KR20220135531A - Metrhod for evaluating dissoultion quality of binder solution for secondary battery electrode and producing method of electrode slurry for secondary battery by the evaluation method - Google Patents

Abstract

A method for evaluating the dissolution quality of a binder solution for a secondary battery electrode according to the present invention comprises the steps of: measuring a haze value of the binder solution by transmitting light through a predetermined amount of a sampled binder solution; and evaluating the dissolution quality of the binder solution according to the dimension of the haze value. In addition, a method of producing electrode slurry for a secondary battery comprises the steps of: measuring a haze value of a binder solution by transmitting light through a predetermined amount of a sampled binder solution; evaluating the dissolution quality of the binder solution according to the dimension of the haze value; and producing electrode slurry by mixing an electrode active material and a conductive material with the binder solution with dissolution quality equal to or less than a predetermined haze value. A surface defect of the electrode for the secondary battery can be improved.

Description

Method for evaluating the dissolution quality of a binder solution for a secondary battery electrode and a method for manufacturing an electrode slurry for a secondary battery according thereto

The present invention relates to a method for evaluating the dissolution quality of a binder solution for a secondary battery electrode. More particularly, it relates to a dissolution quality evaluation method of a binder solution for a secondary battery electrode capable of quantitatively evaluating dissolution quality by measuring a haze value.

In addition, the present invention relates to a method of manufacturing an electrode slurry for a secondary battery based on the dissolution quality evaluation method.

As technology development and demand for mobile, automobile, and energy storage devices increase, the demand for batteries as an energy source is rapidly increasing. It has also been commercialized and widely used.

Electrodes used in lithium secondary batteries are formed by coating a mixture layer containing an active material on an electrode substrate made of a metal foil, and the mixture layer is formed by coating and drying a positive electrode or negative electrode slurry on an electrode substrate. Such an electrode slurry is prepared by mixing and drying solids such as a positive electrode/negative electrode active material and a conductive material in a binder solution.

The binder serves to improve the adhesion of the electrode and adjust the viscosity of the slurry by attaching the active material or the active material and the electrode substrate. Since the binder is mixed with an active material, a conductive material, and the like in the form of a binder solution dissolved in a predetermined solvent, the dissolution quality of the binder affects the quality characteristics of the electrode slurry or the electrode. For example, when the quality of dissolving a binder such as CMC or PVDF is not good, various problems such as an increase in the viscosity of the slurry and a poor electrode coating surface may be caused. The dissolution quality of such a binder depends on how much undissolved matter in the binder solution can be minimized.

Conventionally, in order to check the dissolution quality of the binder solution, simply visually check the less dissolved binder in the solution, or after applying the binder solution to the OHP film with a blade of a certain thickness, visually measure the number of foreign substances on the film. observation methods were used. However, this method has disadvantages in that it is difficult to grasp the quality of the whole solution because the amount of sample to be evaluated is small, and external foreign substances such as dust can be introduced, so that it is not distinguished from foreign substances of undissolved substances, and thus measurement accuracy is deteriorated. In addition, there is a problem such as a large error occurs depending on the evaluator because the evaluation with the naked eye.

As described above, if the dissolution quality of the binder solution is not accurately evaluated, even if a binder solution in which the same amount of binder is dissolved in a solvent is used, quality characteristics such as electrode slurry for secondary batteries or surface defects of electrodes vary greatly depending on the dissolution quality. For this reason, quality stability of an electrode cannot be ensured and it becomes difficult to improve the surface defect of an electrode.

Therefore, it is desired to develop a technology capable of improving the surface defect of the electrode by accurately quantitatively evaluating the dissolution quality of the binder solution for manufacturing the secondary battery electrode.

Japanese Laid-Open Patent Publication No. 2013-053919 (2013.03.21)

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a method for evaluating the dissolution quality of a binder solution for secondary battery electrodes capable of quantitatively evaluating the dissolution quality based on the haze value of the binder solution.

Another object of the present invention is to provide a method of manufacturing an electrode slurry for a secondary battery using a binder solution whose dissolution quality is evaluated based on the dissolution quality evaluation method of the binder solution.

The dissolution quality evaluation method of the binder solution for a secondary battery electrode of the present invention for solving the above problems comprises the steps of: measuring a haze value of the binder solution by transmitting light through a sampled predetermined amount of the binder solution; and evaluating the dissolution quality of the binder solution according to the size of the haze value.

The haze value refers to the ratio of the scattering transmittance to the total transmittance of the binder solution when light is transmitted through the binder solution.

As an example, the binder, which is a solute of the binder solution, is polyvinylidene fluoride-hexafluoropropylene (Poly (vinylidene fluoride-co-hexafluoropropylene), PVDF-co-HFP), polyvinylidene fluoride (polyvinylidene fluoride) , PVDF), polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxyl methyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl non-aqueous binders of pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, polytetrafluoroethylene (PTFE); an aqueous binder of acrylonitrile-butadiene rubber, styrene-butadiene rubber (SBR) or acrylic rubber; And it may be at least one selected from the group consisting of a polymer resin of hydroxyethyl cellulose, carboxymethyl cellulose, or polyvinylidene fluoride.

In addition, as an example, the solvent of the binder solution may be at least one selected from the group consisting of N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), acetone, an organic solvent of dimethyl acetamide, and water.

As a specific example, the binder solution may be a CMC solution in which a predetermined amount of CMC is dissolved in water.

As an example, the dissolution quality of the CMC solution may be quantitatively evaluated by measuring haze values of a plurality of CMC solutions having different at least one of a mixing time, a mixing temperature, a mixer type, and a mixer blade type.

As another aspect of the present invention, a method of manufacturing an electrode slurry for a secondary battery includes: measuring a haze value of the binder solution by transmitting light through a sampled predetermined amount of a binder solution; evaluating the dissolution quality of the binder solution according to the size of the haze value; and preparing an electrode slurry by mixing an electrode active material and a conductive material with a binder solution having a dissolution quality having a haze value of less than or equal to a predetermined value.

As a specific example, the binder solution may be a CMC solution in which a predetermined amount of CMC is dissolved in water.

As an example, the electrode slurry may be a negative electrode slurry.

As a specific example, the haze value of the CMC solution may be 2% or less.

According to the present invention, by preparing an electrode slurry with a binder solution whose dissolution quality is quantitatively evaluated by a haze value, the surface defect of the electrode for a secondary battery can be predicted.

In addition, it is possible to improve the surface defect of the electrode for a secondary battery by preparing the electrode slurry with a binder solution of dissolution quality having a haze value of less than or equal to a predetermined value.

1 is a view showing one form of a surface defect of an electrode for a secondary battery.

Hereinafter, the present invention will be described in detail. Prior to this, 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 should properly understand the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined in

In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Also, when a part of a layer, film, region, plate, etc. is said to be “on” another part, this includes not only cases where it is “directly on” another part, but also cases where another part is in between. Conversely, when a part of a layer, film, region, plate, etc. is said to be “under” another part, this includes not only cases where it is “directly under” another part, but also cases where there is another part in between. In addition, in the present application, “on” may include the case of being disposed not only on the upper part but also on the lower part.

As a raw material for electrode slurry for secondary batteries, the binder serves to improve the adhesion of the coated electrode by attaching active materials or active materials to the surface of the current collector. The binder is mixed with an electrode active material, a conductive material, etc. in the form of a binder solution obtained by dissolving the binder solid content in a predetermined solvent to prepare an electrode slurry. However, if the binder contained in the binder solution is not completely dissolved and is in the state of an undissolved substance in a microgel or the like form, the part interposed therebetween does not perform the original role of the binder. Such a portion appears as a surface defect of the electrode such as a gray spot, a pinhole, or a crater shape, and in severe cases becomes an active material defect region, thereby reducing the adhesion of the electrode.

1 is a view showing one form of a surface defect of an electrode for a secondary battery. As shown in FIG. 1 , it can be confirmed that a surface defect in the form of gray spots appears on the electrode for a secondary battery.

Therefore, although the dissolution quality of the binder solution of the secondary battery electrode is an important factor for improving the electrode surface defect, it has been difficult to accurately determine the dissolution quality in the prior art. In the present invention, prior to the electrode slurry preparation, in order to quantitatively evaluate the dissolution quality of the binder solution for improving the surface defect of the electrode, the haze value of the binder solution is measured and the dissolution quality of the binder solution is evaluated according to the size of the haze value. process was introduced. That is, since the accurate quantitative evaluation of the dissolution quality of the binder solution is not guaranteed by the method of visually observing the number of foreign substances on the film after applying the binder solution to the OHP film with a blade as in the prior art, the sampled binder A process for measuring the haze value of the solution was introduced.

Haze refers to a phenomenon in which when light passes through a transparent material, light is diffused according to the inherent properties of the material in addition to reflection or absorption, resulting in an opaque, cloudy appearance.

When the haze value is expressed as a formula, it is as shown in Equation 1 below.

[Equation 1]

As shown in Equation 1, when light is transmitted through the binder solution in order to measure the haze value, the ratio of the scattering transmittance to the total transmittance of the binder solution becomes the haze value of the binder solution. That is, the haze value of the binder solution refers to the degree of scattering of light when the light is transmitted. When foreign matter or undissolved particles of several hundred nm or more are present in the binder solution, the haze value increases as the difference between the refractive indices of these particles and the solvent increases and the size of the particles increases. Therefore, as the number of undissolved substances (microgels) in the solution increases, the haze value increases. However, measuring the haze value does not count the number of microgels, but is a concept of measuring the intensity of light scattered by undissolved substances.

The dissolution quality evaluation method of a binder solution for a secondary battery electrode of the present invention comprises the steps of: measuring a haze value of the binder solution by transmitting light through a sampled predetermined amount of the binder solution; and evaluating the dissolution quality of the binder solution according to the size of the haze value.

Prior to haze value measurement, a binder is added to a predetermined solvent and mixed to prepare a predetermined binder solution.

The binder, which is a solute of the binder solution, is used for preparing electrode slurry for secondary batteries, and polyvinylidene fluoride-hexafluoropropylene (Poly (vinylidene fluoride-co-hexafluoropropylene), PVDF-co-HFP), polyvinyl polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxyl methyl cellulose (CMC), starch, hydroxypropyl cellulose , non-aqueous binders of regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, polytetrafluoroethylene (PTFE); an aqueous binder of acrylonitrile-butadiene rubber, styrene-butadiene rubber (SBR) or acrylic rubber; And it may be at least one selected from the group consisting of a polymer resin of hydroxyethyl cellulose, carboxymethyl cellulose, or polyvinylidene fluoride.

In addition, the solvent of the binder solution may be at least one selected from the group consisting of N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), acetone, an organic solvent of dimethyl acetamide, and water.

Meanwhile, even when the same amount of solute is added to the solvent, the binder solution has different dissolution quality depending on the mixing time, the mixing temperature, the type of mixer and the type of the mixer blade. In addition, the dissolution quality is also different depending on the type, size, etc. of the undissolved material contained in the solution. For this reason, only the information about the concentration of the binder solution cannot accurately evaluate the dissolution quality.

Therefore, it is necessary to quantitatively evaluate the dissolution quality of the CMC solution by measuring the haze values of a plurality of CMC solutions having different at least one of a mixing time, a mixing temperature, a mixer type, and a mixer blade type. As the type of mixer, for example, a TK mixer, a homo disper, or the like can be selected. Mixer blades include pitched paddles, anchors, helical blades, and the like, and one of these blades may be selected or two or more blades may be used in combination. In order to prepare a binder solution for a secondary battery, the binder may be generally dissolved at 30 to 130°C.

The haze value can be measured with a haze meter. For example, a haze meter such as HM-150 manufactured by Murakami Color Research Laboratories can be used. As will be described later, the haze value measurement in the present specification was measured in accordance with JIS 7136. The haze meter can not only use the standard light source of the D65 light source, but can also be changed to the A light source and irradiate the target binder solution with light. Specifically, a predetermined amount (for example, 3 to 4 ml) of a binder solution is sampled in a haze meter and applied to a quartz glass cell, and the quartz glass cell is put into a haze meter and irradiated with light from a light source to increase the haze of the binder solution. value can be measured.

When the size of the haze value is measured, it is possible to quantitatively evaluate the dissolution quality of the binder solution. That is, even for a binder solution in which the same amount of solute is dissolved, the dissolution quality of the binder solution can be quantitatively evaluated by measuring the haze value.

As another aspect of the present invention, the method comprising: measuring a haze value of the binder solution by transmitting light through a sampled predetermined amount of the binder solution; evaluating the dissolution quality of the binder solution according to the size of the haze value; and preparing an electrode slurry by mixing an electrode active material and a conductive material with a binder solution having a dissolution quality having a haze value of less than or equal to a predetermined value. That is, the method for manufacturing the electrode slurry for a secondary battery of the present invention, as described above, measures the haze value of the binder solution and quantitatively evaluates the dissolution quality of the binder solution therefrom. When the dissolution quality of the binder solution is confirmed, a binder solution of dissolution quality having a haze value below a predetermined value is selected in accordance with the characteristics of the electrode to be manufactured or in order to improve the surface defect of the electrode, and the binder solution is electrically conductive with the electrode active material. The ash is mixed to prepare an electrode slurry.

The electrode active material may include a predetermined positive electrode active material and a negative electrode active material. The cathode active material may be a lithium-containing oxide, and as the lithium-containing oxide, a lithium-containing transition metal oxide may be used.

For example, the lithium-containing transition metal oxide is Li _x CoO ₂ (0.5<x<1.3), Li _x NiO ₂ (0.5<x<1.3), Li _x MnO ₂ (0.5<x<1.3), Li _x Mn ₂ O ₄ (0.5<x<1.3), Li _x (Ni _a Co _b Mn _c )O ₂ (0.5<x<1.3, 0<a<1, 0<b<1, 0<c<1, a +b+c=1), Li _x Ni _1-y Co _y O ₂ (0.5<x<1.3, 0<y<1), Li _x Co _1-y Mn _y O ₂ (0.5<x<1.3, 0 ≤y<1), Li _x Ni _1-y Mn _y O ₂ (0.5<x<1.3, O≤y<1), Li _x (Ni _a Co _b Mn _c )O ₄ (0.5<x<1.3, 0 <a<2, 0<b<2, 0<c<2, a+b+c=2), Li _x Mn _2-z Ni _z O ₄ (0.5<x<1.3, 0<z<2), Li _x Mn _2-z Co _z O ₄ (0.5<x<1.3, 0<z<2), Li _x CoPO ₄ (0.5<x<1.3) and Li _x FePO ₄ (0.5<x<1.3) It may be any one selected from or a mixture of two or more thereof. In addition, the lithium-containing transition metal oxide may be coated with a metal such as aluminum (Al) or a metal oxide. In addition, in addition to the lithium-containing transition metal oxide, at least one of sulfide, selenide, and halide may be used.

The negative active material may include a carbon material, lithium metal, silicon or tin. When a carbon material is used as the negative electrode active material, both low crystalline carbon and high crystalline carbon may be used. As low crystalline carbon, soft carbon and hard carbon are representative, and as high crystalline carbon, natural graphite, Kish graphite, pyrolytic carbon, and liquid crystal pitch-based carbon fiber are representative. (mesophase pitch based carbon fiber), carbon microspheres (mesocarbon microbeads), liquid crystal pitches (Mesophase pitches), and high-temperature calcined carbon such as petroleum and coal-based cokes (petroleum orcoal tar pitch derived cokes) are representative examples.

The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery. Examples of the conductive material include graphite such as natural graphite or artificial graphite; carbon black, such as acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive materials such as polyphenylene derivatives.

As a preferred binder solution capable of evaluating the dissolution quality by measuring the haze value, for example, a CMC solution in which a predetermined amount of CMC is dissolved in water as a solvent may be selected. Most of the CMC solutions have a size of 7 to 15 µm of undissolved substances in the solution, and thus, since they contain undissolved substances having a size that can measure haze, dissolution quality can be evaluated relatively accurately by haze value.

Meanwhile, the electrode slurry of the present invention may be a negative electrode slurry.

An electrode slurry of a positive electrode slurry or a negative electrode slurry can be prepared by mixing the electrode active material and a conductive material with the binder solution whose dissolution quality is evaluated by measuring the above haze value. By preparing the electrode slurry with a binder solution having a haze value (dissolution quality) of a predetermined amount or less, the surface defect of the electrode can be greatly improved.

Example

Hereinafter, examples will be given to describe the present invention in detail, but the present invention is not limited by these examples.

Comparative Example 1

A constant amount of CMC was added to distilled water to prepare a CMC solution having a concentration of 1.5%. A homodisper was used and the mixing time was changed to stir.

For the prepared CMC solution, dissolution quality was evaluated by a conventional evaluation method. That is, the results of observing the number of foreign substances on the film with the naked eye after applying the CMC solution to a thickness of 200 μm on an OHP film having an area of 5×5 cm with a doctor blade are as follows.

Sample No. #One #2 #3 #4 #5 #6 #7 #8 mixing time
(min) 60 80 40 140 100 120 160 180 Microgel (dog) 21 19 23 One 3.5 One 0.5 0

As shown in Table 1, as the mixing time increases, the number of foreign substances tends to decrease approximately. However, in the case of samples #4 and #6, it was not possible to determine which sample had superior dissolution quality even though the mixing time was different because the number of foreign substances was the same. In addition, since the dissolution quality is judged by the number of foreign substances, when the difference in the number of foreign substances between each sample is too large or small, it is difficult to quantitatively evaluate the dissolution quality. In particular, in the case of sample #8, since the number of foreign substances becomes 0, it was difficult to evaluate to what extent the dissolution quality can be quantified.

Example 1

A CMC solution having a concentration of 1.5% was prepared by mixing under the same conditions as in Comparative Example 1.

4ml of the prepared solution was sampled, applied to a quartz glass cell, and put into a haze meter to measure the haze value. As a haze meter, HM-150 of Murakami Color Research Laboratory was used, and the haze value of the binder solution was measured in accordance with JIS 7136.

Sample No. #One #2 #3 #4 #5 #6 #7 #8 mixing time
(min) 60 80 40 140 100 120 160 180 Haze (%) 2.44 2.35 2.48 1.96 2.10 2.02 1.82 1.7

As shown in Table 2, it can be seen that as the mixing time increases, the haze value gradually decreases, and this trend is similar to Table 1. However, unlike Comparative Example 1, samples #4 and #6 had haze values of 1.96 and 2.02, indicating that the dissolution quality was quantitatively and clearly distinguished. In addition, since the dissolution quality is clearly displayed as a haze value, it can be seen that, for example, even in the case of sample #8, the dissolution quality is quantified, so that the dissolution quality of each binder solution can be determined quantitatively and clearly.

Example 2

In order to evaluate the electrode surface defect characteristics according to the haze value (dissolution quality) of the CMC solution, a sample of the CMC solution having the same concentration (1.5%) having different haze values in Example 1 was selected.

Graphite as an anode active material, carbon black as a conductive material, and a CMC solution as a binder are prepared, and the active material, conductive material, and binder are in a weight ratio of 97:1:2, and the solid content of the active material, conductive material, and binder is adjusted. A negative electrode slurry was prepared by adding graphite and a conductive material to the CMC solution having the amount of solvent (water) adjusted to 40%, and mixing at 80 rpm for 2 hours using a TK mixer. The prepared negative electrode slurry was coated on one surface of a copper current collector under specific coating conditions (coating width 200 mm, coating speed 5 m/min, loading amount 300 mg/cm ² ), dried at a temperature of 100° C., and rolled to prepare a negative electrode.

In the above method, each electrode having the same composition was prepared using CMC solutions having different haze values, and the results of measuring the number of surface defects are shown in Table 3. The prepared electrode was cut to a length of 50 cm, and surface defects per 10 cm × 10 cm unit area of the electrode were visually observed.

Sample No. #3 #6 #8 Haze (%) 2.48 2.02 1.7 Bad surface (pcs) 534 324 107

As shown in Table 3, it can be seen that as the haze value decreases, the number of surface defects also decreases. From this, it is possible to determine the mixing time to improve the dissolution quality. In addition, it is possible to classify and predict a binder solution having a dissolution quality or haze value capable of improving the surface defect of the electrode for a secondary battery. In Example 2, when the haze value was 2.02, the number of surface defects decreased by 200 or more compared to the case of 2.48, and when the haze value was 1.7, the number of surface defects was reduced by 400 or more. could check From this, it was confirmed that at least in the CMC solution, if a solution having a haze value of 2.0% or less is used, the surface defects of the anode slurry prepared thereby can be greatly reduced.

From the above results, it can be seen that the dissolution quality can be evaluated by the haze value of the binder solution, and the electrode slurry can be prepared with a binder solution having a specific haze value or less identified therefrom, thereby predicting and managing the surface defect of the electrode.

Above, the present invention has been described in more detail with reference to drawings and examples. However, since the configuration described in the drawings or embodiments described in the present specification is only one embodiment of the present invention and does not represent all the technical spirit of the present invention, various equivalents and It should be understood that there may be variations.

Claims (10)

measuring a haze value of the binder solution by transmitting light through a sampled predetermined amount of the binder solution; and
A method for evaluating the dissolution quality of a binder solution for a secondary battery electrode, comprising the step of evaluating the dissolution quality of the binder solution according to the size of the haze value.
According to claim 1,
The haze value is the ratio of the scattering transmittance to the total transmittance of the binder solution when light is transmitted through the binder solution.
According to claim 1,
The binder, which is a solute of the binder solution, is polyvinylidene fluoride-hexafluoropropylene (Poly (vinylidene fluoride-co-hexafluoropropylene), PVDF-co-HFP), polyvinylidene fluoride (PVDF), poly Acrylonitrile (polyacrylonitrile), polymethyl methacrylate (polymethyl methacrylate), polyvinyl alcohol, carboxyl methyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetra non-aqueous binders of fluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, polytetrafluoroethylene (PTFE); an aqueous binder of acrylonitrile-butadiene rubber, styrene-butadiene rubber (SBR) or acrylic rubber; And hydroxyethyl cellulose, carboxymethyl cellulose or polyvinylidene fluoride polymer resin of at least one selected from the group consisting of a binder solution for secondary battery electrode dissolution quality evaluation method.
4. The method of claim 3,
The solvent of the binder solution is at least one selected from the group consisting of N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), acetone, an organic solvent of dimethyl acetamide, and water. Dissolution quality of a binder solution for secondary battery electrodes Assessment Methods.
According to claim 1,
The binder solution is a method for evaluating the dissolution quality of a binder solution for a secondary battery electrode, which is a CMC solution in which a predetermined amount of CMC is dissolved in water.
6. The method of claim 5,
A method for evaluating the dissolution quality of a binder solution for secondary battery electrodes, which quantitatively evaluates the dissolution quality of the CMC solution by measuring the haze values of a plurality of CMC solutions with different at least one of mixing time, mixing temperature, mixer type, and mixer blade type.
measuring a haze value of the binder solution by transmitting light through a sampled predetermined amount of the binder solution;
evaluating the dissolution quality of the binder solution according to the size of the haze value; and
A method for producing an electrode slurry for a secondary battery, comprising the step of preparing an electrode slurry by mixing an electrode active material and a conductive material with a binder solution of dissolution quality having a haze value below a predetermined value.
8. The method of claim 7,
The binder solution is a method of manufacturing an electrode slurry for a secondary battery, which is a CMC solution in which a predetermined amount of CMC is dissolved in water.
8. The method of claim 7,
The electrode slurry is a method of manufacturing an electrode slurry for a secondary battery, which is a negative electrode slurry.
8. The method of claim 7,
The haze value of the CMC solution is 2% or less of the method of manufacturing an electrode slurry for a secondary battery.

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