KR20180027872A - secondary battery - Google Patents

Abstract

A secondary battery is disclosed. The secondary battery comprises: a jelly-roll type electrode assembly wound in a first direction and comprising a first electrode plate, a second electrode plate, and a separator; a first electrode tab; a second electrode tab; and a case accommodating the electrode assembly, wherein the first electrode plate and the second electrode plate are opposed to each other with respect to a winding axis extending in one direction at a winding start portion of the electrode assembly, a first electrode active material is disposed on both surfaces of a first current collector, a second electrode active material is disposed on both sides of a second current collector, and the first electrode tab and the second electrode tab can be disposed on a winding completion portion of the electrode assembly. Embodiments of the present invention provide the secondary battery with maximized safety and battery capacity.

Description

Secondary battery

The present invention relates to a secondary battery.

Generally, a secondary battery is a battery capable of charging and discharging, unlike a primary battery which can not be charged. The secondary battery can be used as an energy source for mobile devices, electric vehicles, hybrid vehicles, electric bicycles, and uninterruptible power supplies. The secondary battery may be used in the form of a single battery depending on the type of external device to be applied, or in the form of a battery module assembled in one unit by electrically connecting a plurality of batteries.

The secondary battery includes an electrode assembly as a power generation element. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate. The internal flatness of the electrode assembly may be important. At this time, when electrode tabs are disposed inside the electrode assembly, steps may occur due to the thickness of the electrode tabs. Accordingly, the inner flatness of the electrode assembly may be deteriorated, and as a result, the performance of the secondary battery may be poor.

On the other hand, the secondary battery needs to design an electrode assembly capable of maximizing the capacity of the battery.

Embodiments of the present invention provide a secondary battery with maximized safety and battery capacity.

A secondary battery according to an aspect of the present invention includes a first electrode plate having a first current collector and a first electrode active material disposed on at least one surface of the first current collector, A second electrode plate having a second electrode active material disposed on at least one side of the first electrode plate and the separator interposed between the first electrode plate and the second electrode plate, A first electrode tab electrically connected to the first electrode plate, a second electrode tab electrically connected to the second electrode plate, and a case accommodating the electrode assembly, The first electrode plate and the second electrode plate are opposed to each other with respect to a winding axis extending in one direction, the first electrode active material is disposed on both surfaces of the first current collector, On both sides, The first electrode tab and the second electrode tab may be disposed at the winding completion portion of the electrode assembly.

In one embodiment, the winding start portion of the electrode assembly may be wound around the second electrode plate and spaced apart from the second electrode plate, and may correspond to the innermost layer of the electrode assembly.

In one embodiment, the winding start portion of the electrode assembly is wound in the first direction from the region where the second electrode plate turns at least a half in the first direction and the region where the second electrode plate is turned by 1/2 turn .

In one embodiment, the first electrode plate and the second electrode plate are both wound in a first direction, and the tip of the second electrode plate disposed at the winding start portion of the electrode assembly is provided with a plurality of And an extension corresponding to the curved portion of the second electrode plate may be disposed.

In one embodiment, the extension portion is provided with a second electrode active material on a corresponding surface of a second current collector facing the first electrode plate, and a second electrode active material is disposed on a corresponding surface of the second current collector opposite to the first surface The second electrode active material may not be disposed.

In one embodiment, the first electrode tab and the second electrode tab are disposed on the winding completion portion of the electrode assembly, and may correspond to the outermost layer of the electrode assembly.

In one embodiment, the first electrode plate includes a first region in which a first electrode active material is disposed on both surfaces of a first current collector, and a second region in which the first electrode active material is not disposed on both surfaces of the first current collector, Wherein the second electrode plate includes a third region in which the second electrode active material is disposed on both sides of the second current collector, and a second region in which the second electrode active material is disposed on one side of the second current collector, A fourth region where the second electrode active material is disposed and a fifth region where the second electrode active material is not disposed on both surfaces of the second current collector and the second electrode tab is disposed.

In one embodiment, the first region and the third region may be located at the winding start of the electrode assembly.

In one embodiment, an extension corresponding to the curved portion of the second electrode plate may extend from the tip of the second electrode plate disposed at the winding start portion of the electrode assembly in a second direction opposite to the first direction.

In one embodiment, the extending portion includes a fourth region, a second electrode active material is disposed on a corresponding surface of a second current collector facing the first electrode plate, and a second electrode active material opposite to the first surface, The second electrode active material may not be disposed on the corresponding surface of the current collector.

In one embodiment, the first region, the third region, the fourth region, and the fifth region are positioned between the winding start portion and the winding completion portion of the electrode assembly, The second electrode active material may be disposed on the corresponding surface of the second current collector facing the first electrode plate and the second electrode active material may not be disposed on the corresponding surface of the second current collector not facing the first electrode plate.

In one embodiment, the second region and the fifth region may be located at the winding completion portion of the electrode assembly.

In one embodiment, the first region and the second region may be continuously arranged in the longitudinal direction of the first electrode plate.

In one embodiment, the third region, the fourth region, and the fifth region may be continuously arranged in the longitudinal direction of the second electrode plate.

In one embodiment, a first protective tape may be attached to both sides of the first electrode plate connected to the first region connected to the second region and covering the first electrode active material. .

In one embodiment, a second protective tape may be attached to at least one surface of the first current collector to which the first electrode tab is attached.

In one embodiment, a third protective tape may be attached to at least one surface of the second current collector to which the second electrode tab is attached.

In one embodiment, a seal tape may be attached to an outer surface of the electrode assembly.

In one embodiment, the first electrode plate includes a positive electrode plate, and the second electrode plate includes a negative electrode plate.

In one embodiment, the electrode assembly includes a planar portion in which the first electrode plate, the second electrode plate, and the separator are arranged in a flat plane, and a planar portion in which the first electrode plate, the second electrode plate, Wherein the flat portion and the curved portion are arranged alternately and can be continuously arranged in a winding direction.

Since the secondary battery according to an aspect of the present invention has the curved surface portion extending from the tip of the one electrode plate disposed at the beginning of the electrode when the electrode active material having a different polarity faces the innermost layer of the electrode assembly, Can be increased. Further, since the electrode tabs are disposed in the outermost layer of the electrode assembly, the inner flatness of the electrode assembly can be improved.

It is needless to say that the effects of the present invention can be derived from the following description with reference to the drawings in addition to the above-mentioned contents.

1 is a perspective view illustrating a secondary battery according to an embodiment of the present invention.
FIG. 2 is a perspective view illustrating the secondary battery of FIG. 1; FIG.
Figure 3 is a cross-sectional view of the electrode assembly of Figure 1;
4A is an exploded perspective view of the electrode assembly of FIG.
4B is a cross-sectional view illustrating the first electrode plate, the second electrode plate, and the separator of FIG. 4A in an unfolded state.
FIG. 5A is an exploded perspective view showing a part between the winding start portion and the winding completion portion of the electrode assembly of FIG. 3; FIG.
5B is a cross-sectional view of the first electrode plate, the second electrode plate, and the separator of FIG. 5A in an unfolded state.
FIG. 6A is an exploded perspective view showing the winding completed portion of the electrode assembly of FIG. 3 partially cut away. FIG.
FIG. 6B is a cross-sectional view showing a state in which the first electrode plate, the second electrode plate, and the separator of FIG. 6A are unfolded.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and particular embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, Should not be construed to preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a secondary battery according to the present invention will be described in detail with reference to the accompanying drawings. Referring to the accompanying drawings, the same or corresponding components are denoted by the same reference numerals, A description thereof will be omitted.

FIG. 1 is a perspective view illustrating a secondary battery 100 according to an embodiment of the present invention, and FIG. 2 is a perspective view illustrating the secondary battery 100 of FIG. 1 in a separated state.

1 and 2, the secondary battery 100 includes an electrode assembly 200, a can 300 that houses the electrode assembly 200, and a cap assembly 400 coupled to the can 300. .

The electrode assembly 200 includes a first electrode plate 210, a second electrode plate 230, and a separator 250 interposed between the first electrode plate 210 and the second electrode plate 230 do. In one embodiment, the first electrode plate 210 may be a positive plate and the second electrode plate 230 may be a negative plate or vice versa. The electrode assembly 200 may be wound in a jelly-roll type.

A first electrode tab 260 may be electrically connected to the first electrode plate 210 and a second electrode tab 270 may be electrically connected to the second electrode plate 230. A seal tape 280 may be attached to the outer surface of the electrode assembly 200. The seal tape 280 serves to protect the electrode assembly 200 in the can 300 by preventing the electrode assembly 200 from being unwound.

The electrode assembly 200 may be received within the can 300. The can 300 may be formed of a conductive metal material such as aluminum or an alloy including aluminum. A cap assembly 400 may be installed on the can 300. The opening OP of the can 300 may be sealed by the cap assembly 400.

In the present embodiment, the case where the electrode assembly 200 is accommodated in the square can 300 will be described as an example. However, the present invention is not limited to any case as long as the case accommodates the electrode assembly 200. For example, the electrode assembly 200 may be housed in a pouch-type case.

The cap assembly 400 includes a cap plate 401, an electrode terminal 402, a gasket 403, an insulation plate 404, a terminal plate 405, and an insulation case 406.

The cap plate 401 may be coupled to the can 300 to seal the opening OP of the can 300. The portion where the can 300 contacts the cap plate 401 may be joined to a welding process such as laser welding. The can 300 and the cap plate 401 may have the same polarity. In this embodiment, the can 300 and the cap plate 401 may be of positive polarity.

A first hole 407 and an electrolyte injection hole 408 may be disposed in the cap plate 401. A gasket 403 may be inserted into the first hole 407. The electrolyte injection hole 408 may be filled with an electrolyte solution. The electrolyte injection hole 408 may be closed by a cap 409. The cap plate 40 may be formed of a conductive metal material such as aluminum or an alloy including aluminum.

The electrode terminal 402 passes through a gasket hole 410 formed in the gasket 403, a second hole 411 formed in the insulating plate 404 and a third hole 412 formed in the terminal plate 405 And the end of the electrode terminal 402 may be fixed to the bottom surface of the terminal plate 405. The electrode terminal 402 may be formed of a conductive metal material such as nickel or an alloy including nickel.

The gasket 403 is formed of an insulating material such as a polymer resin, and the cap plate 401 and the electrode terminal 402 can be insulated from each other. In one embodiment, the electrode terminal 402 may be a negative polarity.

The insulating plate 404 is located below the cap plate 401 and can isolate the cap plate 401 and the terminal plate 405 from each other. The insulating plate 404 may be formed of a polymer resin.

The terminal plate 405 may be formed of a conductive metal material such as nickel or an alloy including nickel.

The insulating case 406 may be mounted on the upper surface of the electrode assembly 200. A slit 413 may be formed in the insulating case 406. The second electrode tab 270 may be connected to the terminal plate 405 through the slit 413.

The first electrode tab 260 may be directly connected to the can 300 or the cap plate 401.

The first electrode plate 210, the first electrode tab 260, the can 300, and the cap plate 401 are electrically connected to each other to form a positive electrode path. The second electrode plate 230, The second electrode tab 270, the electrode terminal 402, and the terminal plate 405 may be electrically connected to each other to form a cathode path.

3 is a cross-sectional view of the electrode assembly 200 of FIG.

The electrode assembly 200 includes a first electrode plate 210, a second electrode plate 230, and a separator 230 interposed between the first electrode plate 210 and the second electrode plate 230. (250).

The first electrode plate 210 includes a first current collector 211 and a first electrode active material 212 disposed on at least one surface of the first current collector 211. In one embodiment, the first electrode plate 210 may be a positive electrode plate.

The first current collector 211 may be a conductive metal thin plate such as aluminum. The first electrode active material 211 may include a lithium-based oxide as a main component. The first electrode active material 211 may include a first active material 213 disposed on one surface of the first current collector 211 and a second active material 213 disposed on the other surface of the first current collector 211. In this embodiment, 2 active material 214 as shown in FIG.

The first electrode plate 210 includes a first region 1A in which the first electrode active material 212 is disposed on both surfaces of the first current collector 211 and a first region 211 in which the first current collector 211 is formed, And a second region 2A on which the first electrode active material 212 is not disposed. In one embodiment, the second region 2A may be a positive uncoated area. The first region 1A and the second region 2A may be continuously arranged in the longitudinal direction of the first electrode plate 210. [

The first electrode tab 260 may be disposed in the second region 2A. The first electrode tab 260 may be a conductive metal thin plate such as nickel, copper, and aluminum. The first electrode tab 260 may be integrally formed with the first current collector 211 or may be attached to the first current collector 211 using a separate metal plate. The first electrode tab 260 may protrude from the upper portion of the electrode assembly 200.

The second electrode plate 230 includes a second current collector 231 and a second electrode active material 232 disposed on at least one side of the second current collector 231. In one embodiment, the second electrode plate 230 may be a negative electrode plate.

The second current collector 231 may be a conductive metal thin plate such as copper. The second electrode active material 232 may include graphite as a main component. The second electrode active material 232 may include a third active material 233 disposed on one side of the second current collector 231 and a second active material 233 disposed on the other side of the second current collector 231. In this embodiment, 4 active material 234.

The second electrode plate 230 includes a third region 3A in which a second electrode active material 232 is disposed on both surfaces of the second current collector 231, A fourth region 4A in which the second electrode active material 232 is disposed and a fifth region 5A in which the second electrode active material 232 is not disposed on both sides of the second current collector 231. [ . In one embodiment, the fifth region 5A may be a negative uncoated area. The third region 3A, the fourth region 4A, and the fifth region 5A may be continuously arranged in the longitudinal direction of the second electrode plate 230.

A second electrode tab 270 may be disposed in the fifth region 5A. The second electrode tab 270 may be a conductive metal thin plate such as nickel, copper, and aluminum. The second electrode tab 270 may be integrally formed with the second current collector 231 or may be attached to the second current collector 231 using a separate metal plate. The second electrode tab 270 may protrude from the upper portion of the electrode assembly 200.

The separator 250 is interposed between the first electrode plate 210 and the second electrode plate 230 so that the first electrode plate 210 and the second electrode plate 230 can be insulated from each other. The electrode assembly 200 includes two sheets of separators 250 interposed between a first electrode plate 210 and a second electrode plate 230. However, no.

Micropores may be formed in the separator 250 and lithium ions moving between the first electrode plate 210 and the second electrode plate 230 may pass through the micropores. The separator 250 may be a composite film of polyethylene, polypropylene, or polyethylene and polypropylene.

The electrode assembly 200 may be disposed in the order of a separator 250, a second electrode plate 230, a separator 250 and a first electrode plate 210 and may be wound in a first direction have.

The electrode assembly 200 includes a planar portion PP having the first electrode plate 210, the second electrode plate 230, and the separator 250 arranged in a flat manner, The first electrode 210, the second electrode plate 230, and the separator 250 include a curved portion CP having a curvature. The plane portion PP and the curved portion CP are alternately arranged and can be continuously arranged in a winding direction. The cross-section of the electrode assembly 200 may be elliptical.

In one embodiment, the winding start portion WSP of the electrode assembly 200 is formed with a winding axis WA extending in the horizontal direction (X direction) 210 and the second electrode plate 230 may face each other.

In one embodiment, the first electrode tab 260 and the second electrode tab 270 may be disposed in a winding finish portion WFP of the electrode assembly 200.

3, 4A, and 4B, the winding start portion WSP of the electrode assembly 200 may correspond to the innermost layer of the electrode assembly 200 wound in the first direction have. The second electrode plate 230 may be wound on the winding start portion WSP. Thereafter, the first electrode plate 210 may be wound at an interval.

Specifically, the second electrode plate 230 turns at least once in the first direction on the winding start portion WSP, and the second electrode plate 230 turns from the region where the second electrode 230 turns 1/2, So that the first electrode 210 may be wound in the first direction. In one embodiment, if the second electrode plate 230 is first wound on the winding start portion WSP and the first electrode plate 210 is wound with a gap therebetween, no.

The first region 1A of the first electrode plate 210 and the third region 3A of the second electrode plate 230 may be positioned on the winding start portion WSP. That is, the first electrode active material 212 is disposed on both sides of the first current collector 211 and the second electrode active material 212 is disposed on both sides of the second current collector 231, 232 may be disposed.

The first electrode plate 210 and the second electrode plate 230 may undergo a cell reaction in a region where the first electrode active material 212 and the second electrode active material 232 face each other. The first surface 211a of the first current collector 211 and the first surface 211b of the second current collector 231 are formed on the winding start portion WSP with respect to the winding axis WA arranged in the horizontal direction The first surfaces 231a may be disposed facing each other. The first active material 213 is disposed on the first surface 211a of the first current collector 211 and the third active material 233 is disposed on the first surface 231a of the second current collector 231 .

Since the first active material 213 provided on the first electrode active material 212 and the third active material 233 provided on the second electrode active material 232 face the winding start portion WSP, A battery reaction may occur in the innermost layer of the assembly 200, and the inactive region may be activated.

In one embodiment, the extension 230e may be further disposed at a tip T of the second electrode plate 230 in a second direction opposite to the first direction (e.g., clockwise) . The extension 230e includes a fourth region 4A. As described above, in the electrode assembly 200, a battery reaction may occur in a region where the first electrode active material 212 and the second electrode active material 232 face each other.

However, at the tip T of the second electrode plate 230, the first electrode plate 210 and the second electrode plate 230 do not face each other. That is, in the absence of the extension 230e, only the first electrode plate 210 may be wound on the curved surface CP in the second direction from the tip T of the second electrode plate 230. FIG. Accordingly, during the cell reaction, lithium ions are concentrated at the tip end T of the second electrode plate 230, resulting in lithium precipitation.

An extended portion 230e of the second electrode plate 230 is wound on the tip T of the second electrode plate 230 in the second direction and corresponds to the curved portion CP of the second electrode plate 230, Can be disposed.

Specifically, the first electrode plate 210 and the second electrode plate 230 may be wound together in a first direction. A second current collector extension part 231e wound in a second direction opposite to the first direction may be extended to the tip 231c of the second current collector 231 disposed at the winding start point WSP. The second current collector extension part 231e may extend integrally from the tip end 231c of the second current collector 231. [ The length of the second current collector extension 231e may correspond to a length of the curved portion CP of the second electrode plate 230.

A fourth active material 234 may be disposed on the second surface 231b of the second current collector extension 231e facing the first electrode plate 210. [ On the other hand, the third active material 233 may not be disposed on the first surface 231a of the second current collector extension part 231e which is not opposed to the first electrode plate 210. That is, since the first surface 231a of the second current collector extension portion 231e faces the second current collector 231 having the same polarity, the first surface 231a of the second current collector extension portion 231e faces the second current collector 231, It is not necessary to form the third active material 233 on the first active material layer 231a.

The third active material 233 of the extended portion 230e extending from the tip T of the second electrode plate 230 is electrically connected to the first electrode plate 210 at the curved portion CP of the electrode assembly 200, The lithium ions do not precipitate at the tip T of the second electrode plate 230. As a result, Thus, short circuit of the electrode assembly 200 can be prevented.

Referring to FIGS. 3, 5A, and 5B, a first region 1A of the first electrode plate 210 and a second region 1A of the first electrode plate 210 are interposed between the winding start portion WSP of the electrode assembly 200 and the winding completion portion WFP. The third region 3A, the fourth region 4A, and the fifth region 5A of the second electrode plate 230 may be positioned.

The first region 1A may be positioned in a region connected to the winding start portion WSP of the first electrode plate 210. [ The first active material 213 is disposed on the first surface 211a of the first current collector 211 and the second active material 214 is disposed on the second surface 211b of the first current collector 211 . The first electrode active material 212 disposed on both sides 211a and 211b of the first current collector 211 may extend to a region connected to the winding completion portion WFP.

The third region 3A may be located in a region connected to the winding start portion WSP of the second electrode plate 230. The third active material 233 is disposed on the first surface 231a of the second current collector 231 and the fourth active material 234 is disposed on the second surface 231b of the second current collector 231 .

The fourth region 4A may be located in a region wound around the outermost portion of the electrode assembly 200. The second electrode active material 232 may be disposed on the second electrode plate 230 only on a surface facing the first electrode plate 210. The third active material 233 may be disposed on the first surface 231a of the second current collector 231 facing the first electrode plate 210. [ On the other hand, the second surface 231b of the second current collector 231 does not face the first electrode plate 210, and instead, the second surface 231b of the second current collector 231 The separator 250, and the seal tape 280, respectively. Therefore, the fourth active material 234 may not be disposed on the second surface 231b of the second current collector 231. [

The fourth region 4A of the electrode assembly 200 may be connected to the fifth region 5A. The second electrode active material 232 may not be disposed on both surfaces 231a and 231b of the second current collector 231 in the fifth region 5A. The fifth region 5A may extend to the winding completion portion WFP. In another embodiment, the fifth region 5A is omitted, and the fourth region 4A can be directly connected to the winding completion portion WFP.

Meanwhile, a first protective tape 291 may be disposed on both sides of the first electrode plate 210 connected to the winding completion portion WFP. The first electrode active material 232 disposed on both sides of the first electrode plate 210 may extend to a region connected to the winding completion portion WFP. On the other hand, the first electrode active material 212 may not be disposed on both sides of the first electrode plate 210 of the first rolled-up portion WFP.

The raw material for the first electrode active material 232 is coated on the both surfaces of the first electrode plate 210 connected to the wound finished portion WFP during the application process of the first electrode active material 232 using a spraying means such as a nozzle, May not be uniformly applied to the substrate. That is, in some areas of the first current collector 211, the first electrode active material 212 may be relatively thicker than other regions of the first current collector 211 due to the ejection pressure. Accordingly, a first protective tape 291 covering the non-uniformly coated first electrode active material 212 may be disposed on both sides of the first electrode plate 210 connected to the winding completion portion WFP.

Referring to FIGS. 3, 6A and 6B, the winding completion portion WFP of the electrode assembly 200 may correspond to an outermost layer of the electrode assembly 200 wound in the first direction have. The first electrode tab 260 and the second electrode tab 270 may be disposed in the winding completion portion WFP.

The second region 2A and the fifth region 5A may be disposed in the winding completion portion WFP. The second region 2A may be an uncoated region in which the first electrode active material 212 is not disposed on both sides of the first collector 211. The first electrode tab 260 may be disposed on the second surface 211b of the first current collector 211. [ The first electrode tab 260 may be attached to the first current collector 211 using a separate metal plate. In one embodiment, the one-electrode tab 260 may be integral with the first current collector 211.

A second protective tape 292 may be attached to at least one surface of the first current collector 211 to which the first electrode tab 260 is attached. The second protective tape 292 may have a first surface 211a opposite to the second surface 211b of the first current collector 211 on which the first electrode tab 260 is disposed, As shown in FIG. On the other hand, the second protective tape 292 may not be disposed on the second surface 211b of the first current collector 211 where the first electrode tab 260 is disposed. Since the second surface 211b of the first current collector 211 in which the first electrode tab 260 is disposed is a surface corresponding to the inner surface of the can (300 in FIG. 2) having the same polarity, The first electrode tab 292 may not be disposed on the second surface 211b of the first current collector 211 where the first electrode tab 260 is disposed.

The fifth region 5A may be an uncoated region in which the second electrode active material 232 (see FIG. 3) is not disposed on both surfaces of the second current collector 231. The fifth region 5A may be connected to the fourth region 4A of FIG. 5A. The second electrode tab 270 may be disposed on the second surface 231b of the second current collector 231. [ The second electrode tab 270 may be attached to the second current collector 231 using a separate metal plate. In another embodiment, the two-electrode tab 270 may be integral with the second current collector 231.

A third protective tape 293 may be attached to at least one surface of the second current collector 231 to which the second electrode tab 270 is attached. The third protective tape 293 is formed on the first surface 231a of the second current collector 233 and the second current collector 233 on which the second electrode tab 270 is disposed And may be disposed on the second surface 231b.

Since the first electrode tab 260 and the second electrode tab 270 are disposed in the winding completion portion WFP of the electrode assembly 200, The step of the electrode assembly 200 due to the electrode tab 260 and the second electrode tab 270 does not occur. As a result, the inner flatness of the electrode assembly 200 can be improved, and as a result, deformation of the secondary battery during charging and discharging can be prevented.

100 ... secondary battery 200 ... electrode assembly
210 ... first electrode plate 211 ... first current collector
212 ... First electrode active material 213 ... First active material
214 ... second active material 230 ... second electrode plate
230e ... Extension portion 231 ... Second Collector
231e ... second collector extension part 232 ... second electrode active material
233 ... third active material 234 ... fourth active material
250 ... separator 260 ... first electrode tab
270 ... second electrode tab 280 ... seal tape
300 ... can 400 ... cap assembly

Claims (20)

A first electrode plate having a first current collector and a first electrode active material disposed on at least one side of the first current collector, and a second electrode active material disposed on at least one side of the second current collector and the second current collector, A jelly-roll type electrode assembly including a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate, the electrode assembly being wound in a first direction;
A first electrode tab electrically connected to the first electrode plate;
A second electrode tab electrically connected to the second electrode plate; And
And a case for accommodating the electrode assembly,
Wherein the first electrode plate and the second electrode plate are opposed to each other with respect to a winding axis extending in one direction at the winding start portion of the electrode assembly, a first electrode active material is disposed on both surfaces of the first current collector, The second electrode active material is disposed on both sides of the collector,
Wherein the first electrode tab and the second electrode tab are disposed in the winding completion portion of the electrode assembly. The method according to claim 1,
Wherein the winding start portion of the electrode assembly is wound around the second electrode plate with a predetermined interval and the first electrode plate is wound at an interval to correspond to the innermost layer of the electrode assembly. 3. The method of claim 2,
Wherein the winding start portion of the electrode assembly turns at least a half turn of the second electrode plate in a first direction and the first electrode plate is wound in a first direction from a region where the second electrode plate turns 1/2 turn. 3. The method of claim 2,
The first electrode plate and the second electrode plate are wound together in the first direction,
Wherein an end of the second electrode plate is wound in a second direction opposite to the first direction, and an extension corresponding to the curved surface portion of the second electrode plate is disposed on the tip of the second electrode plate disposed at the winding start portion of the electrode assembly. 5. The method of claim 4,
The second electrode active material is disposed on the corresponding surface of the second current collector facing the first electrode plate and the second electrode active material is disposed on the corresponding surface of the second current collector opposite to the first surface, Non-deployed secondary battery. The method according to claim 1,
Wherein the first electrode tab and the second electrode tab are disposed in the winding completion portion of the electrode assembly and correspond to the outermost layer of the electrode assembly. The method according to claim 1,
Wherein the first electrode plate includes a first region in which a first electrode active material is disposed on both surfaces of a first current collector and a first region in which the first electrode active material is not disposed on both surfaces of the first current collector, And a second region,
The second electrode plate includes a third region in which the second electrode active material is disposed on both sides of the second current collector, a fourth region in which the second electrode active material is disposed on one surface of the second current collector, And a fifth region in which the second electrode active material is not disposed on both sides of the second current collector, and a second electrode tab is disposed. 8. The method of claim 7,
Wherein the first region and the third region are located at the winding start portion of the electrode assembly. 9. The method of claim 8,
And an extension corresponding to a curved portion of the second electrode plate is extended in a second direction opposite to the first direction on the tip of the second electrode plate disposed at the winding start portion of the electrode assembly. 10. The method of claim 9,
Wherein the extending portion includes a fourth region, a second electrode active material is disposed on a corresponding surface of the second current collector facing the first electrode plate, and a surface of the second current collector opposite to the first surface In which the second electrode active material is not disposed. 8. The method of claim 7,
Wherein the first region, the third region, the fourth region, and the fifth region are positioned between the winding start portion and the winding completion portion of the electrode assembly, and the fourth region is positioned between the first and second regions facing the first electrode plate, Wherein the second electrode active material is disposed on a corresponding surface of the first electrode plate and the second electrode active material is disposed on a corresponding surface of the second current collector not facing the first electrode plate. 8. The method of claim 7,
Wherein the second region and the fifth region are located in the winding completion portion of the electrode assembly. 8. The method of claim 7,
Wherein the first region and the second region are continuously arranged in the longitudinal direction of the first electrode plate. 8. The method of claim 7,
Wherein the third region, the fourth region, and the fifth region are continuously disposed in the longitudinal direction of the second electrode plate. 8. The method of claim 7,
And a first protective tape covering the first electrode active material is attached to both sides of the first electrode plate connected to the first end connected to the second region. The method according to claim 1,
And a second protective tape is attached to at least one surface of the first current collector to which the first electrode tab is attached. The method according to claim 1,
And a third protective tape is attached to at least one surface of the second current collector to which the second electrode tab is attached. The method according to claim 1,
And a seal tape is attached to an outer surface of the electrode assembly. The method according to claim 1,
Wherein the first electrode plate includes a positive electrode plate,
And the second electrode plate comprises a negative electrode plate. The method according to claim 1,
Wherein the electrode assembly includes a flat surface portion in which the first electrode plate, the second electrode plate, and a separator are arranged flatly, and a curved surface portion in which the first electrode plate, the second electrode plate, and the separator have a curvature, And the curved portions are alternately arranged, and are arranged continuously in the winding direction.

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