KR20150031257A - Device for Controlling Coating-Quantity of Electrode - Google Patents

Abstract

The present invention relates to a device for automatic coating quantity adjustment that is used in a process of coating a metal sheet, as a current collector to be continuously transported, with an electrode compound. Provided is a device for automatically adjusting an electrode coating quantity including: a pair of dies that roll an electrode compound on a metal sheet when the metal sheet is interposed; a loading quantity measuring unit that measures the loading quantity of the electrode compound on the metal sheet; a control unit that sends a control signal to a position adjusting unit based on the loading quantity data received from the loading quantity measuring unit; and the position adjusting unit that adjusts the positions of an upper die and a lower die in accordance with the control signal received from the control unit so that a uniform electrode compound coating quantity can be provided for the metal sheet. Therefore, the device for automatically adjusting an electrode coating quantity according to the present invention changes the roll pressure of the die by the position adjusting unit and locally controls the coating quantity even when the electrode compound is loaded without uniformity on the surface of the metal sheet. Accordingly, an electrode sheet with the uniform coating quantity of the electrode compound can be obtained so that the quality of a product can uniformized and operation processing and efficiency can be improved.

Description

Device Controlling Coating-Quantity of Electrode

More particularly, the present invention relates to an apparatus for automatically adjusting the coating amount in a process of coating an electrode mixture onto a metal sheet as a current collector which is continuously transported, A pair of dies for rolling the electrode assemblies onto the metal sheet in the state of being rolled; A loading amount measuring unit for measuring a loading amount of the electrode mixture on the metal sheet; A control unit for transmitting a control signal to the position adjusting unit based on the loading amount data received from the loading amount measuring unit; And a position adjuster for adjusting a position of the upper die and the lower die in accordance with a control signal received from the control unit so as to provide a uniform coating amount of the electrode mixture to the metal sheet. To an automatic coating amount adjustment apparatus.

As technology development and demand for mobile devices have increased, there has been a rapid increase in demand for secondary batteries as energy sources. Among such secondary batteries, lithium secondary batteries, which exhibit high energy density and operational potential, long cycle life, Batteries have been commercialized and widely used.

The electrode assembly of the separation membrane structure sandwiched between the positive electrode and the negative electrode constituting the secondary battery and the separator structure sandwiched between the positive electrode and the negative electrode is largely divided into a jelly-roll type (wound type) and a stacked type (laminated type) according to its structure. In the jelly-roll type electrode assembly, an electrode active material or the like is coated on a metal foil used as a current collector, dried and pressed, cut into a band shape having a desired width and length, and a cathode and an anode are diaphragm- . Although the jelly-roll type electrode assembly is suitable for a cylindrical battery, when it is applied to a square or pouch type battery, it has disadvantages such as separation of electrode active material and low space utilization. On the other hand, the stacked electrode assembly has a structure in which a plurality of anode and cathode unit members are sequentially laminated, and it is easy to obtain a rectangular shape. However, when the manufacturing process is troublesome and impact is applied, .

On the other hand, these electrode assemblies have a common point in that they are based on a structure in which a sheet-like current collector such as a metal foil is coated with an electrode mixture including an electrode active material. Generally, the coating of the electrode material mixture is performed by loading a slurry for an electrode material mixture in a metal foil, followed by drying and rolling. Rolling is performed using a slot die apparatus as in Fig.

1, the slot die apparatus 600 includes an upper die 610 and a lower die 620, and a slurry for electrode assembly is loaded on a current collector (not shown) Is placed on the lower die 620, and the upper die 610 is lowered to perform the rolling process.

However, when performing rolling using such a slot die apparatus 600, uniform coating can not be achieved when the electrode slurry slurry does not have a uniformly loaded state at the front face of the current collector. Specifically, although the thickness of the coating layer of the electrode mixture is determined by the distance between the upper die 610 and the lower die 620 in the state where the upper die 610 is lowered, due to the low fluidity of the slurry, Where there is more or less, there may be more or less regions of the coating amount locally after rolling.

The uneven coating amount of the electrode mixture in the current collector lowers the structural stability in a jelly-roll type electrode assembly having a structure in which a long electrode sheet is wound several times or a stacked or stacked / folded electrode assembly in which a plurality of electrode sheets are stacked , Thereby deteriorating battery performance and safety.

Therefore, there is a great need for a technology that can fundamentally solve these problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments and, as will be described later, in a process of coating an electrode mixture onto a metal sheet as a current collector which is continuously transported, a pair of dies, The present invention has been made to develop an electrode coating amount automatic regulating apparatus having a specific configuration including an electrode coating amount adjusting unit and an electrode coating amount adjusting unit. When such an automatic electrode coating amount adjusting apparatus is used in a process of coating an electrode mixture on a metal sheet as a current collector, It was confirmed that the coating amount of the electrode mixture could be controlled locally, resulting in a uniform coating, and the present invention has been accomplished.

Accordingly, the present invention is an apparatus for automatically adjusting the coating amount in the process of coating an electrode mixture onto a metal sheet as a current collector which is continuously transported,

A pair of dies for rolling the electrode mixture on the metal sheet with the metal sheet interposed therebetween;

A loading amount measuring unit for measuring a loading amount of the electrode mixture on the metal sheet;

A control unit for transmitting a control signal to the position adjusting unit based on the loading amount data received from the loading amount measuring unit; And

A position adjuster for adjusting a position of the upper die and the lower die according to a control signal received from the controller, so as to provide a uniform coating amount of the electrode assembly to the metal sheet;

As shown in FIG.

That is, the apparatus for automatically adjusting the coating amount of the electrode according to the present invention can adjust the coating amount locally by adjusting the position of the upper die and the lower die based on the measurement of the loading amount of the electrode mixture on the metal sheet, Lt; RTI ID = 0.0 > of < / RTI >

The apparatus for automatically adjusting the coating amount of the electrode according to the present invention can be used both for manufacturing the positive electrode and the negative electrode. Current collectors used for such anodes and cathodes generally consist of metal sheets having a thickness of 3 to 500 μm.

In the case of the anode, the current collector may be a surface treated with carbon, nickel, titanium or silver on the surface of stainless steel, aluminum, nickel, titanium, sintered carbon or aluminum or stainless steel The current collector may be a surface treated with carbon, nickel, titanium or silver on the surface of copper, stainless steel, aluminum, nickel, titanium, fired carbon, copper or stainless steel, Aluminum-cadmium alloy and the like may be used. However, it is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and it is also possible to form fine irregularities on the surface to enhance the bonding force of the electrode active material, Sieves, foams, nonwoven fabrics, and the like.

The electrode mixture is loaded on the current collector in the form of a slurry, for example, and includes an electrode active material such as a cathode active material and a negative active material.

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 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 , LiMnO ₂ and the like; 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 ; A Ni-site type lithium nickel oxide expressed 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); 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; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The negative electrode active material may include, for example, carbon such as non-graphitized carbon or 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' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x < 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, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The electrode material mixture may further include a conductive material, a binder, a filler, and the like.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the electrode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or 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 metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the electrode active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the electrode active material. 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.

The filler is optionally used as a component for suppressing the expansion of the electrode, and is not particularly limited as long as it is a fibrous material without causing any chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

Therefore, the electrode material mixture may be a slurry-type electrode material mixture in which an electrode active material or the like is contained in a predetermined solvent such as NMP in order to appropriately coat the current collector.

In the present invention, the pair of dies are not particularly limited as long as they can roll the metal sheet loaded with the electrode mixture and adjust the position by the position adjuster.

In one preferred embodiment, the pair of dies includes a top die made of a metal material and locally resiliently deformed by the position adjuster, and a bottom die on which the metal sheet loaded with the electrode material mixture is mounted on the top surface And the upper die is lowered toward the lower die to roll the electrode assembly. The die of this structure can perform a predetermined rolling process due to the inherent rigidity of the metal material and can adjust the gap with the lower die at a desired position by local elastic deformation of the upper die.

In the present invention, the loading amount measuring unit may be any unit as long as it can measure the thickness of the electrode mixture loaded on the surface of the metal sheet loaded on the metal sheet loaded with the electrode mixture. For example, Lt; / RTI >

In one preferred example, the loading amount measurement unit may include:

An ultrasonic wave generator for scanning the surface of the metal sheet with ultrasonic waves;

An ultrasonic receiver for scanning the electrode mixture loaded with the ultrasonic waves generated by the ultrasonic generator and receiving the returned ultrasonic waves; And

A data transfer unit for transferring the data obtained by the scan to the controller;

As shown in FIG.

The loading amount data in the loading amount measurement unit may be configured to include, for example, information on the density and / or thickness of the loading amount.

As described above, the control unit transmits a control signal to the position adjusting unit based on the loading amount data received from the loading amount measuring unit. For example, the control unit transmits standard data on the uniform coating amount And comparing the loading amount data with standard data and sending a control signal to the position adjusting unit when the difference value is larger than a threshold value.

For example, when it is determined that the measurement value of the loading amount of the ultrasonic signal is deflected in one direction as compared with the standard data, the control unit may send a signal compensating for the deflected length to the position adjustment unit in the opposite direction.

The standard data refers to information about a loading amount standardized for a specific electrode in the process, and thus may vary depending on the specifications of the battery. The control unit can calculate the degree of deflection of the loaded electrode compound in one direction by comparing the information such as the density and the thickness of the loading amount of the electrode compound obtained in the loading amount measurement unit with the standard data.

On the other hand, the position adjusting unit can be configured to adjust the positions of the upper die and the lower die in various ways according to a control signal from the control unit, for example, by locally resiliently deforming the upper die to adjust the gap with the lower die Can be configured.

This position adjuster may preferably be a servo motor module mounted on the upper die.

In one preferred example, the servo motor module comprises:

A metal block installed at one end of the upper die and applying elastic deformation to one end of the upper die by a driving force transmitted from a shaft;

A shaft for transmitting the driving force of the servo motor to the metal block;

A driving force switching unit mounted between the shaft and the servo motor for switching the rotational driving force of the servo motor to a linear driving force and transmitting the driving force to the shaft; And

A servo motor for supplying a driving force to the shaft through the driving force switching unit;

As shown in FIG.

In the servo motor module having such a configuration, the servo motor is driven by a control signal received from the control section, and the driving force is converted to a linear driving force by the driving force switching section and transmitted to the metal block by the shaft. The driving force transmitted to the metal block locally resiliently deforms one end of the upper die and the amount of electrode coating can be adjusted by one end of the elastically deformed upper die.

The servo motor may be an AC servo motor or a DC servo motor.

The present invention also provides a secondary battery manufactured using the apparatus for automatically adjusting the coating amount of the electrode.

The secondary battery may preferably be a lithium secondary battery having high energy density, discharge voltage, and output stability. Other components of the lithium secondary battery according to the present invention will be described in detail below.

Generally, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, a non-aqueous electrolyte containing a lithium salt, and the like. The positive electrode and the negative electrode are the same as described above.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The lithium salt-containing nonaqueous electrolyte solution is composed of a nonaqueous electrolyte and a lithium salt. As the nonaqueous electrolyte solution, a liquid nonaqueous electrolyte, a solid electrolyte, and an inorganic solid electrolyte are used.

The lithium secondary battery according to the present invention can be manufactured by a conventional method known in the art. That is, a porous separator may be inserted between the anode and the cathode, and an electrolyte may be injected into the separator.

The present invention also provides a battery pack comprising two or more of the above-described secondary batteries as unit cells.

The battery pack according to the present invention is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or an electric power storage device which is exposed to frequent vibration and strong impact and is required to have a long service life in consideration of structural stability, Can be preferably used.

Such a structure for a battery pack, a device such as an electric vehicle, and a manufacturing method thereof are well known in the art, and a detailed description thereof will be omitted herein.

INDUSTRIAL APPLICABILITY As described above, the apparatus for automatically adjusting the coating amount of the electrode according to the present invention can provide a uniform coating amount of the electrode mixture to the metal sheet, thereby improving not only the process efficiency but also the structural uniformity A secondary battery excellent in stability and operation performance can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a portion of an apparatus for coating electrode assemblies on metal sheets using a slot die in the prior art;
2 is a partial perspective view of an apparatus for automatically adjusting the coating amount of an electrode according to an embodiment of the present invention;
3 is a side schematic view of an apparatus for automatically adjusting the coating amount of an electrode according to an embodiment of the present invention;
4 is a side view schematically showing an apparatus for automatically adjusting the coating amount of an electrode, which shows a scene in which a gap between an upper die and a lower die is opened by elastically deforming the upper die by the position adjusting unit of FIG. 3;
5 is a side view schematically showing an apparatus for automatically adjusting the coating amount of an electrode, which shows a scene in which the gap between the upper die and the lower die is narrowed by elastically deforming the upper die by the position adjusting unit of FIG. 3;
6 is a process schematic diagram of an apparatus for automatically adjusting the coating amount of an electrode according to an embodiment of the present invention;
7 is a block diagram of an apparatus for automatically adjusting an amount of coated electrodes according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the drawings, but the present invention is not limited by the scope of the present invention.

FIG. 2 is a perspective view of a pair of dies and a position adjusting unit according to an embodiment of the present invention, and FIGS. 3 to 5 are schematic views showing a state where the position adjusting unit is elastically deformed. FIG. 6 is a schematic view of the apparatus, and FIG. 7 is a structural view of the apparatus.

Referring to the drawings, an electrode sheet supply unit 500 for sequentially supplying an electrode sheet 10 is composed of a conveyor belt driven by rollers at both ends thereof. When the electrode sheet 10 is placed on the upper surface of the conveyor belt .

The electrode sheet 10 on which the electrode assembly is loaded is continuously fed to the electrode sheet feeder 500 in the direction in which the loading amount measuring unit 400 is positioned and the loading amount measuring unit 400 located on the electrode sheet feeder 500, The loading amount of the electrode mixture on the surface of the electrode sheet 10 is measured.

The data obtained by the loading amount measuring unit 400 includes information on the loaded density and thickness of the electrode mixture, and the data is transmitted to the controller 300. [

The control unit 300 compares the data with the standard data stored in the control unit 300. When the deviation exceeds a threshold value, the control unit 300 sends a position correction signal to the position adjustment unit 200 to compensate the deviation.

The position adjustment unit 200 receives the position correction signal from the control unit 300 and includes a servo motor 210, a drive force switching unit (not shown), a shaft 220, and a metal block 230.

The servo motor 210 is driven by the correction signal of the controller 300 and the driving force is transmitted to the metal block 230 mounted on one end of the upper die 110 by the shaft 220. The driving force transmitted to the metal block 230 elastically deforms one end of the upper die 110.

4, when the upper die 110 is elastically deformed in a direction opposite to the lower die 120 positioned below the upper die 110 by the servo motor module 200, As the clearance of the die 120 spreads, the rolling force is reduced.

5, when the upper die 110 is elastically deformed toward the lower die 120 by the servo motor module 200, the upper die 110 and the lower die 120 ), The rolling force is increased.

Thus, since the rolling force can be locally controlled, a uniform coating amount of the electrode mixture to the metal sheet can be obtained in the process of coating the electrode mixture on the metal sheet.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (14)

An apparatus for automatically adjusting a coating amount in a process of coating an electrode mixture onto a metal sheet as a current collector which is continuously transported,
A pair of dies for rolling the electrode mixture on the metal sheet with the metal sheet interposed therebetween;
A loading amount measuring unit for measuring a loading amount of the electrode mixture on the metal sheet;
A control unit for transmitting a control signal to the position adjusting unit based on the loading amount data received from the loading amount measuring unit; And
A position adjuster for adjusting a position of the upper die and the lower die according to a control signal received from the controller, so as to provide a uniform coating amount of the electrode assembly to the metal sheet;
And a controller for controlling the amount of coating of the electrode. The apparatus of claim 1, wherein the electrode mixture is an electrode mixture in the form of a slurry. The apparatus of claim 1, wherein the pair of dies includes a top die made of a metal material and locally resiliently deformed by the position adjuster, and a bottom die on which the metal sheet loaded with the electrode material mixture is mounted on the top surface And the upper die is lowered toward the lower die to roll the electrode mixture. The apparatus according to claim 1,
An ultrasonic wave generator for scanning the surface of the metal sheet with ultrasonic waves;
An ultrasonic receiver for scanning the electrode mixture loaded with the ultrasonic waves generated by the ultrasonic generator and receiving the returned ultrasonic waves; And
A data transfer unit for transferring the data obtained by the scan to the controller;
And a controller for controlling the amount of coating of the electrode. The apparatus of claim 1, wherein the loading amount data includes information on a density and a thickness of the loading amount. 2. The apparatus according to claim 1, wherein the controller includes standard data on a uniform coating amount, compares the loading amount data with standard data, and transmits a control signal to the position adjusting unit when the difference value is greater than a threshold value. And an electrode coating amount adjusting device for adjusting the coating amount of the electrode. The apparatus of claim 1, wherein the position adjuster adjusts an interval between the upper die and the lower die by locally deforming the upper die. The apparatus of claim 1, wherein the position adjusting unit is a servo motor module mounted on an upper die. The servo motor module according to claim 8,
A metal block installed at one end of the upper die and applying elastic deformation to one end of the upper die by a driving force transmitted from a shaft;
A shaft for transmitting the driving force of the servo motor to the metal block;
A driving force switching unit mounted between the shaft and the servo motor for switching the rotational driving force of the servo motor to a linear driving force and transmitting the driving force to the shaft; And
A servo motor for supplying a driving force to the shaft through the driving force switching unit;
And a controller for controlling the amount of coating of the electrode. The apparatus of claim 9, wherein the servomotor is an AC servomotor or a DC servomotor. The apparatus of claim 8, wherein the upper die is capable of locally varying the rolling force from 1 kPa to 1 MPa by means of the servo motor module. 12. A secondary battery comprising: an electrode manufactured by using the automatic coating apparatus for an amount of coated electrode according to any one of claims 1 to 11. A battery pack comprising two or more secondary batteries according to claim 12 as unit cells. 14. The battery pack according to claim 13, wherein the battery pack is used as a power source for an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

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