KR20210127064A - Quality evaluation method of electrode and manufacturing method of electrode - Google Patents

Abstract

The present invention provides a method of evaluating the quality of an electrode that can easily and quickly filter out defective electrodes among electrodes, and a method of manufacturing an electrode. The method of evaluating the quality of an electrode includes the steps of: preparing a plurality of electrodes including a current collector and an active material layer formed on the current collector and not subjected to a rolling process; measuring a color coordinate value of an active material layer of each of the plurality of electrodes by using an optical system and obtaining an average value; and determining that the product is good when the difference between the color coordinate value measured from each electrode and the average value is less than or equal to a preset value, and determining that the product is defective when the difference exceeds the preset value. In addition, the method of manufacturing an electrode includes the steps of: manufacturing a plurality of electrodes without a rolling process by applying a slurry including an active material, a conductive material, and a binder to the current collector and drying the slurry to form the active material layer; evaluating the quality of the electrode by the described method; and rolling the electrode, which is determined as a good product.

Description

A method for evaluating the quality of an electrode and a method for manufacturing an electrode

The present invention relates to a method for evaluating the quality of an electrode and a method for manufacturing an electrode comprising the step of evaluating the quality of the electrode by the method.

Electrodes produced under the same prescription and under the same process conditions should have the same physical properties in theory, but differences in physical properties may exist for each manufacturing unit during actual electrode production. Therefore, even if the electrodes are produced under the same conditions, there may be defective electrodes among them, and the defective electrodes must be selected through quality inspection of the electrodes.

Commonly known quality inspection items for electrodes include adhesion, thickness, and loading. Among the quality inspection items of the electrode, adhesion is a very important quality inspection item as an item for filtering out an electrode that is detached in the electrode assembly process or an electrode that has peel-off in an activation process.

However, in order to check the adhesion of the electrode, a rolling process must be performed, and there is a problem in that the quality of the electrode cannot be evaluated in real time.

Therefore, there is a need for development of a method for selecting defective electrodes by evaluating the quality of the electrodes through physical property evaluation before the rolling process.

The present invention is to solve the above problems, and to provide a method for evaluating the quality of an electrode that can easily and quickly filter out defective electrodes from among the electrodes through a simple measurement of color coordinate values for the electrodes before the rolling process. .

According to one embodiment, the present invention includes the steps of preparing a plurality of electrodes including a current collector and an active material layer formed on the current collector and not subjected to a rolling process; measuring a color coordinate value of an active material layer of each of the plurality of electrodes using an optical system and obtaining an average value; And when the difference between the color coordinate value measured from the respective electrodes and the average value is less than or equal to a predetermined value, determining that the product is good, and when it exceeds the predetermined value, determining that the product is defective. provides

In addition, according to another embodiment, the present invention comprises the steps of applying a slurry including an active material, a conductive material, and a binder on a current collector and drying the slurry to form an active material layer, thereby manufacturing a plurality of electrodes without a rolling process; evaluating the quality of the electrode by the method described above; And it provides a method of manufacturing an electrode comprising the step of rolling the electrode determined to be a good product.

The electrode quality evaluation method of the present invention can easily and quickly filter out defective electrodes from among the electrodes by measuring the color coordinate values of the electrodes before the rolling process. That is, the defective electrode can be selected without going through the rolling process, and accordingly, the defect rate of the finished electrode product that has undergone the rolling process can be significantly reduced.

The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

In the present specification, terms such as "comprise", "comprising" or "have" are intended to designate the presence of an embodied feature, number, step, element, or a combination thereof, but one or more other features or It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, elements, or combinations thereof.

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

<Evaluation method of electrode quality>

The electrode quality evaluation method according to the present invention comprises the steps of: preparing a plurality of electrodes including a current collector and an active material layer formed on the current collector and not subjected to a rolling process; measuring a color coordinate value of an active material layer of each of the plurality of electrodes using an optical system and obtaining an average value; and judging a good product when the difference between the color coordinate value measured from each of the electrodes and the average value is less than or equal to a preset value, and judging a defective product when it exceeds a preset value.

When the color coordinate value of the active material layer of each of the plurality of electrodes that has not undergone the rolling process measured using the optical system is compared with the average value, the difference between the measured color coordinate value of each electrode and the average value is a preset value. When the intrinsic electrode is subjected to the rolling process, the adhesion between the current collector and the active material layer is excellent, so that poor adhesion may not occur. For example, when the electrode classified as a good product according to the present invention undergoes a rolling process, the adhesive force between the current collector and the active material layer of the electrode may be secured to 20 gf/20 mm or more.

According to the present invention, by measuring the color coordinate values of the electrodes before rolling, it is possible to simply and quickly filter out defective electrodes from among the electrodes. That is, defective electrodes can be selected without going through the rolling process, and the defect rate of the finished electrode product that has undergone the rolling process can be significantly reduced.

Hereinafter, each step of the method for evaluating the quality of the electrode of the present invention will be described in more detail.

Preparing a plurality of electrodes that have not undergone a rolling process

The present invention includes a step of preparing a plurality of electrodes including a current collector and an active material layer formed on the current collector and not subjected to a rolling process.

According to the present invention, the plurality of electrodes may be those produced under the same prescription and the same process conditions. Electrodes produced under the same prescription and under the same process conditions should have the same physical properties in theory, but differences in physical properties may exist for each manufacturing unit during actual electrode production. Therefore, even if the electrodes are produced under the same prescription and under the same process conditions, there may be defective electrodes among them, and the inventors of the present invention have embodied the present invention to simply and quickly select the defective electrodes.

The present invention does not evaluate the electrode that has undergone the rolling process like the quality evaluation of the existing battery electrode, but evaluates the quality of the electrode that has not undergone the rolling process to filter out defective electrodes before the rolling process, which can significantly lower the defect rate after the rolling process. will be.

Measuring the color coordinate values of the active material layer of each of the plurality of electrodes to obtain an average value

The present invention includes measuring the color coordinate values of the active material layers of each of the electrodes using an optical system to obtain an average value.

The optical system is a device including a light source and an image sensor, and when the active material layer of each of the electrodes is photographed using the optical system, color information on the surface of the active material layer of each of the electrodes is converted into a color coordinate value and detected. The image sensor is a device that converts incoming light into an electrical signal, and may be, for example, a Charge Coupled Device (CCD) sensor or a Complementary Metal Oxide Semiconductor (CMOS) sensor.

According to the present invention, the optical system may be a spectrophotometer or a colorimeter.

The color coordinate values collectively refer to numerical values expressed as coordinates in a three-dimensional color space. For example, the color coordinate values may be L ^* , a ^* , b ^* , whiteness or yellowness values.

According to the present invention, the color coordinate value of the active material layer may be measured using a contact or non-contact color difference meter. That is, the color difference meter may be a contact type or non-contact type color difference meter. In the case of using a non-contact colorimeter, measurement can be performed without direct contact with the sample, so measurement is simple, and the measurement can be performed during a continuous production process.

The color coordinate value of the active material layer may be measured using, for example, CM2600d manufactured by Konica Minolta as a color difference meter. Specifically, after setting the measurement mode to SCI (Specular Component Included) or SCE (Specular Component Excluded), standard light source D65 (color temperature: 6500K), CIE 1976 10° standard observer using Konica Minolta's CM2600d as a colorimeter, The measurement may be performed by contacting a colorimeter to a position to be measured after white calibration.

Comparing the color coordinate values measured from the respective electrodes with the average value to determine whether the product is good or bad

The present invention includes determining a good product when the difference between the color coordinate value measured from the respective electrodes and the average value is less than or equal to a preset value, and judging a defective product when it exceeds a preset value. For example, when the preset value is 1, if the difference between the measured color coordinate value of the electrode and the average value is 0.5, it is judged as good product, and if the difference between the measured color coordinate value and the average value is 1.5, it is defective. is to judge

When the difference between the measured color coordinate value and the average value of each electrode is within a preset value range, excellent adhesion between the current collector and the active material layer can be secured after rolling, thereby significantly reducing the defect rate of the finished electrode product that has undergone the rolling process. have.

According to the present invention, when the color coordinate value is an L ^* value, the preset value may be 1, preferably 0.5.

According to the present invention, when the color coordinate value is a ^* value, the preset value may be 0.02, preferably 0.01.

According to the present invention, when the color coordinate value is a b ^* value, the preset value may be 0.06, preferably 0.03.

According to the present invention, when the color coordinate value is a whiteness value, the preset value may be 0.7, preferably 0.3.

According to the present invention, when the color coordinate value is a yellowness value, the preset value may be 0.2.

As a result of the comparison, the difference between the measured color coordinate values of each electrode, that is, L ^* , a ^* , b ^* , whiteness and yellowness values, and the average value of each color coordinate satisfies within the range of the above-described preset values, resulting in a good product. The classified electrode may have excellent electrode quality when subjected to a rolling process. Specifically, when an electrode classified as a good product according to the electrode quality evaluation method of the present invention undergoes a rolling process, the adhesive force between the current collector and the active material layer may be excellent. For example, the adhesive force between the current collector and the active material layer may be secured to 20 gf/20 mm or more.

<Method for manufacturing electrode>

The method of manufacturing an electrode according to the present invention comprises the steps of applying a slurry including an active material, a conductive material, and a binder on a current collector, drying the slurry to form an active material layer, and manufacturing a plurality of electrodes without a rolling process; evaluating the quality of the electrode with the method according to claim 1 ; and rolling the electrode determined to be a good product.

Hereinafter, each step of the method of manufacturing the electrode of the present invention will be described in more detail.

Manufacturing a plurality of electrodes that have not undergone a rolling process

The present invention includes manufacturing a plurality of electrodes without a rolling process by applying a slurry including an active material, a conductive material and a binder on a current collector and drying the slurry to form an active material layer. The active material layer may be formed on one or both surfaces of the current collector.

The current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and in the case of a positive electrode current collector, for example, stainless steel, aluminum, nickel, titanium, sintered carbon, or surface of aluminum or stainless steel In the case of a negative electrode current collector, for example, a surface treated with carbon, nickel, titanium, silver, etc. may be used, for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, the surface of copper or stainless steel Carbon, nickel, titanium, silver, etc. surface-treated, aluminum-cadmium alloy, etc. may be used.

The current collector may typically have a thickness of 3 μm to 500 μm, and may increase the adhesion of the positive electrode material or the negative electrode material by forming fine irregularities on the surface of the current collector. For example, it may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven body, and the like.

The slurry may be prepared by dissolving or dispersing an active material, a conductive material, and a binder in a solvent.

When the active material is a positive active material, the positive active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically includes lithium and one or more transition metals such as cobalt, manganese, nickel or aluminum. It may be a lithium composite metal oxide. More specifically, the lithium composite metal oxide is a lithium-manganese-based oxide (eg, LiMnO ₂ , LiMn ₂ O _{4 ,} etc.), a lithium-cobalt-based oxide (eg, LiCoO _{2 ,} etc.), lithium-nickel-based oxide (eg, LiNiO ₂ ), lithium-nickel-manganese oxide (eg, LiNi _1-Y Mn _Y O ₂ (0<Y<1), LiMn _2-z Ni _z O ₄ (0<Z) <2), lithium-nickel-cobalt-based oxide (eg, LiNi _1-Y1 Co _Y1 O ₂ (0<Y1<1), lithium-manganese-cobalt-based oxide (eg, LiCo _1-Y2 Mn _Y2) O ₂ (0<Y2<1), LiMn _2-z1 Co _z1 O ₄ (0<Z1<2), lithium-nickel-manganese-cobalt oxide (eg, Li(Ni _p Co _q Mn _r1 )O ₂ (0<p<1, 0<q<1, 0<r1<1, p+q+r1=1) or Li(Ni _p1 Co _q1 Mn _r2 )O ₄ (0<p1<2, 0 < q1 <2, 0 <r2<2, p1+q1+r2=2), or lithium-nickel-cobalt-transition metal (M) oxide (eg, Li(Ni _p2 Co _q2 Mn _r3 M _S2 )O ₂ ( M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg and Mo, and p2, q2, r3 and s2 are atomic fractions of each independent element, 0 < p2 < 1, 0 < q2 <1, 0<r3<1, 0<s2<1, p2+q2+r3+s2=1), and the like, and any one or two or more of these compounds may be included.

When the active material is an anode active material, various anode active materials used in the art, for example, a carbon-based anode active material, a silicon-based anode active material, a metal alloy, etc. may be used as the anode active material.

Examples of the carbon-based negative active material include various carbon-based negative active materials used in the art, for example, graphite-based materials such as natural graphite, artificial graphite, and Kish graphite; Pyrolytic carbon, mesophase pitch based carbon fiber, meso-carbon microbeads, liquid crystal pitches (Mesophase pitches) and petroleum and coal tar pitch derived cokes (petroleum or coal tar pitch derived cokes) High-temperature calcined carbon, soft carbon, hard carbon, etc. may be used. The shape of the carbon-based anode active material is not particularly limited, and various shapes of materials such as amorphous, plate-like, scale-like, spherical or fibrous shape may be used.

The silicon-based negative active material is, metal silicon (Si), silicon oxide (SiO _x , where 0<x<2) silicon carbide (SiC) and a Si-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, a group 13 element, 14 It is an element selected from the group consisting of group elements, transition metals, rare earth elements, and combinations thereof, and may include at least one selected from the group consisting of (not Si). The element Y includes Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, It may be selected from the group consisting of Se, Te, Po, and combinations thereof.

The active material may be included in an amount of 80 wt% to 99 wt%, more specifically 85 wt% to 98 wt%, based on the total weight of the active material layer. When the content of the active material is within the above range, excellent capacity characteristics and electrochemical characteristics can be obtained.

The conductive material is used to impart conductivity to the electrode, and may be used without any particular limitation as long as it has electronic conductivity without causing chemical change in the configured battery. Specific examples include graphite such as natural graphite and artificial graphite; carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like, and one type alone or a mixture of two or more types thereof may be used.

The conductive material may be included in an amount of 1 wt% to 30 wt% based on the total weight of the active material layer.

The binder serves to improve adhesion between active material particles and adhesion between the active material and the current collector. Specific examples of the binder include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile (polyacrylonitrile), carboxymethyl cellulose Woods (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, and styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, and any one of them or a mixture of two or more thereof may be used.

The binder may be included in an amount of 1 wt% to 30 wt% based on the total weight of the positive active material layer.

The solvent may be a solvent generally used in the art, dimethyl sulfoxide (DMSO), isopropyl alcohol (isopropyl alcohol), N-methylpyrrolidone (NMP), acetone (acetone) or water and the like, and any one of them or a mixture of two or more thereof may be used. The amount of the solvent used is not particularly limited, as long as it can be adjusted so that the slurry has an appropriate viscosity in consideration of the application thickness of the slurry, the production yield, workability, and the like.

According to the present invention, a slurry containing an active material, a conductive material and a binder is applied on a current collector in a loading amount of ^{0.005 g/cm 2} to 0.050 g/cm ^{2 and dried to form an active material layer.} Loading of the slurry is preferably can be a 0.005g / cm ² to about 0.030g / cm ^2, may more preferably be a 0.005g / cm ² to about 0.025g / cm ^2. When the loading amount of the slurry is within the above range, an active material layer having an appropriate thickness may be formed on the current collector.

According to the present invention, the drying may be drying with a total amount of heat of 1000kW to 1500kW. Preferably, the drying may be performed with a total heat amount of 1100kW to 1400kW, more preferably, a total heat amount of 1200kW to 1400kW. When the total amount of heat during drying is within the above range, the electrode may be dried so that defects do not occur, and thus the quality of the electrode may be excellent.

According to the present invention, the thickness of the active material layer may be 100㎛ to 500㎛. The thickness of the active material layer may be preferably 200 μm to 500 μm, more preferably 250 μm to 450 μm. When the thickness of the active material layer is within the above range, it is possible to significantly lower the defect rate of the electrode while maximally expressing the performance of the active material layer.

Assessing the quality of the electrode

The method of manufacturing an electrode according to the present invention includes evaluating the quality of the electrode by the method described above.

That is, using a plurality of manufactured electrodes (electrodes that have not undergone a rolling process), the color coordinate values of the active material layers of each of the plurality of electrodes are measured with an optical system to obtain an average value, and the measurement is performed from the respective electrodes. and judging a good product when the difference between the obtained color coordinate value and the average value is less than or equal to a preset value, and judging a defective product when it exceeds a preset value. Specific details are the same as described above.

Step of rolling the electrode judged to be a good product

The present invention includes a step of manufacturing an electrode by rolling the electrode determined to be a good product.

As described above, the electrode determined as a good product according to the quality evaluation method of the electrode of the present invention may be used to manufacture a lithium secondary battery after rolling, and in this case, the lithium secondary battery may have a significantly low defect rate. The lithium secondary battery may be usefully used in portable devices such as mobile phones, notebook computers, digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs).

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

manufacturing example

10 parts by weight of natural graphite, 35 parts by weight of artificial graphite, 0.5 parts by weight of a conductive material, 3.5 parts by weight of SBR and 1 part by weight of CMC were mixed with 50 parts by weight of water to prepare a slurry.

^{After applying the slurry at a loading amount of 0.015 g/cm 2} to one side of a copper current collector having a thickness of 8 μm, it was dried with a total amount of heat of 1300 kW to form an active material layer having a thickness of 340 μm, and on the other surface of the current collector. An electrode was manufactured by forming an active material layer under the same prescription and same process conditions.

Seven electrodes (electrodes A to G) prepared by the above method were prepared.

Example: Evaluation of the quality of electrodes

Using Konica Minolta's CM2600d as a colorimeter, set the measurement mode to SCI, standard light source D65 (color temperature: 6500K), and CIE 1976 10° standard observer, and after white calibration, contact the colorimeter to the position to be measured and contact electrode A ^{to the color coordinate L *} value, color coordinate a ^* value, color coordinate b ^* value, whiteness and yellowness of the active material layer of both surfaces (one side, the other side) of each electrode G were measured, and the results are shown in Table 1 below.

electrode L ^* a ^* b ^* whiteness yellowness one side ride one side ride one side ride one side ride one side ride A 39.19 38.71 0.61 0.60 0.26 0.23 11.79 11.48 2.30 2.17 B 39.34 38.93 0.61 0.59 0.25 0.23 11.92 11.66 2.24 2.13 C 39.37 38.25 0.60 0.60 0.24 0.17 11.97 11.25 2.17 1.95 D 39.20 38.48 0.61 0.60 0.24 0.19 11.84 11.38 2.20 2.01 E 39.07 38.79 0.60 0.60 0.25 0.18 11.71 11.65 2.24 1.94 F 39.31 38.77 0.60 0.59 0.25 0.21 11.89 11.58 2.24 2.04 G 39.22 37.21 0.60 0.63 0.22 0.13 11.89 10.58 2.11 1.80 average value 39.24 38.45 0.60 0.60 0.24 0.20 11.86 11.37 2.21 2.01

electrode IL ^* - mean value l la ^* - mean value l lb ^* -mean value l l whiteness - average value l l yellowness - average value l one side ride one side ride one side ride one side ride one side ride A 0.05 0.26 0.01 0 0.02 0.03 0.07 0.11 0.09 0.16 B 0.1 0.48 0.01 0.01 0.01 0.03 0.06 0.29 0.03 0.12 C 0.13 0.2 0 0 0 0.03 0.11 0.12 0.04 0.06 D 0.04 0.03 0.01 0 0 0.01 0.02 0.01 0.01 0 E 0.17 0.34 0 0 0.01 0.02 0.15 0.28 0.03 0.07 F 0.07 0.32 0 0.01 0.01 0.01 0.03 0.21 0.03 0.03 G 0.02 1.24 0 0.03 0.02 0.07 0.03 0.79 0.1 0.21

Referring to Table 2, the difference between the color coordinate value and the average value of the active material layer on both sides of each of the electrodes A to F is within 1 when the ^{color coordinate is L * , within 0.02 when the color coordinate is a *} , and the color coordinate is b ^* Electrodes A to F were judged as good products from within 0.06 in the case of whiteness, within 0.7 when the color coordinate was yellow, and within 0.2 when the color coordinate was yellow.

On the other hand, the electrode G was judged to be defective because the difference between the color coordinate value and the average value of the active material layer on the other surface was out of the preset value range.

Experimental Example: Adhesion evaluation

After each of the electrodes A to G was rolled (roll press), the rolled electrode was attached to the slide glass using a double-sided tape. Thereafter, using a UTM device (Lloyed), the electrode was pulled at a 90° angle at a speed of 100 mm/min, and the force to peel off from the slide glass was measured. The results are shown in Table 2 below.

electrode used Adhesion (gf/20mm) evaluation one side ride normal A 32 24 normal B 33 23 normal C 30 24 normal D 31 23 normal E 29 25 normal F 32 26 normal G 31 15 Poor adhesion

As shown in Table 3, in the case of electrodes A to F classified as good products according to the quality evaluation method of the electrode of the present invention, it can be confirmed that the adhesion of the electrodes after the rolling process is excellent as 20 gf/20 mm or more.

On the other hand, in the case of electrode G, in which the difference between the color coordinate value and the average value of the active material layer on the other surface is out of the range of the preset value, the adhesion of the other surface of the electrode after the rolling process is 15 gf/20 mm. You can see what's not good. That is, it can be confirmed that the adhesive strength is poor.

Therefore, according to the present invention, it can be seen that, through a simple measurement of color coordinate values for the electrodes before rolling, bad electrodes among the electrodes can be easily and quickly filtered out. That is, it can be seen that the defective electrode can be selected without going through the rolling process, and the defect rate of the finished electrode product can be significantly reduced.

Claims (13)

preparing a plurality of electrodes including a current collector and an active material layer formed on the current collector and not subjected to a rolling process;
measuring a color coordinate value of an active material layer of each of the plurality of electrodes using an optical system and obtaining an average value; and
When the difference between the color coordinate value measured from the respective electrodes and the average value is less than or equal to a preset value, determining that the product is good, and when it exceeds the preset value, determining that the product is defective.
The method according to claim 1,
The color coordinate value is the L ^* value, and the preset value is 1, the electrode quality evaluation method.
The method according to claim 1,
The color coordinate value is a ^* value, and the preset value is 0.02.
The method according to claim 1,
The color coordinate value is a b ^* value, and the preset value is 0.06.
The method according to claim 1,
The color coordinate value is a whiteness value, and the preset value is 0.7.
The method according to claim 1,
The color coordinate value is a yellowness value, and the preset value is 0.2.
The method according to claim 1,
The plurality of electrodes are produced under the same prescription and the same process conditions, the electrode quality evaluation method.
The method according to claim 1,
The optical system is a spectrophotometer or a color difference meter, the quality evaluation method of the electrode.
9. The method of claim 8,
The color difference meter is a method for evaluating the quality of an electrode that is a contact or non-contact color difference meter.
manufacturing a plurality of electrodes without a rolling process by applying a slurry including an active material, a conductive material, and a binder on a current collector and drying the slurry to form an active material layer;
evaluating the quality of the electrode with the method according to claim 1 ; and
A method of manufacturing an electrode comprising the step of rolling the electrode determined to be a good product.
11. The method of claim 10,
The method of manufacturing an electrode by applying the slurry in a loading amount of 0.005 g/cm ² to 0.050 g/cm ^{2 .}
11. The method of claim 10,
The drying is a method of manufacturing an electrode that is dried with a total amount of heat of 1000kW to 1500kW.
11. The method of claim 10,
The thickness of the active material layer is 100㎛ to 500㎛ method of manufacturing an electrode.