KR20140099710A - Method for preparing electrode assembly, electrode assembly therefrom, and electrochemical device comprising the same - Google Patents

Abstract

The present invention relates to a manufacturing method of an electrode assembly, an electrode assembly thereby, and an electrochemical device including the same. According to an aspect of the present invention, provided is a manufacturing method of an electrode assembly, which comprises a first electrode forming step, a separator membrane coating layer forming step, a separator membrane forming step, a second electrode forming step, and an electrode assembly forming step. According to another aspect of the present invention, provided is an electrode assembly, which comprises a first electrode including a first electrode active material layer having multiple pores; a separator membrane combined with the first electrode active material layer, and positioned on the surface of the first electrode active material layer and within the pores; and a second electrode combined with the separator membrane, having multiple pores, and including a second electrode active material layer having the separator membrane positioned on the surface and within the pores. The electrode assembly according to the method of the present invention and the electrochemical device including the same can remarkably improve output performance while maintaining the binding force between the electrodes and the separator membrane.

Description

FIELD OF THE INVENTION The present invention relates to a method of manufacturing an electrode assembly, an electrode assembly thereof, and an electrochemical device including the electrode assembly,

The present invention relates to a method of manufacturing an electrode assembly, an electrode assembly thereof, and an electrochemical device including the same.

Recently, interest in energy storage technology is increasing. As the application fields of cell phones, camcorders, notebook PCs and even electric vehicles are expanding, efforts for research and development of electrochemical devices are becoming more and more specified. The electrochemical device is one of the most attracting fields in this respect, and development of a rechargeable secondary battery is of particular interest.

BACKGROUND OF THE INVENTION [0002] Electrochemical devices have been developed by continuous research as electrode active materials whose various performances, particularly those with significantly improved power. In the case of a separation membrane, a film-type separation membrane is used, and a coating layer containing inorganic particles is applied to the separation membrane. However, the electrode active materials in the electrochemical device still show insufficient output, and the separation membrane interposed between these electrodes is complicated in the process, and there is a problem that a space is formed between the electrodes after assembly.

Therefore, there is still a demand for an electrode assembly and an electrochemical device including the electrode assembly, which are excellent in productivity and greatly reduce the resistance between both electrodes.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to maximize the output of an electrode assembly and an electrochemical device including the electrode assembly in which a separation membrane is interposed between both electrodes without space.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a first electrode including a first electrode active material layer; Forming a separation membrane coating layer by applying a polymer solution or a polymer gel on the first electrode; Drying the coated separation membrane coating layer to form a separation membrane; Forming a second electrode including a second electrode active material layer on the separation layer; And forming an electrode assembly by rolling the first electrode, the separator, and the second electrode.

According to another aspect of the present invention, there is provided a plasma display panel comprising: a first electrode including a first electrode active material layer having a plurality of pores; A separator coupled to the first electrode active material layer and positioned within a surface of the first electrode active material layer and the pores; And a second electrode coupled to the separator and having a plurality of pores, the separator including a second electrode active material layer positioned on the surface and in the pores.

The electrode assembly and the electrochemical device including the same according to the method of the present invention can greatly improve the output performance while maintaining the bonding force between the electrode and the separator.

1 is a process flow diagram schematically showing a method of manufacturing an electrode assembly according to the present invention.
2 schematically shows a process of applying a separation membrane solution or gel according to an embodiment of the present invention.
3 is a schematic cross-sectional view of an electrode assembly manufactured in accordance with an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor may designate the concept of a term appropriately in order to describe its own invention in the best way possible. It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the constitutions described in the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents which can be substituted at the time of application It should be understood that variations can be made.

1 is a process flow diagram schematically showing a method of manufacturing an electrode assembly according to the present invention. Referring to FIG. 1, a method of manufacturing an electrode assembly according to an embodiment of the present invention includes forming a first electrode S1, forming a separation membrane coating layer S2, forming a separation membrane S3, (S4) of forming an electrode assembly and a forming step (S4) of forming an electrode assembly.

In step S1, a first electrode including the first electrode active material layer is formed.

The first electrode active material layer may be produced using a method commonly used in the art. For example, a slurry in which electrode active material particles are dispersed in a binder solution in which a binder is dissolved in a solvent is coated on a current collector, and the solvent is removed to prepare an electrode active material layer. Forming the slurry, applying the slurry, and forming the electrode active material layer.

Formation of the slurry is achieved by dispersing the electrode active material particles in a binder solution in which the binder is dissolved in the solvent. That is, a binder suitable for a desired electrode active material is put in a solvent and dissolved to produce a binder solution. Then, the desired electrode active material particles are added to the resulting binder solution, and the mixture is further uniformly dispersed in the binder solution by stirring or the like using a mixer to prepare a slurry.

The electrode active materials (that is, the positive electrode active material and the negative electrode active material) and the current collectors (i.e., the positive electrode current collector and the negative electrode current collector) are not particularly limited and may be prepared according to a conventional method known in the art, can do.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with at least one transition metal; A lithium manganese oxide (LiMnO ₂ ) such as LiMnO ₃ , LiMn ₂ O ₃ , LiMnO _2, etc. represented by the formula Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33); Lithium copper oxide (Li ₂ CuO ₂ ); LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ , Cu ₂ V ₂ O ₇ Vanadium oxide; Nickel type lithium nickel oxide represented by the formula LiNi _{1 - x} M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3) oxide); Formula _{LiMn 2 - x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 to 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which part of the lithium in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) _3, or a composite oxide formed of a combination of these materials, and the like, and are not limited thereto.

The cathode current collector has a thickness of, for example, about 3 to about 500 mu m. Such a positive electrode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery. For example, the positive electrode current collector may be formed on the surface of stainless steel, aluminum, nickel, titanium, sintered carbon or aluminum or stainless steel Carbon, nickel, titanium, silver, or the like may be used. The current collector may form fine irregularities on the surface of the current collector to increase the adhesive force of the cathode 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.

A conductive material may be further mixed with the positive electrode active material particles. Such a conductive material is added, for example, in an amount of 1 to 50% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is added in an amount of about 1 to about 50 wt% based on the total weight of the mixture including the cathode active material, for example, as a component that assists in binding of the cathode active material particles to the conductive material or the like and bonding to the current collector. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

Non-limiting examples of the solvent include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (N -methyl-2-pyrrolidone, NMP), cyclohexane, water, or a mixture thereof. These solvents provide an appropriate level of viscosity so that a slurry coating layer can be formed at a desired level on the current collector surface.

The negative electrode is manufactured by applying negative electrode active material particles on a negative electrode current collector, and drying the negative electrode active material particles, and may further include components such as the above-described conductive material, binder, solvent and the like.

The cathode current collector has a thickness of, for example, about 3 to about 500 mu m. The negative electrode current collector is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver or the like, aluminum-cadmium alloy, or the like can be used. In addition, as in the case of the positive electrode current collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0} = x = 1), Li x WO 2 (0 = x = 1), Sn x Me 1 -x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : A metal complex oxide of Al, B, P, Si, group 1, group 2, group 3 elements of the periodic table, halogen, 0? X = 1; y = 3; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, Bi ₂ O ₅ and the like; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The application of the slurry can be carried out continuously or discontinuously by various methods such as slot die coating, slide coating, curtain coating and the like. Particularly, in terms of productivity, it is preferable that the application is carried out continuously or simultaneously at the same time.

Formation of the electrode active material layer comprises removing solvent from the applied slurry. The solvent can be removed by drying. The slurry applied on the current collector is dried by using a drier or the like to remove the solvent to obtain an electrode.

In step S2, a separation coating layer is formed on the first electrode formed in step S1.

The separation membrane coating layer can be formed, for example, using a polymer for separation membrane which is conventionally produced in the art. The polymer may take the form of particles. The separation membrane coating layer can be formed by applying the polymer solution or the polymer gel formed by dissolving the polymer particles in a solvent onto the supernatant 1 electrode.

The polymer solution or the polymer gel may be independently formed of a material selected from the group consisting of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, a polymer selected from the group consisting of polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylenesulfide, and polyethylenenaphthalene. Or two of them But may include on the mixture are not limited.

It is preferable that the solvent has a solubility index similar to that of the polymer to be used and a low boiling point. This is because the mixing and dissolution can be made uniform, and then the solvent can be easily removed by drying. Non-limiting examples of the solvent include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (N methyl-2-pyrrolidone, NMP), cyclohexane, and water. These solvents provide an appropriate level of viscosity so that the separator coating layer can be formed at a desired level on the surface of the electrode active material layer.

The separator coating layer may be formed by spray coating, dip coating, slot coating, die coating, roll coating, gravure coating, comma coating, or the like. Or a combination of two or more thereof.

In addition, the polymer solution or gel may further contain a pore-forming agent. This pore-forming agent is a substance which is dispersed in the polymer particles and exhibits a heterogeneity of the membrane produced through extrusion, stretching and the like, and is subsequently removed from such a membrane. Therefore, the site where the pore-forming agent is located in the polymer of the membrane remains in the form of pores. The pore former is preferably a liquid material in the extrusion process, but a material that maintains a solid state may be used.

The pore-forming agent may be an aliphatic hydrocarbon-based solvent such as liquid paraffin, paraffin oil, mineral oil or paraffin wax; Vegetable oils such as soybean oil, sunflower oil, rapeseed oil, palm oil, palm oil, coconut oil, corn oil, grape seed oil, cotton seed oil and the like; Or a plasticizer such as a dialkyl phthalate. In particular, the plasticizer is selected from the group consisting of di-2-ethylhexyl phthalate (DOP), di-butyl phthalate (DBP), di- isononyl phthalate Di-isodecyl phthalate (DIDP), butyl benzyl phthalate (BBP), and the like.

In addition, the content of such pore-former may be from about 50 to about 80 wt% based on the total amount of polymer particles and pore-former. If the content of the pore-forming agent falls within this limited range, pores are produced in a desired range, for example, at a pore size of about 40% or more and / or a thickness of 20 m or less and a pore size of about 400 sec / 100 cc or less.

In step S3, a separation membrane is formed from the separation membrane coating layer formed in step S2. For example, formation of this separation membrane can be achieved by removing the solvent from the separation membrane coating layer.

This removal of the solvent is possible by batchwise or continuous drying using an oven or a heated chamber or the like at a temperature range in consideration of the vapor pressure of the solvent used.

The separator may further comprise inorganic particles. The inorganic particles are selected from the group consisting of inorganic particles having a dielectric constant of at least about 5, inorganic particles having lithium ion transport capability, and mixtures thereof.

In step S4, a second electrode including a second electrode active material layer is formed on the separation film formed in step S3.

The second electrode may be formed on the separation membrane coating layer formed in step S2 at the same time as the separation membrane formation in step S3. This is because the solvent of the separation membrane coating layer easily penetrates the second electrode, especially the surface of the second electrode active material layer, and the pores therein, and the second electrode, which is formed in close contact with the separation membrane, . Therefore, steps S3 and S4 may be performed sequentially or simultaneously.

The step S4 may be similar or identical to the step S1, except that the first electrode active material particle and the other electrode active material are used. That is, when the first electrode active material layer includes the cathode active material particles, the second electrode active material layer may include the anode active material particles. In contrast, when the first electrode active material layer includes the negative electrode active material particles, the second electrode active material layer may include the positive electrode active material particles.

The electrode active material, binder, solvent and / or conductive agent used in the step S4 may be selected from those exemplified in the above step S1.

The steps S1 and S4 may produce the first and second electrode active material layers as separate steps of preparing the slurry and the electrode active material, and the sequence thereof is not important. That is, the order of steps S1 and S4 may be changed.

Alternatively, the first electrode active material layer and the second electrode active material layer formed in steps S1 and S4 may be patterned. The patterning may be performed such that the first electrode active material layer and the second electrode active material layer face each other. Facing and facing each other means a state in which a surface having a predetermined surface characteristic contacts with another surface facing the surface with little or no space therebetween. In the patterning, the patterns of the first electrode active material layer and the second electrode active material layer may be the same or different from each other. That is, if the first electrode active material layer and the second electrode active material layer are patterned so as to face each other, the patterned shapes may be different from each other, although they may be the same. If the patterned shapes are equal to each other, a repetitive cycle length will be formed. In addition, the depth of the electrode active material layer and the cycle length in the case of the same patterned shape are determined depending on the characteristics of the electrode active material layer, namely, the kind and content of the electrode active material constituting the electrode active material layer, the kind and content of the binder, The type and thickness of the separation membrane, the bonding state with the separation membrane, the performance of the patterning apparatus, and the like. The first electrode active material layer and the second electrode active material layer may be patterned simultaneously or sequentially.

As described above, in the method of manufacturing the electrode assembly according to one aspect of the present invention, unlike the conventional method in which the separation membrane is laminated or laminated in the form of a film or a membrane, And the bonding property with both electrodes is greatly improved.

An electrode assembly according to another aspect of the present invention includes: a first electrode including a first electrode active material layer having a plurality of pores; A separator coupled to the first electrode active material layer and positioned within a surface of the first electrode active material layer and the pores; And a second electrode coupled to the separator and including a second electrode active material layer having a plurality of pores and the separator being disposed on the surface and the pores.

The first electrode active material layer, the first electrode, the separator, the second electrode active material layer and the second electrode are as described above in connection with the method for manufacturing the electrode assembly hereinabove.

The first electrode is coated on at least one surface of the first current collector, and the first electrode active material particles are bound by the first binder. The second electrode is coated on at least one surface of the second current collector, and the second electrode active material particles are bound by the second binder. The first current collector, the first electrode active material particle, the first binder, the second current collector, the second electrode active material particle, and the second binder are as described above in connection with the method of manufacturing the electrode assembly hereinabove.

The first electrode active material layer may include cathode active material particles, and the second electrode active material layer may include anode active material particles. In addition, the first electrode active material layer may include negative electrode active material particles, and the second electrode active material layer may include positive electrode active material particles.

The patterns of the first electrode active material layer and the second electrode active material layer may be the same or different.

Alternatively, the separation membrane may further include inorganic particles. These inorganic particles are as hereinbefore described with respect to the method of making the electrode assembly hereinabove.

The above-described electrode assembly may be advantageous for a stack & folding or folding electrochemical device in which more than one electrode assembly is bent, This may be due to the constitutional characteristic of the separator, which is closely interposed between the surface of the electrode active material layer and the pores therein.

According to another aspect of the present invention, an electrochemical device including the above-described electrode assembly can be manufactured.

The electrolytic solution which can be used in the electrochemical device of the present invention is a salt having a structure such as A ⁺ B ^- , wherein A ⁺ includes an alkali metal cation such as Li ⁺ , Na ⁺ , K ^{+ -} it is _{^{PF 6 -, BF 4 -,}} Cl -, Br -, I -, ClO 4 -, AsF 6 -, CH 3 CO 2 -, CF 3 SO 3 -, N (CF 3 SO 2) 2 -, C (CF ₂ SO _{2) 3} ^- anion, or a salt containing an ion composed of a combination of propylene carbonate (PC) such as, ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl (DMP), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), gamma butyrolactone -Butyrolactone), or a mixture thereof, but the present invention is not limited thereto.

The electrolyte may be injected at an appropriate stage of the battery manufacturing process, depending on the manufacturing process and required properties of the final product. That is, it can be applied before assembling the cell or at the final stage of assembling the cell.

In addition, the electrochemical device of the present invention includes all devices that perform an electrochemical reaction, and specific examples thereof include capacitors such as all kinds of primary cells, secondary cells, fuel cells, solar cells, or super capacitor devices, And so on. Particularly, a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery among the above secondary batteries is preferable.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

Claims (18)

Forming a first electrode comprising a first electrode active material layer;
Forming a separation membrane coating layer by applying a polymer solution or a polymer gel on the first electrode;
Drying the coated separation membrane coating layer to form a separation membrane;
Forming a second electrode including a second electrode active material layer on the separation layer; And
Forming an electrode assembly by rolling the first electrode, the separator, and the second electrode;
Wherein the electrode assembly includes a first electrode and a second electrode. The method according to claim 1,
Wherein the first electrode active material layer comprises a cathode active material particle and the second electrode active material layer comprises an anode active material particle. The method according to claim 1,
Wherein the first electrode active material layer comprises a negative electrode active material particle and the second electrode active material layer comprises a positive electrode active material particle. The method according to claim 1,
The polymer solution or the polymer gel may be independently selected from the group consisting of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, poly But are not limited to, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, A polymer selected from the group consisting of polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylenesulfide and polyethylenenaphthalene. One polymer or two of these And a mixture of two or more species. The method according to claim 1,
Wherein the polymer solution or the polymer gel further comprises a pore-forming agent. 6. The method of claim 5,
Wherein the pore forming agent is one or a mixture of two or more kinds selected from the group consisting of aliphatic hydrocarbon solvents, vegetable oils, and plasticizers. The method according to claim 1,
The polymer solution or polymer gel may be applied by spray coating, dip coating, slot coating, die coating, roll coating, gravure coating and comma coating. Wherein the first electrode layer is formed on the first electrode layer and the second electrode layer is formed on the second electrode layer. The method according to claim 1,
Wherein the polymer solution or the polymer gel further comprises inorganic particles. 9. The method of claim 8,
Wherein the inorganic particles are selected from the group consisting of inorganic particles having a dielectric constant of 5 or more, inorganic particles having lithium ion transferring ability, and mixtures thereof. The method according to claim 1,
Wherein the step of forming the separation membrane and the step of forming the second electrode are performed sequentially or simultaneously. A first electrode including a first electrode active material layer having a plurality of pores;
A separator coupled to the first electrode active material layer and positioned within a surface of the first electrode active material layer and the pores; And
And a second electrode coupled to the separator and having a plurality of pores, the separator including a second electrode active material layer positioned on the surface and in the pores. 12. The method of claim 11,
Wherein the first electrode active material layer comprises a cathode active material particle and the second electrode active material layer comprises an anode active material particle. 12. The method of claim 11,
Wherein the first electrode active material layer comprises negative electrode active material particles and the second electrode active material layer comprises positive electrode active material particles. 12. The method of claim 11,
Wherein the separation membrane is made of a material selected from the group consisting of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate for example, polycarbonate, polycarbonate, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyether A polymer selected from the group consisting of polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylenesulfide and polyethylenenaphthalene, or a polymer selected from the group consisting of 2 It is formed from mixture of species or more. The electrode assembly according to claim. 12. The method of claim 11,
Wherein the separation membrane further comprises inorganic particles. 16. The method of claim 15,
Wherein the inorganic particles are selected from the group consisting of inorganic particles having a dielectric constant of 5 or more, inorganic particles having lithium ion transferring ability, and mixtures thereof. An electrochemical device comprising the electrode assembly of any one of claims 11 to 16. 18. The method of claim 17,
Wherein the electrochemical device is a lithium secondary battery.

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