WO2018038479A1

WO2018038479A1 - Electrode for secondary battery comprising fine holes

Info

Publication number: WO2018038479A1
Application number: PCT/KR2017/009079
Authority: WO
Inventors: 이솔닢; 이혁무; 오송택
Original assignee: 주식회사 엘지화학
Priority date: 2016-08-25
Filing date: 2017-08-21
Publication date: 2018-03-01

Abstract

The present invention relates to an electrode for a secondary battery, comprising an electrode combined layer comprising an electrode active material formed on one side or both sides of a current collector, wherein the electrode combined layer comprises a plurality of fine holes indented from a vertical cross-sectional surface toward the current collector, and each of the fine holes has a horn shape which gradually decreases in diameter in the direction from the vertical cross-sectional surface toward the current collector.

Description

Secondary Battery Electrode with Fine Holes

The present invention relates to a secondary battery electrode containing fine holes.

Recently, the increase in the price of energy sources due to the depletion of fossil fuels, interest in environmental pollution is amplified, and the demand for environmentally friendly alternative energy sources has become an indispensable factor for future life. Accordingly, researches on various power production technologies such as nuclear power, solar energy, wind power, tidal power, etc. continue, and power storage devices for more efficient use of the generated energy are also drawing attention.

In particular, as technology development and demand for mobile devices increase, the demand for batteries as energy sources is rapidly increasing, and accordingly, a lot of researches on batteries that can meet various needs have been conducted.

Representatively, there is a high demand for square and pouch type secondary batteries that can be applied to products such as mobile phones with a thin thickness in terms of shape of batteries, and high energy density, discharge voltage, and output stability in terms of materials. Demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries is high.

In general, the electrode assembly constituting the secondary battery has a structure in which a positive electrode and a negative electrode are manufactured by forming an electrode mixture layer including an electrode active material on one or both surfaces of the electrode assembly, and a separator is interposed between the positive electrode and the negative electrode. Is formed.

Recently, the capacity of such an electrode assembly may be maximized by increasing the loading amount of the electrode mixture layer on the current collector.

However, the electrode having a very high loading amount of the electrode mixture layer has an excessively thick thickness of the electrode mixture layer, so that electrolyte diffusion does not easily occur in the depth direction of the electrode mixture layer, and the electrode loading layer has a lower loading amount than the electrode. , Li-plating phenomenon in which lithium is precipitated at low SOC occurs frequently.

In particular, in recent years, as the demand for mobile devices increases, research into a battery capable of rapid charging has been actively conducted. However, due to the above problem, the loading amount of the electrode mixture layer is increased to maximize the capacity of the electrode. In the case of electrodes, rapid charging may be more difficult.

That is, when the loading amount of the electrode mixture layer formed on the current collector is increased so as to maximize the capacity of the electrode, diffusion of the electrolyte solution in the depth direction of the electrode mixture layer is not easy, and thus, lithium-plating If a phenomenon occurs or a secondary battery including an electrode having a high loading amount of an electrode mixture layer, there is a problem that rapid charging may be more difficult.

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

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

After extensive research and various experiments, the inventors of the present application, as will be described later, a plurality of fine particles consisting of a horn shape in which the electrode mixture layer is sequentially reduced in diameter from the vertical cross-sectional surface toward the current collector By including holes, the electrolyte can be more easily diffused through the fine holes in the depth direction of the electrode mixture layer, and thus, despite the high loading amount of the electrode mixture layer, lithium-plating phenomenon It is possible to prevent the occurrence of the electrical performance of the electrode, and to prevent the deterioration of the electrode, during the charging and discharging process, the movement of lithium ions is smooth, the rapid charging performance can be improved, the fine holes include protrusions corresponding to the fine holes Since it is formed by a mold or a roller to be formed, compared to the conventional form of a pattern structure using a laser, The present invention has been completed to prevent a decrease in capacity and to eliminate or significantly reduce a defective rate of a product caused by particles separated from the electrode mixture layer by the laser.

Secondary battery electrode according to the present invention for achieving this object,

An electrode mixture layer containing an electrode active material is formed on one or both surfaces of the current collector;

The electrode mixture layer includes a plurality of fine holes indented toward the current collector from the vertical cross-sectional surface,

Each of the fine holes may have a horn-shaped structure in which the diameter decreases gradually from the surface in the vertical section toward the current collector.

Therefore, through the fine holes, the electrolyte can be more easily diffused in the depth direction of the electrode mixture layer, thereby preventing the occurrence of lithium-plating phenomenon, despite the high loading amount of the electrode mixture layer, Deterioration of the electrical performance of the electrode can be prevented, and during the charging and discharging process, the lithium ions can be smoothly moved, thereby improving the quick charging performance.

In one specific example, the fine holes may be a structure formed in the electrode mixture layer having a loading amount of 3.5 to 5.5 mAh / cm ² and porosity of 25% to 35%.

That is, the loading amount and porosity range of the electrode mixture layer is a range capable of exhibiting a desired high capacity of the secondary battery including the electrode, and the electrode for secondary batteries according to the present invention has an electrode mixture layer to have the loading amount and porosity range. Despite this formation, unlike the conventional electrodes, the electrolyte can be more easily diffused in the depth direction of the electrode mixture layer, whereby a desired effect can be obtained.

If the loading amount of the electrode mixture layer is out of the range, is too small, or the porosity is out of the range, is too large, the capacity of the secondary battery including the electrode cannot be improved, on the contrary, the electrode When the loading amount of the mixture layer is out of the range, is too large, or the porosity is out of the range, and is too small, easy diffusion of the electrolyte may be difficult even though the plurality of fine holes are formed in the electrode mixture layer. .

In addition, the depth of the fine hole may be 80% to 90% of the depth of the electrode mixture layer corresponding to the depth formed from the surface portion in the vertical section toward the current collector.

If the depth of the fine holes is less than 80% of the thickness of the corresponding electrode mixture layer, the depth of the fine holes is too low, so that the electrolyte cannot be easily diffused in the depth direction of the electrode mixture layer. It may not work.

On the contrary, when the depth of the fine holes exceeds 90% of the thickness of the electrode mixture layer corresponding thereto, a mold or a roller for forming a fine hole including a corresponding protrusion may be formed to form the fine holes. In the process of pressurizing the electrode mixture layer by using, an excessively high pressure may be applied to the electrode mixture layer portion located in the current collector direction end portion of the micro-holes, which causes the portion to be rolled to lower the porosity of the electrode mixture layer. Rather, there is a problem that the diffusion of the electrolyte can be reduced.

On the other hand, the fine holes are made to be indented into a horn shape whose diameter gradually decreases toward the current collector from the vertical cross-sectional surface, if the desired effect can be achieved, the planar structure is not significantly limited, in detail The micro holes may be triangular, square, pentagonal, hexagonal, circular, semicircular, or elliptical in planar shape on the surface of the electrode mixture layer, and more specifically, uniform diffusion of an electrolyte and the process of forming the fine holes. Considering the uniform transmission of the pressure applied in the, it may be circular.

In one specific example, the fine holes may have an average diameter of 100 micrometers to 200 micrometers in the surface portion on the vertical cross section, and an average diameter of 20 micrometers to 50 micrometers in the inner end portion.

If the average diameter of the micro holes in the surface portion on the vertical cross section is less than 100 micrometers, the diameter of the micro holes in the surface portion where the electrolyte starts to flow is too small, so that diffusion of the electrolyte through the micro holes may not be easy. On the contrary, when the average diameter of the fine holes in the surface portion on the vertical cross section exceeds 200 micrometers, the diameter of the fine holes in the surface portion is too large, rather, the capacity of the electrode may be lowered.

In addition, when the average diameter at the inner end portion is less than 20 micrometers, the projections of the mold or the roller for forming the fine holes in the electrode mixture layer become too thin, so that the fine holes are formed by pressing against the electrode mixture layer. On the contrary, when the average diameter at the inner end portion exceeds 50 micrometers, on the contrary, the protruding end of the metal mold or the roller for forming the micro holes is too large, and the electrode In the process of forming the fine holes by pressing against the mixture layer, the inner end portion may be rolled, and as a result, the porosity decreases at the inner end portion of the fine hole of the electrode mixture layer, rather the electrolyte diffusion decreases. Can be.

Here, the inner end portion of the micro-holes may be formed in a circular arc shape in the vertical cross-section, so that the diameter of the inner end portion, in the end portion formed of the circular arc shape, the side edges of the fine holes made of a linear shape and the circular arc It means the diameter in the site where the end portion formed in the shape abuts.

If the inner end portion of the fine hole has a needle-like structure, since the protrusion end of the micro-hole forming die or roller corresponding thereto must also have a very thin needle-like structure, in the pressing process by the mold or roller, As the protrusions are deformed, the minute holes may not be easily formed in the electrode mixture layer.

On the other hand, the plurality of fine holes may have a regular arrangement in planar shape at the surface portion of the electrode mixture layer.

Therefore, the electrolyte solution can be more uniformly diffused to all parts of the electrode mixture layer, and the performance degradation due to the local diffusion difference of the electrolyte solution can be prevented.

In one specific example, the fine hole may have a structure having a shape in which the diameter decreases continuously or discontinuously from the vertical cross section surface toward the current collector. As a result, the micro holes may have a shape having a shape of continuously decreasing diameter so that the micro holes may be more easily formed.

On the other hand, in recent years, a predetermined pattern is formed on the electrode mixture layer while detaching a part of the electrode mixture layer using a laser so as to solve the problem of lowering of electrolyte diffusion of a conventional electrode having a high loading amount of the electrode mixture layer. Some techniques are used.

FIG. 1 schematically illustrates a vertical cross-sectional structure of an electrode in which patterned fine holes are formed in an electrode mixture layer using a conventional laser, and FIG. 2 illustrates an enlarged structure of part “A” of FIG. 1. A schematic partial enlarged view is shown.

1 and 2 together, an electrode mixture layer 120 is formed on an upper surface of the current collector 110.

The plurality of fine holes 130 are formed in the electrode mixture layer 120 to form a predetermined pattern.

Since the fine hole 130 is formed by detaching some of the electrode mixture layer 120 by a laser, the diameter R1 is formed in a substantially uniform structure toward the current collector 110 from the surface of the electrode mixture layer 120 on a vertical cross section. have.

In particular, when forming the fine holes 130 using a laser, it is not easy to adjust the depth (D1) of the fine holes 130, the fine holes 130 are in contact with the upper surface of the current collector (110). The depth D1 is formed to be equal to the thickness T1 of the electrode mixture layer 120.

However, such a technique of forming fine holes using a laser desorbs some of the electrode mixture layers in the process of forming the micro holes, thereby reducing the overall capacity of the electrode, and removing the electrode mixture layer particles from the electrode manufacturing process. In, by acting as an impurity scattering in the atmosphere, causing a defect of the product, there is a problem that can increase the overall manufacturing cost of the electrode because it requires an additional process or apparatus to prevent it.

On the other hand, the present invention provides a device for manufacturing the secondary battery electrode to solve this problem, the device includes a mold for forming a fine hole; The micro holes are formed in the mold for forming fine holes such that when one surface is pressed in a state facing the surface of the electrode mixture layer, horn-shaped fine holes indented toward the current collector from the surface portion of the electrode mixture layer may be formed. Horn-shaped protrusions corresponding to the structure may protrude on one surface.

In another specific example, the apparatus includes a roller for forming fine holes; The fine hole forming rollers may be formed such that when the outer surface is pressed against the surface of the electrode mixture layer in a rotational manner, horn-shaped fine holes indented toward the current collector from the surface of the electrode mixture layer may be formed. Horn-shaped protrusions corresponding to the structure may protrude to the outer surface.

That is, the electrode manufacturing apparatus for a secondary battery according to the present invention may have a structure in which protrusions protruding from the mold or the roller press the electrode mixture layer to form fine holes.

Therefore, unlike a conventional electrode manufacturing apparatus for a secondary battery using a laser, since a part of the electrode mixture layer is not detached, a reduction in the capacity of the electrode is prevented, and a product defect rate that may occur due to the detached electrode mixture layer particles. The problem of increase and increase of manufacturing cost can be effectively prevented.

In this case, the horn-shaped protrusions have an average diameter of 100 micrometers to 200 micrometers at an end portion having a relatively large diameter in a vertical cross section, and an average diameter of 20 micrometers at an end portion having a relatively small diameter. To 50 micrometers.

Therefore, by adjusting the particle diameter of the fine holes formed by the protrusions in the above range, the electrolyte solution is easily impregnated in the depth direction of the electrode mixture layer, while preventing a decrease in capacity, the electrode at the inner end portion of the fine holes The phenomenon that a mixture layer rolls can be prevented easily.

The present invention also provides a method for manufacturing the secondary battery electrode, the method is

a) applying a slurry for electrode mixture including an electrode active material on a current collector;

b) drying and rolling the current collector coated with the slurry for electrode mixture to form an electrode mixture layer; And

c) applying a pressure with the mold or roller facing the surface of the electrode mixture layer to form a plurality of fine holes indented in the shape of a horn in the electrode mixture layer;

It may include.

That is, after the electrode mixture layer is formed, the fine holes of the electrode mixture layer may be formed by pressing the metal mold or roller for forming the hole.

In this case, the electrode mixture layer formed in the process b) may be a structure having a loading amount of 3.5 to 5.5 mAh / cm ² and porosity of 25% to 35%.

That is, the fine holes may prevent the lowering of the capacity of the electrode mixture layer while exhibiting an excellent effect of diffusion of the electrolyte solution in a structure in which the loading amount of the electrode mixture layer is high so as to maximize the capacity of the electrode.

In addition, the mold or roller may have a structure including minute hole forming protrusions formed in a shape corresponding to the horn-shaped fine holes at a portion facing the surface of the dried and rolled electrode mixture layer.

Therefore, the fine holes of the electrode mixture layer may be formed by the metal hole forming protrusions formed in the metal mold or the roller, when the pressure is applied to the surface of the electrode mixture layer by a mold or roller, accordingly Unlike the conventional method of detaching some electrode mixture layers using a laser, a decrease in electrode capacity can be prevented, and a reduction in product defect rate and an increase in manufacturing cost that can occur due to scattering electrode mixture layer particles can be suppressed.

On the other hand, each of the horn-shaped projections by adjusting the particle diameter of the fine holes formed by the projections in the above range, while easily impregnating the electrolyte in the depth direction of the electrode mixture layer, while preventing a decrease in capacity, In order to prevent the electrode mixture layer from rolling at the inner end portions of the fine holes, the diameter of each portion may be adjusted to a specific range, and in detail, each of the horn-shaped protrusions may have a relatively large vertical cross section. It may have a structure in which the average diameter at the end portion having the diameter is 100 micrometers to 200 micrometers, and the average diameter at the end portion having the relatively small diameter is 20 micrometers to 50 micrometers.

Since the rest of the configuration of the secondary battery electrode to the electrode manufacturing apparatus except for the above structure to the structure is known in the art, detailed description thereof will be omitted herein.

As described above, the electrode for secondary batteries according to the present invention is configured such that the electrode mixture layer includes a plurality of fine holes formed in a horn shape, the diameter of which gradually decreases from the surface in the vertical section toward the current collector. Through the fine holes, the electrolyte can be more easily diffused in the depth direction of the electrode mixture layer, thereby preventing the occurrence of lithium-plating phenomenon, despite the high loading amount of the electrode mixture layer, It is possible to prevent the electrical performance deterioration, in the process of charging and discharging, the smooth movement of lithium ions can be improved, the rapid charging performance can be improved, the fine holes are formed by a mold or a roller including protrusions corresponding to the fine holes Therefore, as compared with the conventional method of forming a pattern structure by using a laser, it is possible to prevent a decrease in capacitance of the electrode and There is an effect that can eliminate or significantly reduce the defective rate of the product caused by the particles separated from the electrode mixture layer by the weiser.

1 is a schematic diagram schematically showing a vertical cross-sectional structure of an electrode in which fine holes having a pattern shape are formed in an electrode mixture layer using a conventional laser;

FIG. 2 is a partially enlarged view schematically showing an enlarged structure of a portion “A” of FIG. 1;

3 is a schematic diagram schematically showing a vertical cross-sectional structure of a secondary battery electrode according to an embodiment of the present invention;

FIG. 4 is a partially enlarged view schematically showing an enlarged structure of part “B” of FIG. 3;

FIG. 5 is a partially enlarged view schematically showing an enlarged structure of a portion “C” of FIG. 4;

6 and 7 are schematic diagrams illustrating a process of forming fine holes in the electrode mixture layer using the electrode manufacturing apparatus for a secondary battery according to another embodiment of the present invention.

8 is a graph showing the negative electrode profile for the battery of Example 1 and Comparative Example.

9 is a result of measuring the capacity of the batteries of Example 1 and Comparative Example.

Hereinafter, the present invention will be described in more detail with reference to the drawings according to embodiments of the present invention, but the scope of the present invention is not limited thereto.

FIG. 3 is a schematic diagram schematically showing a vertical cross-sectional structure of a secondary battery electrode according to one embodiment of the present invention, and FIG. 4 is a partially enlarged view schematically showing an enlarged structure of part “B” of FIG. 3. 5 is a partially enlarged view schematically showing an enlarged structure of a portion “C” of FIG. 3.

3 to 5 together, an electrode mixture layer 320 is formed on an upper surface of the current collector 310.

In the electrode mixture layer 320, a plurality of fine holes 330 is formed in a structure having a regular arrangement.

The fine holes 330 are indented toward the current collector 310 from the vertical cross-sectional surface, and have a horn shape in which diameters R2 and R3 continuously decrease toward the current collector 310.

The fine hole 330 is formed such that the depth D2 formed from the surface portion toward the current collector 310 has a size of about 90% of the thickness T2 of the electrode mixture layer 320 corresponding thereto.

The fine holes 330 may have an average diameter R2 at the surface portion of 100 micrometers to 200 micrometers, and the average diameter R3 at the inner end portion 332 may be 20 micrometers to 50 micrometers. Can be done.

The fine hole 330 has a circular arc shape in which the inner end portion 332 is rounded in a vertical cross section, so that the average diameter R3 of the inner end portion 332 is formed in a straight shape. It means the average diameter R3 in the site | part 333 which the side edge 331 and the inner end part 332 which consists of said arc shape contact | connects.

6 and 7 schematically show a process of forming fine holes in the electrode mixture layer using the electrode manufacturing apparatus for a secondary battery according to another embodiment of the present invention.

First, referring to FIG. 6, an electrode manufacturing apparatus for a secondary battery includes a metal hole forming mold 640.

In the fine hole forming mold 640, the horn-shaped protrusions 641 corresponding to the fine holes 630 protrude from one surface facing the surface of the electrode mixture layer 620.

Accordingly, the one surface of the fine hole forming mold 640 is pressed in a state facing the surface of the electrode mixture layer 620, so that the shape of the horn is indented from the surface portion of the electrode mixture layer 620 toward the current collector 610. Fine holes 630 may be easily formed.

After the fine holes 630 are formed in the electrode mixture layer 620, the fine hole forming mold 640 is separated from the electrode mixture layer 620.

Referring to FIG. 7, an electrode manufacturing apparatus for a secondary battery includes a roller 740 for forming a fine hole.

In the fine hole forming roller 740, the horn-shaped protrusions 741 corresponding to the fine holes 730 protrude from the outer surface facing the surface of the electrode mixture layer 720.

Therefore, the outer surface of the fine hole forming roller 740 is rotated and pressed in a state facing the surface of the electrode mixture layer 720, the horn-shaped fine holes indented toward the current collector from the surface portion of the electrode mixture layer 720 730 can be easily formed.

After the fine holes 730 are formed in the electrode mixture layer 720, the fine hole forming roller 740 is separated from the electrode mixture layer 720.

Hereinafter, the present invention will be described in detail by way of examples, but the following examples are provided to illustrate the present invention, and the scope of the present invention is not limited thereto.

Artificial graphite, carbon black, CMC, and SBR were mixed with distilled water in a weight ratio of 95.8: 1: 1.2: 2 to prepare a negative electrode slurry. The negative electrode slurry was coated on a copper foil to form a thin electrode plate, dried at 135 ° C. for at least 3 hours, and then rolled to prepare a negative electrode mixture. The loading amount of the negative electrode mixture was 4.5 mAh / cm 2, and the volume of the pores having a long diameter of the pores of 0.5 μm to 3 μm was 30%. Thereafter, as shown in FIG. 5, the pressure is applied while the mold for forming the micro holes having the horn-shaped protrusions is formed to face the surface of the negative electrode mixture layer, thereby forming a plurality of fine holes in the horn shape in the negative electrode mixture layer. Formed. At this time, the diameter of the microholes was 200 micrometers at the surface portion and 35 micrometers at the inner end portion.

Li (Ni _1/3 Co _1/3 Mn _1/3 ) O ₂ is used as a positive electrode active material, and is mixed with carbon black and PVDF in distilled water at 96: 2: 2 to prepare a positive electrode slurry. It was. The positive electrode slurry was coated on aluminum foil to form a thin electrode plate, dried at 135 or more for 3 hours, and rolled to prepare a positive electrode.

In the electrolyte solution, ethylene carbonate and ethyl methyl carbonate were mixed at a vol% ratio of 3: 7, and LiPF ₆ was added thereto at a concentration of 1.0 M. In addition, vinylene carbonate, propane sultone and ethylene sulfate were added in an amount of 0.2% by weight based on the total amount of the electrolyte.

A battery was manufactured using the negative electrode, the positive electrode, and the electrolyte solution prepared above. Celcel 2320 was used as a separator.

A battery was manufactured in the same manner as in Example 1, except that the loading amount of the negative electrode was changed to 3.7 mAh / cm 2 and the porosity was 34%.

A battery was manufactured in the same manner as in Example 1, except that the loading amount of the negative electrode was changed to 5.3 mAh / cm 2 and the porosity was changed to 27%.

Comparative Example

A secondary battery was manufactured in the same manner as in Example, except that a negative electrode prepared by omitting the process of forming fine holes in the negative electrode mixture layer was used.

8 analyzes the negative electrode profile for the cells of Example 1 and Comparative Example. The negative electrode profile was identified by differentially extracting the negative electrode profile (1.5C charge) during charging through the three-electrode system and differentially graphing the potential value for the SOC. In FIG. 8, A is the battery of Example 1, and B is the point where the inclination of the battery is changed. The battery according to Example 1 has a depth of charge about 7% deeper than that of the battery of Comparative Example, thereby preventing lithium plating. It can be seen that there is an effect.

9 is a result of measuring the capacity of the batteries of Example 1 and Comparative Example. According to FIG. 9, the Example 1 cell appears to show little loss in capacity compared to the Comparative Example cell.

100 cycles of charging / discharging were performed on the batteries of Examples 1 to 3 and Comparative Examples under the condition of 0.3C discharge / 1C charging within the 4.1-2.5V driving voltage range, and then the batteries were disassembled to visually check whether lithium was deposited on the electrodes. Observation, and the results are shown in Table 1.

	실시예 1Example 1	실시예 2Example 2	실시예 3Example 3	비교예 Comparative example
리튬 석출 여부Lithium Precipitation	XX	XX	XX	OO

As described above, the electrode for secondary batteries of the present invention prevents the occurrence of lithium-plating phenomenon, despite the high loading amount of the electrode mixture layer, while having almost no loss of capacity compared to the electrode without the conventional fine holes. The performance degradation can be prevented.

Claims

As an electrode for secondary batteries, the electrode mixture layer containing an electrode active material is formed in one or both surfaces of an electrical power collector;

The electrode mixture layer includes a plurality of fine holes indented toward the current collector from the vertical cross-sectional surface,

Each fine hole is a secondary battery electrode, characterized in that the horn (horn) shape that the diameter gradually decreases toward the current collector from the vertical cross-section surface.
The electrode of claim 1, wherein the fine holes are formed in an electrode mixture layer having a loading amount of 3.5 to 5.5 mAh / cm 2 and a porosity of 25% to 35%.
The method of claim 1, wherein the fine hole is a secondary battery electrode, characterized in that the depth formed from the surface portion in the vertical cross-section toward the current collector has a size of 80% to 90% of the thickness of the electrode mixture layer corresponding thereto.
The electrode of claim 1, wherein the fine holes have a triangular, square, pentagonal, hexagonal, circular, semicircular, or elliptical shape in plan view at the surface portion of the electrode mixture layer.
The method of claim 1, wherein the fine hole has a mean diameter of 100 micrometers to 200 micrometers in the surface portion on the vertical cross section, the average diameter at the inner end portion of 20 to 50 micrometers for secondary batteries electrode.
The electrode of claim 1, wherein the plurality of fine holes have a regular arrangement in planar shape at a surface portion of the electrode mixture layer.
The secondary battery electrode of claim 1, wherein the fine holes have a shape in which the diameter decreases continuously or discontinuously from the surface in the vertical section toward the current collector.
An apparatus for manufacturing the secondary battery electrode according to claim 1,

The apparatus includes a mold for forming fine holes;

The micro holes are formed in the mold for forming fine holes such that when one surface is pressed in a state facing the surface of the electrode mixture layer, horn-shaped fine holes indented toward the current collector from the surface portion of the electrode mixture layer may be formed. Electrode manufacturing apparatus for a secondary battery, characterized in that the projections of the horn shape corresponding to the protruding on one surface.
An apparatus for manufacturing the secondary battery electrode according to claim 1,

The apparatus comprises a roller for forming fine holes;

The fine hole forming rollers may be formed such that when the outer surface is pressed against the surface of the electrode mixture layer in a rotational manner, horn-shaped fine holes indented toward the current collector from the surface of the electrode mixture layer may be formed. Electrode manufacturing apparatus for a secondary battery, characterized in that the projections of the horn shape corresponding to the projecting on the outer surface.
10. The horn shaped projections of claim 8 or 9, wherein the horn-shaped protrusions have an average diameter at an end portion having a relatively large diameter in a vertical cross section of 100 micrometers to 200 micrometers, and at an end portion having a relatively small diameter. Secondary battery electrode manufacturing apparatus, characterized in that the average diameter is 20 to 50 micrometers.
A method for manufacturing the secondary battery electrode according to any one of claims 1 to 7,

a) applying a slurry for electrode mixture including an electrode active material on a current collector;

b) drying and rolling the current collector coated with the slurry for electrode mixture to form an electrode mixture layer; And

c) applying a pressure with the mold or roller facing the surface of the electrode mixture layer to form a plurality of fine holes indented in the shape of a horn in the electrode mixture layer;

Secondary battery electrode manufacturing method comprising a.
The method of claim 11, wherein the electrode mixture layer formed in step b) has a loading amount of 3.5 to 5.5 mAh / cm 2 and a porosity of 25% to 35%.
12. The method of claim 11, wherein the mold or roller, the site facing the surface of the electrode mixture layer dried and rolled, and comprises a fine hole forming projections formed in a shape corresponding to the horn-shaped fine holes Secondary battery electrode manufacturing method.
15. The method of claim 13, wherein each of the horn-shaped protrusions has an average diameter at an end portion having a relatively large diameter in a vertical cross section of 100 micrometers to 200 micrometers, and an average diameter at an end portion having a relatively small diameter. 20 micrometers-50 micrometers, The electrode manufacturing method for secondary batteries characterized by the above-mentioned.