KR102231583B1 - Electrode assembly for secondary battery, method of manufacturing the same and lithium secondary battery comprising the same - Google Patents

Abstract

An electrode assembly according to an embodiment of the present invention includes a pocketing anode provided in a shape surrounded by an anode by a separator, and a cathode disposed to be stacked on at least one of an upper or lower portion of the pocketing anode, and the pocketing An anode receiving portion accommodating an upper or lower portion of the anode includes a cathode formed in a shape that is recessed or engraved on a contact surface of the cathode in contact with the pocketing anode.

Description

Electrode assembly for secondary battery, manufacturing method thereof, and lithium secondary battery including the same TECHNICAL FIELD [ELECTRODE ASSEMBLY FOR SECONDARY BATTERY, METHOD OF MANUFACTURING THE SAME AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME}

The present invention relates to an electrode assembly for a secondary battery, a method of manufacturing the same, and a lithium secondary battery including the same, and in more detail, the insulating polymer film used in the conventional pocketing positive electrode can be omitted by pocketing the positive electrode only as a separator. , An electrode assembly for a secondary battery capable of maximizing battery performance by increasing a contact cross-sectional area between a positive electrode and a negative electrode, a method of manufacturing the same, and a lithium secondary battery including the same.

With the recent development of the high-tech electronics industry, the use of portable electronic devices and various types of mobile devices is increasing as electronic devices can be reduced in size and weight. As the need for a battery having a high energy density increases as a power source for such portable electronic devices and mobile devices, the demand for a lithium secondary battery is greatly increased, and research for improving the performance of a lithium secondary battery is being actively conducted.

In particular, the rapid thinning and miniaturization of electronic devices and mobile devices is rapidly expanding the demand for thin-walled lithium secondary batteries. Meanwhile, the conventional cylindrical or prismatic lithium secondary battery has a limitation in that it is not excellent in terms of energy density per volume due to the thinning of the battery. Therefore, it is difficult to obtain a sufficient driving time when a thin battery having a thickness of 5 mm or less is generally employed in high-performance portable electronic devices such as mobile phones, camcorders, notebook computers, and mobile devices.

Specifically, the prismatic lithium secondary battery has poor efficiency of the battery compared to the volume due to the electrode body structure having a jelly roll shape, and the battery thickness is reduced due to technical restrictions on reducing the wall thickness of the metal packaging material manufactured by low temperature stretching. The energy density is lowered.

On the other hand, in the case of a lithium polymer battery assembled by sealing the stacked electrode assembly with an aluminum laminate packaging material, the waste of space generated by the jelly roll can be reduced, but an excessive amount of a polymer binder is used to increase the adhesion between the electrodes. Since the adhesive layer must be applied to the electrode-electrolyte interface, there is a problem in that energy density and thus battery performance are deteriorated. In addition, due to the mechanical fragility of the aluminum laminate packaging material itself and the lack of adhesive strength of the adhesive surface made of the polymer inner skin layer and the metal tab, there are also problems in that the durability and safety of the battery are weak.

To solve this problem, the present applicant developed and implemented a technology for manufacturing a lithium secondary battery by stacking the pocketing electrode body (anode) disclosed in Korean Patent No. 10-1168650 or Korean Patent No. 10-1168651. Is coming.

However, as shown in Fig. 3 of Korean Patent No. 10-1168650 or Korean Patent No. 10-1168651, in the conventional pocketing electrode body (anode), a separate insulating property is used to encapsulate the positive electrode. The anode is pocketed with a member and a separator. That is, in order to make a conventional pocketing electrode body (anode), a storage space similar to the shape of a positive electrode plate must be made by punching (perforating) or punching an insulating polymer film. At this time, since the insulating polymer film corresponding to the storage space, that is, the punched insulating polymer film, cannot be reused and is discarded as it is, there is a problem of wasting the insulating polymer film. In addition, there is a problem of low productivity because it is necessary to perform a repetitive punching process in order to manufacture the pocketing electrode body (anode).

To solve this problem, a positive electrode plate that is thinner than the thickness of the insulating polymer film may be used.However, if a positive electrode plate thinner than the insulating polymer film is used, it is disadvantageous in terms of the energy density of the battery, and if the electrode body is unstable, battery failure may occur. There is a problem that it is likely to occur.

Korean Patent Registration No. 10-1168650 (Registration Announcement 2012.07.25.) Korean Patent Registration No. 10-1168651 (Registration Announcement 2012.07.26.)

An embodiment of the present invention provides an electrode assembly for a secondary battery, a method of manufacturing the same, and a lithium secondary battery including the same, which can omit the insulating polymer film used for the conventional pocketing positive electrode by pocketing the positive electrode only as a separator.

In addition, in the embodiment of the present invention, as the insulating polymer film used for pocketing of the positive electrode is omitted, a number of processes related to the insulating polymer film can be omitted to improve productivity, and the insulating polymer film is not used. It provides an electrode assembly for a secondary battery capable of reducing manufacturing cost, a method for manufacturing the same, and a lithium secondary battery including the same.

In addition, an embodiment of the present invention provides an electrode assembly for a secondary battery capable of improving energy density and output by increasing a contact cross-sectional area between a positive electrode and a negative electrode, a method of manufacturing the same, and a lithium secondary battery including the same.

In addition, an embodiment of the present invention is an electrode assembly for a secondary battery that can be easily applied not only to a secondary battery of a quadrangular structure, but also to a secondary battery of a different shape such as triangle, pentagon, circle, ellipse, etc., a manufacturing method thereof, and lithium containing the same. Provides secondary batteries.

According to an embodiment of the present invention, a pocketing anode provided in a shape surrounded by an anode by a separator, and stacked on at least one of an upper or a lower portion of the pocketing anode and accommodating the upper or lower portion of the pocketing anode. It provides an electrode assembly for a secondary battery including a negative electrode provided in a shape in which the positive electrode accommodating part is recessed or engraved on a contact surface with the pocketing positive electrode.

Preferably, the positive electrode receiving portion may be provided in a shape in which the negative active material applied to the contact surface of the negative electrode is depressed or engraved.

Preferably, the separator is formed in a larger area than the anode, and is formed in the same shape as the first separator and the first separator provided on the upper surface of the anode so that the anode is located in the center, and corresponds to the first separator. It may include a second separator provided on the lower surface of the anode to be disposed.

In the pocketing anode, edges of the first separator and the second separator to which the anode is not located are adhered to each other, so that the anode may be pocketed by the first separator and the second separator.

Here, the edge portions of the first separator and the second separator may be directly bonded to each other by heating, or heat-bonded in a state in which an adhesive is applied to the contact surface of the edge portion.

In addition, the upper and lower portions of the pocketing anode may protrude symmetrically to each other in the same shape on the upper side and the lower side with respect to the edge portions of the first and second separators. The anode accommodating portion may be formed to accommodate an upper portion or a lower portion of the pocketing anode, and may be equally provided on at least one of both surfaces of the cathode.

In addition, the positive electrode receiving portion may be disposed in the center of the contact surface of the negative electrode. The edge portion of the contact surface of the negative electrode may be disposed to be in close contact with the edge portion of the first separator and the second separator.

In addition, the positive electrode may include a positive electrode current collector, a positive electrode active material applied to both surfaces of the positive electrode current collector, and a positive electrode uncoated portion formed in an elongated shape in which the positive electrode active material is not applied. One end of the positive electrode uncoated portion may be connected to the positive electrode current collector, and the other end of the positive electrode uncoated portion may be disposed in a shape penetrating between the first and second separators.

Preferably, the anode may be a single-sided cathode or a double-sided cathode depending on the lamination position and lamination conditions. The single-sided cathode may be disposed to be stacked on only one of the upper or lower portions of the pocketing anode, and the anode receiving portion may be formed only on one surface in contact with the pocketing anode. The double-sided cathode may be disposed to be stacked between the pocketing anodes, and the anode receiving portions may be formed on both sides of the pocketing anode and in contact with each other.

The pocketing anode and the cathode may be stacked to cross each other. The single-sided cathode may be disposed in the top layer and the bottom layer, and the double-sided cathode may be disposed in an intermediate layer positioned between the top and bottom layers. In this case, the pocketing anode may be disposed between the single-sided cathodes, disposed between the single-sided cathode and the double-sided cathode, or disposed between the double-sided cathodes.

Here, the single-sided negative electrode has a negative electrode current collector, a negative electrode active material applied to one surface of the negative electrode current collector, and the negative electrode active material is formed long in a shape not applied, one end is connected to the negative electrode current collector, and the other end is externally formed. It may include a negative electrode uncoated portion disposed in an exposed shape. In this case, the positive electrode receiving part may be provided in a shape that is recessed or engraved in the negative active material applied to one surface of the negative electrode current collector.

In addition, the double-sided negative electrode has a negative electrode current collector, a negative electrode active material applied to both surfaces of the negative electrode current collector, and the negative electrode active material is formed long in a shape not applied, one end is connected to the negative electrode current collector, and the other end is external It may include a negative electrode uncoated portion disposed in a shape exposed to. In this case, the positive electrode accommodating portion may be provided in a shape that is recessed or engraved in the negative electrode active material applied to both surfaces of the negative electrode current collector, and may be formed in a shape symmetrical to each other with respect to the negative electrode current collector.

In addition, the single-sided negative electrode or the negative electrode active material of the double-sided negative electrode may be pressed by upper and lower pressure rollers spaced apart in the vertical direction. On an outer peripheral surface of at least one of the upper pressing roller and the lower pressing roller, an anode receiving part pattern protrusion may be provided to protrude in a pattern shape corresponding to an upper or lower portion of the pocketing anode. The positive electrode receiving part may correspond to the positive electrode receiving part pattern protrusion to the negative active material in the process of pressing the negative active material disposed on one side of the single-sided negative electrode or on both sides of the double-sided negative electrode by the upper pressing roller and the lower pressing roller. It may be formed in a concave or engraved shape.

The shape of the positive electrode receiving part may be determined according to the shape of the positive electrode receiving part pattern protrusion provided on the upper pressing roller or the lower pressing roller. The positive electrode receiving part pattern protrusion may be formed in any one of polygonal, circular, or deformed shape.

Meanwhile, according to another aspect of the present invention, there is provided a lithium secondary battery including the electrode assembly described above, and a battery case provided in a shape surrounding the outside of the electrode assembly and in which an electrolyte is sealed and accommodated together with the electrode assembly. .

In addition, according to another aspect of the present invention, the steps of preparing a separator with an area of a desired size, preparing an anode formed with an area smaller than that of the separator, disposing the separators on both sides of the anode, respectively, and then Forming a pocketing anode by heat bonding the edge portion, preparing a cathode with an area larger than the anode and smaller than or equal to the separation membrane, and both sides of the anode receiving portion for accommodating the upper or lower portion of the pocketing anode It provides a method of manufacturing an electrode assembly comprising the step of forming on at least one surface of the, and laminating the pocketing anode and the cathode.

Preferably, the forming of the pocketing anode comprises: disposing a plurality of anodes at regular intervals on an upper surface of the second separation membrane while supplying the second separation membrane in a roll-to-roll manner, and forming the first separation membrane in a roll-to-roll manner. Supplying in a manner to cover the first separation membrane on the upper surface of the second separation membrane on which the anodes are disposed, pressurizing and heating the first separation membrane and the second separation membrane, and the first separation membrane in which the anodes are not located, and the Adhering the contact portion of the second separator, and cutting or punching the adhesive portion between the first separator and the second separator, so that the anode is positioned at the center of the first separator and the second separator. It may include the step of obtaining an anode.

Preferably, the step of forming the positive electrode receiving part comprises: supplying the negative electrode between the upper and lower pressure rollers in a roll-to-roll method to press both sides of the negative electrode with the upper and lower pressure rollers, The positive electrode receiving portion is formed on only one surface of the negative electrode by a positive electrode receiving portion pattern protrusion formed on the outer circumferential surface of either the upper pressing roller or the lower pressing roller, and then cut or punched based on the positive electrode receiving portion. Forming the single-sided cathode, and forming the anode accommodating portions at regular intervals on both sides of the cathode by the anode accommodating pattern protrusions formed on the outer circumferential surfaces of the upper pressing roller and the lower pressing roller. It may include the step of forming the double-sided negative electrode by cutting or punching as a reference.

Preferably, in the step of stacking the pocketing anode and the cathode, the pocketing anode and the cathode may be stacked in a shape that crosses each other. The single-sided cathode may be disposed in the top layer and the bottom layer, the pocketing anode may be disposed in an intermediate layer between the top and bottom layers, and the double-sided cathode may be disposed between a plurality of the pocketing anodes, respectively. .

The electrode assembly for a secondary battery, a method for manufacturing the same, and a lithium secondary battery including the same according to an embodiment of the present invention have a structure in which a pocketing positive electrode is formed in a shape surrounded by a positive electrode by a separator, so that the positive electrode is pocketed only with the separator. The insulating polymer film used in the pocketing anode of can be omitted, and manufacturing cost can be reduced due to the omission of the insulating polymer film.

In addition, since the electrode assembly for a secondary battery, a method for manufacturing the same, and a lithium secondary battery including the same according to an embodiment of the present invention are structured to form a pocketing positive electrode without using an insulating polymer film, the insulating polymer film is perforated or punched out. Processes such as can be omitted, thereby greatly improving productivity.

In addition, the electrode assembly for a secondary battery, a method of manufacturing the same, and a lithium secondary battery including the same according to an embodiment of the present invention form a positive electrode receiving portion for accommodating the upper or lower portion of the pocketing positive electrode on the contact surface of the negative electrode in contact with the pocketing positive electrode. Since it is one structure, it is possible to increase the contact cross-sectional area between the anode and the cathode by providing the anode receiving portion in a shape corresponding to the upper or lower portion of the pocketing anode and in a shape that is recessed or engraved on the contact surface of the cathode, thereby increasing the energy density and output. It can improve the performance of the battery.

In addition, the electrode assembly for a secondary battery according to an embodiment of the present invention, a method for manufacturing the same, and a lithium secondary battery including the same, in the manufacturing process of the negative electrode, by using an upper pressure roller and a lower pressure roller having a positive electrode receiving part pattern protrusion formed thereon. Since the anode receiving portion is formed in a concave or engraved shape on either side of both sides, the anode receiving portion of various shapes can be easily formed on the cathode through a simple method of changing the shape of the pattern protrusion of the anode receiving portion. It is possible to easily manufacture not only secondary batteries having a conventional rectangular structure, but also secondary batteries having different shapes such as triangles, pentagons, circles, ellipses, and the like.

In addition, the electrode assembly for a secondary battery, a method for manufacturing the same, and a lithium secondary battery including the same according to an embodiment of the present invention have a structure in which the upper and lower portions of the pocketing positive electrode are formed in the same shape, and the positive electrode receiving part is also formed in the same shape on the negative electrode. Therefore, when the pocketing anode and the cathode are stacked, the stacking direction of the cathode is removed, so that the pocketing anode and the cathode can be easily and quickly stacked.

In addition, the electrode assembly for a secondary battery according to an embodiment of the present invention, a method for manufacturing the same, and a lithium secondary battery including the same, when the pocketing positive electrode and the negative electrode are stacked, the upper and lower portions of the pocketing positive electrode are inserted into the positive electrode receiving part of the negative electrode in close contact. In addition to being accommodated in a shape that is accommodated, the edge portions of the separators formed at the edge of the pocketing anode are arranged in a shape that closely adheres to the edge of the cathode, so that when the pocketing anode and the cathode are stacked, the contact cross-sectional area between the anode and the cathode can be increased. Since the anode and the cathode form a structure completely separated by the separator, the risk of internal short circuit can also be eliminated, and stability can be secured when the pocketing anode and the cathode are stacked.

1 is a front view showing an electrode assembly according to an embodiment of the present invention.
2 is a front view showing an exploded state of the electrode assembly shown in FIG. 1.
3 is an exploded perspective view showing the electrode assembly shown in FIG. 1.
4 is a diagram showing a manufacturing process of the pocketing anode shown in FIG. 1.
5 is a view showing a manufacturing process of the single-sided cathode shown in FIG. 1.
6 is a diagram showing a manufacturing process of the double-sided cathode shown in FIG. 1.
7 is a plan view showing a double-sided cathode and an upper pressing roller shown in FIG. 6.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited or limited by the embodiments. The same reference numerals shown in each drawing indicate the same members.

1 is a front view showing an electrode assembly 100 according to an embodiment of the present invention, FIG. 2 is a front view showing an exploded state of the electrode assembly shown in FIG. 1, and FIG. 3 is an electrode assembly shown in FIG. It is an exploded perspective view showing 100. 4 is a view showing a manufacturing process of the pocketing anode 110 shown in FIG. 1, FIG. 5 is a view showing the manufacturing process of the cross-sectional cathode 122 shown in FIG. 1, and FIG. 6 is shown in FIG. It is a view showing the manufacturing process of the double-sided cathode 124, Figure 7 is a plan view showing the double-sided cathode 124 and the upper pressure roller 130 shown in FIG.

1 to 3, a lithium secondary battery (not shown) according to an embodiment of the present invention may include an electrode assembly 100 and a battery case (not shown).

The electrode assembly 100 is a configuration in which electricity is charged or discharged, and may be formed in a structure in which a negative electrode and a positive electrode are stacked to cross each other in the vertical direction. The electrode assembly 100 as described above may have a very thin thickness of 0.2 mm or less. In addition, the electrode assembly 100 is generally formed in a rectangular planar structure, but is not limited thereto and may be formed in a planar structure of various shapes. In particular, in the present embodiment, although it will be described in detail below, it may be very easy to form the electrode assembly 100 in a plane structure of a different shape such as a triangle, a pentagon, a circle, an ellipse, etc., and thereby, a lithium secondary battery is used as a release cell. It can be easily manufactured as a type.

The battery case may be provided in a shape surrounding the outside of the electrode assembly 100. That is, the electrolyte may be sealed and accommodated together with the electrode assembly 100 in the battery case.

Meanwhile, a separator constituting the electrode assembly 100, a positive electrode (a positive electrode current collector and a positive electrode active material), a negative electrode (a negative electrode current collector and a negative electrode active material), an electrolyte, and the like, are disclosed in Korean Patent No. 10-1168650 or Korean Patent No. 10. Since it is the same as that used in the electrode assembly and lithium secondary battery disclosed in -1168651, a detailed description thereof will be omitted.

Hereinafter, the technical characteristics of the electrode assembly 100 for a secondary battery according to an embodiment of the present invention will be described in more detail.

1 to 3, an electrode assembly 100 for a secondary battery according to an embodiment of the present invention includes a pocketing positive electrode 110 and negative electrodes 122 and 124.

In the electrode assembly 100 for a secondary battery according to the present embodiment, the pocketing anode 110 and the cathodes 122 and 124 may be vertically stacked in a shape that crosses each other. That is, the pocketing anode 110 may be disposed one by one between the plurality of cathodes 122 and 124.

The pocketing positive electrode 110 and the negative electrode 122 and 124 as described above may be manufactured by a separate manufacturing process and then used separately when the electrode assembly 100 is stacked. The pocketing anode 110 and the cathode 122 and 124 may be formed in the same plane shape and may be stacked in parallel with each other.

1 to 4, the pocketing anode 110 of the present embodiment may include an anode 112 and separators 114 and 116. That is, the pocketing anode 110 may be provided in a shape in which the anode 112 is pocketed by the separators 114 and 116. Accordingly, the anode 112 may be disposed in an encapsulation structure inside the separators 114 and 116.

The positive electrode 112 may include a positive electrode current collector 112a, a positive electrode active material 112b, and a positive electrode uncoated portion 112c. The positive electrode active material 112b may be applied to both surfaces of the positive electrode current collector 112a. The positive electrode uncoated portion 112c may be formed to have a long shape in which the positive electrode active material 112b is not applied. One end of the positive electrode uncoated portion 112c may be connected to the positive electrode current collector 112a, and the other end of the positive electrode uncoated portion 112c is an edge portion 118 of the first separator 114 and the second separator 116 to be described later. ) It can be arranged in a shape passing through.

The separators 114 and 116 may include a first separator 114 and a second separator 116. The first separator 114 may be formed to have a larger area than the anode 112, and may be provided on the upper surface of the anode 112 so that the anode 112 is positioned at the center. The second separator 116 may be formed in the same shape as the first separator 114, and may be provided on the lower surface of the anode 112 so as to be disposed to correspond to the first separator 114.

Here, by bonding the edge portion 118 of the first separator 114 and the second separator 116 to each other, the anode 112 is encapsulated by the first separator 114 and the second separator 116. It can be pocketed. The rim portion 118 of the first and second separators 114 and 116 as described above corresponds to a portion of the first and second separators 114 and 116 where the anode 112 is not located. The edge portion 118 of the first separator 114 and the second separator 116 may be directly bonded to each other by heating, or may be heat bonded while an adhesive is applied to the contact surface of the edge portion 118.

For example, the edge portion 118 of the first separator 114 and the second separator 116 may be bonded by directly heating the edge portion 118 using a heat-sealing method without using a separate adhesive. Alternatively, the edge portion 118 of the first separator 114 and the second separator 116 is coated with a polymer adhesive on the contact surface of the edge portion 118, and then heated the polymer adhesive in a thermal fusion method to form the edge portion 118. ) Can be bonded.

On the other hand, the upper portion (110a) and the lower portion (110b) of the pocketing anode (110) is a portion that is inserted and received in the anode receiving portion 126 of the cathode (122, 124) to be described later, the first separator 114 and the first 2 It may be formed to protrude symmetrically to each other in the same shape on the upper side and the lower side with respect to the edge portion 118 of the separator 116. The upper portion 110a of the pocketing anode 110 is formed of a first separator 114 covering the upper portion of the anode 112 and the upper portion of the anode 112, and the lower portion 110b of the pocketing anode 110 is an anode. It is formed of a second separator 116 covering the lower portion of 112 and the lower portion of the anode 112.

When the upper portion 110a and the lower portion 110b of the pocketing anode 110 are formed in the same shape as described above, the anode receiving portion 126 in which the upper portion 110a or the lower portion 110b of the pocketing anode 110 is accommodated. ) May also be formed in the same shape on the cathodes 122 and 124. For example, in this embodiment, the upper (110a) or lower (110b) of the pocketing anode (110) may be formed to be half the size of the pocketing anode (110), the anode receiving portion of the cathode (122, 124) 126 may also be formed in a single shape in which the upper portion 110a or the lower portion 110b of the pocketing anode 110 is accommodated.

1 to 3, 5, and 6, the cathodes 122 and 124 of this embodiment are arranged to be stacked on at least one of the upper (110a) or lower (110b) of the pocketing anode (110). Can be. On the contact surfaces of the cathodes 122 and 124 in contact with the pocketing anode 110 as described above, the anode receiving portion 126 accommodating the upper portion 110a or the lower portion 110b of the pocketing anode 110 is recessed or It can be provided in an engraved shape.

When the pocketing anode 110 and the cathodes 122 and 124 are stacked in the anode receiving portion 126, the upper portion 110a or the lower portion 110b of the pocketing anode 110 may be inserted and accommodated. Since the upper portion 110a and the lower portion 110b of the pocketing anode 110 as described above are formed in the same shape, at least one anode receiving portion 126 provided in the cathodes 122 and 124 may also be formed in the same shape. have. The anode receiving portion 126 may be formed only on one side of the cathodes 122 and 124, or may be formed on both sides of the cathodes 122 and 124, respectively.

For example, as the cathodes 122 and 124, a single-sided cathode 122 or a double-sided cathode 124 may be used depending on the stacking position and stacking conditions.

As shown in FIGS. 1 to 3 and 5, the cross-sectional cathode 122 may be disposed in a shape that is stacked on only one of the upper portion 110a or the lower portion 110b of the pocketing anode 110. The anode receiving portion 126 may be formed only on one side of the cross-sectional cathode 122. The cross-sectional cathode 122 as described above may be disposed on the uppermost layer and the lowermost layer of the electrode assembly 100. In this case, the cross-sectional negative electrode 122 may be disposed on the uppermost layer and the lowermost layer of the electrode assembly 100 in a shape exposing the negative electrode current collector 112a to the upper side of the uppermost layer or the lower side of the lowermost layer.

For example, the single-sided negative electrode 122 may include a first negative electrode current collector 122a, a first negative electrode active material 122b, and a first negative electrode uncoated part 122c.

Here, the first negative active material 122b may be applied to one surface of the first negative current collector 122a. In this case, the positive electrode accommodating part 126 may be provided in a shape that is recessed or engraved in the central portion of the first negative active material 122b applied to one surface of the first negative current collector 122a.

In addition, the first negative electrode uncoated portion 122c may be formed to have a long shape in which the first negative electrode active material 122b is not applied. One end of the first negative electrode uncoated portion 122c may be connected to one side of the first negative electrode current collector 122a, and the other end of the first negative electrode uncoated portion 122c is exposed to the outside of the first electrode assembly 100. It can be arranged in shape.

As shown in FIGS. 1 to 3, 6, and 7, the double-sided cathode 124 may be disposed in a shape that is simultaneously stacked on the upper portion 110a and the lower portion 110b of the pocketing anode 110. The anode receiving portions 126 may be formed on both sides of the double-sided cathode 124, respectively. The double-sided cathode 124 as described above may be disposed in an intermediate layer positioned between the uppermost layer and the lowermost layer of the electrode assembly 100. That is, the double-sided cathode 124 may be stacked in a structure disposed between the pocketing anodes 110, respectively.

For example, the double-sided negative electrode 124 may include a second negative electrode current collector 124a, a second negative electrode active material 124b, and a second negative electrode uncoated part 124c.

Here, the second negative active material 124b may be applied to both surfaces of the second negative current collector 124a, respectively. At this time, the positive electrode accommodating part 126 may be provided in a shape recessed or engraved in the central portion of the second negative active material 124b applied to both sides of the second negative current collector 124a, and in particular, the second negative electrode It may be formed to be symmetrical to each other along the vertical direction with respect to the current collector 124a. Meanwhile, the second negative electrode current collector 124a may be formed of the same structure and material as the first negative electrode current collector 122a, and the second negative electrode active material 124b is also formed of the same composition as the first negative electrode active material 122b. Can be.

In addition, the second negative electrode uncoated portion 124c may be formed to have a long shape in which the second negative electrode active material 124b is not applied. One end of the second negative electrode uncoated portion 124c may be connected to the second negative electrode current collector 124a, and the other end of the second negative electrode uncoated portion 124c is exposed to the outside of the first electrode assembly 100. Can be placed. Meanwhile, the second negative electrode uncoated portion 124c may be disposed at a position opposite to the first negative electrode uncoated portion 122c so as not to contact the first negative electrode uncoated portion 122c.

1 to 3, in this embodiment, the pocketing anode 110 is disposed between the single-sided cathode 122, or between the single-sided cathode 122 and the double-sided cathode 124, Alternatively, it may be disposed between the double-sided cathodes 124. At this time, the anode 112 of the pocketing anode 110 may be formed in a smaller area than the separators 114 and 116 and may be disposed in the center of the separators 114 and 116, and the single-sided cathode 122 and the double-sided cathode 124 ) May be formed to have the same size as the area of the separation membranes 114 and 116 and may be stacked in parallel at the same location corresponding to the separation membranes 114 and 116.

Here, the anode receiving portion 126 may be disposed in the central portion of the single-sided cathode 122 or the double-sided cathode 124. Accordingly, the edge portion of the single-sided cathode 122 or the double-sided cathode 124 may be disposed at a relatively protruding position compared to the anode receiving portion 126. The edge portion of the single-sided cathode 122 or the double-sided cathode 124 as described above, when the pocketing anode 110 and the cathodes 122 and 124 are stacked, the edge portion of the first separator 114 and the second separator 116 It can be placed in close contact with the 118.

Specifically, the upper (110a) or lower (110b) of the pocketing anode (110) may be formed to protrude to each other in the same shape, and the anode receiving portion (126) is the upper (110a) of the pocketing anode (110) Alternatively, it may be formed in a shape corresponding to the lower portion 110b. Accordingly, the edge portion of the single-sided cathode 122 or the double-sided cathode 124 is a step formed between the edge portions 118 of the separators 114 and 116 in the upper portion 110a or lower portion 110b of the pocketing anode 110 It can be formed to a height corresponding to.

As shown in FIGS. 5 to 7, the positive electrode receiving portion 126 of the present embodiment includes the upper pressing roller 130 and the lower pressing roller 132 when the single-sided cathode 122 or the double-sided cathode 124 is manufactured. It may be formed on the first negative active material 122b of the single-sided negative electrode 122 and the second negative active material 124b of the double-sided negative electrode 124. The upper pressure roller 130 and the lower pressure roller 132 may be disposed to be spaced apart from each other in the vertical direction, and the single-sided cathode 122 or the double-sided cathode 124 is an upper pressure roller (roll-to-roll). 130) and the lower pressure roller 132 may be supplied between.

On the other hand, on the outer circumferential surface of at least one of the upper pressing roller 130 or the lower pressing roller 132, the anode receiving part pattern protrusion in a pattern shape corresponding to the upper (110a) or lower (110b) of the pocketing anode (110) ( 130a and 132a) may be provided to protrude. Therefore, when the first negative electrode active material 122b or the second negative electrode active material 124b is pressed by the upper pressure roller 130 and the lower pressure roller 132, the positive electrode receiving portion 126 is a positive electrode receiving portion pattern protrusion. It may be formed in the first negative active material 122b present on one surface of the single-sided negative electrode 122 or the second negative active material 124b present on both surfaces of the double-sided negative electrode 124 by (130a, 132a).

The positive electrode receiving part 126 as described above may be determined according to the shape of the positive electrode receiving part pattern protrusions 130a and 132a provided on the upper pressing roller 130 or the lower pressing roller 132. Accordingly, by changing the shape of the positive electrode receiving portion pattern protrusions 130a and 132a, secondary batteries having various shapes can be easily manufactured. For example, the anode-receiving part pattern protrusions 130a and 132a may be formed in any one of polygonal, circular, or deformed shape.

A method of manufacturing the electrode assembly 100 according to an embodiment of the present invention configured as described above is as follows.

4 to 7, a method of manufacturing an electrode assembly 100 according to an embodiment of the present invention includes preparing the separators 114 and 116 to have a desired size (refer to FIG. 4), and the separator ( Preparing the anode 112 formed in an area smaller than 114 and 116 (see FIG. 4), after disposing the separators 114 and 116 on both sides of the anode 112, respectively, the edges of the separators 114 and 116 Forming the pocketing anode 110 by heat bonding 118 (refer to FIG. 4), preparing the cathodes 122 and 124 with the same area as the separators 114 and 116 (FIG. 5A ) And Figure 6 (a)), the anode receiving portion 126 for accommodating the upper (110a) or lower (110b) of the pocketing anode 110 is at least one of both sides of the cathode (122, 124) Forming on the surface (see FIGS. 5(b), 6(b), and 7), and laminating the pocketing anode 110 and the cathodes 122 and 124 (see FIGS. 1 to 3 ).

In the step of preparing the separation membranes 114 and 116 (refer to FIG. 4), the separation membranes 114 and 116 are provided in a long strip shape having a predetermined width. The separators 114 and 116 as described above are supplied in a roll-to-roll method when the pocketing anode 110 is manufactured.

In the step of preparing the anode 112 (refer to FIG. 4 ), an anode 112 formed to have a size smaller than that of the separators 114 and 116 is provided. As an example, in the manufacturing method of the positive electrode 112, a positive electrode current collector 112a formed in a long strip shape is supplied in a roll-to-roll manner, while a positive electrode active material 112b is applied to both surfaces of the positive electrode current collector 112a, and the positive electrode collector The entire 112a and the positive electrode active material 112b are cut or punched into an appropriate shape to manufacture a plurality of positive electrodes 112 in a desired shape and size. Hereinafter, in the present embodiment, it will be described that the anode 112 is manufactured in a rectangular planar structure.

In the step of forming the pocketing anode 110 (see FIG. 4), the separation membranes 114 and 116 are respectively disposed on both sides of the anode 112 (see FIG. 4(b)), and in that state, the separation membrane 114 , 116) of the edge portions 118 are heated and bonded to prepare a pocketing anode 110 (see Fig. 4(c)).

As shown in FIG. 4, in the forming of the pocketing anode 110, the anode 112 is provided on the upper surface of the second separation membrane 116 at regular intervals while supplying the second separation membrane 116 in a roll-to-roll manner. Arranging a plurality (see Fig. 4(a)), by supplying the first separator 114 in a roll-to-roll manner to provide the first separator 114 on the upper surface of the second separator 116 on which the anodes 112 are disposed. (See FIG. 4(b)), by pressing and heating the first separator 114 and the second separator 116, the first separator 114 and the second separator ( 116) bonding the contact portion (refer to FIG. 4(c)), and cutting or punching the adhesive portion between the first separator 114 and the second separator 116 so that the anode 112 becomes the first separator 114 ) And obtaining the pocketing anode 110 in a shape disposed at the center of the second separator 116 (see FIG. 4C ).

Accordingly, the anode 112 is provided in an encapsulation shape surrounded by the first and second separators 114 and 116 at the centers of the first and second separators 114 and 116. At this time, the first separator 114 and the second separator 116 adhere the edge portion 118 to pocket the anode 112 in a sealed shape. The first separator 114 and the second separator 116 are bonded to each other by means of a heat-sealing method of heating and pressing, and the rim portion 118 is formed in a ring shape surrounding the anode 112.

In the step of preparing the cathodes 122 and 124 (refer to FIGS. 5A and 6A ), the cathodes are formed in the same area as the separators 114 and 116.

As an example, in the manufacturing method of the negative electrode used for the single-sided negative electrode 122, the first negative electrode current collector 122a formed in the same long strip shape as the separators 114 and 116 is supplied in a roll-to-roll manner, and the first negative electrode active material (122b) is applied to one surface of the first negative electrode current collector 122a to prepare a negative electrode used for manufacturing the single-sided negative electrode 122 (see FIG. 5(a)).

Alternatively, in the method of manufacturing the negative electrode used in the positive negative electrode 122 and 124, the second negative electrode current collector 124a formed in the same long strip shape as the separators 114 and 116 is supplied in a roll-to-roll manner, and the second negative electrode The active material 124b is coated on both sides of the second negative electrode current collector 124a to prepare a negative electrode used for manufacturing the double-sided negative electrode 124 (see FIG. 6(a)).

In the step of forming the anode accommodating portion 126 (see FIGS. 5B, 6B, and 7), the anode accommodating portion 126 is replaced with at least one of both sides of the cathodes 122 and 124. Formed on the surface, and then the cathodes 122 and 124 are cut or punched into an appropriate shape. The anode receiving portion 126 is formed in a shape to accommodate the upper (110a) or lower (110b) of the pocketing anode 110, and the cathodes 122 and 124 have a rectangular planar structure like the pocketing anode 110 Cut or punched with.

As shown in FIGS. 5 to 7, the step of forming the anode receiving portion 126 (see FIGS. 5(b), 6(b), and 7) is to roll the cathodes 122 and 124. A step of supplying between the upper pressing roller 130 and the lower pressing roller 132 in a lu-roll method to press both sides of the cathodes 122 and 124 with the upper pressing roller 130 and the lower pressing roller 132 (FIG. 5 (B), see FIGS. 6(b) and 7), the cathode by the anode receiving portion pattern protrusions 130a and 132a formed on the outer circumferential surface of any one of the upper pressure roller 130 or the lower pressure roller 132 Forming the anode receiving portion 126 to be spaced apart at regular intervals on only one side of (122, 124), and then cutting or punching based on the anode receiving portion 126 to form the single-sided cathode 122 (( b)), and the anode receiving portion 126 on both sides of the cathode 122 and 124 by the anode receiving portion pattern protrusions 130a and 132a formed on the outer circumferential surfaces of the upper pressing roller 130 and the lower pressing roller 132 A step of forming the double-sided cathode 124 by cutting or punching with respect to the anode receiving portion 126 after forming them to be spaced apart at regular intervals (see FIGS. 6B and 7 ).

That is, in this embodiment, the first negative active material 122b or the second negative active material 124b of the negative electrodes 122 and 124 is pressed using the upper pressing roller 130 and the lower pressing roller 132, In the process, the positive electrode is accommodated in the negative electrode active materials 122a, 124a of the negative electrode 112, 124 using the positive electrode receiving part pattern protrusions 130a, 132a formed on at least one of the upper pressing roller 130 and the lower pressing roller 132 Form part 126.

Therefore, by simply changing the structure of forming the positive electrode receiving portion pattern protrusions 130a and 132a on the upper pressing roller 130 and the lower pressing roller 132, the anode receiving portion ( 126 can be formed easily, and the anode receiving portion 126 can be transformed into various shapes by changing the shape of the anode receiving portion pattern protrusions 130a and 132a. That is, in this embodiment, since the positive electrode receiving part 126 of various shapes is formed by changing the shape of the positive electrode receiving part pattern protrusions 130a and 132a, the lithium secondary battery is used according to the shape of the positive electrode receiving part 126. It can be manufactured in various shapes, and in particular, a lithium secondary battery can be conveniently formed in a release cell structure.

In the step of stacking the pocketing anode 110 and the cathodes 122 and 124 (see FIGS. 1 to 3 ), the pocketing anode 110 and the cathodes 122 and 124 are stacked upward while crossing each other. At this time, the single-sided cathode 122 is disposed on the uppermost layer and the lowermost layer of the electrode assembly 100, and the double-sided cathode 124 is disposed between the two pocketing anodes 110, respectively.

For example, if the number of pocketing anodes 110 is singular, the electrode assembly 100 is manufactured by stacking the pocketing anodes 110 in a structure arranged between the two cross-sectional cathodes 122. That is, the electrode assembly 100 is stacked in the order of'one-sided cathode 122 / pocketing positive electrode 110 / one-sided negative electrode 122'. At this time, the cross-sectional negative electrode 122 disposed on the lowermost layer and the uppermost layer of the electrode assembly 100 is stacked in opposite directions so that the first negative electrode current collector 122a is exposed to the outside.

In addition, if there are a plurality of pocketing anodes 110, a plurality of pocketing anodes 110 are arranged in a shape that is stacked between two single-sided cathodes 122, but the double-sided cathode 124 is provided with the pocketing anodes 110. The electrode assembly 100 is manufactured by stacking in a structure disposed therebetween. That is, assuming that there are three pocketing anodes 110, the electrode assembly 100 is'one-sided cathode 122 / pocketing anode 110 / double-sided cathode 124 / pocketing anode 110 / double-sided cathode (124) / pocketing anode 110 / single-sided cathode 122' are stacked in this order. At this time, the cross-sectional negative electrode 122 disposed on the lowermost layer and the uppermost layer of the electrode assembly 100 is stacked in opposite directions so that the first negative electrode current collector 122a is exposed to the outside.

As described above, the embodiments of the present invention have been described by specific matters such as specific components and limited embodiments and drawings, but these are provided only to help a more general understanding of the present invention, and the present invention is limited to the above embodiments. It is not, and a person having ordinary knowledge in the field to which the present invention pertains can make various modifications and variations from this description. Therefore, the spirit of the present invention is limited to the described embodiments and should not be determined, and all things that are equivalent or equivalent to the claims as well as the claims to be described later fall within the scope of the present invention. .

100: electrode assembly
110: pocketing anode
112: anode
114: first separation membrane
116: second separation membrane
118: edge portions of the first separator and the second separator
122: single-sided cathode
124: double-sided cathode
126: anode receiving portion
130: upper pressure roller
132: lower pressure roller

Claims (18)

Pocketing anode provided in a shape surrounded by the anode by the separator; And
And a negative electrode stacked on at least one of the upper or lower portions of the pocketing positive electrode and having an anode receiving portion for receiving the upper or lower part of the pocketing positive electrode formed in a shape that is recessed or engraved in a contact surface with the pocketing positive electrode; and,
The positive electrode receiving portion is provided in a shape in which the negative active material applied to the contact surface of the negative electrode is depressed or engraved to a preset depth,
The separator may include: a first separator formed in an area larger than that of the anode and provided on an upper surface of the anode such that the anode is positioned at a central portion; And a second separator formed in the same shape as the first separator and provided on a lower surface of the anode to be disposed to correspond to the first separator; and
In the pocketing anode, edge portions of the first separator and the second separator in which the anode is not positioned are adhered to each other so that the anode is pocketed by the first separator and the second separator,
The positive electrode receiving portion is disposed at the center of the contact surface of the negative electrode,
The edge portion of the contact surface of the negative electrode is disposed to be in close contact with the edge portion of the first separator and the second separator,
The edge portion of the cathode is formed to protrude to a predetermined height with respect to the central portion of the cathode, and the protrusion height of the cathode is a step formed between the edge portion of the first separator and the second separator above or below the pocketing anode. The electrode for a secondary battery, characterized in that the gap between the first separator and the second separator and the edge of the negative electrode is removed when the pocketing positive electrode and the negative electrode are stacked. Assembly.
delete delete The method of claim 1,
An electrode assembly for a secondary battery, characterized in that the edge portions of the first separator and the second separator are directly bonded to each other by heating or heat-bonded in a state in which an adhesive is applied to the contact surface of the edge portion.
The method of claim 1,
The upper and lower portions of the pocketing anode protrude symmetrically to each other in the same shape on the upper and lower sides with respect to the edge portions of the first and second separators,
The positive electrode receiving portion is an electrode assembly for a secondary battery, characterized in that the shape to accommodate the upper or lower portion of the pocketing positive electrode and provided in the same manner on at least one of both surfaces of the negative electrode.
delete The method of claim 1,
The anode,
Positive electrode current collector;
A positive electrode active material applied to both surfaces of the positive electrode current collector; And
Including; a positive electrode uncoated portion formed in a long shape in which the positive electrode active material is not applied,
One end of the positive electrode uncoated portion is connected to the positive electrode current collector, and the other end of the positive electrode uncoated portion is disposed in a shape penetrating between the first and second separators.
The method of claim 1,
The cathode may be a single-sided cathode or a double-sided cathode depending on the lamination position and lamination conditions,
The single-sided cathode is disposed to be stacked on only one of the upper or lower portions of the pocketing anode, and the anode receiving portion is formed only on one surface in contact with the pocketing anode,
The double-sided cathode is disposed to be stacked between the pocketing anodes, and the anode receiving portions are formed respectively on both sides of the pocketing anode and in contact with the pocketing anode.
The method of claim 8,
The pocketing anode and the cathode are stacked to cross each other,
The single-sided cathode is disposed in the top layer and the bottom layer, the double-sided cathode is disposed in an intermediate layer located between the top layer and the bottom layer,
The pocketing anode is an electrode assembly for a secondary battery, characterized in that disposed between the single-sided negative electrodes, the single-sided negative electrode and the double-sided negative electrode, or disposed between the double-sided negative electrodes.
The method of claim 8,
The single-sided cathode,
Negative electrode current collector;
A negative active material applied to one surface of the negative current collector; And
Including; a negative electrode uncoated portion formed in an elongated shape in which the negative active material is not applied, one end is connected to the negative electrode current collector, and the other end is disposed in a shape that is exposed to the outside,
The electrode assembly for a secondary battery, characterized in that the positive electrode receiving part is provided in a shape that is recessed or engraved in the negative active material applied to one surface of the negative electrode current collector.
The method of claim 8,
The double-sided cathode,
Negative electrode current collector;
An anode active material applied to both surfaces of the anode current collector, respectively; And
Including; a negative electrode uncoated portion formed in an elongated shape in which the negative active material is not applied, one end is connected to the negative electrode current collector, and the other end is disposed in a shape that is exposed to the outside,
The positive electrode accommodating part is provided in a shape that is recessed or engraved in the negative active material applied to both surfaces of the negative current collector, and is formed in a shape symmetrical to each other with respect to the negative current collector.
The method of claim 8,
The negative electrode active material of the single-sided negative electrode or the double-sided negative electrode is pressed by an upper pressure roller and a lower pressure roller spaced apart in the vertical direction,
On an outer circumferential surface of at least one of the upper pressing roller or the lower pressing roller, an anode receiving portion pattern protrusion is provided to protrude in a pattern shape corresponding to an upper or lower portion of the pocketing anode,
The positive electrode receiving part may correspond to the positive electrode receiving part pattern protrusion to the negative active material in the process of pressing the negative active material disposed on one side of the single-sided negative electrode or on both sides of the double-sided negative electrode by the upper pressing roller and the lower pressing roller. Electrode assembly for a secondary battery, characterized in that formed in a concave or intaglio shape.
The method of claim 12,
The shape of the positive electrode receiving part is determined according to the shape of the positive electrode receiving part pattern protrusion provided on the upper pressing roller or the lower pressing roller,
The positive electrode receiving portion pattern protrusion is an electrode assembly for a secondary battery, characterized in that formed in any one of polygonal, circular, or deformed shape.
The electrode assembly according to any one of claims 1, 4, 5, and 7 to 13; And
A battery case provided in a shape surrounding the outside of the electrode assembly and in which an electrolyte is sealed and accommodated together with the electrode assembly;
Lithium secondary battery comprising a.
In the manufacturing method of the electrode assembly according to any one of claims 1, 4, 5, 7 to 13,
Preparing the separation membrane in an area of a desired size;
Preparing an anode formed with an area smaller than that of the separator;
Forming a pocketing anode by disposing the separators on both sides of the anode and then heat-adhering the edges of the separators;
Preparing a negative electrode with the same area as the separator;
Forming an anode receiving portion for accommodating an upper or lower portion of the pocketing anode on at least one of both surfaces of the cathode; And
Stacking the pocketing anode and the cathode;
Method of manufacturing an electrode assembly comprising a.
The method of claim 15,
The separator may include: a first separator formed in an area larger than that of the anode and provided on an upper surface of the anode such that the anode is positioned at a central portion; And a second separator formed in the same shape as the first separator and provided on a lower surface of the anode so as to be disposed to correspond to the first separator,
The step of forming the pocketing anode,
Disposing a plurality of the anodes at regular intervals on the upper surface of the second separator while supplying the second separator in a roll-to-roll manner;
Supplying the first separator in a roll-to-roll manner to cover the first separator on an upper surface of the second separator on which the anodes are disposed;
Bonding the contact portions of the first separator and the second separator to which the anodes are not located by pressing and heating the first separator and the second separator; And
Cutting or punching the adhesive portion between the first separator and the second separator to obtain the pocketing anode in a shape in which the anode is positioned at the center of the first separator and the second separator;
Method of manufacturing an electrode assembly comprising a.
The method of claim 15,
The cathode may be a single-sided cathode or a double-sided cathode depending on the stacking position,
The single-sided cathode is disposed to be stacked on only one of the upper or lower portions of the pocketing anode, and the anode receiving portion is formed only on one surface in contact with the pocketing anode,
The double-sided cathode is disposed to be stacked between the pocketing anodes, and the anode receiving portions are respectively formed on both sides in contact with the pocketing anode,
The step of forming the anode receiving portion,
Supplying the negative electrode between an upper pressing roller and a lower pressing roller in a roll-to-roll method to press both sides of the negative electrode with the upper pressing roller and the lower pressing roller;
The positive electrode receiving portion is formed on only one surface of the negative electrode by a positive electrode receiving portion pattern protrusion formed on the outer circumferential surface of either the upper pressing roller or the lower pressing roller, and then cut or punched based on the positive electrode receiving portion. Forming the single-sided cathode; And
The positive electrode receiving portions are formed at regular intervals on both sides of the negative electrode by a positive electrode receiving portion pattern protrusion formed on the outer circumferential surface of the upper pressing roller and the lower pressing roller, and then cut or punched based on the positive electrode receiving portion to the double-sided negative electrode. Forming a;
Method of manufacturing an electrode assembly comprising a.
The method of claim 17,
In the step of laminating the pocketing positive electrode and the negative electrode, the pocketing positive electrode and the negative electrode are stacked in a shape that crosses each other,
The single-sided cathode is disposed in the top layer and the bottom layer, the pocketing anode is disposed at least in an intermediate layer between the top and bottom layers, and the double-sided cathode is disposed between a plurality of the pocketing anodes, respectively. Manufacturing method.

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