WO2019039815A2

WO2019039815A2 - Secondary battery electrode, manufacturing method therefor, and electrode assembly

Info

Publication number: WO2019039815A2
Application number: PCT/KR2018/009533
Authority: WO
Inventors: 김남원; 박필규; 송한갑; 윤덕중; 김대현; 정안수
Original assignee: 주식회사 엘지화학
Priority date: 2017-08-21
Filing date: 2018-08-20
Publication date: 2019-02-28
Also published as: WO2019039815A3

Abstract

The present invention relates to a secondary battery electrode, a manufacturing method therefor, and an electrode assembly and, more specifically, to a secondary battery electrode for improving the stability of a secondary battery, a manufacturing method therefor, and an electrode assembly. The secondary battery electrode according to an embodiment of the present invention comprises: a current collector formed extending in one direction; a first active material layer formed on one surface of the current collector and including a first inclination part and a first protrusion part; and a second active material layer formed on the other surface of the current collector and including a second inclination part and a second protrusion part, wherein the position of the second protrusion part on the second active material layer is controlled so that the second protrusion part is formed at a position that is not opposite the first inclination part with the current collector therebetween.

Description

Secondary battery electrode, method for manufacturing same, and electrode assembly

The present invention relates to an electrode for a secondary battery, a method of manufacturing the electrode, and an electrode assembly, and more particularly, to an electrode for a secondary battery, a method of manufacturing the electrode, and an electrode assembly for improving the stability of the secondary battery.

BACKGROUND ART [0002] In recent years, rechargeable secondary batteries have been widely used as energy sources for wireless mobile devices. In addition, the secondary battery is an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (HEV), and the like, which are proposed as solutions for air pollution of existing gasoline vehicles and diesel vehicles using fossil fuels (Plug-In HEV) and the like.

In small mobile devices, one or two or more battery cells are used per device, while a middle- or large-sized battery module such as an automobile is used as a middle- or large-sized battery module in which a plurality of battery cells are electrically connected due to the necessity of a large-

Since the middle- or large-sized battery module is preferably manufactured in a small size and weight, a prismatic battery, a pouch-shaped battery, or the like, which can be charged with a high degree of integration and has a small weight to capacity, is mainly used as a battery cell have. In particular, a pouch-shaped battery using an aluminum laminate sheet or the like as an exterior member has recently attracted a lot of attention due to its advantages such as small weight, low manufacturing cost, and easy shape deformation.

There are various methods for manufacturing such an electrode assembly of a secondary battery. One of the most commonly used techniques is to wind the anode, the cathode, and the separator interposed between the anode and the cathode together to form a jellyroll. However, since such a jelly-roll type electrode assembly has a long sheet-like anode and an anode wound in a densified state to form a cylindrical or elliptical structure in a sectional shape, stress caused by the expansion and contraction of the electrode during charging / And accumulation of the stress accumulation inside the assembly causes deformation such as cracks of the electrode assembly when the stress accumulation exceeds a certain limit. Such deformation of the electrode assembly causes a problem that the performance of the battery is rapidly deteriorated and the safety of the battery is threatened due to an internal short circuit.

(Prior art document)

Korean Patent Publication No. 10-2015-0054702

The present invention provides an electrode for a secondary battery, a method of manufacturing the electrode, and an electrode assembly that can prevent deformation of the current collector by mitigating the pressure applied to the current collector, and prevent cracks from being generated in the production of the electrode.

An electrode for a secondary battery according to an embodiment of the present invention includes: a current collector extended in one direction; A first active material layer formed on one surface of the current collector, the first active material layer including a first inclined portion and a first projected portion; And a second active material layer formed on the other surface of the current collector, the second active material layer including a second inclined portion and a second protruding portion, wherein the second protruding portion is formed so as not to face the first inclined portion The position on the second active material layer is controlled.

The second protrusion may be spaced apart from the second inclined portion by a predetermined distance.

An unoccupied portion where the first active material layer is not provided may be formed on one surface of the current collector.

Wherein the first inclined portion and the first projected portion are formed on one side of the first active material layer and the second inclined portion and the second projected portion are formed on one side of the second active material layer in the same direction as one side of the first active material layer .

The first active material layer and the second active material layer may be formed of an electrode active material for a cathode or an electrode active material for a cathode.

According to another aspect of the present invention, there is provided a method of manufacturing an electrode for a secondary battery, the method including: providing a current collector having a first active material layer including a first inclined portion and a first projection on one surface thereof; Transferring the current collector in one direction; And forming a second active material layer including a second inclined portion and a second protruding portion by applying a second active material to the other surface of the current collector. In forming the second active material layer, And the position of the second projecting portion on the second active material layer is controlled so as to be formed at a position not facing the first inclined portion with respect to the current collector.

In the process of forming the second active material layer, the second projecting portion may be spaced apart from the second inclined portion by a predetermined distance.

The position of the second protrusion can be controlled by adjusting the application pressure of the second active material layer.

The position of the second projecting portion can be controlled by adjusting the conveying speed of the current collector.

Also, an electrode assembly according to an embodiment of the present invention includes an anode, a cathode, and a separator interposed between the anode and the cathode, wherein at least one of the anode and the cathode includes any one of the above- .

According to the electrode for a secondary battery, the method for manufacturing the same, and the electrode assembly according to the embodiment of the present invention, the position of the protrusion formed on the second active material layer is controlled to a position not facing the inclined portion of the first active material layer, Thus, it is possible to prevent the deformation of the current collector by reducing the pressure applied to the current collector, and to prevent the generation of cracks during the production of the electrode.

According to the embodiment of the present invention, the shape of the first active material layer and the second active material layer formed on both surfaces of the current collector is controlled so that the thickness of the electrode does not increase abruptly to obtain an electrode for a secondary battery of uniform thickness And can improve product stability, economy, and yield.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a general secondary battery electrode. Fig.

2 is a view showing a state where a pressure is applied to a current collector in a general secondary cell electrode.

3 is a view showing a position where cracks are generated in a current collector in a general secondary cell electrode.

4 is a graph showing the plastic strain of a current collector in a general secondary cell electrode.

5 is a view showing an electrode for a secondary battery according to an embodiment of the present invention.

6 is a view showing an electrode for a secondary battery according to another embodiment of the present invention.

7 is a view showing a state where a pressure is applied to a current collector in an electrode for a secondary battery according to an embodiment of the present invention.

8 is a graph showing the plastic strain of a current collector in an electrode for a secondary battery according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, Is provided to fully inform the user. Wherein like reference numerals refer to like elements throughout.

There are various methods for manufacturing such an electrode assembly of a secondary battery. One of the most commonly used techniques is to wind the anode, the cathode, and the separator interposed between the anode and the cathode together to form a jellyroll. Here, the electrodes such as the positive electrode and the negative electrode included in the electrode assembly of the secondary battery include a step of forming the electrode active material layer on the current collector. The step of forming the electrode active material layer includes the steps of applying the active material slurry in which the electrode active material particles are injected into the binder solution to the current collector and drying the active material slurry applied to the current collector to remove the solution and moisture present in the active material slurry Thereby forming an electrode active material layer on the current collector.

The active material slurry has a high viscosity coefficient due to its physical characteristics. Therefore, when the electrode active material layer is formed on the current collector, an inclined portion which is defined as a drag region and is sharply formed at the tip portion of the application region is formed, and is defined as a balcony region and is convexly formed at a position spaced apart from the inclined portion A protrusion is formed.

FIG. 1 is a view showing a state of a general secondary battery electrode, and FIG. 2 is a view showing a state where a pressure is applied to a current collector in a general secondary battery electrode. 3 is a view showing a position where cracks are generated in a current collector in a general secondary battery electrode, and FIG. 4 is a view showing a plastic strain of the current collector in a general secondary battery electrode.

Referring to FIGS. 1 to 4, a general secondary cell electrode includes a current collector 100 extending in one direction, and a first inclined portion 210 and a first protruding portion 220, (200) is formed. The second active material layer 300 including the second inclined portion 310 and the second protruding portion 320 is formed on the other surface of the current collector 100. Here, the inclined portion refers to a drag region that is sharply generated at the tip portion of the application region as described above, and the projected portion refers to a balcony region that is convexly generated at a predetermined interval from the inclined portion.

A battery having a jelly-roll type electrode assembly is formed with a non-coated portion N on one surface of a current collector 100, in which the first active material layer 200 is not provided. However, when the non-coated portion N is provided on one surface of the current collector 100 and the first active material layer 200 is not provided and the second active material layer 300 is formed on the other surface of the current collector 100 The second protrusion 320 of the second active material layer 300 is located in a region of the first active material layer 200 opposite to the first inclined portion 210.

When the second protruding portion 320 of the second active material layer 300 is positioned in the region of the first active material layer 200 facing the first inclined portion 210 of the first active material layer 300, The thickness of the electrode in the region where the second protrusion 320 is located is rapidly increased, and the rolling rate is locally increased in the region, so that deformation of the current collector 100 occurs. 2, the current collector 100 maintains a thickness of about 16.7 μm between the first active material layer 200 and the second active material layer 300. However, the first active material layer 200, The current collector 100 is deformed to a thickness of about 12.8 占 퐉 in a region where the second projecting portion 320 of the second active material layer 300 is opposed to the first inclined portion 210 of the current collector 100 .

The non-coated portion N in which the first active material layer 200 is not provided on one surface of the current collector 100 is formed to have a predetermined length from the end portion of the current collector 100 along the extending direction of the current collector 100 (The plain portion is formed in a length of 13 mm in Figs. 2 to 4). 3, the thickness of the electrode including the first active material layer 200 and the current collector 100 continuously increases from the position where the electrode length, that is, the length from the end of the current collector is 0 mm, The first active material layer 200 starting from the first inclined portion 210 is formed in a region where the second protruding portion 320 of the second active material layer 300 is located. Accordingly, the first active material layer 200, the current collector 100, and the second active material layer 300 (see FIG. 1) are formed at a point where the electrode length including the boundary between the non-coated portion N and the second active material layer 300 is about 15 to 20 mm. ) Is increased sharply.

Due to such an increase in the electrode thickness, in a certain region including the boundary between the uncoated portion N and the second active material layer 300 at a point about 15 to 20 mm from the end of the current collector 100, . 4, the current collector 100 at a length of 15 to 20 mm from the end of the collector increases the peak value of the plastic strain PEEQ of the current collector 100 by increasing the local rolling rate Is increased to a value of about 0.06 or more so that deformation occurs in the current collector 100 and cracks, that is, disconnection, occur at the time of winding.

Accordingly, the secondary battery electrode, the method of manufacturing the same, and the electrode assembly according to the present invention can prevent the deformation of the current collector 100 by reducing the pressure applied to the current collector 100, This is a technical feature that can be prevented in advance.

FIG. 5 is a view showing a state of an electrode for a secondary battery according to an embodiment of the present invention, and FIG. 6 is a view showing a state of an electrode for a secondary battery according to another embodiment of the present invention.

5 and 6, an electrode for a secondary battery according to an embodiment of the present invention includes a collector 100 extended in one direction; A first active material layer 200 formed on one surface of the current collector 100 and including a first inclined portion 210 and a first protruding portion 220; And a second active material layer 300 formed on the other surface of the current collector 100 and including a second inclined portion 310 and a second projected portion 320, The position on the second active material layer 300 is controlled so as to be formed at a position not facing the first inclined portion 210 with the current collector 100 as a center.

The first inclined portion 210 and the first projected portion 220 are formed on one side of the first active material layer 200 and the second inclined portion 310 and the second projected portion 320 are formed on the first active material layer 200 200 formed on one side of the second active material layer 300, which are located in the same direction as the first active material layer 300. 5 and 6, the first inclined portion 210 and the first projected portion 220 may be formed on the left side of the first active material layer 200 and the second inclined portion 210 310 and the second protrusion 320 may be formed on the left side of the second active material layer 300 in the same direction.

As described above, the battery having the jelly-roll type electrode assembly has a non-coated portion N on one surface of the current collector 100, in which the first active material layer 200 is not provided, in order to ensure stability in winding . However, when the non-coated portion N is provided on one surface of the current collector 100 and the first active material layer 200 is not provided and the second active material layer 300 is formed on the other surface of the current collector 100 The second protruding portion 320 of the second active material layer 300 is located in the region of the first active material layer 200 facing the first inclined portion 210 to increase local rolling rate and crack there was. The electrode for a secondary battery according to an embodiment of the present invention includes a first active material layer 300 and a second active material layer 300. The second active material layer 300 has a second protrusion 320 formed on the first active material layer 200, The position on the second active material layer 300 is controlled so as to be formed at a position not opposed to the inclined portion 210.

The non-coated portion N may be formed to have a length of 10 to 20 mm along the extending direction of the current collector 100. The first inclined portion 210 may be formed at the end portion of the first active material layer 200, And the second inclined portion 310 refers to a drag region formed in the shape of a sharp point at the end portion of the second active material layer 300. [

The second protrusion 320 included in the second active material layer 300 may be divided into the first inclined portion 210 included in the first active material layer 200 around the current collector 100, The electrode thickness does not change abruptly at the end of the first active material layer 200, that is, the first inclined portion 210. That is, the second protrusion 320 is formed at a position not opposed to the first inclined portion 210 in order to solve the problem that the thickness of the electrode is drastically changed by the first inclined portion 210 and the second protrusion 320 The electrode thickness changes only in the region of the first inclined portion 210 by the first inclined portion 210, so that the abrupt change of the electrode thickness can be prevented.

5 is a view illustrating an electrode for a secondary battery according to an embodiment of the present invention. A second protrusion 320 included in the second active material layer 300 is located at a position opposite to the first inclined portion 210 (Left side in the figure) of the current collector 100. [0064] Therefore, it is possible to prevent the electrode thickness from being drastically changed in the region facing the first inclined portion 210, whereby the local rolling rate is rapidly increased due to the first inclined portion 210 and the second projected portion 320 It is possible to prevent the current collector 100 from being deformed and cracked during the electrode winding.

6 is a view showing an electrode for a secondary battery according to another embodiment of the present invention. A second protrusion 320 included in the second active material layer 300 is opposite to the first slope part 210 To the opposite side of the end of the current collector 100 (right side in the figure). That is, the second projections 320 are spaced apart from the second slopes 310 by a predetermined distance. As a result, it is possible to prevent the electrode thickness from changing drastically in the area opposite to the first inclined portion 210, as in the embodiment of the present invention. As a result, the first inclined portion 210 and the second projected portion 210 It is the same as described above that the local rolling rate is prevented from increasing sharply by the slab 320 to prevent deformation and cracking of the current collector 100 in advance. Here, a configuration for moving the position of the second protrusion 320 on the second active material layer will be described in detail with reference to the following method for manufacturing an electrode for a secondary battery.

A method of manufacturing an electrode for a secondary battery according to an embodiment of the present invention includes a current collector 100 having a first inclined portion 210 and a first active material layer 200 including a first protruding portion 220 formed on one surface thereof Process; Transferring the current collector 100 in one direction; And forming a second active material layer (300) including a second inclined portion (310) and a second projected portion (320) by applying a second active material to the other surface of the current collector (100) The second protrusions 320 may be formed in the second active material layer 300 such that the second protrusions 320 are formed at positions not facing the first slopes 210 with respect to the current collector 100, The position on layer 300 is controlled.

The coating apparatus for forming the active material layer includes a supply roll for continuously supplying the current collector 100 wound in a roll form and continuously supplying the current collector 100 in one direction, A drying device for drying the active material slurry coated on the current collector 100 to form an active material layer on the current collector 100 and a current collector for forming an active material layer on the active material slurry 100) is wound and recovered in a roll state.

The process of preparing the current collector 100 in which the first active material layer 200 including the first inclined portion 210 and the first protruding portion 220 is formed on one side is performed by the coating device described above, The active material slurry is coated on one surface of the entire body 100 and dried to form the first active material layer 200. The first active material layer 200 may be formed at a position spaced apart from the ends of the current collector 100 by a length of 10 to 20 mm to form a plain weave N on one surface of the current collector 100, A first inclined portion 210 is formed at an end of the first active material layer 200 and a first protrusion 220 is formed at a position spaced apart from the first inclined portion 210 by a predetermined distance.

After the first active material layer 200 is formed on one surface of the current collector 100 by the above process, the second active material layer 300 is formed on the other surface of the current collector 100 by the above- do. This is a process of transferring the current collector 100 in one direction; Forming a second active material layer 300 including a second inclined portion 310 and a second projected portion 320 by applying a second active material, that is, a second active material slurry, to the other surface of the current collector 100; . Here, the process of transporting the current collector 100 in one direction and the process of forming the second active material layer 300 on the other surface of the current collector 100 may be performed by the coating apparatus described above.

The second protrusion 320 included in the second active material layer 300 may be removed from the current collector 100 in the process of forming the second active material layer 300. In this case, And is formed so as not to face the first inclined portion 210 as a center.

The positional control of the second protrusion 320 may be performed by adjusting the application pressure of the second active material layer 300. That is, in forming the second active material layer 300 on the other surface of the current collector 100, the position of the second protrusion 320 can be controlled by changing the application pressure of the coating die for supplying the second active material slurry .

4, the second protrusions 320 included in the second active material layer 300 are formed in the first inclined portion 210 and the second inclined portion 210 in the second active material layer 300, To the end side (left side in the figure) of the current collector 100 at a position opposed to the current collector 100. [ When the application pressure of the coating die for supplying the second active material slurry is reduced, the second projecting portion 320 included in the second active material layer 300 is positioned at a position opposite to the first inclined portion 210 100 (right side in the figure). In addition, it is needless to say that the position of the second protrusion 320 can be adjusted by locally changing the application pressure of the coating die supplying the second slurry of the active material. That is, when supplying the second active material slurry, the application pressure of the coating die is lowered on the position of the first inclined portion 210 so that the second projected portion 320 is inclined with respect to the current collector 100, As shown in Fig.

As such, adjusting the coating pressure of the coating die can be accomplished by controlling the valve for supplying the second active material slurry. That is, the coating die may include a receiving portion for receiving the second active material slurry, a nozzle for discharging the second active material slurry from the receiving portion, and a valve for regulating the pressure in the receiving portion. Here, the valve may be constituted by, for example, a rod which is installed in the housing part so as to be able to move up and down so as to press the second active material slurry contained in the housing part. At this time, the valve can be driven by the motor. The motor for driving the valve may use an electric motor operated by an electrical signal. However, it is preferable to use a voice coil motor (VCM) to finely control the pressure in the receiver. The voice coil motor is a motor which is used for fine work of several micrometers or less without fluctuation of force due to its position due to the operation of a coil in a uniform magnetic field. The response speed is very fast and the application of the coating die for supplying the second active material slurry The pressure can be finely adjusted.

The position of the second protrusion 320 may be controlled by adjusting the feed rate of the current collector 100 when the second active material layer 300 is applied. That is, when the second active material layer 300 is formed on the other surface of the current collector 100, the rotating speed of the supply roll and the winding roll for conveying the current collector 100 in one direction is changed, The position of the second protrusion 320 can be controlled by adjusting the feed speed.

4, the second protruding portion 320 included in the second active material layer 300 may be formed in the second active material layer 300 in the case where the current velocity of the current collector 100 is reduced. (Left side in the figure) of the current collector 100 at a position opposed to the first inclined portion 210. As shown in Fig. The second protrusions 320 included in the second active material layer 300 may be formed in the first inclined portion 210 and the second inclined portion 210 in the second active material layer 300, To the opposite side of the end of the current collector 100 (right side in the figure). In addition, the position of the second protrusion 320 may be adjusted by locally changing the feed rate of the current collector 100. That is, in conveying the current collector 100, the conveyance speed of the current collector 100 is increased at a position opposed to the first inclined portion 210 so that the second protrusion 320 is centered on the current collector 100 It is possible to perform control so as to be formed at a position not opposed to the first inclined portion 210.

The electrode according to the embodiment of the present invention can be used in a jelly-roll type electrode assembly. That is, an electrode assembly in which a separator interposed between an anode, a cathode, and an anode and a cathode is wound, and at least one of the anode and the cathode may be an electrode for a secondary battery described above.

7 is a view showing a state where pressure is applied to a current collector in an electrode for a secondary battery according to an embodiment of the present invention. 7A is a sectional view of the current collector 100 when the protrusion 320 of the second active material layer 300 is positioned at a position opposite to the first inclined portion 210 of the first active material layer 200. [ 7B shows a state where the protrusion 320 of the second active material layer 300 is located at a position opposite to the first inclined portion 210 of the first active material layer 200 The pressure in the current collector 100 is applied.

The protruding portion 320 of the second active material layer 300 is formed to have a width of about 8 mm and a height of 8 탆 and the first inclined portion 210 of the first active material layer 200 is formed in the current collector 100 ) To a thickness of 20 mu m.

7A, when the protruding portion 320 of the second active material layer 300 is positioned at a position opposite to the first inclined portion 210 of the first active material layer 200, Between the layer 200 and the second active material layer 300, the current collector 100 has a thickness of approximately 13.2 占 퐉. However, in the case of the electrode for a secondary battery according to the embodiment of the present invention shown in FIG. 7 (b), the current collector 100 has a thickness of about 17.5 占 퐉 and the pressure applied to the current collector 100 is reduced, It can be seen that the local rolling rate caused thereby is effectively reduced.

The plastic strain of the current collector according to the thickness variation of the current collector 100 is shown in Fig. The portion indicated by a dotted line in FIG. 8 indicates that when the protrusion 320 of the second active material layer 300 is positioned at a position opposite to the first inclined portion 210 of the first active material layer 200, The protruding portion 320 of the second active material layer 300 is located at a position opposite to the first inclined portion 210 of the first active material layer 200 (PEEQ) of the current collector 100 when it is not positioned.

8, when the protrusion 320 of the second active material layer 300 is positioned at a position opposite to the first inclined portion 210 of the first active material layer 200, The peak value of the plastic strain PEEQ of the current collector 100 is set to a value of about 0.06 or more by an increase in the local rolling rate in the current collector 100 at a length of 10 to 20 mm from the end of the current collector 100 . However, according to the embodiment of the present invention, as shown by a solid line in FIG. 8, the protrusion of the second active material layer 300 is located at a position opposite to the first inclined portion 210 of the first active material layer 200 , The peak value of the plastic strain (PEEQ) is about 50% reduced to about 0.03 at the maximum. The protrusion 320 of the second active material layer 300 may be positioned at a position opposite to the first inclined portion 210 of the first active material layer 200, (K = 1,000) secondary battery electrodes manufactured by electrode winding, cracks were generated in 104K secondary battery electrodes, resulting in a defective ratio of about 1.54%. On the other hand, as in the embodiment of the present invention, (K = 1,000) secondary battery electrodes prepared when the projecting portion 320 of the second active material layer 300 is not located at a position opposite to the first inclined portion 210 of the layer 200, Cracks do not occur, and it is possible to manufacture an electrode for a secondary battery with a defective ratio of 0%, and it is possible to prevent a crack from being generated during electrode production.

As described above, according to the electrode for a secondary battery, the method for manufacturing the same, and the electrode assembly according to the embodiment of the present invention, the second active material (second active material layer) is formed at a position not facing the inclined portion of the first active material layer 200, It is possible to prevent the deformation of the current collector 100 by preventing the pressure applied to the current collector 100 by controlling the position of the protrusion formed on the layer 300 and prevent cracks have.

According to the embodiment of the present invention, the shapes of the first active material layer 200 and the second active material layer 300 formed on both surfaces of the current collector 100 are controlled so that the electrode thickness does not increase sharply, An electrode for a secondary battery having a uniform thickness can be obtained, and the product stability, economy, and yield can be improved.

While the preferred embodiments of the present invention have been described and illustrated above using specific terms, such terms are used only for the purpose of clarifying the invention, and the embodiments of the present invention and the described terminology are intended to be illustrative, It will be obvious that various changes and modifications can be made without departing from the spirit and scope of the invention. Such modified embodiments should not be individually understood from the spirit and scope of the present invention, but should be regarded as being within the scope of the claims of the present invention.

Claims

A current collector extended in one direction;

A first active material layer formed on one surface of the current collector, the first active material layer including a first inclined portion and a first projected portion; And

And a second active material layer formed on the other surface of the current collector and including a second inclined portion and a second projected portion,

Wherein a position of the second protruding portion on the second active material layer is controlled such that the second protruding portion is formed at a position not facing the first inclined portion with respect to the current collector.
The method according to claim 1,

And the second projecting portion is spaced apart from the second inclined portion by a predetermined distance.
The method according to claim 1,

Wherein an uncoated portion not provided with the first active material layer is formed on one surface of the current collector.
The method according to claim 1,

Wherein the first inclined portion and the first projected portion are formed on one side of the first active material layer,

Wherein the second inclined portion and the second protrusion are formed on one side of the second active material layer positioned in the same direction as one side of the first active material layer.
The method according to claim 1,

Wherein the first active material layer and the second active material layer are formed of an electrode active material for a negative electrode or formed of an electrode active material for a positive electrode.
Providing a current collector having a first active material layer including a first inclined portion and a first protruding portion on one surface thereof;

Transferring the current collector in one direction; And

And forming a second active material layer including a second inclined portion and a second projected portion by applying a second active material to the other surface of the current collector,

In the process of forming the second active material layer,

Wherein the position of the second active material layer is controlled such that the second protrusion is formed at a position not facing the first inclined portion with respect to the current collector.
The method of claim 6,

In the process of forming the second active material layer,

And the second projecting portion is spaced apart from the second inclined portion by a predetermined distance.
The method of claim 6,

Wherein an unoccupied portion not provided with the first active material layer is formed on one surface of the current collector.
The method of claim 6,

Wherein the position of the second protrusion is controlled by adjusting a coating pressure of the second active material layer.
The method of claim 6,

Wherein the position of the second protrusion is controlled by adjusting a feed rate of the current collector.
An electrode assembly comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode,

Wherein at least one of the positive electrode and the negative electrode comprises an electrode for a secondary battery according to any one of claims 1 to 5.