The jelly-roll type electrode assembly is wound by laminating a positive electrode plate, a negative electrode plate, and a separator, and the adhesive tape is attached to the outermost end of the electrode assembly, that is, the winding end, so that the electrode assembly is not loosened and the wound state is maintained. do. In addition, the electrode assembly attached with the adhesive tape is accommodated in the metal can together with the electrolyte, and the cap assembly in which the electrode terminal is formed on the open top of the battery case is coupled.

However, the secondary battery having the above structure has a problem that the electrode assembly can move up and down or left and right inside the battery when the battery is dropped or an external impact is applied. This flow of electrode assembly can cut a tab connected between the electrode assembly and the cap assembly. In addition, the up and down flow of the electrode assembly may deform the electrode assembly by pressing the upper or lower portion of the electrode assembly to cause a short circuit, resulting in damage to the secondary battery as well as an accident such as ignition or explosion, which may cause a great damage. . In addition, the vertical flow of the electrode assembly may cause a problem that the electrolyte inside the secondary battery is leaked by applying a shock to the cap assembly coupled to the upper part of the secondary battery to break or separate the sealing part.

In order to solve this problem, researches on adhesive tapes, etc. using a material exhibiting adhesion when exposed to an electrolyte as a base layer have been conducted. However, in this case, when the adhesive force of the adhesive layer is increased, the base layer is damaged by the adhesive layer when the tape in the form of a roll is used, and thus there is a problem that the adhesive force of the adhesive layer cannot be increased to a desired degree.

Therefore, there is a high need for an adhesive tape which is excellent in adhesive force and capable of preventing damage to the base layer.

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.

After repeated studies and various experiments, the inventors of the present application include an adhesive layer and a base layer, and when the base layer of the lower structure is not damaged by the adhesive layer of the upper structure even when stored in a roll form and used, By confirming that it can manufacture, this invention was completed.

Accordingly, the adhesive tape according to the present invention is an adhesive tape attached to an outer surface including the winding end of the electrode assembly to maintain the wound state of the electrode assembly, wherein the adhesive layer is in contact with the outer surface of the electrode assembly, and the adhesive layer is coated. Including a base material layer,

The adhesive tape is a roll (roll) wound in a multi-layer structure when stored, in the roll form the adhesive layer is in contact with the surface of the base layer of the lower structure, the adhesive layer is not formed, the adhesive layer is not formed of the base layer When the adhesive layer of the upper structure is separated from the surface, the adhesive layer of the upper structure has the property of not damaging the base layer of the underlying structure.

In general, the adhesive tape may have a double layer structure of an adhesive layer and a base layer. In such a structure, it is in a roll form wound in a multilayer structure when stored, and in use, it is unrolled from a roll by using a double layer structure as a unit. In this case, when the adhesive force of the adhesive layer is large, while the bilayer unit of the upper structure is separated from the bilayer unit of the lower structure, the base layer of the lower structure may be damaged by the adhesive layer of the upper structure. Because of this, the base layer is attached to the adhesive layer of the upper structure is not able to easily exhibit the adhesive force, the base layer of the damaged lower structure also does not play its role.

However, the adhesive tape of the present invention solves the above problems.

It is preferable that the adhesive force of the adhesive layer is 500 gf / 25 mm or more in consideration of the fact that the adhesive force is partially reduced in the electrolyte solution. If the adhesive force of the adhesive layer is less than 500 gf / 25 mm, when the adhesive force is lowered by the electrolyte solution, the electrode assembly is loosened and the interface resistance between the electrodes is increased, which is not preferable. For this reason, the adhesive force of the adhesive layer is more preferably in the range of 600gf / 25mm to 1000gf / 25mm. When the adhesive force of the adhesive layer is more than 1000gf / 25mm it is not preferable because the base layer may be damaged.

The base layer is not particularly limited, but may be one or more selected from the group consisting of polystyrene, polyamide, polyacrylonitrile, polyvinyl alcohol, polycarbonate, polyethylene vinyl acetate, and oriented polystyrene (OPS). . More preferably, the base material layer is OPS.

The OPS does not exhibit adhesiveness in the step of inserting the electrode assembly into the battery can, but may react with the nonpolar organic solvent of the electrolyte in the can, thereby exhibiting adhesiveness. In this case, the adhesion may be derived from the adhesive layer, or may be derived from the reaction between the OPS and the nonpolar organic solvent.

According to this property, smooth insertion can be achieved in the process of inserting the electrode assembly into the can, and the vertical flow of the electrode assembly can be prevented at the completion of the battery.

The adhesive layer may be used as long as the material does not damage the substrate layer while increasing the adhesive force, but may be, for example, at least one selected from the group consisting of an acrylic polymer and a rubber-based material. Among them, acrylic polymers are preferred because they have excellent heat resistance, no adhesive odor, and easy manufacturing process.

As described above, higher adhesion is required when the adhesive layer performs not only the jelly-roll electrode assembly but also the adhesion between the electrode assembly and the battery can. However, the general adhesive tape could damage the base layer when improving the adhesive strength of the adhesive layer, and did not increase the adhesive strength to a desired degree.

On the other hand, in the case of using the adhesive layer having the same characteristics as in the present invention, it does not damage the substrate layer while improving the adhesive force to a desired level.

In one preferred embodiment of the present invention, the adhesive tape may be composed of an adhesive layer and a base layer. More preferably, the adhesive layer may be composed of a first adhesive layer / auxiliary layer / second adhesive layer.

The first adhesive layer is a layer adhered to the electrode assembly, the auxiliary layer serves to separate and space the first adhesive layer and the second adhesive layer, and the second adhesive layer is a layer in contact with the substrate layer. In the case of having the structure as described above, since the first adhesive layer and the second adhesive layer are separately responsible for the adhesion of the electrode assembly and the adhesion between the electrode assembly and the battery can, a more efficient adhesion effect can be exhibited.

The first adhesive layer and the second adhesive layer may use a material usable as the adhesive layer described above. The auxiliary layer may be used as long as it is a material capable of separating and separating the first adhesive layer and the second adhesive layer, but for example, one selected from the group consisting of polyethylene terephthalate, polypropylene, polyethylene, and polyimide. It may be abnormal.

In one preferred example of the invention, the thickness of the adhesive tape may be in the range of 10 μm to 60 μm. When the thickness of the adhesive tape is less than 10 μm, the thickness of the adhesive layer and the base layer may be too thin to exhibit sufficient adhesive strength, and may cause a problem due to breakage during the winding process. In contrast, the thickness of the adhesive tape is greater than 60 μm. In this case, the thickness of the adhesive layer and the substrate layer is too thick to act as a limit point to increase the capacity by reducing the reaction space in the battery is not preferred.

The present invention also provides an electrode assembly, wherein the adhesive tape is attached to the surface of the electrode assembly. The electrode assembly may have a structure in which a separator is positioned between the anode, the cathode, and the anode and the cathode. Preferably, the electrode assembly may be in the form of a jelly-roll.

In the electrode assembly of the present invention, the positive electrode is prepared, for example, by applying and drying a slurry prepared by adding a positive electrode mixture containing a positive electrode active material to a solvent such as NMP on a positive electrode collector, May further include a binder, a conductive material, a filler, a viscosity adjusting agent, and an adhesion promoter.

The cathode current collector generally has a thickness of 3 to 500 mu m. 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 positive electrode current collector may have fine unevenness formed on the surface thereof to increase the adhesive force of the positive electrode active material as in the case of the negative electrode current collector. Alternatively, the positive electrode current collector may have various properties such as a film, sheet, foil, net, porous body, Form is possible.

The cathode active material is a material capable of causing an electrochemical reaction. Examples of the lithium transition metal oxide include lithium cobalt oxide (LiCoO ₂ ) containing two or more transition metals and substituted with one or more transition metals, lithium Layered compounds such as nickel oxide (LiNiO ₂ ); Lithium manganese oxide substituted with one or more transition metals; Formula _{LiNi 1-y M y O 2} ( where, M = Co, Mn, Al , Cu, Fe, Mg, B, Cr, Zn or Ga and Lim, 0.01≤y≤0.7 include one or more elements of the element) A lithium nickel-based oxide represented by the following formula: _{Li 1 + z Ni 1/3 Co 1/3} Mn 1/3 O 2, Li 1 + z Ni 0.4 Mn 0.4 Co 0.2 O 2 , such as _{Li 1 + z Ni b Mn c} Co 1- (b + c + d _{) M d O (2-e} ) A e ( where, -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2 , 0≤e≤0.2, b + c + d <1, M = Al, Mg, Cr, Ti, Si or Y, and A = F, P or Cl; lithium nickel cobalt manganese composite oxide; And the formula _{Li 1 + x M 1-y} M 'y PO 4-z X z ( wherein, M = a transition metal, preferably Fe, Mn, Co or Ni, M' = Al, Mg or Ti, X = F, S or N, and -0.5? X? +0.5, 0? Y? 0.5, and 0? Z? 0.1), but the present invention is not limited thereto.

Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), cellulose, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluorine rubber, various copolymers, high molecular weight polyolefins such as polyolefin, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, Vinyl alcohol, and the like.

The conductive material is not particularly limited as long as it has electrical conductivity without causing any chemical change in the battery, for example, 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 whiskeys 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. Concrete examples of commercially available conductive materials include acetylene black series such as Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, etc.), Ketjenblack, EC (Armak Company), Vulcan XC-72 (Cabot Company), and Super P (Timcal).

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

The viscosity modifier may be added up to 30% by weight based on the total weight of the negative electrode mixture as a component for adjusting the viscosity of the electrode mixture so that the mixing process of the electrode mixture and the coating process on the current collector may be easy. Examples of such viscosity modifiers include carboxymethylcellulose, polyvinylidene fluoride and the like, but are not limited thereto. In some cases, the above-described solvent may play a role as a viscosity adjusting agent.

The adhesion promoter may be added in an amount of 10% by weight or less based on the binder, for example, oxalic acid, adipic acid, Formic acid, acrylic acid derivatives, itaconic acid derivatives, and the like.

The negative electrode may be formed by applying a slurry prepared by adding a negative electrode active material containing a negative active material on a negative electrode current collector to a solvent such as NMP and drying the negative electrode active material. Fillers, viscosity modifiers, and adhesion promoters, and the like.

The negative electrode collector is generally made to have a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and may be formed of a material such as copper, stainless steel, aluminum, nickel, titanium, fired carbon, surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the negative electrode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

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, Pt, and Ti that can be alloyed with lithium and compounds containing these elements; Complexes of metals and their compounds and carbon and graphite materials; Lithium-containing nitrides, and the like. Among them, a carbon-based active material, a tin-based active material, a silicon-based active material, or a silicon-carbon based active material is more preferable, and these may be used singly or in combination of two or more.

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 present invention also provides a secondary battery including the electrode assembly, a case accommodating the electrode assembly, and an electrolyte. Preferably, the secondary battery may be a lithium secondary battery, in this case, the electrolyte may be a lithium salt-containing non-aqueous electrolyte.

The lithium salt-containing nonaqueous electrolyte solution is composed of an electrolyte solution and a lithium salt. As the electrolyte solution, a nonaqueous organic solvent, an organic solid electrolyte, and an inorganic solid electrolyte may be used.

Examples of the non-aqueous organic solvent 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, A polymer containing an ionic dissociation group and the like may 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 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 electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (Fluoro-Ethylene carbonate, PRS (propene sultone), FPC (fluoro-propylene carbonate), and the like.

The case may be selected from the group consisting of rectangular cans, cylindrical cans and pouch cases. Preferably, the case may be a cylindrical can.

The secondary battery according to the present invention can be used not only in a battery cell used as a power source for a small device but also as a unit cell in a middle or large battery module including a plurality of battery cells.

Preferred examples of the medium-to-large device include, but are not limited to, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, power storage systems, and the like.

As described above, since the adhesive tape according to the present invention has excellent adhesive strength and does not damage the substrate layer, there is an advantage that the adhesive tape can maintain excellent adhesive strength even when the adhesive tape reacts with the electrolyte in the battery and adheres to the case. .

1 is a partial cross-sectional view schematically showing the configuration of an adhesive tape according to one embodiment of the present invention;
2 is a partial cross-sectional view schematically showing the configuration of an adhesive tape according to another embodiment of the present invention;
3 is a perspective view schematically showing a configuration in which the adhesive tape according to the present invention is wound in a roll form;
4 is a partial cross-sectional view schematically showing a configuration in which the adhesive tape according to the present invention is wound in a roll form.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited by the scope of the present invention.

1 is a partial cross-sectional view schematically showing the configuration of the adhesive tape according to an embodiment of the present invention, Figure 2 is a partial cross-sectional view showing the configuration of the adhesive tape according to another embodiment of the present invention Is shown as an example.

Referring to these drawings, the adhesive tape 100 according to an embodiment of the present invention is composed of an adhesive layer 110 and a base layer 120. The adhesive tape 200 according to another embodiment includes a first adhesive layer 210, an auxiliary layer 220, a second adhesive layer 230, and a base layer 240.

The adhesive layer 110 and the first adhesive layer 210 are attached to the outer surface of the electrode assembly to prevent loosening of the electrode assembly.

The substrate layers 120 and 240 are layers in which an adhesive layer is formed and supported, and various materials used in the art may be used. However, in order to prevent the flow of the electrode assembly in the secondary battery, a material that reacts with the electrolyte solution and dissolves or exhibits adhesion is preferable, and particularly preferably OPS.

3 is a perspective view schematically showing a configuration in which the adhesive tape according to the present invention is wound in a roll form, and FIG. 4 illustrates a configuration in which the adhesive tape according to the present invention is wound in a roll form. The partial cross section shown is typically shown.

Referring to these drawings, the adhesive tape wound in a roll form has an adhesive layer 310 and a base material layer 320 continuously connected, but when viewed in cross section, the outer adhesive tape is located on the upper side, It can be seen that the adhesive tape is located at the bottom. That is, the adhesive layer of the upper structure is in contact with the surface of the base layer of the lower structure in which the adhesive layer is not formed, and the adhesive layer of the upper structure and the base layer of the lower structure are separated from each other for use of the adhesive tape.

In this case, in the case of the existing adhesive tape, the higher the adhesive force, the problem that the base layer of the lower structure is damaged by the adhesive layer of the upper structure occurs, there was a limit to increase the adhesive strength of the adhesive layer 310.

However, the adhesive tape of the present invention solves this problem and realizes that the adhesive layer is high and does not damage the substrate layer.

To this end, the adhesive layer may be at least one selected from the group consisting of an acrylic polymer and a rubber-based material.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (13)

An adhesive tape attached to an outer surface including a wound end of an electrode assembly to maintain a wound state of the electrode assembly,
An adhesive layer in contact with the outer surface of the electrode assembly, and a substrate layer on which the adhesive layer is applied,
The adhesive tape is a roll (roll) wound in a multi-layer structure when stored,
In the roll form, the adhesive layer is in contact with the surface of the base layer of the lower structure, the adhesive layer is not formed,
The adhesive tape of the upper structure when the adhesive layer of the upper structure is separated from the surface on which the adhesive layer is not formed, the adhesive tape, characterized in that it has a property that does not damage the base layer of the lower structure. The adhesive tape according to claim 1, wherein the adhesive force of the adhesive layer is 300 gf to 600 gf. The adhesive tape of claim 1, wherein the base layer is at least one selected from the group consisting of polystyrene, polyamide, polyacrylonitrile, polyvinyl alcohol, polycarbonate, polyethylene vinyl acetate, and oriented polystyrene (OPS). . The adhesive tape according to claim 1, wherein the adhesive layer is composed of a first adhesive layer / auxiliary layer / second adhesive layer. The adhesive tape according to claim 4, wherein the auxiliary layer is at least one selected from the group consisting of polyethylene terephthalate, polypropylene, polyethylene, and polyimide. The adhesive tape according to claim 1, wherein the adhesive tape has a thickness in the range of 10 µm to 60 µm. The electrode assembly according to any one of claims 1 to 6, wherein the adhesive tape is attached to the surface of the electrode assembly. 8. The electrode assembly of claim 7, wherein the electrode assembly is in a jelly-roll form. A secondary battery comprising an electrode assembly according to claim 7, a case accommodating the electrode assembly, and an electrolyte. The secondary battery of claim 9, wherein the secondary battery comprises a cylindrical case. A battery module comprising a secondary battery according to claim 9 as a unit cell. A device comprising the battery module according to claim 11 as a power source. 13. The device of claim 12, wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or a system for power storage.

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