KR20090076282A - Electrode assembly and secondary battery having the same - Google Patents

Abstract

An electrode assembly is provided to improve charging and discharging properties of high efficiency because lithium positive ions can freely move between pores of ceramic powder, and to reduce danger of rupture and explosion caused by O2 gas. An electrode assembly comprises a positive electrode having a positive active material layer; a negative electrode having a negative active material layer; a separator separating the positive electrode and the negative electrode; and a Si- containing material layer formed on the separator. The separator comprises a porous membrane which is bonded by the ceramic material and binder. The Si-containing material layer is a hexamethyl disilazane compound of chemical formula 1.

Description

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

The present invention relates to an electrode assembly and a secondary battery having the same, and more particularly, to a secondary battery having low battery corrosion and excellent high rate charge / discharge characteristics.

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.

In the conventional separator, polyolefin-based microporous polymer membranes such as polypropylene and polyethylene or multiple membranes thereof are used. However, since the porous membrane layer has a sheet or film shape, internal short-circuit or overcharge The sheet-like separator also shrinks due to pore blocking of the porous membrane due to heat generation by the heat generation.

Therefore, when the sheet-like separator breaks down due to internal heat generation of the battery, the separator is reduced and the missing part is directly in contact with the positive electrode and the negative electrode, which leads to ignition, rupture, and explosion.

Therefore, in order to compensate for the above problems of the film-like separator, the ceramic material of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ) and titanium oxide (TiO ₂ ) is combined with a binder. There is an active research on ceramic separators that apply a porous membrane formed as a separator.

However, in order to remove the conventional film-like separator and completely prevent the internal short circuit with only the porous film containing the ceramic material, the porous film layer including the ceramic material must be denser.

To this end, the ceramic powder particles should be made small in nano size, but the smaller the ceramic powder particles, the larger the specific surface area, so that the problem of easily moistening the moisture in the air.

In addition, when the moisture-condensed ceramic powder is present inside the battery, it reacts with lithium salts such as LiPF ₆ and LiBF ₄ in the electrolyte to form a strong acid of HF. When HF is formed, a current collector and a battery can of aluminum or copper foil are produced. There is a problem of deteriorating battery performance by corroding the metal of the inner wall.

Further, the surface of the moist ceramic particle also a lot of moisture is OH in H ₂ O ^- group or O ^{2 -} due to by a is negatively charged is to capture attracted lithium cations to move lithium ions through between the pores of the ceramic powder There is a problem that the high rate charge-discharge characteristics are reduced.

Accordingly, the present invention is to solve the above-mentioned disadvantages and problems of the prior art, and to inhibit the ceramic powder from deteriorating battery performance by corroding the metal of the inner wall of the battery can by the strong acid such as HF generated by reaction with the electrolyte. There is an object of the present invention.

In addition, an object of the present invention is to provide a secondary battery having improved high rate charge / discharge characteristics when the particle diameter of the ceramic powder is small.

The present invention is a positive electrode having a positive electrode active material layer; A negative electrode having a negative electrode active material layer; A separator separating the positive electrode and the negative electrode; And an Si-containing material layer formed on the separator, wherein the separator includes a porous film formed by bonding a ceramic material and a binder.

In addition, the present invention is 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 a secondary battery comprising an electrolyte solution, formed on the separator It includes a Si-containing material layer, the separator provides a secondary battery characterized in that it comprises a porous film which is bonded by a ceramic material and a binder.

The present invention also provides an electrode assembly and a secondary battery having the same, wherein the Si-containing material layer is a hexamethyl disilazane (HMDS) compound represented by Formula 1 below.

[Formula 1]

In addition, the present invention is characterized in that the ceramic material is made of at least one material selected from the group consisting of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ) and titanium oxide (TiO ₂ ). It provides an electrode assembly and a secondary battery having the same.

In addition, the present invention provides an electrode assembly and a secondary battery having the same, characterized in that the particle diameter (D50) of the ceramic material is greater than 0 and 0.8 μm or less.

Therefore, the electrode assembly of the present invention and the secondary battery having the same have an effect of inhibiting deterioration of battery performance by corrosion of metal on the inner wall of the battery can by a strong acid such as HF.

In addition, the present invention has the effect of providing a secondary battery with improved high rate charge and discharge characteristics when the particle diameter of the ceramic powder is small.

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 is composed of a porous membrane 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 the porous membrane is formed on the positive electrode, the negative electrode, or both electrodes using the paste. Can be formed.

The porous membrane may serve as a film-like separator of conventional polyethylene (PE), polypropylene (PP) and the like.

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.

At this time, the particle diameter (D50) of the ceramic material is preferably more than 0 and 0.8㎛ or less.

When the particle diameter (D50) of the ceramic material exceeds 0.8 μm, the moisture content of the battery is not large, and thus the high rate charge / discharge characteristics of the battery are not significantly deteriorated. However, since the compactness of the porous membrane layer including the ceramic material is lowered, the internal short circuit is prevented. There is a problem that cannot be completely prevented.

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. Combined with the structure, you can 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-dimethacrylate 1,1-dimethylpropenyl acrylate, 3,3-dimethylbutenyl methacrylate, 3,3-dimethylbutenyl acrylate Alkenyl acrylate or alkenyl methacrylate selected from among; 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.

Next, the electrode assembly including the separator of the present invention and the secondary battery having the same include a Si-containing material layer on the porous membrane layer formed by the ceramic material and the binder.

In this case, the Si-containing material layer is characterized in that it comprises a compound of formula (1).

[Formula 1]

Wherein R1, R2 and R3 each independently represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted amine group, -SH, a substituted or unsubstituted C1-20 alkyl group, a substituted or unsubstituted C3 ~ 20 cycloalkyl groups, substituted or unsubstituted alkenyl groups having 1 to 20 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted carbon atoms Aryloxy group of 6 to 30, substituted or unsubstituted alkylcarbonyl group of 1 to 20 carbon atoms, X is -NR- (where R is a possible substituent such as hydrogen, alkyl group), -O-, -SO _3- , Substituted or unsubstituted C1-20 alkylene group, substituted or unsubstituted C2-20 alkenylene group, substituted or unsubstituted silanylene group, substituted or unsubstituted C6-30 arylene group, substituted Or an unsubstituted peptyl group, Substituted or unsubstituted carbonylene group, substituted or unsubstituted oxyalkylene group having 1 to 20 carbon atoms, heteroalkylene group, A is a hydrogen atom, a halogen atom, -SH, a substituted or unsubstituted amino group, substituted or unsubstituted Heterocycloalkyl group having 2 to 15 carbon atoms, alkenyl group having 2 to 20 carbon atoms substituted or unsubstituted, silanyl group having 1 to 10 carbon atoms substituted or unsubstituted, and aryl group having 6 to 20 carbon atoms substituted or unsubstituted.

In addition, as the compound of Formula 1, a compound of Formula 2 is preferable.

[Formula 2]

(Wherein R1, R2, R3 and X are as defined above)

In addition, as the compound of Formula 1, a compound of Formula 3 is preferable.

[Formula 3]

Wherein R1, R2 and R3 are as defined above, and R4, R5 and R6 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted amine group, a substituted or unsubstituted thiol group, a substituted or unsubstituted A substituted C1-C20 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C1-C20 alkenyl group, a substituted or unsubstituted C1-C20 alkoxy group, substituted or An unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a substituted or unsubstituted alkylcarbonyl group having 1 to 20 carbon atoms, X 1 represents -O-, -NH-, A substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms, and a substituted or unsubstituted arylene group having 6 to 30 carbon atoms.

In addition, as the compound of Formula 1, an HMDS (hexamethyl disilazane) compound of Formula 4 is preferable.

[Formula 4]

The HMDS (hexamethyl disilazane) compound reacts, for example, as follows.

Firstly reacted with water to capping as shown in Scheme 1.

Scheme 1

(CH ₃ ) ₃ SiNHSi (CH ₃ ) ₃ + H ₂ O → (CH ₃ ) ₃ SiOSi (CH ₃ ) ₃ + NH ₃

In addition, if an acid is present, a reaction is performed as in Scheme 2 to Scheme 4 below.

Scheme 2

(CH ₃ ) ₃ SiNHSi (CH ₃ ) ₃ + 2HCi → 2 (CH ₃ ) ₃ SiCl + NH ₃

Scheme 3

(CH ₃ ) ₃ SiNHSi (CH ₃ ) ₃ + 2HF → 2 (CH ₃ ) ₃ SiF + NH ₃

Scheme 4

(CH ₃ ) ₃ SiNHSi (CH ₃ ) ₃ + 2H ₂ SO ₄ → 2 (CH ₃ ) ₃ SiOSO ₃ H + NH ₃

Group or O ^{2 - -} the Si-containing material layer, the multi When applied to the surface of the porous layer Si Si-containing material layer is OH in the surface of the membrane layer being able to be capped (capping) group, through this, the negative It is possible to make the ceramic powder charged with neutral neutral or to charge positively.

Therefore, powders do not aggregate with each other during ceramic paste mixing, so that dispersibility is also improved, and Li ⁺ ions can be prevented from being trapped on the surface of the ceramic powder. As a result, lithium cations can move freely between pores of the ceramic powder. High rate charge and discharge performance can also be improved.

In addition, as in the reaction schemes 2 to 4, by removing HF, it becomes possible to prevent the risk of rupture and explosion due to the generation of O ₂ gas due to corrosion by HF or the like.

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 capable of reversibly intercalating and deintercalating lithium ions. Representative examples of the positive electrode active material include LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , or LiNi _{1 −} Lithium-transition metal oxides such as _{x- y} Co xMyO ₂ (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ x + y ≤ 1, M is a metal of Al, Sr, Mg, La, etc.) can be used However, the present invention is not limited to the type of the cathode active material.

The negative electrode includes a negative electrode active material capable of intercalating and deintercalating lithium ions, 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. In the present invention, the type of the negative electrode active material is not limited.

In addition, the positive electrode includes a positive electrode current collector, aluminum and an aluminum alloy may be used as the positive electrode current collector, the negative electrode may include a negative electrode current collector, and copper and a copper alloy may be used as the negative electrode current collector. Can be. Examples of the positive electrode current collector and the negative electrode current collector include a foil, a film, a sheet, a punched one, a porous body, a foam, and the like.

The two electrodes may be laminated in a state in which the porous membrane of the present invention is formed on the positive electrode or the negative electrode, or both, or may be wound after the lamination to form an electrode group. As described above, since the porous membrane itself may serve as a separator, it may be omitted to provide a separate separator between the two electrodes.

Conventional film type separators have a problem of shrinkage at high temperatures, but the porous membrane is not likely to shrink or melt. Conventional polyolefin-based film separators generate harder shorts because the peripheral film is continuously shrunk or melted in addition to the parts damaged by initial heat generation during internal short-circuit, and thus the film separator burns out. The electrode on which the porous membrane is formed has only a small damage in a portion where an internal short circuit occurs, and does not lead to a widening of the short circuit region. In addition, the electrode formed with the porous membrane generates a very small short instead of a hard short when overcharging and continuously consumes the overcharge current, thereby maintaining a constant voltage between 5V and 6V and a battery temperature of 100 ° C. or less. Stability can also be improved.

In particular, in the present invention, through the Si-containing material layer formed on the porous membrane layer, lithium cations can move freely between pores of the ceramic powder, thereby improving high rate charge and discharge performance, and further, O ₂ gas due to corrosion by HF or the like. It can reduce the risk of rupture or explosion due to occurrence.

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, the ester is butyrolactone (BL), decanolide (decanolide), valerolactone (valerolactone), mevalonolactone ( mevalonolactone), caprolactone (caprolactone), n-methyl acetate, n-ethyl acetate, n-propyl acetate and the like can be used, the ether may be dibutyl ether and the like, the ketone polymethyl vinyl ketone However, the present invention is not limited to the type of non-aqueous 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 desirable when mixed in the 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.

The separator of the present invention as described above is laminated between the negative electrode and the positive electrode, or after lamination, is wound up to form an electrode group, and then placed in a can or a similar container, and then an electrolyte is injected to prepare a secondary battery. .

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

Four kinds of alpha alumina, zirconia, titanium barium acid and silica were selected as ceramic powder types. The ceramic powder was prepared by mixing and mixing the ceramic powder, the solvent, and the binder by particle diameter (D50) of the ceramic powder, and then coating the surface of the negative electrode active material layer with a thickness of 10 μm to manufacture a battery.

The surface of the negative electrode active material layer was surface treated with a hexamethyl disilazane (HMDS) compound, and a battery was manufactured by a general battery manufacturing process.

[Comparative Example]

Except that the surface of the negative electrode active material layer was not surface-treated with HMDS (hexamethyl disilazane) compound was carried out in the same manner as in Example.

The high rate filling amount (%) (3C filling amount / 0.2C filling amount × 100) of the above Examples and Comparative Examples was measured to indicate “OK” when 90% or more and “NG” when 90% or less.

In addition, the high-rate discharge amount (%) (3C charge amount / 0.2C charge amount × 100) of the above Examples and Comparative Examples was measured to display "OK" when 90% or more, and "NG" when less than 90%.

The results shown in Tables 1 to 4 were obtained for each ceramic powder type and particle size.

TABLE 1

division Alpha alumina particle size (D50) (nm) HMDS surface treatment High rate charge amount (%) High rate discharge rate (%) Example 1 200 U OK OK Example 2 400 U OK OK Example 3 600 U OK OK Example 4 800 U OK OK Example 5 1000 U OK OK Example 6 1200 U OK OK Comparative Example 1 200 radish NG NG Comparative Example 2 400 radish NG NG Comparative Example 3 600 radish NG NG Comparative Example 4 800 radish NG NG Comparative Example 5 1000 radish OK OK Comparative Example 6 1200 radish OK OK

TABLE 2

division Zirconia particle size (D50) (nm) HMDS surface treatment High rate charge amount (%) High rate discharge rate (%) Example 7 200 U OK OK Example 8 400 U OK OK Example 9 600 U OK OK Example 10 800 U OK OK Example 11 1000 U OK OK Example 12 1200 U OK OK Comparative Example 7 200 radish NG NG Comparative Example 8 400 radish NG NG Comparative Example 9 600 radish NG NG Comparative Example 10 800 radish NG NG Comparative Example 11 1000 radish OK OK Comparative Example 12 1200 radish OK OK

TABLE 3

division Titanium Barium Particle Size (D50) (nm) HMDS surface treatment High rate charge amount (%) High rate discharge rate (%) Example 13 200 U OK OK Example 14 400 U OK OK Example 15 600 U OK OK Example 16 800 U OK OK Example 17 1000 U OK OK Example 18 1200 U OK OK Comparative Example 13 200 radish NG NG Comparative Example 14 400 radish NG NG Comparative Example 15 600 radish NG NG Comparative Example 16 800 radish NG NG Comparative Example 17 1000 radish OK OK Comparative Example 18 1200 radish OK OK

TABLE 4

division Silica Particle Size (D50) (nm) HMDS surface treatment High rate charge amount (%) High rate discharge rate (%) Example 19 200 U OK OK Example 20 400 U OK OK Example 21 600 U OK OK Example 22 800 U OK OK Example 23 1000 U OK OK Example 24 1200 U OK OK Comparative Example 19 200 radish NG NG Comparative Example 20 400 radish NG NG Comparative Example 21 600 radish NG NG Comparative Example 22 800 radish NG NG Comparative Example 23 1000 radish OK OK Comparative Example 24 1200 radish OK OK

Tables 1 to 4 show the characteristics of particle diameters (D50) of alpha alumina, zirconia, titanium barium acid, and silica, respectively.

As can be seen in Comparative Examples 5, 6, 11, 12, 17, 18, 23, and 24, when the D50 value of the ceramic powder is large enough to exceed 0.8um, the moisture content is not large, so the high rate charge / discharge characteristics of the battery deteriorate. The problem does not occur.

However, if the D50 value becomes smaller than 0.8um regardless of the ceramic type, the moisture content in the air increases, which adversely affects the high rate charge / discharge characteristics of the battery. Therefore, the surface of the fine ceramic powder is treated with Removing the state of negative charge by water can improve the high rate charge and discharge characteristics of the battery.

When the particle diameter (D50) of the ceramic material exceeds 0.8 μm, the moisture content of the battery is not large, and thus the high rate charge / discharge characteristics of the battery are not significantly deteriorated. However, since the compactness of the porous membrane layer including the ceramic material is lowered, the internal short circuit is prevented. There is a problem that cannot be completely prevented.

Therefore, in the present invention, when the particle diameter (D50) of the ceramic material exceeds 0 and is 0.8 탆 or less, it is preferable that the Si-containing material layer is included on the porous film layer which is bonded by the ceramic material and the binder.

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 (11)

A positive electrode having a positive electrode active material layer; A negative electrode having a negative electrode active material layer; A separator separating the positive electrode and the negative electrode; And A Si-containing material layer formed on the separator, The separator is an electrode assembly, characterized in that it comprises a porous membrane which is bonded by a ceramic material and a binder. The method of claim 1, The Si-containing material layer is an electrode assembly, characterized in that the hexamethyl disilazane (HMDS) compound of the formula (1). [Formula 1]

The method of claim 1, The ceramic material comprises at least one material selected from the group consisting of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ) and titanium oxide (TiO ₂ ). The method of claim 1, The particle diameter (D50) of the ceramic material is greater than 0 and the electrode assembly, characterized in that less than 0.8㎛. The method of claim 1, The binder is an electrode assembly, characterized in that the synthetic rubber-based latex binder or acrylic rubber having a crosslinked structure. In the 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, A Si-containing material layer formed on the separator, The separator comprises a porous film formed by bonding a ceramic material and a binder. The method of claim 6, The Si-containing material layer is a secondary battery, characterized in that the HMDS (hexamethyl disilazane) compound of the formula (1). [Formula 1]

The method of claim 6, The ceramic material is at least one material selected from the group consisting of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ) and titanium oxide (TiO ₂ ). The method of claim 6, Particle diameter (D50) of the ceramic material is greater than 0 and the secondary battery, characterized in that less than 0.8㎛. The method of claim 6, The binder is a secondary rubber, characterized in that the synthetic rubber-based latex binder or acrylic rubber having a crosslinked structure. The method of claim 6, The electrolyte solution is a secondary battery comprising a non-aqueous organic solvent and a lithium salt.