KR102256297B1 - secondary battery - Google Patents

Abstract

Disclosing a secondary battery. The present invention includes a first electrode plate, a second electrode plate, and a separator, and includes a jelly-roll type electrode assembly wound in a first direction; and, a first electrode tab; and, a second electrode tab; and, an electrode Including a case for accommodating the assembly, wherein the first electrode plate and the second electrode plate face each other with respect to the winding axis extending in one direction at the winding start portion of the electrode assembly, and a first electrode active material on both sides of the first current collector Is disposed, the second electrode active material may be disposed on both surfaces of the second current collector, and the first electrode tab and the second electrode tab may be disposed on the winding-off portion of the electrode assembly.

Description

Secondary battery

The present invention relates to a secondary battery.

Typically, a secondary battery is a battery capable of charging and discharging, unlike a primary battery that cannot 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 applied, or may be used in the form of a battery module assembled as a unit by electrically connecting a plurality of batteries.

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 internal flatness of the electrode assembly may be important. 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. Accordingly, the internal flatness of the electrode assembly may be deteriorated, and as a result, the performance of the secondary battery may be poor.

Meanwhile, 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 in which safety and battery capacity are maximized.

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 jelly-roll type electrode assembly wound in a first direction, comprising a second electrode plate having a second electrode active material disposed on at least one side of the second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate And, a first electrode tab electrically connected to the first electrode plate; and 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 with respect to the winding axis extending in one direction at the winding start portion of the first current collector, and a first electrode active material is disposed on both surfaces of the first current collector, and The second electrode active material may be disposed on both surfaces, and the first electrode tab and the second electrode tab may be disposed on the winding-completed portion of the electrode assembly.

In one embodiment, the winding start portion of the electrode assembly may be the second electrode plate is wound preferentially, the first electrode plate is wound at intervals, 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 a region in which the second electrode plate turns at least 1/2 in the first direction, and the second electrode plate turns 1/2 in the first direction. I can.

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

In one embodiment, 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. The second electrode active material may not be disposed.

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

In an embodiment, in the first electrode plate, a first region in which the first electrode active material is disposed on both surfaces of the first current collector, and the first electrode active material is not disposed on both surfaces of the first current collector, And a second area in which a first electrode tab is disposed, and the second electrode plate includes a third area in which a second electrode active material is disposed on both surfaces of the second current collector, and the second electrode plate is disposed on either side of the second current collector And a fourth area in which the second electrode active material is disposed, and a fifth area 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 an embodiment, the first region and the third region may be located at a winding start portion of the electrode assembly.

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

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

In an embodiment, the second region and the fifth region may be located in the winding-completed portion of the electrode assembly.

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

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

In one 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 region connected to the second region and connected to the winding-completed part. .

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 the 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 flat portion in which the first electrode plate, the second electrode plate, and the separator are disposed flat, and a curved surface in which the first electrode plate, the second electrode plate, and the separator have a curvature. It includes a portion, and the planar portion and the curved portion are alternately arranged, and may be continuously arranged in a winding direction.

In the secondary battery according to an aspect of the present invention, electrode active materials having different polarities face each other on the innermost layer of the electrode assembly, and an extension portion extending from the tip of one electrode plate disposed at the beginning of the electrode has a curved portion, thereby reducing battery capacity. Can be increased. In addition, since the electrode tab is disposed on the outermost layer of the electrode assembly, it is possible to improve the internal flatness of the electrode assembly.

It goes without saying that the effects of the present invention can be derived from the contents to be described below with reference to the drawings in addition to the above-described contents.

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

Since the present invention can apply various transformations and have various embodiments, specific embodiments are illustrated in the drawings, and will be described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, when it is determined that a detailed description of a related known technology may obscure the subject matter of the present invention, a detailed description thereof will be omitted.

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

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other features. It is to be understood that the possibility of addition or presence of elements, numbers, steps, actions, components, parts, or combinations thereof, is not excluded in advance.

Hereinafter, embodiments of a secondary battery according to the present invention will be described in detail with reference to the accompanying drawings, and in the description with reference to the accompanying drawings, the same or corresponding components are assigned the same reference numbers, and overlapped Description will be omitted.

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

1 and 2, the secondary battery 100 includes an electrode assembly 200, a can 300 accommodating the electrode assembly 200, and a cap assembly 400 coupled to the can 300. 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 one embodiment, the first electrode plate 210 is a positive plate, and the second electrode plate 230 is a negative plate, but the opposite may be the case. 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 sealing tape 280 serves to prevent the electrode assembly 200 from being released and to protect the electrode assembly 200 within 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 containing aluminum. A cap assembly 400 may be installed on the can 300. The cap assembly 400 may seal the opening OP of the can 300.

In the present embodiment, a case in which the electrode assembly 200 is accommodated in the rectangular can 300 is described as an example, but the case is not limited to any one if the electrode assembly 200 is accommodated. For example, the electrode assembly 200 may be accommodated 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. A portion of the can 300 and the cap plate 401 in contact with each other 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 this 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 containing aluminum.

The electrode terminal 402 passes through the gasket hole 410 formed in the gasket 403, the second hole 411 formed in the insulating plate 404, and the 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 is 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 under 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 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 pass through the slit 413 and be connected to the terminal plate 405.

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

In this way, 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. Includes 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 thin conductive metal plate such as aluminum. The first electrode active material 211 may have a lithium-based oxide as a main component. In this embodiment, the first electrode active material 211 includes a first active material 213 disposed on one surface of the first current collector 211 and a first active material 213 disposed on the other surface of the first current collector 211. It contains 2 active material 214.

The first electrode plate 210 includes a first area 1A in which the first electrode active material 212 is disposed on both surfaces of the first current collector 211 and the amount of the first current collector 211 It includes a second area 2A in which the first electrode active material 212 is not disposed on the surface. 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 length direction of the first electrode plate 210.

A first electrode tab 260 may be disposed in the second region 2A. The first electrode tab 260 may be a thin conductive metal 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 above 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 negative electrode plate.

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

The second electrode plate 230 includes a third area 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 area 4A in which the second electrode active material 232 is disposed, and a fifth area 5A in which the second electrode active material 232 is not disposed on both surfaces of the second current collector 231 Includes. In one embodiment, the fifth area 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 length direction of the second electrode plate 230.

A second electrode tab 270 may be disposed in the fifth area 5A. The second electrode tab 270 may be a thin conductive metal 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 above the electrode assembly 200.

The separator 250 is 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 this embodiment, the electrode assembly 200 includes one first electrode plate 210 and two separators 250 interposed between the one second electrode plate 230, but is limited thereto. 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 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 wound in a first direction (eg, counterclockwise). have.

In one embodiment, the electrode assembly 200 includes a planar portion (PP) in which the first electrode plate 210, the second electrode plate 230, and the separator 250 are flatly disposed, The first electrode 210, the second electrode plate 230, and the separator 250 include a curved portion (CP) having a curvature. The flat portion PP and the curved portion CP are alternately arranged, and may be continuously arranged in a winding direction. The cross section of the electrode assembly 200 may have an elliptical shape.

In one embodiment, in the winding start portion (WSP) of the electrode assembly 200, the first electrode plate ( 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 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 the innermost layer of the electrode assembly 200 wound in the first direction. have. The second electrode plate 230 may be preferentially wound around the winding start portion WSP. Thereafter, at intervals, the first electrode plate 210 may be wound.

Specifically, the first electrode plate from a region in which the second electrode plate 230 turns at least 1/2 in the first direction and the second electrode 230 turns 1/2 in the winding start part WSP. 210 may be wound in the first direction. In one embodiment, if the second electrode plate 230 is preferentially wound on the winding start portion (WSP), and the first electrode plate 210 is wound at an interval, it is limited to any one no.

A first region 1A of the first electrode plate 210 and a third region 3A of the second electrode plate 230 may be positioned in the winding start portion 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 ( 232) can be deployed.

In the first electrode plate 210 and the second electrode plate 230, 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. The winding start portion WSP includes the first surface 211a of the first current collector 211 and the second current collector 231 with respect to the winding axis WA disposed in the horizontal direction (X direction). The first surfaces 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. I can.

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 each other, the electrode A battery reaction may occur in the innermost layer of the assembly 200 and may activate an inactive region.

In an embodiment, an extension part 230e may be further disposed at a tip (T) of the second electrode plate 230 in a second direction (eg, clockwise) opposite to the first direction. . The extension part 230e includes a fourth area 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, 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, in the absence of the extension portion 230e, 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 the battery reaction, lithium ions are concentrated at the tip T of the second electrode plate 230, and as a result, lithium precipitation may occur.

To prevent this, a predetermined length is wound around the tip T of the second electrode plate 230 in a second direction, and an extension portion 230e corresponding to the curved portion CP of the second electrode plate 230 Can be placed.

Specifically, both the first electrode plate 210 and the second electrode plate 230 may be wound in the first direction. A second current collector extension part 231e wound in a second direction opposite to the first direction may extend from the tip 231c of the second current collector 231 disposed on the winding start part WSP. The second current collector extension part 231e may integrally extend from the front end 231c of the second current collector 231. The length of the second current collector extension portion 231e may correspond to a length capable of forming 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 231e not facing the first electrode plate 210. That is, since the first surface 231a of the second current collector extension part 231e faces the second current collector 231 of the same polarity, the first surface of the second current collector extension part 231e It is not necessary to form the third active material 233 on the 231a.

In this way, the fourth active material 234 of the extension portion 230e extending from the tip T of the second electrode plate 230 is formed from the first electrode plate 210 in the curved portion CP of the electrode assembly 200. ) Faces the first active material 213, so lithium precipitation does not occur at the tip T of the second electrode plate 230. Accordingly, a short circuit of the electrode assembly 200 may be prevented.

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

A first region 1A may be positioned in a region of the first electrode plate 210 connected to the winding start portion WSP. 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. I can. The first electrode active material 212 disposed on both surfaces 211a and 211b of the first current collector 211 may extend to a region connected to the winding completed portion WFP.

A third area 3A may be located in an area of the second electrode plate 230 connected to the winding start portion WSP. 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. I can.

A fourth area 4A may be positioned in an area wound to the outermost side 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. A 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 is It may face the separator 250 and the seal tape 280. Accordingly, 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 area 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 completed portion WFP. In another embodiment, the fifth region 5A may be omitted, and the fourth region 4A may be directly connected to the winding-completed portion WFP.

Meanwhile, a first protective tape 291 may be disposed on both surfaces of the first electrode plate 210 connected to the winding completed 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 completed portion 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 completed portion 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 on both sides of the first electrode plate 210 connected to the winding completion unit (WFP). May not be uniformly applied to the surface. That is, in a partial region of the first current collector 211, the first electrode active material 212 may be formed to be relatively thicker than other regions of the first current collector 211 by spray pressure. Accordingly, a first protective tape 291 covering the non-uniformly coated first electrode active material 212 may be disposed on both surfaces of the first electrode plate 210 connected to the winding completed portion WFP.

3, 6A, and 6B, the winding-completed portion WFP of the electrode assembly 200 may correspond to the outermost layer of the electrode assembly 200 wound in the first direction. have. A first electrode tab 260 and a second electrode tab 270 may be disposed in the winding completed portion WFP.

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

The fifth area 5A may be an uncoated 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 area 5A may be connected to the fourth area 4A of FIG. 5A. A 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 second 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. In this embodiment, the third protective tape 293 includes a first surface 231a of the second current collector 233 and a second current collector 233 on which the second electrode tab 270 is disposed. Both may be disposed on the second surface 231b.

As such, since the first electrode tab 260 and the second electrode tab 270 are disposed on the winding-completed portion (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. There is no level difference between the electrode assembly 200 due to the electrode tab 260 and the second electrode tab 270. Accordingly, 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.

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 part 231... second current collector
231e...second current collector extension 232...second electrode active material
233...3rd active material 234...4th 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 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 type electrode assembly wound in a first direction, including a second electrode plate provided and a 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
Including; a case for accommodating the electrode assembly,
The winding start portion of the electrode assembly corresponds to the innermost layer 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 both surfaces of the first current collector A first electrode active material is disposed, and a second electrode active material is disposed on both surfaces of the second current collector,
The first electrode tab and the second electrode tab are disposed in the winding-completed portion of the electrode assembly,
A secondary battery in which an extension portion corresponding to a curved portion of the second electrode plate extends in a second direction at a tip end of the second electrode plate disposed at a winding start portion of the electrode assembly. The method of claim 1,
A secondary battery corresponding to an innermost layer of the electrode assembly in which the second electrode plate is preferentially wound, the first electrode plate is wound at an interval, and the winding start portion of the electrode assembly. The method of claim 2,
A secondary battery in which the first electrode plate is wound in a first direction from a region in which the second electrode plate turns at least 1/2 in a first direction and the second electrode plate turns 1/2 in a first direction of the winding start portion of the electrode assembly. The method of claim 2,
The first electrode plate and the second electrode plate are wound together in a first direction,
The secondary battery is wound in a second direction opposite to the first direction. The method of claim 4,
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. Secondary battery not placed. The method of claim 1,
A secondary battery having the first electrode tab and the second electrode tab disposed in the winding-complete portion of the electrode assembly, and corresponding to the outermost layer of the electrode assembly. The method of claim 1,
In the first electrode plate, a first region in which a first electrode active material is disposed on both surfaces of a first current collector, and a first electrode active material is not disposed on both surfaces of the first current collector, and a first electrode tab is disposed. And a second area
The second electrode plate includes a third area in which a second electrode active material is disposed on both surfaces of the second current collector, a fourth area in which the second electrode active material is disposed on any one side of the second current collector, and the A secondary battery including 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 tabs are disposed. The method of claim 7,
The first region and the third region are located at a winding start portion of the electrode assembly. The method of claim 8,
A secondary battery in which an extension portion corresponding to a curved portion of the second electrode plate is extended in a second direction opposite to the first direction to a tip of the second electrode plate disposed at the winding start portion of the electrode assembly. The method of claim 9,
The extension 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 on a corresponding surface of the second current collector opposite the first surface. A secondary battery in which the second electrode active material is not disposed. The method of claim 7,
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 a second house facing the first electrode plate. A secondary battery in which a second electrode active material is disposed on an entire corresponding surface, and a second electrode active material is not disposed on a corresponding surface of a second current collector that does not face the first electrode plate. The method of claim 7,
The second area and the fifth area are located in the winding-completed portion of the electrode assembly. The method of claim 7,
The first region and the second region are continuously disposed in a length direction of the first electrode plate. The method of claim 7,
The third region, the fourth region, and the fifth region are continuously disposed in a length direction of the second electrode plate. The method of claim 7,
A secondary battery that corresponds to a first region connected to the second region, and to which a first protective tape covering a first electrode active material is attached to both surfaces of the first electrode plate connected to the winding-complete portion. The method of claim 1,
A secondary battery to which 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 of claim 1,
A secondary battery to which 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 of claim 1,
A secondary battery to which a seal tape is 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 is a secondary battery including a negative electrode plate. The method of claim 1,
The electrode assembly includes a flat 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 a curvature, and the plane A secondary battery that is alternately arranged and continuously arranged in a winding direction.

Images