KR20090088636A - Electrode assembly and lithium secondary battery having the same - Google Patents

Abstract

An electrode assembly is provided to ensure excellent thermal stability and internal short property in a lithium secondary battery by using an olivine structure compound as a positive electrode active material. An electrode assembly comprises a positive electrode equipped with a positive electrode active material layer; a negative electrode equipped with a negative electrode active material layer; and a separator separating the positive electrode and the negative electrode. The separator comprises a porous membrane which is bound by a ceramic material and a binder. The positive electrode active material layer has na olivine structure compound of chemical formula 1: Li_yMXO_k.

Description

Electrode assembly and lithium secondary battery having same {Electrode Assembly and Lithium secondary Battery having the Same}

The present invention relates to an electrode assembly and a lithium secondary battery having the same, and more particularly, to a lithium secondary battery having excellent thermal stability and internal short circuit characteristics in a secondary battery.

As miniaturization and light weight of portable electronic devices have recently advanced, the necessity for miniaturization and high capacity of batteries used as driving power sources thereof is increasing. In particular, the lithium secondary battery has an operating voltage of 3.6 V or more, which is three times higher than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for portable electronic devices, and rapidly expands in terms of high energy density per unit weight. There is a trend.

Lithium secondary batteries generate electrical energy by oxidation and reduction reactions when lithium ions are intercalated / deintercalated at the positive and negative electrodes. A lithium secondary battery is prepared by using a material capable of reversibly intercalating / deintercalating lithium ions as an active material of a positive electrode and a negative electrode, and filling an organic electrolyte or a polymer electrolyte between the positive electrode and the negative electrode.

A lithium secondary battery includes an electrode assembly in which a negative electrode plate and a positive electrode plate are wound in a form such as a jelly-roll with a separator interposed therebetween, a can containing the electrode assembly and an electrolyte, and a can It consists of a cap assembly assembled on the top.

As a cathode active material of a conventional lithium secondary battery, a lithium composite metal compound, for example, LiCoO ₂ , LiNiO _2, or LiMn ₂ O ₄ , is used. These materials have an advantage of having a high energy density and a high voltage.

However, these positive electrode active materials containing metal elements having a low Clark number in the composition have problems such as high cost and supply instability and vulnerable to thermal stability, and thus new alternative materials that can be used as positive electrode active materials. The demand for is increasing.

Accordingly, although it has been proposed to use a compound having an olivinic structure excellent in thermal stability as a cathode active material for a lithium secondary battery, even in the case of a compound having such an olivine structure, an internal short circuit caused by a battery internal short circuit. The characteristic has a weak problem.

In particular, a conventional polyolefin-based microporous polymer membrane such as polypropylene, polyethylene, or a multilayer thereof is used. However, since the porous membrane layer has a sheet or film shape, an internal short circuit In addition, since the sheet-like separator also shrinks due to pore blockage of the porous membrane due to heat generation due to overcharging, the internal short-circuit characteristic is more important when a compound having an olivinic structure is used as the cathode active material. have.

Accordingly, the present invention is to solve the above-mentioned disadvantages and problems of the prior art, to provide an electrode assembly having excellent thermal stability and at the same time excellent internal short circuit characteristics in a lithium secondary battery and a lithium secondary battery having the same. There is an object of the invention.

The present invention provides a lithium secondary battery comprising a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, an electrode assembly including a separator separating the positive electrode and the negative electrode and an electrolyte, wherein the separator comprises a ceramic material and Comprising a porous membrane bonded by a binder, the positive electrode active material layer provides an electrode assembly and a lithium secondary battery comprising the same, comprising an olivine (olivine) compound of the formula [1].

[Formula 1]

Li _y MXO _k (wherein M is Na, K, Mg, Ca, Sr, Ni, Co, Si, Ti, B, Al, Sn, Mn, Cr, Fe, Ce, V, Zr and combinations thereof At least one element selected from the group, X is at least one element selected from the group consisting of P, S, W, and a combination thereof, wherein 0 <y≤1, 2≤k≤4)

In addition, the present invention provides an electrode assembly and a lithium secondary battery having the same, characterized in that the binder is 0.1 to 4% by weight based on 100% by weight of the total porous film.

The present invention also provides an electrode assembly and a lithium secondary battery having the same, wherein the cathode active material layer further includes a compound capable of inserting and detaching lithium ions.

The present invention also provides an electrode assembly and a lithium secondary battery having the same, wherein the cathode active material layer is mixed with the olivine structure compound and a compound capable of inserting and detaching lithium ions. .

In another aspect, the present invention provides an electrode assembly and a lithium secondary battery having the positive electrode active material layer is coated with the olivine (olivine) structure compound on the compound capable of inserting and detaching the lithium ion. do.

Therefore, the electrode assembly and the lithium secondary battery having the same according to the present invention have an effect of providing a secondary battery having excellent thermal stability by using an olivine structure compound as a cathode active material.

In addition, the present invention has the effect of providing a secondary battery having excellent internal short circuiting properties by limiting the content of the binder of the porous membrane formed by the combination of a ceramic material and a binder.

Details of the above object and technical configuration of the present invention and the effects thereof will be more clearly understood by the following detailed description of the present invention.

Referring to the electrode assembly including a separator of the present invention and a secondary battery having the same as follows.

The separator of the present invention comprises a porous film formed by bonding a ceramic material and a binder. The paste is prepared by mixing the ceramic material and the binder in a solvent, and then porous on the positive electrode, the negative electrode, or both electrodes using the paste. A film can be formed.

The ceramic material may be at least one material selected from the group consisting of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), and further, zirconium, Insulating nitrides, hydroxides, ketones, or mixtures of these compounds, each of aluminum, silicon, titanium, can be used. In this case, the limitation of insulating nitride is mentioned because titanium nitride (TiN) and the like have conductivity and are not suitable for the ceramic material of the present invention.

The binder may be a synthetic rubber latex binder or an acrylic rubber having a crosslinked structure.

The synthetic rubber latex binder is styrene butadiene rubber (SBR) latex, nitrile butadiene rubber (NBR) latex, methyl methacrylate butadiene rubber latex, chloroprene rubber latex, carboxy modified styrene butadiene rubber latex and modified polyorganosiloxane polymer latex. It may include one or more selected from the group consisting of. It is preferable that such a polymer latex is made of an aqueous dispersion, and the content thereof is preferably used in an amount of 0.1 to 20 parts by weight as a solid with respect to 100 parts by weight of the electrode active material. There is a concern, and when it exceeds 20 parts by weight, since there is a possibility that adversely affect the battery characteristics, it is not preferable.

In addition, the acrylic rubber having the crosslinked structure may be formed by the crosslinking reaction of the polymer or copolymer of the acrylic main monomer with the crosslinkable comonomer. If only one type of polymer or copolymer of acrylic main monomer is used, the bonding structure is weak and easy to break. However, if a crosslinkable monomer is added to the polymer or copolymer of acrylic main monomer, the crosslinkable monomer is a polymer or copolymer structure of acrylic main monomer. It can be combined with to create a more rigid net structure. The polymer having such a net structure is less likely to swell in a solvent as the degree of crosslinking increases. The acrylic rubber binder having the crosslinking structure may have a three-dimensional crosslinking structure having 2 to 10 crosslinking points, preferably 4 to 5 crosslinking points, for 10,000 molecular weight units of the main chain molecule. Therefore, the acrylic rubber having a crosslinked structure of the present invention may have expansion resistance that does not swell when the electrolyte solution is moistened.

Due to the inherent characteristics of ceramic materials, acrylic rubber binders having a crosslinked structure having a decomposition temperature of 1000 ° C. or higher and a decomposition temperature of 250 ° C. or higher are used, thereby obtaining a battery having high heat resistance and increasing stability against internal short circuits. .

The acrylic main monomers are methoxymethyl acrylate, methoxyethyl acrylate, (methoxyethyl acrylate), ethoxyethyl acrylate, butoxyethyl acrylate, methoxyethoxyethyl Alkoxyalkyl acrylate selected from methoxyethoxyethyl acrylate and dicyclopentenyloxyethyl acrylate; Vinyl methacrylate, vinyl acrylate, allyl methacrylate, 1,1-dimethylpropenyl methacrylate, 1,1-dimethyl Among propenyl acrylate (1,1-dimethylpropenyl acrylate), 3,3-dimethylbutenyl methacrylate (3,3-dimethylbutenyl methacrylate), 3,3-dimethylbutenyl acrylate (3,3-dimethylbutenyl acrylate) Alkenyl acrylate or alkenyl methacrylate selected; Unsaturated dicarboxylic acid esters selected from divinyl itaconate and divinyl maleate; Vinyl group-containing ethers selected from vinyl 1,1-dimethylpropenyl ether and vinyl 3,3-dimethylbutenyl ether; 1-acryloyloxy-1-phenylethene; And methyl methacrylate (methyl methacrylate) may be used one or more selected from the group consisting of.

The crosslinkable comonomers include 2-ethylhexyl acrylate, 2-methylhexyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate. ), An alkyl acrylate selected from octyl acrylate and isooctyl acrylate; an alkyl selected from vinyl chloroacetate and acryl chloroacetate. Alkenyl chloroacetate; Glycidyl group-containing esters or ethers selected from glycidyl acrylate, vinylglycidyl ether, and acryl glycidyl ether; Unsaturated carboxylic acids selected from acrylic acid, methacrylic acid and maleic acid; 2-chloroethyl vinyl ether; Chloromethyl styrene; And one or more selected from the group consisting of acrylonitrile can be used.

In this case, the content of the binder is preferably 0.1 to 4% by weight based on 100% by weight of the total porous film is bonded by a ceramic material and a binder.

The binder serves to bind the ceramic powders to each other, and also to bind the ceramic layer and the active material layer. When the binder content is less than 0.1% by weight, the flexibility of the ceramic layer is reduced, and the binding force of the ceramic layer is insufficient. There is a problem that the scratch strength of the scratch is reduced and well scratched, if it exceeds 4% by weight to prevent pores between the ceramic powder, thereby preventing the smooth movement of lithium ions, there is a problem that the capacity is reduced, In particular, there is no effect of compensating for the internal short circuit characteristic according to the present invention.

Next, an electrode assembly including the separator of the present invention and a secondary battery having the same include a positive electrode and a negative electrode.

The positive electrode includes a positive electrode active material layer and a positive electrode current collector coated with the positive electrode active material.

Aluminum and an aluminum alloy may be used as the cathode current collector, and the cathode active material layer is characterized by including an olivine structure compound of the following [Formula 1].

[Formula 1]

Li _y MXO _k (wherein M is Na, K, Mg, Ca, Sr, Ni, Co, Si, Ti, B, Al, Sn, Mn, Cr, Fe, Ce, V, Zr and combinations thereof At least one element selected from the group, X is at least one element selected from the group consisting of P, S, W, and a combination thereof, wherein 0 <y≤1, 2≤k≤4)

In this case, the olivine structure compound is preferably LiFePo ₄ in the mass production potential, such as price, supply and demand, fairness.

In addition, in the present invention, the positive electrode active material may further include a material capable of inserting and detaching lithium ions, and as a representative example, the lithium-containing compound described below may be preferably used.

Li _x Mn _{1 - y} MyA ₂ (1)

Li _x Mn _{1 - y} M _y O _{2 - z} X _z (2)

Li _x Mn ₂ O _{4 - z} X _z (3)

Li _x Mn _{2 - y} M _y M ' _z A ₄ (4)

Li _x Co _{1 - y} M _y A ₂ (5)

Li _x Co _{1 - y} M _y O _{2 - z} X _z (6)

Li _x Ni _{1 - y} M _y A ₂ (7)

Li _x Ni _{1 - y} M _y O _{2 - z} X _z (8)

Li _x Ni _{1 - y} Co _y O _{2 - z} X _z (9)

Li _x Ni _{1 -y- z} Co _y M _z A _α (10)

Li _x Ni _{1 -y- z} Co _y M _z O _{2 -α} X _α (11)

Li _x Ni _{1 -y- z} Mn _y M _z A _α (12)

Li _x Ni _{1 -y- z} Mn _y M _z O _{2 -α} X _α (13)

(Wherein 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M 'are the same or different, Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and rare earth elements, A is selected from the group consisting of O, F, S and P And X is selected from the group consisting of F, S and P.)

In this case, the positive electrode active material layer may be configured by mixing the olivine structure compound and a compound capable of inserting and desorbing the lithium ions, and the positive electrode active material layer may insert and desorb the lithium ions. The olivine structure compound may be coated on the compound.

In addition, the positive electrode active material layer may be made of only the olivine structure compound, but the conductivity is not good only by the olivine structure compound, the positive electrode active material layer according to the present invention is an olivine structure compound and lithium Preference is given to using compounds which can insert and desorb ions together.

The olivine structure compound is thermally decomposed at a higher temperature than a conventional lithium composite metal compound such as LiCoO ₂ , LiNiO _2, or LiMn ₂ O ₄ when the temperature of the battery rises due to an abnormal battery. Corresponding to a material having excellent stability, and according to such excellent thermal stability, many studies have been made in recent years.

However, there is a weak problem in the internal short-circuit characteristics of the olivine structure compound, and therefore, in order to compensate for this problem, in the present invention, a porous membrane made by combining a ceramic material and a binder as described above is used as a separator. will be.

The separator including the porous membrane formed by the combination of the ceramic material and the binder is a heat-resistant layer that serves to prevent thermal diffusion when an internal short circuit occurs, thereby preventing the electrode from burning, but there is a problem that a conventional film-type separator shrinks at a high temperature. The porous membrane is not likely to shrink or melt.

In addition, the existing polyolefin-based film separator generates harder shorts because the peripheral film is continuously shrunk or melted in addition to the damaged part by the initial heat generation during internal short circuit, and the part where the film separator burns out becomes wider. However, the electrode on which the porous membrane is formed has only a small damage at the portion where the internal short circuit occurs, and does not lead to a phenomenon in which the short circuit portion is widened.

In particular, in the present invention, by using the olivine structure compound as the positive electrode active material, it is possible to improve the thermal stability, and in the case of the olivine structure compound is excellent thermal stability, but the amount of heat generated when the internal short circuit occurs Therefore, the internal short circuit property is not good, and therefore, the internal short circuit property can be compensated for by using the porous membrane by the combination of the ceramic material and the binder as the separator.

In the present invention, the porous membrane may be formed in a form attached or coated on at least one surface of at least one electrode of the positive electrode and the negative electrode of the lithium secondary battery, wherein the porous membrane is a conventional polyethylene (PE), polypropylene (PP), etc. It may serve as a film-like separator made of a polyolefin resin film of the above, and the porous film may also serve as a separator together with film-like separators such as polyethylene (PE), polypropylene (PP) and the like.

In addition, the negative electrode includes a negative electrode active material layer and a negative electrode current collector coated with the negative electrode active material.

Copper and a copper alloy may be used as the negative electrode current collector, and as the negative electrode active material, crystalline or amorphous carbon or a carbon-based negative electrode active material of a carbon composite may be used. It is not limited.

Next, the secondary battery provided with the electrode assembly containing the separator of this invention contains electrolyte solution.

The electrolyte according to the present invention includes a non-aqueous organic solvent, and the non-aqueous organic solvent may be carbonate, ester, ether or ketone. The carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate (MEC) ethylene carbonate (EC), Propylene carbonate (PC), butylene carbonate (BC) and the like can be used, and the ester is butyrolactone (BL), decanolide (decanolide), valerolactone, mevalonolactone (mevalonolactone) , Caprolactone, n-methyl acetate, n-ethyl acetate, n-propyl acetate, and the like may be used. The ether may be dibutyl ether, and the like, and the ketone may include polymethylvinyl ketone. The present invention is not limited to the type of nonaqueous organic solvent.

When the non-aqueous organic solvent is a carbonate-based organic solvent, it is preferable to use a mixture of cyclic carbonate and chain carbonate. In this case, the cyclic carbonate and the chain carbonate are preferably used by mixing in a volume ratio of 1: 1 to 1: 9, and more preferably used by mixing in a volume ratio of 1: 1.5 to 1: 4. The performance of the electrolyte is preferable when mixed in the above volume ratio.

The electrolyte solution of the present invention may further include an aromatic hydrocarbon organic solvent in the carbonate solvent. An aromatic hydrocarbon compound may be used as the aromatic hydrocarbon organic solvent.

Specific examples of the aromatic hydrocarbon-based organic solvent include benzene, fluorobenzene, chlorobenzene, nitrobenzene, toluene, fluorotoluene, trifluorotoluene, xylene and the like. In the electrolyte containing an aromatic hydrocarbon-based organic solvent, the volume ratio of the carbonate solvent / aromatic hydrocarbon solvent is preferably 1: 1 to 30: 1. The performance of the electrolyte is preferable when mixed in the above volume ratio.

In addition, the electrolyte according to the present invention includes a lithium salt, the lithium salt acts as a source of lithium ions in the battery to enable the operation of the basic lithium battery, for example LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiAlO ₄ , LiAlCl ₄ , LiN (C _x F _{2x +1} SO ₂ ) (CyF _{2x + 1} SO ₂ ), where x and y are natural water and LiSO ₃ CF ₃ , including one or more or mixtures thereof.

At this time, the concentration of the lithium salt can be used within the range of 0.6 to 2.0M, preferably 0.7 to 1.6M range. If the concentration of the lithium salt is less than 0.6M, the conductivity of the electrolyte is lowered and the performance of the electrolyte is lowered. If the lithium salt is more than 2.0M, the viscosity of the electrolyte is increased, thereby reducing the mobility of lithium ions.

As described above, two electrodes are laminated or wound after lamination to form an electrode group in a porous film made of a ceramic material and a binder formed on the positive electrode or the negative electrode or both sides according to the present invention, and then placed in a can or a similar container. After the addition, the electrolyte is injected to prepare a lithium secondary battery.

In addition, the external shape of the lithium ion secondary battery produced by the above method is not limited, and, for example, a cylindrical, square or pouch type may be used.

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention and the present invention is not limited to the following examples.

Example 1

LiCoO ₂ and LiFePO ₄ are mixed and used as the positive electrode active material, polyvinylidene fluoride (PVDF) as the binder and carbon as the binder are mixed in a weight ratio of 92: 4: 4, and then N-methyl-2-pyrroli Dispersed in pigs to prepare a positive electrode slurry. The slurry was coated on aluminum foil, followed by drying and rolling to prepare a positive electrode. Artificial graphite as a negative electrode active material, styrene-butadiene rubber as a binder, and carboxymethyl cellulose as a thickener were mixed in a weight ratio of 96: 2: 2, and then dispersed in water to prepare a negative electrode active material slurry. The slurry was coated on copper foil, dried and rolled to prepare a negative electrode.

In addition, a porous membrane paste is prepared by mixing acrylic rubber with a binder and a material such as silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ) and titanium oxide (TiO ₂ ) as a ceramic material. A porous membrane was formed between the cathode and the anode to form a separator, which was wound and compressed to insert into a cylindrical can. In this case, the binder was 1% by weight based on 100% by weight of the entire porous film.

An electrolyte was injected into the cylindrical can to prepare a lithium secondary battery.

Example 2

Except that the content of the binder was 4% by weight based on 100% by weight of the total porous film was carried out in the same manner as in Example 1.

Comparative Example 1

It carried out similarly to Example 1 except having used the polyethylene resin film, without using the porous film which combines a ceramic material and a binder with a separator.

Comparative Example 2

LiCoO ₂ was used as the positive electrode active material, and the contents of the binder were the same as in Example 1 except that the content of the binder was 4% by weight based on 100% by weight of the entire porous film.

Comparative Example 3

Except that the content of the binder was 5% by weight based on 100% by weight of the total porous film was carried out in the same manner as in Example 1.

The thermal exposure characteristics of the lithium batteries of Examples 1 and 2 and Comparative Examples 1 to 3 were measured. The thermal exposure characteristics of the lithium ion secondary battery in the standard charging state after increasing the temperature from room temperature to 200 ℃ for 10 minutes, and observed the change of the battery while maintaining at 200 ℃ 10 minutes. In this case, when there is no smoke or ignition, "OK" is displayed, and when smoke or ignition occurs, "NG" is indicated.

In addition, the internal short circuit characteristics of the lithium batteries of Examples 1 and 2 and Comparative Examples 1 to 3 were measured. The internal short-circuit characteristics were measured through the nail penetration characteristics, specifically, the penetration test was carried out with a nail pin penetration speed of 10mm / s, the thickness of the nail pin to be 3mm Φ, in this case, there is no smoke or ignition "OK" is indicated, and when smoke or ignition occurs "NG".

The measurement results are shown in Table 1 below.

TABLE 1

division Cathode active material Separator Type Binder Content (wt%) Thermal exposure characteristic Internal short circuit characteristics Example 1 LiCoO ₂ and LiFePO ₄ Mix Porous membrane One OK OK Example 2 LiCoO ₂ and LiFePO ₄ Mix Porous membrane 4 OK OK Comparative Example 1 LiCoO ₂ and LiFePO ₄ Mix Polyethylene resin film - OK NG Comparative Example 2 LiCoO ₂ Porous membrane 4 NG OK Comparative Example 3 LiCoO ₂ and LiFePO ₄ Mix Porous membrane 5 OK NG

From the results shown in Table 1 above, Examples 1 and 2 show that the thermal exposure characteristics are excellent by mixing LiFePO ₄ as the positive electrode active material, and the separator is formed by combining a ceramic material and a binder. By using the porous membrane and the content of the binder to 4% by weight or less relative to 100% by weight of the entire porous film, it can be seen that the internal short circuit characteristics are excellent.

However, when comparing Example 1 and Comparative Example 1, it can be seen that the internal short-circuit characteristic is not good in Comparative Example 1 using a polyethylene resin film without using a porous membrane as a separator, and also Example 2 and Comparative Example. In comparison 2, it can be seen that in Comparative Example 2 using LiCoO ₂ as the positive electrode active material, the thermal exposure characteristics are not good.

In addition, when comparing Examples 1, 2 and Comparative Example 3, in the case of Comparative Example 3 in which the content of the binder is more than 5% by weight, that is, more than 4% by weight of the total 100% by weight of the porous membrane, the internal short circuit characteristics are rather It is not good.

Therefore, in the present invention, by including an olivine structure compound in the positive electrode active material layer, it is possible to satisfy the thermal exposure characteristics, and further, by using a porous membrane made of a combination of a ceramic material and a binder as the separator, By setting the content to 4% by weight or less relative to 100% by weight of the entire porous film, the internal short circuit property can be satisfied.

Although the present invention has been shown and described with reference to the preferred embodiments as described above, it is not limited to the above embodiments and those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

Claims (13)

An electrode assembly comprising a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, and a separator separating the positive electrode and the negative electrode, The separator includes a porous film formed by bonding a ceramic material and a binder, The cathode active material layer is an electrode assembly, characterized in that it comprises an olivine (olivine) structure compound of the formula [1]. [Formula 1] Li _y MXO _k (wherein M is Na, K, Mg, Ca, Sr, Ni, Co, Si, Ti, B, Al, Sn, Mn, Cr, Fe, Ce, V, Zr and combinations thereof At least one element selected from the group, X is at least one element selected from the group consisting of P, S, W, and a combination thereof, wherein 0 <y≤1, 2≤k≤4) The method of claim 1, The binder is an electrode assembly, characterized in that 0.1 to 4% by weight relative to 100% by weight of the total porous film. The method of claim 1, The cathode active material layer further comprises a compound capable of inserting and detaching at least one lithium ion selected from the group consisting of the following formulas (1) to (13). Li _x Mn _{1 - y} MyA ₂ (1) Li _x Mn _{1 - y} M _y O _{2 - z} X _z (2) Li _x Mn ₂ O _{4 - z} X _z (3) Li _x Mn _{2 - y} M _y M ' _z A ₄ (4) Li _x Co _{1 - y} M _y A ₂ (5) Li _x Co _{1 - y} M _y O _{2 - z} X _z (6) Li _x Ni _{1 - y} M _y A ₂ (7) Li _x Ni _{1 - y} M _y O _{2 - z} X _z (8) Li _x Ni _{1 - y} Co _y O _{2 - z} X _z (9) Li _x Ni _{1 -y- z} Co _y M _z A _α (10) Li _x Ni _{1 -y- z} Co _y M _z O _{2 -α} X _α (11) Li _x Ni _{1 -y- z} Mn _y M _z A _α (12) Li _x Ni _{1 -y- z} Mn _y M _z O _{2 -α} X _α (13) (Wherein 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M 'are the same or different, Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and rare earth elements, A is selected from the group consisting of O, F, S and P And X is selected from the group consisting of F, S and P.) The method of claim 3, wherein The cathode active material layer is an electrode assembly, characterized in that the compound that can insert and detach the olivine (olivine) structure compound and the lithium ion. The method of claim 3, wherein The positive electrode active material layer is an electrode assembly, characterized in that the olivine (olivine) structure compound is coated on the compound capable of inserting and detaching the lithium ions. The method of claim 1, The olivine (olivine) structure compound is an electrode assembly, characterized in that LiFePO ₄ . In a lithium secondary battery comprising a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, an electrode assembly comprising a separator separating the positive electrode and the negative electrode, and an electrolyte solution, The separator includes a porous film formed by bonding a ceramic material and a binder, The cathode active material layer is a lithium secondary battery comprising an olivine (olivine) structure compound of the formula [1]. [Formula 1] Li _y MXO _k (wherein M is Na, K, Mg, Ca, Sr, Ni, Co, Si, Ti, B, Al, Sn, Mn, Cr, Fe, Ce, V, Zr and combinations thereof At least one element selected from the group, X is at least one element selected from the group consisting of P, S, W, and a combination thereof, wherein 0 <y≤1, 2≤k≤4) The method of claim 7, wherein The binder is a lithium secondary battery, characterized in that 0.1 to 4% by weight based on 100% by weight of the total porous film. The method of claim 7, wherein The cathode active material layer further comprises a compound capable of inserting and detaching at least one lithium ion selected from the group consisting of the following formulas (1) to (13). Li _x Mn _{1 - y} MyA ₂ (1) Li _x Mn _{1 - y} M _y O _{2 - z} X _z (2) Li _x Mn ₂ O _{4 - z} X _z (3) Li _x Mn _{2 - y} M _y M ' _z A ₄ (4) Li _x Co _{1 - y} M _y A ₂ (5) Li _x Co _{1 - y} M _y O _{2 - z} X _z (6) Li _x Ni _{1 - y} M _y A ₂ (7) Li _x Ni _{1 - y} M _y O _{2 - z} X _z (8) Li _x Ni _{1 - y} Co _y O _{2 - z} X _z (9) Li _x Ni _{1 -y- z} Co _y M _z A _α (10) Li _x Ni _{1 -y- z} Co _y M _z O _{2 -α} X _α (11) Li _x Ni _{1 -y- z} Mn _y M _z A _α (12) Li _x Ni _{1 -y- z} Mn _y M _z O _{2 -α} X _α (13) (Wherein 0.9≤x≤1.1, 0≤y≤0.5, 0≤z≤0.5, 0≤α≤2, M and M 'are the same or different, Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, As, Zr, Mn, Cr, Fe, Sr, V and rare earth elements, A is selected from the group consisting of O, F, S and P And X is selected from the group consisting of F, S and P.) The method of claim 9, The positive electrode active material layer is a lithium secondary battery, characterized in that the compound which can insert and detach the olivine (olivine) structure compound and the lithium ion. The method of claim 9, The positive electrode active material layer is a lithium secondary battery characterized in that the olivine (olivine) structure compound is coated on a compound capable of inserting and detaching the lithium ions. The method of claim 7, wherein The olivine structure compound is a lithium secondary battery, characterized in that LiFePO ₄ . The method of claim 7, wherein The electrolyte solution is a lithium secondary battery comprising a non-aqueous organic solvent and a lithium salt.