KR102136624B1 - Manufacturing method of electrode for energy storage device with dispersibility improvement effect using jet mill - Google Patents

Abstract

Disclosed is a method for manufacturing an electrode for an energy storage device with improved dispersibility using a jet mill, which improve the durability and resistance of the energy storage device by improving the binding and flexibility of the electrode through the improvement of the dispersibility and stretchability of a binder. A method for manufacturing the electrode for the energy storage device having an effect of improving dispersibility using the jet mill according to the present invention includes the steps of: (a) preparing an active material, a conductive material, and a solid binder; (b) mixing by stirring at a weight ratio of 75 to 90 wt% of the active material, 5 to 17.5 wt% of a conductive material, and 2 to 14.5 wt% of a solid binder; (c) pulverizing the mixed active material, the conductive material, and the solid binder with the jet mill to form an electrode active material powder; and (d) adding the electrode active material powder to a solvent and stirring to form electrode slurry.

Description

MANUFACTURING METHOD OF ELECTRODE FOR ENERGY STORAGE DEVICE WITH DISPERSIBILITY IMPROVEMENT EFFECT USING JET MILL}

The present invention relates to a method of manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill, and more specifically, by improving the binding property and flexibility of an electrode through improvement of dispersibility and stretchability of a binder. It relates to a method for manufacturing an electrode for an energy storage device having a dispersibility improvement effect using a jet mill that can improve the durability and resistance characteristics of the storage device.

The supercapacitor (Super Capacitor) is also called an ultracapacitor (ultra capacitor), and is an energy storage device having a higher energy density than a conventional electrolytic capacitor and a higher output density than a secondary battery. Therefore, the supercapacitor is a next-generation energy storage device that can be used and replaced with a secondary battery due to its high efficiency and semi-permanent life characteristics.

The supercapacitor may be divided into an electric double layer capacitor (EDLC) and a pseudo capacitor according to the energy storage mechanism.

The pseudo-capacitor accumulates charges by oxidation and reduction reactions of metal oxides and conductive polymers used as electrode materials, and electric double-layer capacitors use the property that charges are adsorbed on the electric double layer at the interface between the activated carbon electrode and the electrolyte.

The electric double layer capacitor forms an electric double layer on the surface of the electrode material and the contact surface of the electrolyte by using a material having a large surface area, such as activated carbon, as an active material of the electrode. The electric double layer capacitor stores electric charges in the electric double layer formed at the interface of the electrolyte, unlike a storage battery in which a mechanism for storing electricity uses a chemical reaction. That is, since the electricity storage phenomenon by the accumulation of physical charges is used, there is no deterioration phenomenon due to repeated use, and it has a high reversible characteristic and a long service life.

On the other hand, the supercapacitor is not easy to maintain (maintenance) and is used as an alternative to storage batteries for applications that require a long service life, and hybrids with secondary and primary batteries with high energy density. Is used.

These supercapacitors are used as auxiliary power sources for memory backup and mobile communication information devices such as cell phones, laptops, PDAs, etc. based on output characteristics (fast charging and discharging at high current) and semi-permanent characteristics. In addition, supercapacitors are very suitable as main power or auxiliary power sources, such as electric vehicles, night road lights, and UPS (Uninterrupted Power Supply), which require a high amount of employment, and thus are widely used for such applications.

As a related prior document, there is Korean Registered Patent Publication No. 10-1211916 (announced on December 18, 2012), and the document describes a super capacitor-based energy storage device and a manufacturing method thereof.

An object of the present invention is to improve the dispersibility and elongation of the binder by improving the binding and flexibility of the electrode by improving the durability and resistance properties of the energy storage device, energy having a dispersibility improvement effect using a jet mill It is to provide a method for manufacturing an electrode for storage.

A method for manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to an embodiment of the present invention for achieving the above object includes: (a) providing an active material, a conductive material, and a solid phase binder; (b) stirring and mixing at a weight ratio of 75 to 90% by weight of the active material, 5 to 17.5% by weight of the conductive material, and 2 to 14.5% by weight of the solid binder; (c) pulverizing the mixed active material, conductive material and solid binder with a jet mill to form an electrode active material powder; And (d) adding the electrode active material powder to a solvent and stirring to form an electrode slurry.

In this case, the conductive material includes one or more selected from Super-P, Ketjen black, carbon black, and Carbon fiber, and has an average particle diameter of 0.01 to 0.1 μm. Have

The solid binder includes at least one selected from polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), carboxymethylcellulose (CMC), polyacrylic acid (PAA), and polyvinyl acetate (PVA).

At this time, the solid phase binder is more preferably added in CMC: 1 to 2.5 wt%, SBR: 0.5 to 4 wt% and PTFE: 0.5 to 8 wt%.

The solid binder has an average particle diameter of 0.01 ~ 0.1㎛.

The jet mill is preferably carried out for 10 to 30 minutes.

After the step (d), (e) applying and drying the electrode slurry on the electrode current collector, followed by pressing to form an electrode; may further include.

The electrode manufacturing method for an energy storage device having an effect of improving dispersibility using a jet mill according to the present invention does not induce dispersion of a binder in an active material and a conductive material through an existing wet mixing process, but a jet mill in a dry state Inducing the application and dispersion of the binder to the active material and the conductive material through (High energy mill), and at the same time, the heat energy at the moment generated in the jet mill process improves the elongation of the binder, evenly and widely distributed over the active material and the binder particles, resulting in shorter By manufacturing the electrode slurry in time, an electrode having high binding property and excellent flexibility can be prepared to improve life characteristics and resistance characteristics.

In addition, the electrode manufacturing method for the energy storage device having the effect of improving the dispersibility using the jet mill according to the present invention, the manufacturing time of the electrode slurry using the conventional wet mixing through the manufacture of an electrode having excellent dispersibility (about 6-8 hours) In short, it is possible to shorten the time for inducing the dispersion of the active material and the binder to shorten the production time of the electrode slurry by up to 30% or more.

In addition, a method for manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to the present invention is obtained by preparing an electrode with an electrode slurry prepared using a jet mill, resulting in conventional wet mixing. By significantly reducing the binder cohesiveness compared to the prepared electrode, the binder particles are uniformly and widely distributed in the active material and the conductive material, thereby improving the binding property between the conductive materials.

As a result, the electrode manufacturing method for an energy storage device having an effect of improving dispersibility using a jet mill according to the present invention improves the binding strength and flexibility between a metal current collector and an active material while improving the durability of the energy storage device while reducing electrode resistance. The effect can be exerted.

1 is a process flow chart showing a method of manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to an embodiment of the present invention.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the present embodiments allow the disclosure of the present invention to be complete, and the ordinary knowledge in the technical field to which the present invention pertains. It is provided to fully inform the holder of the scope of the invention, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Hereinafter, a method of manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a process flow chart showing a method for manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to an embodiment of the present invention.

As shown in Figure 1, the electrode manufacturing method for an energy storage device having an effect of improving dispersibility using a jet mill according to an embodiment of the present invention is a raw material preparation step (S110), mixing step (S120), jet mill grinding step (S130), electrode slurry forming step (S140) and coating and pressing step (S150).

Raw material arrangement

In the raw material preparation step (S110), an active material, a conductive material, and a solid binder are prepared.

The active material may include at least one of activated carbon and graphite. At this time, as activated carbon, one or more selected from among hard wood, palm tree, coconut, petroleum pitch and phenol may be activated by steam activation to have a specific surface area of 1,400 to 2,000 m2/g. , But is not limited thereto.

The conductive material may include one or more selected from super-P, ketjen black, carbon black, and carbon fiber. As such a conductive material, it is preferable to use one having an average particle diameter of 0.01 to 0.1 μm.

The solid binder may include one or more selected from polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), carboxymethylcellulose (CMC), polyacrylic acid (PAA), and polyvinyl acetate (PVA).

It is more preferable to use such a solid binder having an average particle diameter of 0.01 to 0.1 μm.

mix

In the mixing step (S120), the active material is stirred and mixed at a weight ratio of 75 to 90% by weight, 5 to 17.5% by weight of the conductive material, and 2 to 14.5% by weight of the solid binder.

In this step, the active material, the conductive material, and the solid binder are mixed in a dry manner using a ball mill or a PD mixer to have the above composition ratio while stirring for 0.5 to 1.5 hours.

Here, it is more preferable to use a different type of binder as the solid phase binder. Specifically, it is preferable to use a solid binder added with polytetrafluoroethylene (PTFE), rubber-based resin, and acrylic-based resin. In addition, as the secondary binder of the solid phase binder, a cellulose resin, a fluorine resin containing polyvinylidene fluoride (PVDF), a thermoplastic resin including polyimide, polyamide, polyethylene and polypropylene, and carboxymethyl cellulose ( CMC) and mixtures thereof.

More specifically, it is preferable to use the solid phase binder added with CMC: 1 to 2.5 wt%, SBR: 0.5 to 4 wt% and PTFE: 0.5 to 8 wt%.

Jet mill grinding

In the jet mill grinding step (S130), the mixed active material, conductive material, and solid binder are pulverized with a jet mill to form an electrode active material powder.

At this time, the jet mill refers to a fine pulverizer that blows compressed air having a pressure of several atmospheres or more from a nozzle to suck the pulverized raw material into this high-speed jet stream, accelerates it sufficiently, and then collides particles with each other, or collides the accelerated particles with a collision plate. .

Accordingly, the mixed active material, the conductive material, and the solid binder can finely crush the solid binder that has been agglomerated through a high injection energy crushing process by jet mill pulverization, and utilizes high temperature and crushing energy generated during the crushing process. By inducing the elongation of the solid binder, it is possible to manufacture an electrode active material powder uniformly distributed in the active material.

As described above, the jet mill crushes the solid binder, which is agglomerated by colliding the active material, the conductive material, and the solid binder with the injection energy from the nozzle under the pressure of air.

As a result, through the performance of the high energy mill of the jet mill, the cohesive force of the active material, the conductive material, and the solid phase binder is crushed to realize uniform dispersibility, thereby realizing high binding and dispersibility.

In addition, in the present invention, it is possible to uniformly disperse the solid binder in the active material by realizing a wide and uniform dispersibility by destroying the cohesive force of the solid binder at high temperature instantaneously through the high energy of the jet mill. Accordingly, it is possible to improve the binding property between the electrode and the current collector.

In this step, the jet mill grinding is preferably carried out for 10 to 30 minutes, more preferably for 20 minutes. When the jet mill grinding time is less than 10 minutes, it may be difficult to weaken the cohesive force of the active material, the conductive material and the solid binder. Conversely, when the jet mill grinding time exceeds 30 minutes, it is not economical because it can act as a factor that increases only the manufacturing cost and time without further effect increase.

Electrode slurry formation

In the electrode slurry forming step (S140), the electrode active material powder is added to the solvent and stirred to form the electrode slurry.

In this step, stirring is preferably performed for 1.5 to 2.5 hours using a PD mixer.

Accordingly, it takes a total of 3 to 4 hours to perform the raw material preparation step (S110), mixing step (S120), jet mill grinding step (S130) and electrode slurry forming step (S140).

As described above, in the present invention, the electrode slurry is shortened by inducing the dispersion of the active material and the binder in the manufacturing time (about 6 to 8 hours) of the electrode slurry using the conventional wet mixing by preparing the electrode slurry having excellent dispersibility. It may be possible to shorten the manufacturing time of up to 30% or more.

Application and compression

In the application and compression step (S150), the electrode slurry is applied to an electrode current collector and dried, and then compressed to form an electrode.

At this time, the electrode current collector may be made of a metal foil. A conductive adhesive and a conductive coating layer may be further formed on the surface of the electrode current collector, if necessary.

The metal foil used for the electrode current collector may be made of a metal exhibiting conductivity, but is not limited thereto, and aluminum or copper is preferable. The size and thickness of the metal foil are not particularly limited.

By the above process (S110 ~ S150), an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to an embodiment of the present invention can be manufactured.

As described so far, the method for manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to an embodiment of the present invention, induces dispersion of a binder in an active material and a conductive material through a conventional wet mixing process Rather, it induces the application and dispersion of the binder to the active material and the conductive material through a high energy mill in a dry state, and at the same time, the thermal energy at the moment generated in the jet mill process improves the elongation of the binder to improve the active material and By uniformly and widely distributed in the binder particles, an electrode slurry having a high binding property and excellent flexibility can be prepared by manufacturing the electrode slurry in a shorter time, thereby improving lifespan characteristics and resistance characteristics.

In addition, the electrode manufacturing method for the energy storage device having the effect of improving the dispersibility using a jet mill according to an embodiment of the present invention, the production time of the electrode slurry using the conventional wet mixing through the electrode manufacturing excellent dispersibility (about 6 ~ 8 hours) has the advantage that it is possible to shorten the time for inducing the dispersion of the active material and the binder to shorten the production time of the electrode slurry by up to 30% or more.

In addition, a method for manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to an embodiment of the present invention, by manufacturing an electrode with an electrode slurry prepared using a jet mill, Compared to the electrode prepared by wet mixing, the binder cohesiveness is significantly reduced, so that the binder particles are uniformly and widely distributed in the active material and the conductive material, thereby improving the binding property between the conductive materials.

As a result, the method for manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill according to an embodiment of the present invention improves the binding strength and flexibility between a metal current collector and an active material while improving the durability of the energy storage device Resistance can exert a reducing effect.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is provided as a preferred example of the present invention and cannot be interpreted as limiting the present invention in any sense.

The contents not described herein will be sufficiently technically inferred by those skilled in the art, and thus the description thereof will be omitted.

1. Cell manufacturing

Example 1

Electrode manufacturer

Primary stirring was performed for 1 hour in a PD mixer equipped with a blade by quantitatively weighing activated carbon, super-P, and solid phase binder.

Next, the mixed active material, the conductive material, and the solid binder were pulverized with a jet mill to prepare an electrode active material powder. At this time, the binder agglomerated by a jet mill was crushed, and the high temperature and the crushing energy generated during the grinding process were used to induce stretching of the binder so as to be uniformly distributed in the active material and the conductive material.

At this time, the electrode active material powder was composed of 80% by weight of activated carbon, 12% by weight of Super-P, and 8% by weight of a solid binder, and a mixture of polytetrafluoroethylene, methyl cellulose, and styrene-butadiene rubber was used as the solid binder.

Next, the prepared electrode active material powder was mixed with pure water and mixed with a PD mixer to perform secondary mixing for 2 hours to prepare an electrode slurry for a total of 3 hours and 30 minutes.

Next, the prepared electrode slurry was applied and dried using a comma coater on an aluminum foil current collector, and then compressed by a roll pressing process to prepare an electrode.

Cell manufacturing

After attaching the positive and negative external terminals to each of the positive electrode and the negative electrode, a separator was disposed between the positive electrode and the negative electrode, and wound in a roll form to manufacture a winding element.

Next, the winding element was dried in an oven at 150° C. for 24 hours.

Next, after inserting the dried coiling element into the cylindrical case, the electrolyte was impregnated, cured and then sealed to prepare an energy storage device (cell).

Comparative Example 1

Electrode manufacturer

After the active carbon and super-P were subjected to dry mixing in a PD mixer, pure water and a binder were sequentially added in sequence to perform mixing for a total of 6 hours to prepare an electrode slurry.

At this time, the composition was composed of 80 wt% activated carbon, 12 wt% super-P, and 8 wt% binder, and a mixture of polytetrafluoroethylene, methyl cellulose, and styrene-butadiene rubber was used as the binder.

Next, the prepared electrode slurry was applied and dried using a comma coater on an aluminum foil current collector, and then compressed by a roll pressing process to prepare an electrode.

Cell manufacturing

After attaching the positive and negative external terminals to each of the positive electrode and the negative electrode, a separator was disposed between the positive electrode and the negative electrode, and wound in a roll form to manufacture a winding element.

Next, the winding element was dried in an oven at 150° C. for 24 hours.

Next, after inserting the dried coiled element into the cylindrical case, the electrolyte was impregnated, cured and then sealed to prepare an energy storage device (cell).

2. Property evaluation

Table 1 shows the results of analyzing the peeling state between the electrode and the metal current collector for the cells prepared according to Example 1 and Comparative Example 1. To compare the difference in binding between the electrode of the cell prepared according to Example 1 and Comparative Example 1 and the metal current collector, after soaking in an organic electrolytic solution (1Mol TEA-BF ₄ /ACN), 6 to 12 hours in an 80°C environment The peeling state between the electrode and the metal current collector was analyzed in units.

[Table 1]

As shown in Table 1, the electrode is exposed to a high temperature environment in an organic electrolyte to accelerate the binding of the electrode.

At this time, in the cell of Comparative Example 1, electrode peeling occurred between the electrode and the electrolyte within 48 hours.

On the other hand, it was confirmed that the cell of Example 1 was peeled off at 96 hours and showed a higher binding performance of the electrode compared to the cell of Comparative Example 1.

On the other hand, Table 2 shows the results of measuring the cell capacity by current density for the cells prepared according to Example 1 and Comparative Example 1, Table 3 is high temperature for the cells prepared according to Example 1 and Comparative Example 1 It shows the result of load measurement.

[Table 2]

[Table 3]

As shown in Table 2, it can be seen that the cell resistance is reduced due to the decrease in electrode resistance due to uniform dispersion of the binder and the active material and improved binding property, thereby improving output performance.

In order to confirm this, a cell with a diameter of ø10 and a length of 25 mm was manufactured with a capacity of 10F.

When the fabricated cell was charged and discharged at a current density of 10 mA (1 mA/F) to 1,000 mA (100 mA/F), the capacity retention was measured as the cell of Example 1 increased as the current density increased compared to the cell of Comparative Example 2 It was confirmed that the difference occurred up to 3.4%.

As shown in Table 3, the cell of Example 1 and the cell of Comparative Example 1 were tested for durability with respect to the cell of Comparative Example 1, and the cell of Example 1 was subjected to a high temperature load (aging) in an environment of 2.7V 65° C. for 1,000 hours. Contrast capacity reduction rate was measured as 1.6% lower, which proved that it is possible to improve the power and improve the durability due to the improvement of the binding force of the electrode and the reduction of the cell resistance.

In the above, the embodiments of the present invention have been mainly described, but various changes or modifications can be made at the level of a person skilled in the art to which the present invention pertains. Such changes and modifications can be said to belong to the present invention without departing from the scope of the technical idea provided by the present invention. Therefore, the scope of the present invention should be judged by the claims set forth below.

S110: Raw material preparation step
S120: mixing step
S130: Jet mill grinding step
S140: electrode slurry forming step
S150: application and compression step

Claims (7)

(a) preparing an active material, a conductive material, and a solid phase binder;
(b) stirring and mixing at a weight ratio of 75 to 90% by weight of the active material, 5 to 17.5% by weight of the conductive material, and 2 to 14.5% by weight of the solid binder;
(c) pulverizing the mixed active material, conductive material and solid binder with a jet mill to form an electrode active material powder; And
(d) adding the electrode active material powder to a solvent and stirring to form an electrode slurry;
The solid binder is added in CMC (carboxymethylcellulose): 1 to 2.5 wt%, SBR (styrene butadiene rubber): 0.5 to 4 wt% and PTFE (polytetrafluoroethylene): 0.5 to 8 wt%,
The solid binder has an average particle diameter of 0.01 ~ 0.1㎛,
In the step (b), the stirring is performed for 0.5 to 1.5 hours in a dry manner using a ball mill or PD mixer,
In the step (c), the jet mill is performed for 10 to 20 minutes,
In the step (c), the solid binder that is agglomerated by the jet mill is crushed, and elongation of the solid binder is induced by using energy generated during the pulverization process, so that it is uniformly distributed in the active material and the conductive material, thereby binding. And an electrode manufacturing method for an energy storage device having an effect of improving dispersibility using a jet mill, characterized by improving dispersibility.
According to claim 1,
The conductive material includes at least one selected from Super-P, Ketjen black, carbon black and Carbon fiber,
Method for manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill, which has an average particle diameter of 0.01 to 0.1 μm.
delete delete delete delete According to claim 1,
After step (d),
(e) applying and drying the electrode slurry on an electrode current collector, followed by pressing to form an electrode;
Method for manufacturing an electrode for an energy storage device having an effect of improving dispersibility using a jet mill further comprising a.

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