WO2018048095A1

WO2018048095A1 - Secondary battery

Info

Publication number: WO2018048095A1
Application number: PCT/KR2017/008084
Authority: WO
Inventors: 정강국
Original assignee: 삼성에스디아이주식회사
Priority date: 2016-09-07
Filing date: 2017-07-27
Publication date: 2018-03-15
Also published as: KR20180027872A; KR102256297B1

Abstract

A secondary battery is disclosed. The present invention comprises: a jelly-roll type electrode assembly, which includes a first electrode plate, a second electrode plate, and a separator, and is wound in a first direction; a first electrode tab; a second electrode tab; and a case for accommodating the electrode assembly, wherein the first electrode plate and the second electrode plate face each other with respect to a winding axis, which is extended in one direction, at a winding start part of the electrode assembly, a first electrode active material is arranged on both sides of a first current collector, a second electrode active material is arranged on both sides of a second current collector, and the first electrode tab and the second electrode tab can be arranged at a winding completion part of the electrode assembly.

Description

Secondary battery

The present invention relates to a secondary battery.

Typically, a secondary battery is a battery that can be charged and discharged, unlike a primary battery that is not rechargeable. Secondary batteries may be used as energy sources for mobile devices, electric vehicles, hybrid vehicles, electric bicycles, uninterruptible power supplies, and the like. The secondary battery may be used in the form of a single battery according to the type of external device applied, or may be used in the form of a battery module assembled by a unit by connecting a plurality of batteries electrically.

The secondary battery includes an electrode assembly that is 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 electrode flatness may be important for internal flatness. In this case, when the electrode tab is disposed inside the electrode assembly, a step may occur due to the thickness of the electrode tab. As a result, the internal flatness of the electrode assembly may decrease, and as a result, the performance of the secondary battery may not be good.

On the other hand, the secondary battery requires the design of an electrode assembly that can maximize the capacity of the battery.

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

An embodiment of the present invention provides 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, and a second current collector and at least one surface of the second current collector. A second electrode plate having a second electrode active material disposed thereon, and a separator interposed between the first electrode plate and the second electrode plate and 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 a case accommodating the electrode assembly; The first electrode plate and the second electrode plate face each other on the basis of the winding axis extending in one direction, the first electrode active material is disposed on both sides of the first current collector, the second electrode on both sides of the second current collector Electrode active material A secondary battery in which the first electrode tab and the second electrode tab are disposed may be disposed in the winding completion part of the electrode assembly.

In the secondary battery according to an aspect of the present invention, since the electrode active material having different polarities faces the innermost layer of the electrode assembly, and an extension portion extending from the tip of the one electrode plate disposed at the start of the electrode has a curved portion, battery capacity is increased. You can increase it. In addition, since the electrode tab is disposed on the outermost layer of the electrode assembly, internal flatness of the electrode assembly may be improved.

In addition to the above, the effects of the present invention can be derived from the following description with reference to the drawings.

1 is a perspective view illustrating a rechargeable battery according to an exemplary embodiment of the present invention.

FIG. 2 is a perspective view illustrating the secondary battery of FIG. 1 separated.

3 is a cross-sectional view of the electrode assembly of FIG. 1.

FIG. 4A is an exploded perspective view illustrating the cutting start of the electrode assembly of FIG. 3 partially cut away; FIG.

4B is a cross-sectional view illustrating an unfolded state of the first electrode plate, the second electrode plate, and the separator of FIG. 4A.

FIG. 5A is an exploded perspective view illustrating a partial cutting between a winding start part and a winding completion part of the electrode assembly of FIG. 3.

FIG. 5B is a cross-sectional view illustrating a state in which the first electrode plate, the second electrode plate, and the separator of FIG. 5A are unfolded.

6A is an exploded perspective view illustrating a partially cut-out winding portion of the electrode assembly of FIG. 3.

FIG. 6B is a cross-sectional view illustrating a state in which the first electrode plate, the second electrode plate, and the separator of FIG. 6A are unfolded.

A secondary battery according to an aspect of the present invention includes a first electrode plate including a first current collector and a first electrode active material disposed on at least one surface of the first current collector, a second current collector, and the second current collector. A second electrode plate having a second electrode active material disposed on at least one surface of the separator, and a separator interposed between the first electrode plate and the second electrode plate and wound in a first direction. And 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. At the start of winding, the first electrode plate and the second electrode plate face each other based on a winding axis extending in one direction, and a first electrode active material is disposed on both surfaces of the first current collector, Second electrode on both sides An active material may be disposed, and the first electrode tab and the second electrode tab may be disposed on the winding completion part of the electrode assembly.

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

In one embodiment, the winding start of the electrode assembly is the first electrode plate to be wound in the first direction from the area in which the second electrode plate is turned at least 1/2 turn in the first direction, the second electrode plate is turned 1/2. Can be.

In one embodiment, the first electrode plate and the second electrode plate are all wound in the first direction, and the tip of the second electrode plate disposed at the winding start of the electrode assembly is opposite to the first direction. An extension part wound in the second direction and corresponding to the curved portion of the second electrode plate may be disposed.

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

In example embodiments, the winding completion part of the electrode assembly may include the first electrode tab and the second electrode tab, and correspond to the outermost layer of the electrode assembly.

In example embodiments, the first electrode plate may include a first region in which a first electrode active material is disposed on both surfaces of a first current collector, and the first electrode active material is not disposed on both surfaces of the first current collector. And a second region in which a first electrode tab is disposed, wherein the second electrode plate includes a third region in which a second electrode active material is disposed on both surfaces of the second current collector, and the one side of the second current collector. And a fourth region in which the second electrode active material is disposed, and a fifth region in which 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 an embodiment, an extension part corresponding to the curved portion of the second electrode plate may extend in a second direction opposite to the first direction to the front end of the second electrode plate disposed at the winding start of the electrode assembly.

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

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, wherein the fourth region is the first electrode plate. The second electrode active material may be disposed on the corresponding surface of the second current collector facing the second electrode active material, 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 example embodiments, the second region and the fifth region may be located at a winding completion portion of the electrode assembly.

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

In example embodiments, the third region, the fourth region, and the fifth region may be continuously disposed in a length direction of the second electrode plate.

In an exemplary embodiment, a first protective tape covering the first electrode active material may be attached to both surfaces of the first electrode plate corresponding to the first area connected to the second area and connected to the winding completion part. .

In example embodiments, 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 comprises a positive electrode plate, the second electrode plate comprises a negative electrode plate.

In example embodiments, the electrode assembly may include a planar portion in which the first electrode plate, the second electrode plate, and the separator are disposed flat, and the curved surface of the first electrode plate, the second electrode plate, and the separator has a curvature. It includes a portion, the flat portion and the curved portion is arranged alternately, it can be disposed continuously in the winding direction.

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms “comprises” or “having” are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present disclosure does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, an embodiment of a secondary battery according to the present invention will be described in detail with reference to the accompanying drawings, and in the following description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals, The description will be omitted.

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

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

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 an 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.

The first electrode tab 260 may be electrically connected to the first electrode plate 210, and the second electrode tab 270 may be electrically connected to the second electrode plate 230. A seal tape 280 may be attached to an outer surface of the electrode assembly 200. The seal tape 280 prevents the electrode assembly 200 from being released and protects the electrode assembly 200 in the can 300.

The electrode assembly 200 may be accommodated in the can 300. The can 300 may be formed of a conductive metal material such as aluminum or an alloy including aluminum. The 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 electrode assembly 200 is described in the case of being accommodated in the rectangular can 300, for example, but is not limited to any one housing 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 insulating plate 404, a terminal plate 405, and an insulating case 406.

The cap plate 401 may be coupled to the can 300 to seal the opening OP of the can 300. The contact portion between the can 300 and the cap plate 401 may be coupled to a welding process such as laser welding. The can 300 and the cap plate 401 may have the same polarity. In the present embodiment, the can 300 and the cap plate 401 may have a 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. An electrolyte may be injected into the electrolyte injection hole 408. The electrolyte injection hole 408 may be closed by a stopper 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 may pass 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. 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 containing nickel.

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

The insulating plate 404 is positioned below the cap plate 401, and may insulate 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 containing nickel.

The insulating case 406 may be mounted on an 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.

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

As such, 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 an anode path and 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 illustrating the electrode assembly 200 of FIG. 1.

Referring to the drawings, the electrode assembly 200 includes a first electrode plate 210, a second electrode plate 230, and a separator 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 have a lithium oxide as a main component. In the present exemplary embodiment, 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 surface disposed on the other surface of the first current collector 211. 2 includes an active material 214.

The first electrode plate 210 may include a first region 1A in which the first electrode active material 212 is disposed on both surfaces of the first current collector 211, and an amount of the first current collector 211. The second region 2A on which the first electrode active material 212 is not disposed is included. In one embodiment, the second area 2A may be a positive uncoated area. The first region 1A and the second region 2A may be continuously disposed 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 on 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 upward from 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 surface of the second current collector 231. In one embodiment, the second electrode plate 230 may be a cathode 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. In the present exemplary embodiment, the second electrode active material 232 may include a third active material 233 disposed on one surface of the second current collector 231 and a second surface disposed on the other surface of the second current collector 231. 4 includes an active material 234.

The second electrode plate 230 has a third region 3A in which the second electrode active material 232 is disposed on both surfaces of the second current collector 231, and one surface 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 surfaces of the second current collector 231. It includes. 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 disposed 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 on the second current collector 231 or attached to the second current collector 231 using a separate metal plate. The second electrode tab 270 may protrude upward from the electrode assembly 200.

The separator 250 may be interposed between the first electrode plate 210 and the second electrode plate 230, and may insulate the first electrode plate 210 and the second electrode plate 230 from each other. In the present embodiment, the electrode assembly 200 includes two separators 250 interposed between one first electrode plate 210 and one second electrode plate 230, but is not limited thereto. no.

Fine pores 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 polyethylene, polypropylene, or a composite film of polyethylene and polypropylene.

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

In an exemplary embodiment, the electrode assembly 200 may include a planar portion (PP) having the first electrode plate 210, the second electrode plate 230, and the separator 250 flatly disposed thereon, The first electrode 210, the second electrode plate 230, and the separator 250 include a curved portion CP. The planar portion PP and the curved portion CP may be alternately disposed, and may be continuously disposed in the 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 on the winding axis (WA) extending in the horizontal direction (X direction) based on the first electrode plate ( The 210 and the second electrode plate 230 may face each other.

In an embodiment, the first electrode tab 260 and the second electrode tab 270 may be disposed on 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 an innermost layer of the electrode assembly 200 wound in the first direction. have. The second electrode plate 230 may be preferentially wound on the winding start part WSP. Thereafter, the first electrode plate 210 may be wound at intervals.

In detail, the first electrode plate is formed in the winding start portion WSP from an area in which the second electrode plate 230 is turned at least 1/2 in the first direction and the second electrode 230 is turned 1/2. 210 may be wound in a first direction. In one embodiment, if the winding start portion (WSP), the second electrode plate 230 is wound first, and the first electrode plate 210 is wound at intervals, the structure is not limited to any one 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 in the winding start part WSP. That is, the first electrode active material 212 is disposed on both surfaces of the first current collector 211 in the winding start part WSP, and the second electrode active material (2) is disposed on both surfaces of the second current collector 231. 232 may be disposed.

The first electrode plate 210 and the second electrode plate 230 may generate a battery reaction in a region where the first electrode active material 212 and the second electrode active material 232 face each other. In the winding start part WSP, the first surface 211a of the first current collector 211 and the second current collector 231 of the second current collector 231 may be disposed on the winding axis WA disposed in the horizontal direction (X direction). The first surface 231a may be disposed to face 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. Can be.

As such, since the first active material 213 provided in the first electrode active material 212 and the third active material 233 provided in the second electrode active material 232 face the winding start part WSP, the electrode Cell reactions may occur in the innermost layer of the assembly 200 and may activate the inactive regions.

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

However, the first electrode plate 210 and the second electrode plate 230 do not face each other at the tip T of the second electrode plate 230. That is, when the extension portion 230e is not present, only the first electrode plate 210 may be wound around the curved portion CP in the second direction from the tip T of the second electrode plate 230. Accordingly, during battery reaction, lithium ions are concentrated at the tip T of the second electrode plate 230, and as a result, lithium precipitation may occur.

In order to prevent this, the extension portion 230e is wound around the tip T of the second electrode plate 230 in a second length and corresponds to the curved portion CP of the second electrode plate 230. Can be arranged.

In detail, the first electrode plate 210 and the second electrode plate 230 may be wound together in the first direction. A second current collector extension part 231e wound in a second direction opposite to the first direction may extend to the tip 231c of the second current collector 231 disposed in the winding start part WSP. The second current collector extension part 231e may be integrally extended from the tip 231c of the second current collector 231. The length of the second current collector extension part 231e may correspond to the 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 part 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 that does not face the first electrode plate 210. That is, since the first surface 231a of the second current collector extension 231e faces the second current collector 231 having the same polarity, the first surface of the second current collector extension 231e is It is not necessary to form the third active material 233 on 231a.

As such, the third active material 233 of the extension portion 230e extending from the front end T of the second electrode plate 230 may be formed on the first electrode plate 210 at the curved portion CP of the electrode assembly 200. Since it faces the first active material 213, lithium does not occur at the tip T of the second electrode plate 230. Accordingly, the short circuit of the electrode assembly 200 can be prevented.

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

The first region 1A may be located in an area 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. Can be. The first electrode active material 212 disposed on both

surfaces

211a and 211b of the first current collector 211 may extend to an area connected to the winding completion unit WFP.

A third region 3A may be located in an area 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. Can be.

The fourth region 4A may be located in the outermost region of the electrode assembly 200. The second electrode active material 232 may be disposed only on the surface of the second electrode plate 230 that faces 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. Instead, the second surface 231b of the second current collector 231 It is possible to face the separator 250 and the seal tape 280. 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. In 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. The fifth region 5A may extend to the winding completion unit WFP. In another embodiment, the fifth region 5A may be omitted, and the fourth region 4A may be directly connected to the winding completion unit WFP.

Meanwhile, a first protective tape 291 may be disposed on both surfaces of the first electrode plate 210 connected to the winding completion unit WFP. The first electrode active material 232 disposed on both surfaces of the first electrode plate 210 may extend to an area connected to the winding completion unit WFP. On the other hand, the first electrode active material 212 may not be disposed on both surfaces of the first electrode plate 210 of the first winding completion part WFP.

During the application process of the first electrode active material 232 using a spraying means such as a nozzle, the raw material for the first electrode active material 232 is both surfaces of the first electrode plate 210 connected to the winding completion unit WFP. It may not be uniformly applied to. That is, in some regions of the first current collector 211, the first electrode active material 212 may be formed relatively thicker than other regions of the first current collector 211 by the injection pressure. Accordingly, the first protective tape 291 may be disposed on both surfaces of the first electrode plate 210 connected to the winding completion unit WFP to cover the unevenly coated first electrode active material 212.

3, 6A, and 6B, the winding completion unit 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 unit WFP.

The second region 2A and the fifth region 5A may be disposed in the winding completion unit WFP. The second region 2A may be a plain portion in which the first electrode active material 212 is not disposed on both surfaces of the first current 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 onto the first current collector 211 using a separate metal plate. In another embodiment, the first electrode tab 260 may be integral to 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. In the present exemplary embodiment, the second protective tape 292 is the first surface 211a that is opposite to the second surface 211b of the first current collector 211 on which the first electrode tab 260 is disposed. Can be placed in. On the other hand, the second protective tape 292 may not be disposed on the second surface 211b of the first current collector 211 in which the first electrode tab 260 is disposed. Since the second surface 211b of the first current collector 211 on which the first electrode tab 260 is disposed is a surface corresponding to an inner surface of the can 300 (of FIG. 2) having the same polarity, the second protective tape 292 may not be disposed on the second surface 211b of the first current collector 211 in which the first electrode tab 260 is disposed.

The fifth region 5A may be a non-coated portion in which the second electrode active material 232 of 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 onto the second current collector 231 using a separate metal plate. In another embodiment, the second electrode tab 270 may be integrated 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. In the present exemplary embodiment, the third protection 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. The second surface 231b may be disposed together.

As such, since the first electrode tab 260 and the second electrode tab 270 are disposed in the winding completion unit WFP of the electrode assembly 200, the first electrode tab 260 and the second electrode tab 270 are disposed in the innermost layer 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. Accordingly, the internal flatness of the electrode assembly 200 may be improved, and as a result, deformation occurring during charging and discharging of the secondary battery may be prevented.

According to an embodiment of the present invention, deformation of the electrode assembly may be improved when charging and discharging a secondary battery, and embodiments of the present invention may be applied to various industrial fields using secondary batteries as energy sources in addition to hybrid vehicles and electric vehicles. can do.

Claims

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; and a second electrode active material disposed on at least one surface of the second current collector and the second current collector; A jelly-roll electrode assembly including a second electrode plate and a separator interposed between the first electrode plate and the second electrode plate and 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

Including a case for receiving the electrode assembly;

At the winding start of the electrode assembly, the first electrode plate and the second electrode plate face each other based on a winding axis extending in one direction, and a first electrode active material is disposed on both sides of the first current collector, and the second The second electrode active material is disposed on both sides of the current collector,

The secondary battery of claim 1, wherein the first electrode tab and the second electrode tab are disposed on the winding completion part of the electrode assembly.
The method of claim 1,

The secondary battery of the electrode assembly, wherein the second electrode plate is firstly wound, spaced apart, and the first electrode plate is wound, corresponding to the innermost layer of the electrode assembly.
The method of claim 2,

A secondary battery of which the first electrode plate is wound in a first direction from an area in which the second electrode plate is turned at least 1/2 in the first direction and the second electrode plate is turned 1/2 in the first direction.
The method of claim 2,

The first electrode plate and the second electrode plate are all wound in the first direction,

The secondary battery of the second electrode plate disposed in the winding start of the electrode assembly is wound in a second direction opposite to the first direction, the secondary battery is disposed with an extension corresponding to the curved portion of the second electrode plate.
The method of claim 4, wherein

In the extension part, a second electrode active material is disposed on a corresponding surface of the 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. Unplaced secondary battery.
The method of claim 1,

The secondary battery of the electrode assembly, wherein the first electrode tab and the second electrode tab are disposed and correspond to the outermost layer of the electrode assembly.
The method of claim 1,

The first electrode plate may include a first region in which a first electrode active material is disposed on both surfaces of a first current collector, and the first electrode active material is not disposed on both surfaces of the first current collector, and a first electrode tab is disposed. Second area,

The second electrode plate may include a third region in which a second electrode active material is disposed on both surfaces of the second current collector, a fourth region in which the second electrode active material is disposed on either side of the second current collector, and the The secondary battery includes a fifth region in which the second electrode active material is not disposed on both surfaces of a second current collector, and the second electrode tab is disposed.
The method of claim 7, wherein

The first region and the third region are located at the beginning of the winding of the electrode assembly.
The method of claim 8,

A secondary battery having an extension portion corresponding to the curved portion of the second electrode plate in a second direction opposite to the first direction, is extended at the tip of the second electrode plate disposed at the winding start of the electrode assembly.
The method of claim 9,

The extension part includes a fourth region, and a second electrode active material is disposed on a corresponding surface of the second current collector facing the first electrode plate, and on a corresponding surface of the second current collector opposite to the first surface. The secondary battery in which the second electrode active material is not disposed.
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, wherein the fourth region is a second collection unit facing the first electrode plate. A secondary battery in which a second electrode active material is disposed on a corresponding surface of the whole, and a second electrode active material is not disposed on a corresponding surface of the second current collector not facing the first electrode plate.
The method of claim 7, wherein

The second region and the fifth region are located in the winding completion portion of the electrode assembly.
The method of claim 7, wherein

The first region and the second region are continuously disposed in the longitudinal direction of the first electrode plate.
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.
The method of claim 7, wherein

A secondary battery corresponding to a first region connected to the second region and having a first protective tape covering both surfaces of the first electrode plate connected to the winding completion unit to cover the first electrode active material.
The method of claim 1,

A secondary battery having a second protective tape attached to at least one surface of the first current collector to which the first electrode tab is attached.
The method of claim 1,

A secondary battery having a third protective tape attached to at least one surface of the second current collector to which the second electrode tab is attached.
The method of claim 1,

A secondary battery having a seal tape attached to an outer surface of the electrode assembly.
The method of claim 1,

The first electrode plate includes a positive electrode plate,

The second electrode plate comprises a negative electrode plate.
The method of claim 1,

The electrode assembly includes a planar portion in which the first electrode plate, the second electrode plate, and the separator are disposed flat, and a curved portion in which the first electrode plate, the second electrode plate, and the separator have curvature, and the plane The secondary battery and the curved portion are disposed alternately, and the secondary battery continuously disposed in the winding direction.