KR101696228B1 - Lithium ion capacitor and manufacturing method of thereof - Google Patents

Abstract

The present invention relates to a lithium ion capacitor and a method of manufacturing the same.
A lithium ion capacitor according to the present invention includes: a metal can; A lithium metal attached to an inner peripheral surface of the metal can; An electrode unit accommodated in the metal can and including an anode in the form of a roll, a cathode, and a separator disposed between the anode and the cathode; A lead wire connected to the electrode unit; And an electrolyte injected to impregnate the lithium metal with the electrode unit, wherein the anode is manufactured using a cathode material including activated carbon, and the anode is manufactured using a cathode material including a carbon material.
According to the present invention, lithium metal is attached to the inner circumferential surface of the metal can and the lithium ion can be rapidly and uniformly doped into the negative electrode through charging and discharging, whereby reliability and mass productivity can be secured at the same time, The positive electrode and the negative electrode can be manufactured using the porous current collector so that the lithium ions can smoothly penetrate and move through the current collector and the lithium ion can be discharged at a suitable temperature, Can be uniformly pre-doped.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a lithium ion capacitor,

The present invention relates to a lithium ion capacitor and a method of manufacturing the same. More specifically, the present invention relates to a lithium ion capacitor and a method of manufacturing the same. More particularly, the present invention relates to a lithium ion capacitor, And a lithium ion capacitor capable of having a high energy density per unit volume and a method for manufacturing the lithium ion capacitor.

In general, an electrochemical energy storage device is a key component of an end-of-use device that is essential for all portable information communication and electronic devices. In addition, electrochemical energy storage devices are attracting attention as high-quality energy sources in the renewable energy field that can be applied to future electric vehicles and portable electronic devices.

Among such electrochemical energy storage devices, electrochemical capacitors can be classified into an electric double layer capacitor using an electric double layer principle and a hybrid supercapacitor using an electrochemical oxidation-reduction reaction.

Here, although electric double layer capacitors are widely used in fields requiring high output energy characteristics, the electric double layer capacitors have a problem of small capacitance, and therefore, hybrid super capacitors have been extensively studied as new alternatives for improving capacitance characteristics of electric double layer capacitors have.

In particular, a lithium ion capacitor (LIC) among hybrid supercapacitors can have a storage capacity of about three to four times that of an electric double layer capacitor by doping lithium ions to the negative electrode, .

As these lithium ion capacitors are required to have a high output density (W / Kg) and a high energy density (Wh / Kg), they are required to satisfy the capacity characteristics (mAh / g), charge / discharge rate characteristics, and electrochemical stability Research is being actively carried out. It is aimed at compensating the dynamic characteristics of new and renewable energy sources and extending the operating time or life of battery due to its high power density, small size, light weight, safety and long cycle life. Is widely used.

Currently, it is mainly used as a power supply for memory backup of electronic devices. However, as large-capacity products are developed, it has an unlimited market potential as a next generation energy storage device such as transportation, aerospace and alternative energy.

A typical lithium ion capacitor is a negative electrode made of a positive electrode made of activated carbon and various kinds of carbon materials (for example, graphite, soft carbon and hard carbon) ). Charge and discharge can take place through a process of adsorption / desorption of lithium ions at the anode and intercalation / deintercalation of lithium ions at the cathode.

In order to pre-dope the lithium ion into the cathode, the conventional lithium ion capacitor can be formed by providing a lithium metal film on the upper layer and the lower layer of the electrode structure, respectively, and immersing the lithium metal film in the electrolyte solution.

However, in the conventional lithium ion capacitor, since the lithium metal film is provided in the upper layer and the lower layer of the electrode structure, not only lithium ions are uniformly doped in the entire cathode but also lithium ions are smoothly supplied to the cathode The current collector provided for the positive electrode and the negative electrode has to be provided in the form of a mesh, thereby increasing the internal resistance of the lithium ion capacitor.

In addition, it takes more than 20 days to uniformly dope the negative electrode provided in the conventional lithium ion capacitor, which makes it difficult to apply it to mass production, thereby deteriorating the reliability of the lithium ion capacitor.

: Domestic registered patent No. 10-1179629 (registered on August 29, 2012) : Domestic registered patent No. 10-1297094 (registered on August 09, 2013) : Published Japanese Patent Application No. 10-2012-0099942 (published on September 12, 2012)

According to the present invention, lithium metal is attached to the inner circumferential surface of a metal can, and lithium ions can be rapidly and uniformly doped into the negative electrode through charge and discharge. Thus, reliability and mass productivity can be secured at the same time. And a lithium ion capacitor.

The present invention also provides a method of manufacturing a positive electrode and a negative electrode using a porous current collector so that lithium ions can smoothly permeate and move through the current collector and uniformly free lithium ions in a short time with optimum temperature, And to provide a doped lithium ion capacitor.

The various problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

A lithium ion capacitor according to the present invention includes: a metal can; A lithium metal attached to an inner peripheral surface of the metal can; An electrode unit accommodated in the metal can and including an anode in the form of a roll, a cathode, and a separator disposed between the anode and the cathode; A lead wire connected to the electrode unit; And an electrolyte injected to impregnate the lithium metal with the electrode unit, wherein the anode is manufactured using a cathode material including activated carbon, and the anode is manufactured using a cathode material including a carbon material.

The anode includes a cathode current collector formed of a porous aluminum foil that is precoated, and a hole is formed in the aluminum foil; And a slurry is formed on the positive electrode collector by using a positive electrode material formed by mixing activated carbon, a conductive material, a binder and purified water, and then the slurry is coated on the positive electrode collector by using a comma coater And an anode electrode layer made by drying the cathode, wherein the cathode is formed of a pre-coated porous copper foil, and the cathode foil has a hole formed therein; A slurry is formed on the negative electrode current collector by using a negative electrode material formed by mixing carbon materials, a conductive material, a binder, and purified water, and then the slurry is applied onto the negative electrode collector by using a comma coater And a cathode electrode layer manufactured by drying.

The positive electrode layer is prepared by mixing and stirring 80 to 90 parts by weight of activated carbon, 5 to 15 parts by weight of a conductive material, 2 to 10 parts by weight of a binder and 800 to 1200 parts by weight of purified water. The activated carbon has a specific surface area of 1400 to 2300 m ² / g, the particle size of the activated carbon powder ranges from 1 to 20 mu m, and the cathode electrode layer contains 80 to 90 parts by weight of carbon, 2 to 10 parts by weight of conductive material, 5 to 15 parts by weight of binder, and purified water of 800 to 1200 By weight, and the soft carbon powder may be in the range of 5 to 10 mu m in particle size.

The anode may be formed to a thickness of 100 to 200 탆, and the cathode may be formed to a thickness of 50 to 100 탆.

The metal can includes a cylindrical housing formed of stainless steel (SUS) and having an upper opening; And a cap inserted and mounted in an upper portion of the housing to close the upper portion of the housing. The cap 130 may be coupled (welded) to the first lead wire 400a, A glass metal or a butyl rubber is used on the outer circumferential surface of the first lead wire 400a contacting the cap 130 to prevent a short circuit between the first lead wire 400a and the first lead wire 400a The lead wire may include a first lead wire and a second lead wire. One end of the first lead wire may be electrically connected to the positive electrode of the electrode unit. The other end of the first lead wire may penetrate the cap. And the second lead wire is electrically connected to the negative electrode of the electrode unit at one side and can be fixedly attached to the inner circumferential surface of the metal can by welding.

The metal can may be formed of aluminum, an aluminum alloy, or a metal material other than the aluminum or aluminum alloy.

When the metal can is formed of aluminum or an aluminum alloy, the inside of the metal can can be plated with a metal other than aluminum.

The method for manufacturing a lithium ion capacitor according to the present invention is a method for manufacturing a lithium ion capacitor, which comprises preparing a cathode material formed by mixing activated carbon, a conductive material, a binder and purified water in the form of a slurry, To prepare a cathode. A cathode material formed by mixing carbon materials, a conductive material, a binder and purified water was prepared in the form of a slurry, and the slurry was applied to a porous copper foil housing precoated with a carbon- A first lead wire may be attached to be connected to the positive electrode, a second lead wire may be attached to be connected to the negative electrode, and a second separator may be formed on the second separator, A positive electrode, a first separator, and a negative electrode are laminated and coiled to produce a roll-shaped electrode unit. A lithium metal is fixedly attached on the inner peripheral surface A first lead wire connected to the positive electrode and a second lead wire connected to the negative electrode are disposed on the upper side of the opened housing, And a second lead wire connected to the negative electrode is fused so as to be in contact with the inner circumferential surface of the housing, and an electrolyte solution in which the lithium salt is dissolved in the inside of the housing to impregnate the electrode unit and the lithium metal wound in the roll form And the other end of the first lead wire and the second lead wire penetrates through the cap and is exposed to the outside and is electrically connected to the external terminal through the cap so that the open end of the housing is sealed with a cap containing glass metal or butyl rubber, .

The positive electrode material is prepared by mixing and stirring 80 to 90 parts by weight of activated carbon, 5 to 15 parts by weight of conductive material, 2 to 10 parts by weight of binder and 800 to 1200 parts by weight of purified water, and the specific surface area of activated carbon is 1400 to 2300 m ² / g, coke-based activated carbon is used as the activated carbon, the activated carbon powder has a particle size in the range of 1 to 20 mu m, the cathode material includes 80 to 90 parts by weight of carbon, 2 to 10 parts by weight of conductive material, 15 parts by weight of water and 800-1200 parts by weight of purified water are mixed and stirred. The soft carbon is used as the carbon, the particle size of the soft carbon powder is in the range of 5 to 10 μm, and the electrolyte absorbs and emits lithium ions A solute including a lithium salt that can be dissolved in a solvent may be dispersed in a solvent.

The lithium ion capacitor according to the present invention is prepared by mixing and stirring active carbon, a conductive material and a binder having a specific surface area of 2,000 m ² / g into 1000 parts by weight of purified water to prepare a slurry, A positive electrode having a thickness of 160 mu m is prepared by applying and drying a comma coater on the entire aluminum foil collector, adding 85 parts by weight of the activated carbon, 10 parts by weight of the conductive material and 5 parts by weight of the binder , Carbon black as the conductive material, styrene butadiene rubber and carboxymethyl cellulose as the binder, soft carbon, conductive material and binder each having an average particle diameter of 7 mu m were mixed with purified water Followed by mixing and stirring to prepare a slurry. Thereafter, a comma coater was applied to the porous copper foil collector precoated with a carbon-based conductive material, The soft carbon was added to 1000 parts by weight of purified water in a weight ratio of 85 parts by weight, the conductive material was 6 parts by weight and the binder was 9 parts by weight. The conductive material was carbon black , An acrylic resin binder and carboxyl methyl cellulose are used as the binder. A first lead wire is attached to the positive electrode, a second lead wire is attached to the negative electrode, and a polypropylene The electrode unit was dried in an oven of 120 DEG C for 20 hours and lined with lithium metal on the inner circumferential surface of a cylindrical metal can made of stainless steel (SUS) the electrode unit is inserted into the metal can, and an electrolyte solution is injected into the metal can, and the electrolyte is ethylene carbonate (ethylene carbonate) (LiPF ₆ ) was dissolved in a concentration of 1.2 moles of a solvent obtained by mixing propylene carbonate, carbon tetrachloride, bonate, diethyle carbonate, and propylene carbonate in a weight ratio of 3: 4: 1, A second lead wire connected to the negative electrode is welded to the inner circumferential surface of the housing of the metal can, and a first lead wire connected to the positive electrode is welded to a cap of a metal can including a glass metal or a butyl rubber to form a lithium ion capacitor, And the ionic capacitor is left to stand at 65 캜 for 2 days.

The details of other embodiments are included in the detailed description and drawings.

The lithium ion capacitor according to the present invention is constructed such that lithium metal is attached to the inner circumferential surface of a metal can and lithium ions can be quickly and uniformly doped into the negative electrode through charge and discharge, thereby ensuring both reliability and mass productivity, It can have a suitable high energy density.

In addition, the lithium ion capacitor according to the present invention can form a positive electrode and a negative electrode by using a porous current collector so that lithium ions can smoothly penetrate through the current collector and move, and lithium ions It is possible to uniformly pre-dope in a short time.

It will be appreciated that embodiments of the technical idea of the present invention can provide various effects not specifically mentioned.

1A is a diagram illustrating an anode in a lithium ion capacitor according to the present invention.
FIG. 1B is a view illustrating an anode in a lithium ion capacitor according to the present invention.
2A is a view showing a cathode in a lithium ion capacitor according to the present invention.
FIG. 2B is a view illustrating a negative electrode in a lithium ion capacitor according to the present invention.
3A and 3B are views schematically showing lead wires fused to an anode and a cathode, respectively, in a lithium ion capacitor according to the present invention.
4A and 4B are views showing electrode units in a lithium ion capacitor according to the present invention.
5 is a partially cutaway view showing a state in which the electrode unit is mounted on the metal can in the lithium ion capacitor according to the present invention.
6 is a view showing a state where an electrode unit is mounted on a metal can in a lithium ion capacitor according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity.

Terms such as top, bottom, top, bottom, or top, bottom, etc. are used to distinguish relative positions in components. For example, in the case of naming the upper part of the drawing as upper part and the lower part as lower part in the drawings for convenience, the upper part may be named lower part and the lower part may be named upper part without departing from the scope of right of the present invention .

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a part or a combination thereof is described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be construed as ideal or overly formal in meaning unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of a lithium ion capacitor according to the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1A and 1B are views showing an anode in a lithium ion capacitor according to the present invention, FIGS. 2A and 2B are views showing a cathode in a lithium ion capacitor according to the present invention, FIGS. 3A and 3B are cross- FIGS. 4A and 4B are views showing an electrode unit in a lithium ion capacitor according to the present invention, and FIGS. 5 and 6 are views showing electrode units according to the present invention Fig. 6 is a view showing that the electrode unit is mounted on a metal can in a lithium ion capacitor. Fig.

1A through 6, a lithium ion capacitor 10 according to the present invention includes a metal can 100, a lithium metal 200 attached to an inner circumferential surface of the metal can 100, An electrode unit 300 including an anode 310 in the form of a roll and a cathode 350 and separation membranes 330a and 330b positioned between the anode 310 and the cathode 350, Lead wires 400a and 400b connected to the unit 300 and an electrolyte (not shown) injected to impregnate the lithium metal 200 and the electrode unit 300.

The metal can 100 has a hollow cylindrical shape. A lithium metal 200 is fixedly mounted on the inner circumferential surface of the metal can 100, and the electrode unit 300 can be accommodated therein. The metal can 100 includes a housing 110 and a cap 130.

The housing 110 is made of a metal material such as stainless steel (SUS) or aluminum (Al), and the bottom and side surfaces of the housing 110 are sealed to allow the electrolyte to be impregnated therein to impregnate the lithium metal 200 and the electrode unit have. A lithium metal 200 is fixedly mounted on the inner circumferential surface of the housing 110 and a second lead wire 400b to be described later is welded 150 on the inner circumferential surface of the housing 110 to be fixedly attached thereto . The second lead wire 400b is electrically connected to the cathode 350 and the second lead wire 400b is welded to the metal can 100 to be electrically connected. When a voltage is applied to the metal can 100 through the lead line 400b, the surface of the cathode 350 may be doped with lithium ions.

The cap 130 may be provided to seal the upper portion of the housing 110 and fix the lead wires 400a and 400b. The cap 130 may be formed of a metal such as stainless steel (SUS) or aluminum (Al), and may be inserted into an open upper portion of the housing 110.

In the present invention, the cap 130 may be coupled (welded) to the first lead wire 400a, which will be described below, to prevent a short between the cap 130 and the first lead wire 400a. A gasket made of glass metal or butyl rubber may be provided on the outer circumferential surface of the first lead wire 400a contacting the cap 130. [

The lithium metal 200 is fixed on the bottom and side surfaces of the inner circumferential surface of the housing 110 and is impregnated with the electrolyte injected into the housing 110. When the cathode 350 is doped with lithium when a voltage is applied, It can act as a source.

Generally, lithium metal 200, which is highly reactive with water, is explosive and can be oxidized in the air. In the present invention, the lithium metal 200 is attached to the inner circumferential surface of the housing 110, The cap 130 is used to seal the housing 110, thereby preventing explosion and oxidation in the air.

The electrode unit 300 is accommodated in the metal can 100 and is configured in the form of a roll and includes an anode 310, a cathode 350 and a cathode 350 disposed between the anode 310 and the cathode 350 And the separators 330a and 330b may be stacked.

1A and 1B, the anode 310 may be made of a positive electrode material including activated carbon, and may be formed to a thickness of 100 to 200 mu m, and the anode 310 may be formed of a positive electrode collector (312) and an anode electrode layer (316).

The cathode current collector 312 may be formed of any one selected from aluminum, stainless steel, copper, nickel, tantalum, and niobium, and preferably may be formed of a porous aluminum foil that is precoated. And may have a sieve shape including an aperture 314 that is an empty space. The holes 314 formed on the cathode current collector 312 can be drilled at equal intervals. Due to the above-described configuration, the adhesion strength with the anode electrode layer 316 formed on the cathode current collector 312, And may be preferable in terms of uniform voltage application.

The anode electrode layer 316 is formed on the cathode current collector 312 and is manufactured by preparing a slurry from a cathode material formed by mixing activated carbon, a conductive material, a binder, and purified water, and then subjecting the slurry to a comma coater And then coating and drying the positive electrode collector 312 on the positive electrode collector 312. The anode electrode layer 316 may be prepared by mixing and stirring 80 to 90 parts by weight of activated carbon, 5 to 15 parts by weight of a conductive material, 2 to 10 parts by weight of a binder and 800 to 1200 parts by weight of purified water.

The activated carbon may be graphite used for general electrode production. The specific surface area of the activated carbon is preferably 1400 to 2300 m ² / g. Examples of the activated carbon include coke-based carbonized activated carbon, coconut shell-based activated carbon, phenol resin-based activated carbon, and the like. Coke based activated carbon is preferably used. In the present invention, the particle size of the activated carbon powder may be in the range of 1 to 20 μm in order to facilitate the formation and dispersion of the anode electrode layer 316.

The conductive material is not particularly limited as long as it is an electron conductive material that does not cause a chemical change. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder such as copper, nickel, Fiber and the like.

The binder is selected from at least one of ethylene acrylic acid type, polyacrylic acid type, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl pyrrolidone, polyvinyl chloride, polyethylene, styrene butadiene rubber, carboxyl methyl cellulose, It is preferable that they are mixed and used.

2A and 2B, the cathode 350 may be formed using a cathode material containing carbon and may be formed to a thickness of 50 to 100 μm, and the anode 350 may be formed of a cathode collector And includes a whole body 352 and a cathode electrode layer 356.

The anode current collector 352 may be formed of any one of copper, nickel, and stainless steel, and may be formed of a precoated porous copper foil. The anode current collector 352 may have a thin film shape. However, in the present invention, the anode current collector 352 efficiently transfers ions and includes a plurality of holes 354 for a uniform doping process .

The cathode electrode layer 356 is formed on the anode current collector 352 and is manufactured by preparing a slurry from a cathode material formed by mixing carbon materials, a conductive material, a binder, and purified water, and then subjecting the slurry to a comma coater, And then coating and drying the negative electrode collector 352 on the negative electrode collector 352. The cathode electrode layer 356 may be prepared by mixing and stirring 80 to 90 parts by weight of carbon, 2 to 10 parts by weight of conductive material, 5 to 15 parts by weight of binder and 800 to 1200 parts by weight of purified water.

The carbon species include graphite, hard carbon, soft carbon and the like, preferably lithium metal alloy, oxide containing lithium or lithium ions, preferably soft carbon, and the soft carbon powder has a particle size of 5 to 10 탆 Range can be used.

The conductive material is not particularly limited as long as it is an electron conductive material that does not cause a chemical change. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder such as copper, nickel, Fiber and the like.

The binder is selected from at least one of ethylene acrylic acid type, polyacrylic acid type, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl pyrrolidone, polyvinyl chloride, polyethylene, styrene butadiene rubber, carboxyl methyl cellulose, It is preferable that they are mixed and used.

The separators 330a and 330b may be disposed between the anode 310 and the cathode 350 to prevent the anode 310 and the cathode 350 from being short-circuited. The separators 330a and 330b include a first separator 330a and a second separator 330b. In the present invention, the anode 310 and the cathode 350 are disposed between the first separator 330a and the first separator 330a, Can be positioned opposite to each other.

The first and second separation membranes 330a and 330b may be formed of a polyethylene film, a polypropylene film, a polyester film, a polyacrylonitrile porous separator, a poly (vinylidene fluoride) hexafluoropropane copolymer porous separator, And is not particularly limited as long as it is a separator 330a or 330b generally used in the field of capacitors such as porous separator, kraft paper or rayon fiber.

The lead wires 400a and 400b are connected at one end to the electrode unit 300 and at the other end to the cap 130 or the inner circumferential surface of the housing 110. The first lead wire 400a and the second lead wire 400b.

One end of the first lead wire 400a may be electrically connected to the anode 310 of the electrode unit 300 and the other end may be exposed to the outside through the cap 130. [ In the present invention, the first lead wire 400a may be connected to the cap 130 including the anode 310 and the butyl rubber by fusing a separate terminal, and may be electrically connected to the external terminal, Ultrasonic welding, laser welding, or spot welding may be used as the method, but the present invention is not limited thereto.

One end of the second lead wire 400b may be electrically connected to the cathode 350 of the electrode unit 300 and the other end of the second lead wire 400b may be fixed to the inside of the housing 110 by welding.

The second lead 400b connected to the cathode 350 may be electrically connected to the inner circumferential surface of the housing 110 of the metal can 100 by the welding 150. The second lead 400b may be electrically connected to the cathode 350 through the second lead 400b, When a voltage is applied from the external terminal to the metal can 100, lithium may be doped into the surface of the cathode electrode layer 356 constituting the cathode 350.

That is, lithium ions generated from the lithium metal 200 attached to the metal can 100 reach the surface of the cathode electrode layer 356 through the electrolytic solution, thereby doping the surface of the cathode electrode layer 356, Lithium ions generated from the contained lithium salt may reach the surface of the cathode electrode layer 356 and may be doped to the surface of the cathode electrode layer 356.

Therefore, in the present invention, the lithium metal 200 attached to the inner circumferential surface of the metal can 100 acts as a source of lithium in doping the cathode electrode layer 356 with lithium, The lithium salt contained in the cathode electrode layer 356 may also act as a source of lithium in doping the cathode electrode layer 356 with lithium.

The electrolyte solution is injected into the metal can 100 so as to impregnate the electrode unit 300 and the lithium metal 200 contained in the metal can 100. The electrolyte solution is capable of intercalating and deintercalating lithium ions A solute including a lithium salt may be dispersed in a solvent.

The solute including the lithium salt is not particularly limited as a lithium salt commonly used in a capacitor, and examples of the solute including the lithium salt include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate ( Lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ , LiTFS), lithium bis (trifluoromethanesulfonylimide) _{methanesulfonyl) imide, LiN (CF 3} SO 2) 2, LiTFSI), bis-penta fluoro ethane sulfonyl imide lithium (lithium bis (pentafluoroethanesulfony) imide, LiN (SO 2 C 2 F 5) 2, LiBETI) at least one of Or more can be selected and used.

The solvent is not particularly limited, but cyclic carbonate solvent, chain carbonate solvent, ester solvent, ether solvent, nitrile solvent, amide solvent and the like can be used. Examples of the cyclic carbonate solvent include ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate. As the chain carbonate solvent, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate and the like can be used. Examples of the ester solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and? -Butyrolactone. The ether solvents include 1,2-dimethoxyethane, Ethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran and the like can be used. As the nitrile solvent, acetonitrile and the like can be used. As the amide solvent, dimethylformamide Can be used.

Hereinafter, a method for manufacturing a lithium ion capacitor according to the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, a method of manufacturing the anode 310 of the lithium ion capacitor 10 according to the present invention will be described in detail.

First, a cathode material formed by mixing activated carbon, a conductive material, a binder, and purified water is prepared. The positive electrode material may be prepared by mixing and stirring 80 to 90 parts by weight of activated carbon, 5 to 15 parts by weight of conductive material, 2 to 10 parts by weight of binder, and 800 to 1200 parts by weight of purified water.

The activated carbon may be graphite used for general electrode production. The specific surface area of the activated carbon is preferably 1400 to 2300 m ² / g. Examples of the activated carbon include coke-based carbonized activated carbon, coconut shell-based activated carbon, phenol resin-based activated carbon, and the like. Coke based activated carbon is preferably used. In the present invention, the particle size of the activated carbon powder may be in the range of 1 to 20 μm in order to facilitate the formation and dispersion of the anode electrode layer 316.

The conductive material is not particularly limited as long as it is an electron conductive material that does not cause a chemical change. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder such as copper, nickel, Fiber and the like.

Wherein the binder is at least one of ethylene glycol, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylpyrrolidone, polyvinyl chloride, polyethylene, styrene-butadiene rubber, carboxylmethylcellulose, It is preferable that they are mixed and used.

Next, a slurry is prepared from the positive electrode material containing the activated carbon, and then the slurry is coated on the positive electrode collector 312 using a comma coater and dried to form a slurry having a thickness of 100 to 200 mu m The anode 310 can be formed.

 In the present invention, the cathode material prepared in the form of slurry may be coated on the cathode current collector 312 and dried to form the cathode electrode layer 316.

The cathode current collector 312 may be formed of any one selected from aluminum, stainless steel, copper, nickel, tantalum, and niobium, and preferably may be formed of a porous aluminum foil that is precoated. And may have a sieve shape including an aperture 314 that is an empty space. The holes 314 formed on the cathode current collector 312 can be drilled at equal intervals. Due to the above-described configuration, the adhesion strength with the anode electrode layer 316 formed on the cathode current collector 312, And may be preferable in terms of uniform voltage application.

Hereinafter, a method for manufacturing the cathode 350 of the lithium ion capacitor 10 according to the present invention will be described in detail.

First, a negative electrode material formed by mixing carbon materials, a conductive material, a binder, and purified water is prepared. The negative electrode material may be prepared by mixing and stirring 80 to 90 parts by weight of carbon, 2 to 10 parts by weight of conductive material, 5 to 15 parts by weight of binder and 800 to 1200 parts by weight of purified water.

The carbon species include graphite, hard carbon, soft carbon and the like, preferably lithium metal alloy, oxide containing lithium or lithium ions, preferably soft carbon, and the soft carbon powder has a particle size of 5 to 10 탆 Range can be used.

The conductive material is not particularly limited as long as it is an electron conductive material that does not cause a chemical change. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder such as copper, nickel, Fiber and the like.

Wherein the binder is at least one of ethylene glycol, polyacrylic acid, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylpyrrolidone, polyvinyl chloride, polyethylene, styrene-butadiene rubber, carboxylmethylcellulose, It is preferable that they are mixed and used.

Next, a slurry is prepared from the negative electrode material containing the carbon species, and the slurry is coated on the negative electrode collector 352 using a comma coater and dried to form a slurry having a thickness of 50 to 100 mu m The formed cathode 350 can be formed.

The anode current collector 352 may be made of any one of copper, nickel, and stainless steel, and may preferably be formed of a precoated porous copper foil. The anode current collector 352 may have a thin film shape. However, in the present invention, the anode current collector 352 efficiently transfers ions and includes a plurality of holes 354 for a uniform doping process .

The lithium ion capacitor 10 can be manufactured using the anode 310 and the cathode 350 manufactured as described above. Hereinafter, a method of manufacturing the lithium ion capacitor 10 using the anode 310 and the cathode 350 will be described in detail.

3A and 3B, lead wires 400a and 400b are attached to the positive electrode 310 and the negative electrode 350, respectively. The first lead wire 400a may be attached to the anode 310 and the second lead wire 400b may be attached to the cathode 350. [

4A and 4B, the second separator 330b, the anode 310, the first separator 330a, and the cathode 350 are stacked and coiled to form a roll The electrode unit 300 of FIG. At this time, in order to keep the electrode unit 300 in the form of a roll, an outer circumferential surface of the electrode unit 300 may be wound with an adhesive tape (not shown) to maintain the roll shape.

The first separator 330a located between the anode 310 and the cathode 350 may prevent the anode 310 and the cathode 350 from short circuiting. In the present invention, the first separator 330a and the second separator 330b may be made of any one of a polyethylene nonwoven fabric, a polypropylene nonwoven fabric, a polyester nonwoven fabric, a polyacrylonitrile porous separator, a poly (vinylidene fluoride) hexafluoropropane copolymer porous The separators 330a and 330b are commonly used in the field of capacitors such as a separator, a cellulose porous separator, a kraft paper or a rayon fiber.

5, the roll-shaped electrode unit 300 may be mounted inside the housing 110 of the metal can 100 formed of a metal such as aluminum. A lithium metal 200 is fixedly mounted on the inner circumferential surface of the housing 110 of the metal can 100. The lithium metal 200 may act as a lithium source in doping the cathode 350 with lithium when a voltage is applied.

The first lead 400a connected to the anode 310 and the second lead 400b connected to the cathode 350 may be installed in the upper surface direction of the opened housing 110, The second lead 400b connected to the cathode 350 may be fused to be in contact with the inner circumferential surface of the housing 110. [ Here, ultrasonic welding, laser welding, spot welding, or the like may be used as the welding method. The second lead 400b may be electrically connected to the cathode 350 and the second lead 400b may be electrically connected to the metal can 100. The second lead 400b may be electrically connected to the external terminal, When a voltage is applied to the metal can 100 through the second lead line 400b, lithium may be doped to the surface of the cathode electrode layer 356 constituting the cathode 350. [

Next, an electrolytic solution in which a lithium salt is dissolved is injected into the housing 110 so that the electrode unit 300 wound in a roll form and the lithium metal 200 are impregnated.

The electrolyte is a solvent in which a solute including a lithium salt capable of intercalating and deintercalating lithium ions is dispersed in a solvent. The solute containing the lithium salt is not particularly limited as a lithium salt ordinarily used in a capacitor, For example, the solute including the lithium salt includes lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium 3-fluoromethyl sulfonate _{(lithium trifluoromethanesulfonate, LiCF 3 SO 3} , LiTFS), bis trifluoromethyl sulfonyl imide lithium ((lithium bis (trifluoro methanesulfonyl) imide, LiN CF 3 SO 2) 2, LiTFSI), bis-penta fluoro ethane sulfonyl imide lithium (lithium bis (pentafluoroethanesulfony) imide, LiN (SO 2 C 2 F 5) 2, LiBETI) may be used at least any one or more selected from.

The solvent is not particularly limited, but cyclic carbonate solvent, chain carbonate solvent, ester solvent, ether solvent, nitrile solvent, amide solvent and the like can be used. Examples of the cyclic carbonate solvent include ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate. As the chain carbonate solvent, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate and the like can be used. Examples of the ester solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and? -Butyrolactone. The ether solvents include 1,2-dimethoxyethane, Ethoxyethane, tetrahydrofuran, 1,2-dioxane, 2-methyltetrahydrofuran and the like can be used. As the nitrile solvent, acetonitrile and the like can be used. As the amide solvent, dimethylformamide Can be used.

6, the opened upper portion of the housing 110 may be sealed using the cap 130. In the present invention, the other side of the first lead wire 400a penetrates through the cap 130, The first lead wire 400a and the second lead wire 400b may be electrically connected to the external terminal using the other side of the first lead wire 400a and the second lead wire 400b.

The first lead wire 400a and the second lead wire 400b are fixed to the metal can 100 to which the first lead wire 400a and the second lead wire 400b are attached, In order to prevent leakage of the electrolyte injected into the electrolyte membrane 100, the fusion process may be ultrasonic welding, laser welding, or spot welding. However, the present invention is not limited thereto.

Hereinafter, preferred embodiments of a method of manufacturing the lithium ion capacitor 10 according to the present invention will be described in more detail with reference to the accompanying drawings.

≪ Example 1 >

First, activated carbon, a conductive material and a binder having a specific surface area of 2,000 m ² / g were mixed and stirred in 1000 parts by weight of purified water to prepare a slurry. Then, a comma coater Comma coater and dried to prepare a cathode 310 having a thickness of 160 탆. At this time, 85 parts by weight of activated carbon, 10 parts by weight of conductive material and 5 parts by weight of binder were added. Coke system was used as activated carbon, carbon black was used as conductive material, and styrene butadiene rubber and carboxyl methyl cellulose were used as binders.

Next, a slurry was prepared by mixing and stirring the soft carbon, the conductive material and the binder having an average particle diameter of 7 占 퐉 in purified water to prepare a slurry. Then, the porous copper foil precoated with the carbon conductive material was coated with a comma coater ) To prepare a negative electrode 350 having a thickness of 80 mu m. At this time, the mixture was added to 1000 parts by weight of purified water in a weight ratio of 85 parts by weight of soft carbon, 6 parts by weight of conductive material and 9 parts by weight of binder. Carbon black was used as the conductive material, acrylic resin binder, Respectively.

Next, a first lead wire 400a is attached to the anode 310, a second lead wire 400b is attached to the cathode 350, and then a separation film 330a, 330b (not shown) is formed between the anode 310 and the cathode 350 ), And wound up in the form of a roll to produce an electrode unit 300. Then, the electrode unit 300 was dried in an oven at 120 DEG C for 20 hours.

Next, a lithium metal 200 is lined and attached to the inner circumferential surface of a stainless steel (SUS) metal can 100 formed in a cylindrical shape, and then the electrode unit 300 is inserted into the metal can 100 Respectively.

Next, an electrolyte was injected into the metal can 100, and the electrolyte solution was prepared by mixing ethylene carbonate, diethyle carbonate, and propylene carbonate in a weight ratio of 3: 4: 1 A solution obtained by dissolving lithium hexafluorophosphate (LiPF ₆ ) at a concentration of 1.2 mol of the mixed solvent was used.

Next, a second lead wire 400b connected to the cathode 350 is welded (150) to the inner circumferential surface of the housing 110 of the metal can 100, and the first lead wire 400a connected to the anode 310 Was welded to the cap 130 of the metal can 100 containing the butyl rubber. At this time, the welding was performed using a laser welder, and the lithium ion capacitor 10 was manufactured to have a size of AA (14.6 * 25.1 mm).

Then, the lithium ion capacitor 10 manufactured as described above was left to stand at 65 캜 for 2 days.

The stored lithium ion capacitor 10 was charged at a constant current of 300 mA until the voltage of the lithium ion capacitor 10 reached 3.8 V. Then, a constant voltage of 3.8 V was maintained for 30 minutes and then a constant current of 300 mA After discharging to 2.2V, the initial capacitance was measured.

Thereafter, the high-temperature load reliability at 3.8 V, 60 DEG C, and 1000 hours (Hr) was measured using the lithium ion capacitor 10. [

≪ Example 2 >

A lithium ion capacitor 10 was fabricated in the same manner as in Example 1 except that a metal can 100 made of aluminum and an aluminum alloy was used and a nickel coating was performed on the inner circumferential surface of the metal can 100 .

≪ Comparative Example 1 &

A lithium ion capacitor was produced in the same manner as in Example 1, except that the lithium ion capacitor 10 fabricated as in Example 1 was left at room temperature for 14 days and stored.

≪ Comparative Example 2 &

A lithium ion capacitor was fabricated in the same manner as in Example 1, except that the metal can 100 made of aluminum and an aluminum alloy was used.

The initial characteristic values and the high temperature load reliability of 3.8 V, 70 ° C., and 1000 hours (Hr) were measured using a lithium ion capacitor manufactured by the method 1 or 2 in comparison with the above-described Embodiments 1 and 2, Are shown in Table 1 below.

division Initial property value 3.8 V, 70 占 폚, 1000 hours (Hr) Capacity (F) Resistance (Ω) Capacity retention rate (%) Rate of change in resistance (%) Example 1 30.1 0.13 91 106 Example 2 30.5 0.12 89 110 Comparative Example 1 29.8 0.13 88 102 Comparative Example 2 29.5 0.12 74 256

As shown in Table 1, in the case of the lithium ion capacitor according to Example 1, Example 2, and Comparative Example 1 and Comparative Example 2, initial characteristics were similar.

However, in the case of Comparative Example 2, the capacity retention rate and the rate of change in resistance after 3.8 V, 70 占 폚, and 1000 hours (Hr) are remarkably worse than those of the other cases.

This is because in the metal can 100 formed of aluminum and aluminum alloy, when lithium ions are doped from the lithium ion supply source, the remaining lithium metal 200 is alloyed with aluminum in the metal can 100, It was judged that this was easily caused by the container corrosion and the irreversible reaction was increased.

An initial characteristic value of the lithium ion capacitor held at 65 DEG C for 2 days and aging, and an initial characteristic value of 3.8 (as in Example 2) stored for 14 days at room temperature for 14 days, V, 70 ℃, and 1000 hours (Hr).

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that one embodiment described above is illustrative in all aspects and not restrictive.

10; Lithium ion capacitor 100; Metal can
110; A housing 130; cap
150; Welding 200; Lithium metal
300; Electrode unit 310; anode
312; Anode current collectors 314 and 354; hole
316; Anode electrode layers 330a and 330b; Membrane
350; Cathode 352; Cathode collector
356; Cathode electrode layers 400a and 400b; Lead wire

Claims (10)

Metal can;
A lithium metal attached to an inner peripheral surface of the metal can;
An electrode unit accommodated in the metal can and including an anode in the form of a roll, a cathode, and a separator disposed between the anode and the cathode;
A lead wire connected to the electrode unit; And
And an electrolyte injected to impregnate the lithium metal and the electrode unit,
The positive electrode is manufactured using a positive electrode material containing activated carbon,
The negative electrode is manufactured using a negative electrode material containing carbon species,
The positive electrode
A cathode current collector formed of a precoated porous aluminum foil and having a hole formed in the aluminum foil; And
A slurry is formed on the positive electrode current collector by using a positive electrode material formed by mixing activated carbon, a conductive material, a binder, and purified water, and then the slurry is coated on the positive electrode current collector using a comma coater And an anode electrode layer produced by drying,
The negative electrode,
A negative electrode collector formed of a precoated porous copper foil and having a hole in the copper foil;
A slurry is formed on the negative electrode current collector by using a negative electrode material formed by mixing carbon materials, a conductive material, a binder, and purified water, and then the slurry is applied onto the negative electrode collector by using a comma coater And a cathode electrode layer made by drying,
The positive electrode layer is prepared by mixing and stirring 80 to 90 parts by weight of activated carbon, 5 to 15 parts by weight of a conductive material, 2 to 10 parts by weight of a binder and 800 to 1200 parts by weight of purified water. The activated carbon has a specific surface area of 1400 to 2300 m ² / g, the particle size of the activated carbon powder is in the range of 1 to 20 mu m,
The cathode electrode layer is prepared by mixing and stirring 80 to 90 parts by weight of a carbon material, 2 to 10 parts by weight of a conductive material, 5 to 15 parts by weight of a binder, and 800 to 1200 parts by weight of purified water, The soft carbon powder has a particle size in the range of 5 to 10 mu m,
The anode is formed to a thickness of 100 to 200 탆, the cathode is formed to a thickness of 50 to 100 탆,
The metal can includes a cylindrical housing formed of stainless steel (SUS) and having an upper opening; And
And a cap inserted and mounted in an open upper portion of the housing to close an upper portion of the housing,
Wherein the lead wire includes a first lead wire and a second lead wire,
Wherein one end of the first lead wire is electrically connected to the positive electrode of the electrode unit and the other end is exposed to the outside through the cap to be electrically connected to the external terminal,
Wherein the second lead wire is electrically connected to a cathode of the electrode unit at one side thereof and is fixedly attached to an inner circumferential surface of the metal can.
delete delete delete delete The method according to claim 1,
Wherein the metal can is made of aluminum, an aluminum alloy, or a metal material other than the aluminum or aluminum alloy.
The method according to claim 6,
Wherein when the metal can is formed of aluminum or an aluminum alloy, the inside of the metal can is plated with a metal material other than aluminum.
A cathode material formed by mixing activated carbon, a conductive material, a binder, and purified water in the form of a slurry, applying the slurry on an aluminum foil current collector using a comma coater,
A negative electrode material formed by mixing a carbon material, a conductive material, a binder and purified water in the form of a slurry, and then applying the slurry to a porous copper foil precoated with a carbon-based conductive material using a comma coater And drying to produce a negative electrode,
Attaching a first lead wire to be connected to the positive electrode, attaching a second lead wire to be connected to the negative electrode,
A second separator, an anode, a first separator, and a cathode are laminated and coiled to produce a rolled electrode unit,
A metal can formed of a metal material to which lithium metal is fixedly attached on the inner peripheral surface is prepared,
A first lead wire connected to the positive electrode and a second lead wire connected to the negative electrode are arranged in the direction of the top surface of the opened housing, The second lead wire connected is fused so as to be in contact with the inner peripheral surface of the housing,
An electrolyte solution in which a lithium salt is dissolved is injected into the housing to impregnate the rolled electrode unit with lithium metal,
Wherein an upper portion of the housing is sealed with a glass metal or a cap containing butyl rubber, the other side of the first lead wire and the second lead wire penetrating the cap and exposed to the outside, Respectively,
The positive electrode material is prepared by mixing and stirring 80 to 90 parts by weight of activated carbon, 5 to 15 parts by weight of conductive material, 2 to 10 parts by weight of binder and 800 to 1200 parts by weight of purified water, and the specific surface area of activated carbon is 1400 to 2300 m ² / g, coke-based carbonized activated carbon is used as the activated carbon, the particle size of the activated carbon powder is in the range of 1 to 20 mu m,
The slurry is coated on a positive electrode current collector using a comma coater and dried to form a positive electrode having a thickness of 100 to 200 mu m,
The negative electrode material is prepared by mixing and stirring 80 to 90 parts by weight of a carbon material, 2 to 10 parts by weight of a conductive material, 5 to 15 parts by weight of a binder, and 800 to 1200 parts by weight of purified water, The soft carbon powder has a particle size ranging from 5 to 10 mu m,
The slurry is coated on a negative electrode current collector using a comma coater and dried to form a negative electrode having a thickness of 50 to 100 탆,
A lithium ion capacitor is manufactured using the positive electrode and the negative electrode,
Attaching a first lead wire to be connected to the positive electrode, attaching a second lead wire to be connected to the negative electrode,
A second separator, an anode, a first separator, and a cathode are laminated and coiled to produce a roll-shaped electrode unit,
Wherein the roll-shaped electrode unit is mounted inside the housing of the metal can, wherein a lithium metal is fixedly mounted on the inner circumferential surface of the metal can, and the lithium metal is a lithium source, Lt; / RTI >
A first lead wire connected to the positive electrode and a second lead wire connected to the negative electrode are mounted so as to be positioned in the direction of the top surface of the opened housing and the second lead wire connected to the negative electrode is fused to be in contact with the inner peripheral surface of the housing, When a voltage is applied to the metal can via the second lead wire electrically connected to the external terminal, lithium is doped into the surface of the cathode electrode layer constituting the cathode,
Wherein the electrolytic solution contains a lithium salt capable of intercalating and deintercalating lithium ions in a solvent, and the electrolytic solution having a lithium salt dissolved therein is injected into the housing to impregnate the rolled electrode unit with the lithium metal. Dispersed,
And the upper portion of the housing is sealed using a cap.
delete A slurry was prepared by mixing and stirring active carbon, a conductive material and a binder having a specific surface area of 2,000 m ² / g in 1000 parts by weight of purified water, and then spraying a comma coater on a porous aluminum foil precoated with a carbon- , 85 parts by weight of the activated carbon, 10 parts by weight of the conductive material and 5 parts by weight of the binder were added, and as the activated carbon, a coke-based material, a conductive material Carbon black as a binder, styrene butadiene rubber and carboxyl methyl cellulose as binders,
A slurry was prepared by mixing and stirring soft carbon, conductive material and binder having an average particle diameter of 7 mu m in purified water to prepare a slurry. Then, a comma coater was used on the porous copper foil precoated with a carbon conductive material The negative electrode having a thickness of 80 mu m is prepared by coating and drying. The soft carbon is added to 1000 parts by weight of purified water in a weight ratio of 85 parts by weight, the conductive material is 6 parts by weight and the binder is 9 parts by weight, Carbon black as the binder, acrylic resin binder and carboxymethyl cellulose as the binder,
A first lead wire is attached to the positive electrode, a second lead wire is attached to the negative electrode, a polypropylene film is disposed as a separator between the positive electrode and the negative electrode,
The electrode unit was dried in an oven at 120 ° C for 20 hours,
A lithium metal is lined and attached to the inner peripheral surface of a cylindrical metal can made of stainless steel, the electrode unit is inserted into the metal can,
The electrolytic solution was injected into the metal can, and as the electrolyte, ethylene carbonate, diethyl carbonate, and propylene carbonate were mixed in a weight ratio of 3: 4: 1, and 1.2 mol of a solvent Solution of lithium hexafluorophosphate (LiPF ₆ ) is used in the solution,
A second lead wire having one side connected to the negative electrode is welded to the inner circumferential surface of the housing of the metal can and the first lead wire connected to the positive electrode is welded to a cap of a metal can including a glass metal or a butyl rubber to produce a lithium ion capacitor,
Wherein the lithium ion capacitor is left at 65 占 폚 for 2 days to store the lithium ion capacitor.

Images