KR20180107617A - Electrode assembly and the manufacturing method - Google Patents

Abstract

A secondary battery electrode according to the present invention comprises an electrode current collector and an electrode active material laminated on the electrode current collector, wherein the electrode active material A plurality of large pattern portions are formed, small pattern portions are formed in each of the plurality of large pattern portions, and the small pattern portion is formed into a three dimensional fine pattern formed by forming a plurality of fine grooves.

Description

ELECTRODE ASSEMBLY AND THE MANUFACTURING METHOD BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to an electrode for a secondary battery and a manufacturing method thereof.

Unlike primary batteries, rechargeable secondary batteries can be recharged, and they are being researched and developed recently due to their small size and high capacity. As technology development and demand for mobile devices increase, the demand for secondary batteries as energy sources is rapidly increasing.

The secondary battery is classified into a coin type battery, a cylindrical type battery, a square type battery, and a pouch type battery depending on the shape of the battery case. An electrode assembly mounted in a battery case of a secondary battery is a chargeable and dischargeable power generation device having a stacked structure of an electrode and a separation membrane.

The electrode assembly includes a jelly-roll type in which a separator is interposed between a positive electrode and a negative electrode coated with an active material, and a stacked type in which a plurality of positive electrodes and negative electrodes are sequentially stacked with a separator interposed therebetween And a stack / folding type in which stacked unit cells are wound with a long length separating film.

Recently, a pouch-shaped battery having a structure in which a stacked or stacked / folded electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet has been used for reasons of low manufacturing cost, small weight, , Has attracted much attention and its usage is gradually increasing.

Korean Patent Publication No. 10-2016-0010121

One aspect of the present invention is to provide an electrode for a secondary battery and a method of manufacturing the electrode for a secondary battery capable of improving the rate performance and rapid charging performance using high current charging.

The electrode for a secondary battery according to an embodiment of the present invention includes an electrode current collector and an electrode active material laminated on the electrode current collector, wherein the electrode active material has a plurality of large pattern portions, A small pattern portion may be formed in each of the pattern portions, and the small pattern portion may be formed into a three-dimensional fine pattern formed by forming a plurality of fine grooves.

A method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention is a method of manufacturing an electrode for a secondary battery, comprising the steps of: stacking an electrode active material on an electrode current collector; forming a plurality of large pattern parts on the electrode current collector; And forming a small pattern portion in each of the plurality of large pattern portions. In the pattern forming process, the small pattern portion may be formed into a three-dimensional fine pattern in which a plurality of fine grooves are formed.

According to the present invention, by increasing the surface area of the electrode by forming a three-dimensional pattern on the electrode, the rate performance and rapid charging performance using high current charging can be increased.

1 is a plan view showing an electrode for a secondary battery according to a first embodiment of the present invention.
FIG. 2 is a plan view showing the region A in FIG. 1; FIG.
3 is a cross-sectional view taken along the line B-B 'in FIG.
4 is a graph showing changes in resistance in the electrode for a secondary battery according to the first embodiment of the present invention.
FIG. 5 is a graph illustrating the rate performance in the electrode for a secondary battery according to the first embodiment of the present invention.
6 is a graph showing the cycle performance in the electrode for a secondary battery according to the first embodiment of the present invention.
7 is a partial cross-sectional view illustrating an electrode for a secondary battery according to a second embodiment of the present invention.
8 is a plan view showing a small pattern portion in an electrode for a secondary battery according to a third embodiment of the present invention.
9 is an exemplary view showing an example of a method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention.
10 is an exemplary view partially showing an electrode for a secondary battery manufactured through an example of a method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention.
11 is a diagram showing another example of a method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Furthermore, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In the following description of the present invention, a detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

FIG. 1 is a plan view showing an electrode for a secondary battery according to a first embodiment of the present invention, and FIG. 2 is a plan view showing a region A in FIG.

1 and 2, the electrode 100 for a secondary battery according to the first embodiment of the present invention includes an electrode current collector 110 and an electrode active material 120, (130) and a small pattern portion (131) are formed.

3 is a cross-sectional view taken along the line B-B 'in FIG.

Hereinafter, a secondary battery electrode according to a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6. FIG.

Referring to FIG. 1, the electrode 100 for a secondary battery according to the first embodiment of the present invention can form an electrode assembly (not shown) of a secondary battery together with a separation membrane (not shown). Here, the electrode assembly is a power generation device capable of charging and discharging, and the electrode 100 and the separation membrane can be assembled and alternately stacked. At this time, the separation membrane may be formed of, for example, a polyolefin-based resin film such as polyethylene or polypropylene having micropores.

1 and 3, the electrode 100 may include an electrode current collector 110 and an electrode active material 120 coated on one or both surfaces of the electrode current collector 110. An electrode tab T may be provided at an end of the electrode 100 to be electrically connected to the outside through an electrode lead (not shown).

In addition, the electrode 100 may include a positive electrode and a negative electrode. Here, the positive electrode includes a positive electrode collector and a positive electrode active material coated on the positive electrode collector, and the negative electrode may include a negative electrode collector and a negative electrode active material coated on the negative electrode collector.

The positive electrode collector may be made of, for example, a foil made of aluminum (Al).

The cathode active material may be composed of, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or a compound or mixture thereof containing at least one of the foregoing.

In addition, the cathode active material may be made of a Hi Ni-based cathode material as another example. Here, the Hi Ni-based cathode material may include any one or more of LiNiMnCoO-based, LiNiCoAl-based, and LiMiMnCoAl-based materials. At this time, the content of nickel (Ni) may be 0.5 mol to 0.95 mol.

The anode current collector may be made of, for example, a foil made of copper (Cu) or nickel (Ni).

The negative electrode active material may be made of a material including artificial graphite.

In addition, the negative electrode active material may be made of lithium metal, lithium alloy, carbon, petroleum coke, activated carbon, graphite, silicon compound, tin compound, titanium compound or an alloy thereof.

Referring to FIGS. 1 and 2, a plurality of large pattern units 130 may be formed on the electrode active material 120. Here, the large pattern unit 130 may include a plurality of regular hexagonal patterns and may be arranged in a plurality of rows and columns. However, the shape of the large-pattern portion 130 formed on the electrode 100 for a secondary battery according to the first embodiment of the present invention is not limited to a regular hexagonal shape and may be, for example, a trapezoid, a diamond, May also be formed. That is, the large pattern part 130 can be formed in any one of a hexagonal shape, a trapezoid shape, a diamond shape, a square shape, a triangle shape or a circle shape by forming the small pattern part 131.

In addition, the area of the large-pattern portion 130 on the plan view may be 20 to 40% of the area of the electrode active material 120. More specifically, the area of the large pattern portion 130 including the small pattern portion 131 occupied in the plan view may be 20 to 40% of the total area of the electrode active material 120 on the plan view. That is, the pattern coverage may be 20 to 40%.

Here, if the pattern coverage is less than 20%, the effect may be substantially insufficient. If the pattern coverage is larger than 40%, there is a problem that the electrode active material 120 is peeled off and electrode damage such as turning off the surface occurs.

At this time, more specifically, for example, the area of the large-pattern portion 130 including the small pattern portion 131 occupied in the plan view may be 30% of the total area of the electrode active material 120.

On the other hand, the surface area of the large pattern portion 130 including the small pattern portion 131 can be formed to be 1.2 times or more than the planar surface area of the same size. That is, the large-pattern portion 130 including the small pattern portion 131 forms a three-dimensional pattern, so that it can be formed 1.2 times or more as large as the surface area of the same size plane on the plan view assuming that there is no small pattern portion .

Referring to FIGS. 2 and 3, the small pattern portion 131 may be formed on each of the plurality of large pattern portions 130. At this time, the small pattern portion 131 may be formed as a three-dimensional fine pattern in which a plurality of fine grooves 131a are formed. Here, the fine grooves 131a may have a rectangular cross section. That is, referring to FIG. 3, the cross section perpendicular to the fine grooves 131a may be formed in a rectangular shape.

In addition, the small pattern portion 131 may be formed in a mesh pattern, for example. At this time, a line 131b between the fine grooves 131a and the fine grooves 131a is formed to form a mesh-shaped pattern. The line 131b has a convex cross section and may have a pattern shape formed around the groove 131a on a plan view.

Here, the line width (a) of the mesh pattern is formed to 10um to 50um, the line spacing (b) is formed to be 50 to 100um, and the line height (c) can be formed to 20um to 80um.

Accordingly, the electrode 100 for a secondary battery according to the embodiment of the present invention increases the surface area of the electrode 100 by forming fine three-dimensional patterns on the electrode 100. rate performance and fast charge performance using high current charging.

1 and 2, a plurality of large pattern units 130 and small pattern units 131 may be formed on the anode, for example. That is, a plurality of large pattern units 130 and small pattern units 131 may be formed on the surface of the cathode active material.

4 is a graph showing changes in resistance in the electrode for a secondary battery according to the first embodiment of the present invention.

The graph shown in Fig. 4 shows the resistance change of the electrode (Ref) in which no pattern is formed, the electrode P1 formed only of the large pattern portion, and the electrode P2 formed with the large pattern portion 130 and the small pattern portion 131 .

Here, in the electrode P1 formed with only the large pattern portion, for example, a pattern forming a regularly-shaped groove 131a is formed. That is, the P1 electrode forms a plurality of regular hexagonal grooves without forming a fine pattern.

The electrode P2 having the large pattern portion 130 and the small pattern portion 131 is formed with the small pattern portion 131 to form the large pattern portion 130. [ That is, the P2 electrode forms a three-dimensional fine pattern of the mesh pattern, and forms a plurality of square pattern portions (see Figs. 1 and 2)

Here, the graph in the form of a square box shown in Fig. 4 shows that the uppermost section shows the resistance maximum value and the lowermost section shows the resistance minimum value. Also, r1, r2, and r3, which are circles in a square box, represent average resistance values of the P1, P2, and Ref electrodes, respectively.

Referring to the graph shown in FIG. 4, it can be seen that the discharge resistance of the P2 electrode, which is the electrode for the secondary battery according to the first embodiment of the present invention, is significantly reduced as compared with the P1 and Ref electrodes due to an increase in the electrode surface area.

FIG. 5 is a graph illustrating the rate performance in the electrode for a secondary battery according to the first embodiment of the present invention.

The graph shown in FIG. 5 shows the rate performance of the electrode (Ref) on which no pattern is formed, the electrode P1 formed only of the large pattern portion, and the electrode P2 on which the large pattern portion 130 and the small pattern portion 131 are formed . Here, the rate performance refers to the performance characteristics according to the constant current discharge rate (refer to FIGS. 1 and 2)

The graph shown in FIG. 5 shows the rate performance of the same charge / discharge C-rate (rate capability): C / 10 charge / discharge 3 times -> C / 3 charge / discharge 5 times -> C / 2 charge / discharge 5 times -> 1C Charge / discharge 5 times -> 2C charge / discharge 5 times -> 4C charge / discharge 5 times -> C / 3 charge /

5, the discharge capacity due to the C / 3 charge / discharge after the 4C charge / discharge is much higher than that of the P1 and Ref electrodes because the P2 electrode, which is the electrode for the secondary battery according to the first embodiment of the present invention, .

FIG. 6 is a graph showing cycle performance in the electrode for a secondary battery according to the first embodiment of the present invention.

The graph shown in Fig. 6 shows the cycle performance of the electrode (Ref) in which no pattern is formed, the electrode (P1) formed only with the large pattern portion, and the electrode P2 formed with the large pattern portion 130 and the small pattern portion 131 (Refer to Figs. 1 and 2)

Referring to the graph shown in FIG. 6, it can be seen that the P2 electrode, which is an electrode for a secondary battery according to the first embodiment of the present invention, has a significantly faster charge cycle performance than the P1 and Ref electrodes.

7 is a partial cross-sectional view illustrating an electrode for a secondary battery according to a second embodiment of the present invention.

7, the electrode 200 for a secondary battery according to the second embodiment of the present invention is different from the electrode 100 for a secondary battery according to the first embodiment in that the electrode (231a).

Therefore, the present embodiment will briefly describe the contents overlapping with the first embodiment, and focus on the differences.

The electrode 200 for a secondary battery according to the second embodiment of the present invention includes an electrode current collector 110 and an electrode active material 120. The electrode active material 120 includes a large pattern portion 130 and a small pattern portion 231 Is formed.

Here, the small pattern portion 231 may be formed as a three-dimensional fine pattern in which a plurality of fine grooves 231a are formed. At this time, the bottom surface of the fine groove 231a may form a curved surface. That is, the lower end of the fine groove 231a may be formed in a semicircular shape. At this time, a line 231b between the fine grooves 231a and the fine grooves 231a is formed to form a mesh-shaped pattern.

8 is a plan view showing a small pattern portion in an electrode for a secondary battery according to a third embodiment of the present invention.

8, the electrode 300 for a secondary battery according to the third embodiment of the present invention includes the electrode 100 for the secondary battery according to the first embodiment, the electrode 200 for the secondary battery according to the second embodiment, In comparison, the pattern form of the small pattern portion 331 is different.

Therefore, the present embodiment will briefly describe the contents overlapping with the first embodiment and the second embodiment, and focus on the differences.

The electrode 300 for a secondary battery according to the third embodiment of the present invention includes an electrode current collector 110 and an electrode active material 120 and includes a large pattern portion 130 and a small pattern portion 331 Is formed.

In addition, the small pattern portion 331 may be formed as a three-dimensional fine pattern in which a plurality of fine grooves 331a are formed. In addition, the small pattern portion 331 may be formed of, for example, a mesh pattern. Here, the fine grooves 331a may be formed in a rectangular shape with a flatness. That is, the small pattern portion 331 may be formed as a mesh pattern in which the flat cross-section of the fine grooves 331a is formed in a rectangular shape. At this time, a line 331b between the fine grooves 331a and the fine grooves 331a is formed to form a mesh-shaped pattern.

FIG. 9 is a view illustrating an example of a method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention. FIG. 10 is a cross-sectional view illustrating a method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention. Fig.

Referring to FIG. 9, a method of fabricating an electrode assembly according to an embodiment of the present invention includes a step of laminating the electrode active material 120 and a pattern forming step of forming a pattern in the electrode active material 120.

Hereinafter, a method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3 and FIGS. 9 to 11. FIG.

Referring to FIG. 9, in the laminating process, the electrode active material 120 is laminated on one surface or both surfaces of the electrode current collector 110.

Referring to FIGS. 1, 2 and 9, the pattern forming process includes forming a plurality of large pattern units 130 in the electrode active material 120, forming a plurality of small pattern units 131 ) Can be formed.

In addition, in the pattern formation process, the small pattern portion 131 can be formed into a three-dimensional fine pattern in which a plurality of fine grooves 131a are formed. Here, the pattern formation process may form the small pattern portion 131 in a mesh pattern. 2 and 3, in the pattern formation process, the line width a of the mesh pattern is formed to be 10 to 50 μm, the line spacing b is formed to be 50 to 100 μm, and the line height c is 20 um To 80um. At this time, a line 131b between the fine grooves 131a and the fine grooves 131a is formed to form a mesh-shaped pattern.

Accordingly, the method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention increases the surface area of the electrode 100 by forming a three-dimensional fine pattern on the electrode 100, thereby improving the rate performance and rapid charging performance using high current charging. have.

Referring to FIGS. 1 and 2, the pattern formation process may be arranged in a plurality of rows and columns by forming a plurality of regular pattern portions in the large pattern portion 130, for example. At this time, a plurality of regular hexagon pattern units 130 can be formed by forming the small pattern units 131.

However, the shape of the large-pattern portion 130 formed in the pattern formation process of the electrode for a secondary battery according to the first embodiment of the present invention is not limited to a regular hexagonal shape and may be, for example, a trapezoidal, rhombic, A triangle, a circle, or the like. That is, the pattern formation process can form the large pattern part 130 in any one of a hexagon, a trapezoid, a diamond, a square, a triangle or a circle by forming the small pattern part 131.

For example, the pattern formation process may be performed such that the area of the large pattern portion 130 is 20 to 40% of the area of the electrode active material 120 on a plan view. At this time, the pattern formation process may be more specifically formed such that the area of the large pattern portion 130 is 30% of the area of the electrode active material 120 on a plan view.

Meanwhile, the electrode 100 may include a positive electrode and a negative electrode. Here, the anode may include a cathode current collector and a cathode active material laminated on the cathode current collector. At this time, in the pattern formation process, a plurality of large pattern portions 130 and small pattern portions 131 may be formed on the surface of the cathode active material. That is, in the pattern formation process, the small pattern units 131 may be formed to form a plurality of large pattern units 130, for example, in the shape of a cube.

Referring to FIGS. 9 and 10, the pattern forming process includes rolling the outer surface of the electrode active material 120 through a rolling roll 10 having an embossed pattern 11 formed on the outer circumferential surface thereof, So that the small pattern portion 131 can be formed. (See Figs. 1 and 2)

11 is a diagram showing another example of a method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention.

11, the pattern forming process may include rolling the outer surface of the electrode active material 120 through the rolled plate 20 having the relief pattern 21 formed on its surface to form a plurality of large pattern portions 130 and small pattern portions 130, 1 and 2). The rolled plate 20 may be placed on the electrode active material 120 and the rolling roll 10 may be passed over the rolled plate 20. For example, have.

Although the present invention has been described in detail with reference to specific embodiments thereof, it is to be understood that the present invention is not limited thereto. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Further, the scope of protection of the invention will be clarified by the appended claims.

10: rolling roll
11: Pattern
20: Rolling plate
21: Pattern
100, 200, 300:
110: electrode collector
120: electrode active material
130: large pattern portion
131, 231, 331:
131a, 231a, and 331a:
131b, 231b, and 331b:

Claims (13)

An electrode for a secondary battery,
Electrode collector; And
And an electrode active material laminated on the electrode current collector,
A plurality of large pattern portions are formed on the electrode active material,
A small pattern portion is formed in each of the plurality of large pattern portions,
Wherein the small pattern portion has a three-dimensional fine pattern formed with a plurality of fine grooves. The method according to claim 1,
Wherein the small pattern portion is formed in a mesh pattern. The method of claim 2,
Wherein the line width of the mesh pattern is in a range of 10um to 50um, the line spacing is in a range of 50um to 100um, and the line height is in a range of 20um to 80um. The method according to claim 1,
Wherein an area of the large-pattern portion is 20 to 40% of an area of the electrode active material on a plan view. The method according to claim 1,
Wherein the surface area of the large pattern portion including the small pattern portion is 1.2 times or more than the planar surface area of the same size. The method according to claim 1,
Wherein the electrode comprises a positive electrode and a negative electrode,
Wherein the positive electrode comprises a positive electrode collector and a positive electrode active material laminated on the positive electrode collector,
Wherein the plurality of large pattern portions and the small pattern portions are formed on a surface of the cathode active material. A method of manufacturing an electrode for a secondary battery,
A lamination process of laminating the electrode active material on the electrode current collector; And
Forming a plurality of large pattern portions in the electrode active material and forming small pattern portions in each of the plurality of large pattern portions,
Wherein the pattern forming process comprises forming the small pattern portion into a three-dimensional fine pattern in which a plurality of fine grooves are formed. The method of claim 7,
Wherein the pattern forming process comprises rolling the outer surface of the electrode active material through a rolling roll having an embossed pattern on the outer circumferential surface to form the plurality of large pattern portions and the small pattern portions. The method of claim 7,
Wherein the pattern forming process comprises rolling the outer surface of the electrode active material through a rolled plate having a relief pattern formed on the surface thereof to form the plurality of large pattern portions and the small pattern portions. The method of claim 7,
Wherein the pattern forming process forms the small pattern portion in a mesh pattern. The method of claim 10,
Wherein the pattern forming process comprises forming a line width of 10um to 50um, a line spacing of 50um to 100um, and a line height of 20um to 80um. The method of claim 7,
Wherein the area of the large pattern part is 20 to 40% of the area of the electrode active material on a plan view. The method of claim 7,
Wherein the electrode comprises a positive electrode and a negative electrode,
Wherein the positive electrode comprises a positive electrode collector and the positive electrode active material laminated on the positive electrode collector,
Wherein the pattern forming process forms the plurality of large pattern portions and the small pattern portions on the surface of the cathode active material.

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