KR101777455B1 - Current collector, electrode assembly comprising the same, battery comprising the same and preparation method thereof - Google Patents

Abstract

A current collector, an electrode composite containing the same, a battery including the electrode composite, and a manufacturing method thereof.

Description

TECHNICAL FIELD [0001] The present invention relates to a collector, an electrode composite containing the same, a battery including the electrode composite, a battery including the electrode composite, and a method of manufacturing the same. BACKGROUND ART [0002]

This application claims the benefit of the filing date of Korean Patent Application No. 10-2014-0072473 filed with the Korean Intellectual Property Office on Jun. 13, 2014, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current collector, an electrode composite including the same, a battery including the same, and a manufacturing method thereof.

With the miniaturization and weight reduction of portable electronic devices, there is a continuing need for high capacity, miniaturization and stabilization of the lithium secondary battery used as its power source. Particularly, the lithium secondary battery has a working voltage of 3.6 V or higher, which is three times higher than a nickel-cadmium battery or a nickel-hydrogen battery which is widely used as a power source for portable electronic devices, and is rapidly expanded in terms of high energy density per unit weight There is a trend.

The lithium secondary battery is driven by the principle of introducing an organic electrolyte between two electrodes to enable the reversible insertion and removal of lithium ions, thereby obtaining the electrical energy through the electrochemical oxidation-reduction reaction of the chemical energy of the active material. Due to the chemical potential difference between the anode and the cathode, lithium ions migrate from the cathode to the anode through the electrolyte and reversibly move lithium ions from the anode to the cathode upon charging.

Generally, a lithium secondary battery has a structure of a positive electrode current collector, a positive electrode, an electrolyte, a negative electrode and an anode current collector. Here, aluminum, nickel and the like are mainly used for the positive electrode current collector, and iron, nickel, cobalt, chromium, molybdenum and tungsten are used for the negative electrode current collector.

At this time, each of the active materials, that is, the positive electrode active material or the negative electrode active material, may be coated on the positive electrode collector or the negative electrode collector.

However, in such a lithium secondary battery, the active material is detached from the metal foil current collector by repeatedly charging and discharging several tens to several hundreds of times, and the cycle efficiency is lowered. The weight per unit weight of the whole battery There is a problem that the density is lost.

Japanese Patent Application Laid-Open No. 2000-149958

The present invention provides a current collector, an electrode composite including the same, a battery including the same, and a method of manufacturing the same.

According to one embodiment of the present disclosure, there is provided a current collector for a battery including at least a portion of a carbon layer coated with a metal.

According to another embodiment of the present disclosure, the carbon layer is coated with a metal at its distal end or its entire surface.

According to another embodiment of the present disclosure, the carbon layer provides a porous current collector for a battery.

In addition, one embodiment of the present disclosure

A current collector according to the above-described embodiment; And

And an electrode layer including an electrode active material provided on at least one surface of the current collector.

In addition, one embodiment of the present disclosure

A current collector according to the above-described embodiment;

A first electrode provided on at least one surface of the current collector;

A second electrode facing the first electrode; And

An electrolyte provided between the first electrode and the second electrode

And a battery.

In addition, another embodiment of the present invention is a method of manufacturing a semiconductor device,

An electrode composite according to the above-described embodiment;

An electrode facing the electrode composite; And

An electrolyte provided between the electrode composite and the electrode

And a battery.

One embodiment of the present invention provides a method of manufacturing the current collector.

In addition, one embodiment of the present invention provides a method of manufacturing the electrode composite.

In addition, one embodiment of the present invention provides a method of manufacturing the battery.

According to some embodiments of the present invention, the current collector including the carbon layer, the electrode composite including the same, and the battery including the carbon composite may be improved in that the electrode active material is removed from the current collector when the charge and discharge are repeated.

According to some embodiments of the present invention, the energy density per cell weight can be improved by reducing the weight of the current collector.

FIG. 1 is a schematic view of a porous carbon layer in which a terminal portion is coated with a metal.
2 is a schematic view of a porous carbon layer whose front surface is coated with a metal.
3 is a schematic diagram showing a manufacturing method of a battery according to the first embodiment.
4 is a graph showing the cycle efficiency of the battery manufactured by Example 1 and Comparative Example 1. Fig.

Hereinafter, the present invention will be described in more detail.

According to one embodiment of the present disclosure, there is provided a current collector for a battery including at least a portion of a carbon layer coated with a metal.

A battery using a current collector including a carbon layer at least partially coated with a metal can be made lighter than a battery using a metal foil as a current collector so that the energy density per unit weight of the battery can be improved.

According to another embodiment of the present disclosure, there is provided a current collector for a battery, wherein the carbon layer is coated with a metal at a terminal portion or a front surface thereof.

According to another embodiment of the present invention, the coating of the carbon layer with a metal is performed by coating either one side of the carbon layer with a metal or by processing one side of the carbon layer into a convex shape, It may be coated with a metal, and it is most preferable to coat only the uneven portion.

According to another embodiment of the present invention, the carbon layer is selected from carbon such as natural graphite, artificial graphite, expanded graphite, carbon fiber, hard graphitizable carbon, carbon black, carbon nanotube, fullerene, activated carbon and graphite material One or more of them may be used, but the present invention is not limited thereto.

According to another embodiment of the present invention, the thickness of the carbon layer is 20 to 1000 mu m.

If the thickness of the carbon layer is more than 1000 mu m, the amount of active material to be loaded can be increased in the thickness direction. However, since the ion path becomes longer in the thickness direction of the electrode, the output characteristic may be deteriorated.

According to another embodiment of the present disclosure, the carbon layer is porous.

In the case of the current collector for a battery in which the carbon layer is porous, since the electrode active material is impregnated with the porous carbon layer when charging / discharging is repeated, the active material can be prevented from being separated from the current collector, , Since the porous structure itself can contain the active material, the conductive material can be omitted in the production of the active material slurry. That is, in the case of the current collector for a battery in which the carbon layer is porous, the current collector can simultaneously perform the current collecting role and the conductive material.

According to another embodiment of the present disclosure, the pore size in the carbon layer is 20 nm to 500 μm.

According to another embodiment of the present invention, the porosity of the carbon layer is 10 to 90%.

If the porosity is less than 10%, there is no effect of impregnating the active material, and if the porosity is more than 90%, the active material is refracted and remaining pores are formed. Therefore, the pores can act as a resistor and can not make contact with the active material. I can not perform well.

According to another embodiment of the present invention, the metal coating may be one selected from copper, stainless steel, aluminum, nickel, titanium, and silver, but is not limited thereto.

According to another embodiment of the present invention, the thickness of the metal coating is 1 nm to 20 탆.

If the thickness of the metal coating layer is thinner than 1 nm, the coating layer is completely melted at the welding temperature, so that the welding may not be sufficiently performed. On the other hand, if the coating layer is thicker than 20 탆, the weight of the current collector becomes heavy, which is disadvantageous in terms of energy density per weight, and the carbon layer as a support may not sustain the weight of the thick metal coating.

According to one embodiment of the present disclosure,

A current collector according to the above-described embodiment; And

An electrode layer including an electrode active material provided on at least one surface of the current collector,

And an electrode composite.

According to another embodiment of the present invention, the electrode layer may include a conductive material, and the conductive material may include 0 to 20% by weight of the electrode layer.

For example, a conductive material may not be added to the electrode layer or only a small amount of the conductive material may be added, and an electrode may be formed by directly supporting the electrode active material on the current collector. At this time, the current collector functions not only to collect electrons generated by the electrochemical reaction of the electrode active material, to supply electrons necessary for the electrochemical reaction, but also to provide conductivity to the electrode active material 3D network structure.

In the above-described embodiment, a structure in which a binder is not added or a small amount is added at the time of forming an electrode layer is described, but the present invention is not limited thereto and, if necessary, a binder can be suitably used.

According to another embodiment of the present disclosure, the binder is selected from the group consisting of polyvinylidene fluoride, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene It is possible to use at least one selected from various copolymers such as ethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer, sulfonated ethylene-propylene-diene terpolymer and styrene butylene rubber and fluorine rubber. It is not.

According to another embodiment of the present invention, the electrode active material includes a cathode active material or an anode active material.

According to another embodiment of the present invention, the cathode active material is not particularly limited as long as it is a compound capable of reversibly intercalating and deintercalating lithium ions, and materials known in the art can be used. For example, a lithium intercalation compound may be used, specifically, a compound substituted with a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or one or more transition metals; Lithium manganese oxides such as Li _{1 + x} Mn _{2 - x} O 4 (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , and LiMnO ₂ ; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; Formula _{LiNi 1 - x M x O 2} ( where, the M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, x = 0.01 ~ 0.3 Im) Ni site type lithium nickel oxide which is represented by; Formula _{LiMn 2 - x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Sulfide-based active materials; Sulfur; Titanium sulfide; Titanium disulfide; FeS; CuS; Sulfur carbon composite; And Fe ₂ (MoO ₄ ) ₃ , but are not limited thereto.

According to another embodiment of the present invention, the negative electrode active material is not particularly limited as long as it is a material capable of reversibly intercalating and deintercalating lithium ions, and examples thereof include natural graphite, artificial graphite, expanded graphite, Carbon, carbon such as hard graphitizable carbon, carbon black, carbon nanotube, fullerene, activated carbon and graphite material; Metals such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, Pt and Ti which can be alloyed with lithium; A compound including a metal such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, P and Ti; Metals such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, P and Ti; And lithium-containing nitride, but the present invention is not limited thereto.

According to one embodiment of the present disclosure,

A current collector according to the above-described embodiment;

A first electrode provided on at least one surface of the current collector;

A second electrode facing the first electrode; And

An electrolyte provided between the first electrode and the second electrode

And a battery.

According to another embodiment of the present disclosure, the first electrode is an anode and the second electrode is a cathode.

According to one embodiment of the present disclosure,

An electrode composite according to the above-described embodiment;

An electrode facing the electrode composite; And

An electrolyte provided between the electrode composite and the electrode

And a battery.

According to another embodiment of the present disclosure, the electrode composite is an anode and the electrode is a cathode.

According to another embodiment of the present disclosure, the electrolyte includes a liquid electrolyte or a solid electrolyte. The battery according to the above embodiments may be a non-aqueous electrolyte battery or a pre-solid battery. The battery may be a primary battery or a secondary battery.

According to another embodiment of the present disclosure, the liquid electrolyte comprises a non-aqueous organic solvent.

According to another embodiment of the present invention, the non-aqueous organic solvent includes a cyclic carbonate-based solvent; And a chain carbonate-based solvent.

According to another embodiment of the present invention, the cyclic carbonate-based solvent is selected from the group consisting of ethylene carbonate, fluoroethylene carbonate, propylene carbonate, trifluoropropylene carbonate, butylene carbonate and gamma-butyrolactone. But are not limited thereto.

According to another embodiment of the present invention, the cyclic carbonate-based solvent is at least one selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methylnonafluorobutyl ether and 1,3-dioxirane But are not limited thereto.

According to another embodiment of the present invention, the solid electrolyte further comprises at least one selected from the group consisting of a polymer electrolyte and an inorganic electrolyte.

According to another embodiment of the present invention, the polymer electrolyte includes at least one selected from the group consisting of a hydrocarbon-based polymer, a fluorine-based polymer, and a polyether-based polymer.

According to another embodiment of the present invention, the hydrocarbon-based polymer is at least one selected from the group consisting of a sulfonated polyimide, a sulfonated polysulfone, a polyphenylene ether electrolyte membrane, a sulfonated polybenzoxazole, a polymer containing a ketal group, And polybenzonitrile copolymers, but are not limited to these.

According to another embodiment of the present invention, the fluorine-based polymer is a polymer including at least one selected from the group consisting of polytetrafluoroethylene (PTFE) and nafion, but is not limited thereto.

The polyether-based polymer according to one embodiment of the present invention includes, but is not limited to, polyethylene oxide (PEO).

According to another embodiment of the present invention, the inorganic electrolyte includes at least one selected from the group consisting of sulfides, oxides, and phosphates.

According to another embodiment of the present invention, the sulfide is selected from the group consisting of P ₂ S ₅ -Li ₂ S, B ₂ S ₃ -Li ₂ S, Li _{4 - x} Ge _{1 - x} P _x S ₄ (0 _{? X?} 1) and Li _{4 - x} Ge _{1 - x} P _x S ₁ (0? X? 1), but is not limited thereto.

According to another embodiment of the present invention, the oxide is selected from the group consisting of GeO ₂ , Li ₄ SiO ₄ , (La, Li) TiO ₃ and LiAl _x Co _{1 - x} O ₂ But are not limited thereto.

According to yet an embodiment of the present specification, the phosphates is _{Li 1 + x Al x Ge 2} - x (PO 4) 3 (0≤x≤0.5), Li 1 + x Ti 2 - x Al (PO 4) ₃ (0≤x≤0.4), and _{Li 1 + x Ti 2 - x} Al x (PO 4) including, at least one member selected from the group consisting of ₃ (0≤x≤0.4), but this is not limited.

According to one embodiment of the present disclosure,

Preparing a carbon layer; And

Coating a surface of at least a portion of the carbon layer with a metal

The present invention also provides a method of manufacturing a current collector.

According to one embodiment of the present disclosure,

And forming an electrode layer including an electrode active material on at least one surface of the current collector.

According to one embodiment of the present disclosure,

Collecting house; A first electrode; Electrolyte; And the second electrode are assembled,

Collecting house; A first electrode; And injecting an electrolyte after assembling the second electrode.

According to one embodiment of the present disclosure,

Electrode composite; Electrolyte; And electrodes,

Electrode composite; And assembling the electrode and injecting an electrolyte.

According to another embodiment of the present disclosure, a method of manufacturing a battery includes the steps of welding a plurality of electrodes, wherein the welding is characterized by welding of a coated end portion.

According to another embodiment of the present invention, the battery is packaged in a battery case, and at least a part of the metal coated on the carbon layer of the current collector is pressed and welded to the battery case .

In this specification, metal coating formation can be performed by methods known in the art. For example, a method of forming a metal layer by a sintering method, a chemical vapor deposition method (CVD), a metal substitution method, a spray method, a screen printing method, a sputtering method, an electroplating method and an inkjet printing method Inkjet printing), but is not limited thereto.

In this specification, the thickness of the carbon layer and the metal coating can be measured by a method known in the art. For example, it is possible to use one or more kinds of devices including a scanning electron microscope, an alpha-step, an ellipsometer, a reflectometer, a thickness measuring device and an X-ray fluorescence analyzer (XRF) But is not limited thereto.

In this specification, pore size and porosity can be measured by methods known in the art. For example, one or more species including, but not limited to, a transmission electron microscope (TEM), a nitrogen adsorption method, an FT-electron scanning microscope (FE-SEM), and a Mercury Porosimeter can be used.

The constitution of the battery or parts thereof not described in this specification, and the manufacturing method thereof can be used those known in the art.

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are intended to illustrate the invention and are not intended to limit the scope of the invention.

<Production Example>

Production Example 1. Production of current collector

5 wt% of an inorganic binder composed of SiO ₂ , Al ₂ O ₃ and PbO, 85 wt% of Ag powder having a D _{50 of} 1 to 2 μm, 15 wt% of ethyl cellulose in a butyl carbitol solvent And 10 wt% of the organic binder dissolved therein were mixed to prepare a silver paste. The silver paste was coated on carbon paper (Toray Co., Ltd.) having 80% pore size and then sintered at 800 ° C for 1 hour to obtain a carbon paper coated with Ag metal .

Production Example 2. Preparation of positive electrode

The positive electrode active material _{LiNi 1/3 Mn 1/3} Co 1/3 O 2, a conductive material vapor-grown carbon fiber (VGCF), electrolyte Li ₂ SP ₂ S _5, the hydrocarbon-based binder (8 wt% in xylene (xylene), manufacturer: : Zeon Co.) were mixed in an amount of 60 wt%: 4 wt%: 34 wt%: 2 wt%, respectively, to prepare a slurry, and then the Ag coated carbon paper ) To prepare a positive electrode.

Production Example 3. Preparation of positive electrode

A positive electrode was prepared in the same manner as in Production Example 2 except that aluminum foil (20 占 퐉) was used instead of the current collector produced in Production Example 1 in Production Example 2. [

<Examples>

Example 1. Preparation of cell

0.25 g of a sulfide-based solid electrolyte Li ₂ SP ₂ S _{5 is} put into a mold having a diameter of Φ 16 mm and a force of 3700 Kg / cm ² is applied by a hydraulic press to form a separator layer. The long axis of the mold mold was drawn and the positive electrode prepared in Preparation Example 2 was raised on one side of the separator layer and a force of 3700 Kg / cm ² was applied to the separator layer, and the lithium foil was placed on the opposite side Kg / cm &lt; ² &gt; to give a negative electrode.

3 is a schematic diagram showing a manufacturing method of a battery according to the first embodiment. 3,

1. Insert a short shaft into a PP panel and pour 0.25 g of solid electrolyte.

2. Evenly spread the liquid from the top to the long axis and press it down with a small pressure to gently solidify the solid electrolyte.

3. Extract the long axis, insert the anode prepared in Production Example 2, and press it at 3700 Kg / cm ² for 5 minutes.

4. Pull out the short shaft, put a 0.15 mm thick lithium foil with Φ 14 on the short shaft, put it on a polypropylene panel and press it at 1,500 kg / cm ² for 2 minutes.

5. Install a mechanism to pressurize constantly and attach the screw for collecting.

Comparative Example 1. Preparation of battery

A battery was prepared in the same manner as in Example 1, except that the positive electrode prepared in Production Example 3 was used instead of the positive electrode prepared in Production Example 1 as the positive electrode in Example 1 above.

&Lt; Evaluation example &

The cycle efficiency experiment of the battery manufactured by Example 1 and Comparative Example 1 was carried out, and the results are shown in FIG. Charging and discharging of all the solid batteries was performed at 60 DEG C and 0.1 C at 2.5 V to 4.2 V region.

In the case of using a conventional aluminum foil (20um) collector in FIG. 4, the battery using the silver coated carbon paper according to Example 1 as a current collector is caused by the volume change of the active material during charging and discharging It is confirmed that the cycle efficiency is improved by preventing the desorption of the active material.

10: End-portion metal coating
20: Front metal coating

Claims (21)

At least a portion of the surface comprising a carbon layer coated with a metal,
One side of the carbon layer is processed into a convex shape, the concavo-convex portion is coated with a metal,
The thickness of the carbon layer is 20 to 1000 탆,
The thickness of the metal coating is 1 nm to 20 탆,
The carbon layer is porous,
The size of the pores in the carbon layer is 20 nm to 500 탆,
And the porosity of the carbon layer is 10 to 90%. delete delete delete delete delete delete A current collector according to claim 1; And
And an electrode layer including an electrode active material provided on at least one surface of the current collector. The electrode composite according to claim 8, wherein the electrode layer comprises a conductive material, and the content of the conductive material is in a range of 0 to 20% by weight of the electrode layer. The electrode composite according to claim 8, wherein the electrode active material is a cathode active material or an anode active material. A current collector according to claim 1;
A first electrode provided on at least one surface of the current collector;
A second electrode facing the first electrode; And
And an electrolyte disposed between at least the first electrode and the second electrode. The battery according to claim 11, wherein the first electrode is an anode and the second electrode is a cathode. 12. The battery according to claim 11, wherein the electrolyte is a liquid electrolyte or a solid electrolyte. The electrode composite of claim 8;
An electrode facing the electrode composite; And
And at least an electrolyte disposed between the electrode composite and the electrode. 15. The cell of claim 14, wherein the electrode composite is an anode and the electrode is a cathode. The battery according to claim 14, wherein the electrolyte is a liquid electrolyte or a solid electrolyte. Preparing a carbon layer; And
The method of manufacturing a current collector according to claim 1, further comprising a step of machining any one side of the carbon layer into a convex shape and coating the concavo-convex portion with a metal. A method for producing an electrode composite according to claim 8, comprising the step of forming an electrode layer including an electrode active material provided on at least one side of the current collector. Collecting house; A first electrode; Electrolyte; And the second electrode are assembled,
Collecting house; A first electrode; A method of manufacturing a battery according to claim 11, comprising the step of injecting an electrolyte after assembling the second electrode. Electrode composite; Electrolyte; And electrodes,
Electrode composite; And assembling the electrode, and then injecting the electrolyte. delete

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