Electrode, electrode assembly and method for manufacturing the same

Abstract

The present invention provides an electrode assembly, in which a plurality of electrodes are laminated, and a separator is inserted between adjacent electrodes. The outermost electrode disposed at an outermost layer of the electrode assembly includes a slurry applied to one surface of a current collector, and a protection layer adhered to the other surface of the current collector. Further, the outermost electrode is laminated to allow the slurry to contact the separator. Furthermore, a method for manufacturing the electrode assembly comprises applying a slurry to one surface of a current collector and laminating a protection layer on the other surface of the current collector to form an outermost electrode; allowing the outermost electrode to pass between a pair of press-rollers to perform a rolling process; and laminating the rolled outermost electrode to be disposed on an uppermost layer or a lowermost layer of the electrode assembly.

Claims

1. An electrode assembly, in which a plurality of electrodes are laminated with a separator interposed between adjacent electrodes, wherein an outermost electrode disposed at an outermost layer of the electrode assembly comprises: a current collector; a slurry applied on the current collector on one surface that faces the separator; and a protection layer adhered to the other surface of the current collector, wherein the protection layer is made of a polymer material having a molecular weight equal to or greater than 10,000, wherein, the electrode assembly is prepared by rolling the outermost electrode with a pair of press-rollers to form a rolled outermost electrode, wherein the protection layer is deformed to offset deformation of the slurry; and laminating the rolled outermost electrode on the outermost layer of the electrode assembly.

2. The electrode assembly of claim 1, wherein the polymer material has electrical insulation.

3. The electrode assembly of claim 1, wherein the outermost electrode is an electrode disposed at an uppermost layer of the electrode assembly, and wherein the protection layer is laminated to be disposed at the uppermost layer of the electrode assembly.

4. The electrode assembly of claim 1, wherein the outermost electrode is an electrode disposed at a lowermost layer of the electrode assembly, and wherein the protection layer is laminated to be disposed at the lowermost layer of the electrode assembly.

5. A method for manufacturing an electrode assembly, in which a plurality of electrodes are laminated with a separator interposed between adjacent electrodes, the method comprising: applying a slurry to one surface of a current collector and laminating a protection layer on the other surface of the current collector to form an outermost electrode; rolling the outermost electrode with a pair of press-rollers to form a rolled outermost electrode, wherein the protection layer is deformed to offset deformation of the slurry; and laminating the rolled outermost electrode to be disposed on an uppermost layer or a lowermost layer of the electrode assembly, wherein the protection layer is made of a polymer material having a molecular weight equal to or greater than 10,000, and wherein, when the rolling is performed, the protection layer is deformed to offset deformation of the slurry.

6. The method of claim 5, wherein, when the outermost electrode is disposed at the uppermost layer of the electrode assembly, the protection layer is disposed at the uppermost layer, and wherein, when the outermost electrode is disposed at the lowermost layer of the electrode assembly, the protection layer is disposed at the lowermost layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1A is a view illustrating states before and after a single-sided electrode passes through a press-roller according to a related art.

(2) FIG. 1B is a view illustrating a state in which a nail penetrates to cause a short circuit when the single-sided electrode is laminated on the outermost layer of an electrode assembly according to the related art.

(3) FIG. 2 is a view illustrating states before and after a single-sided electrode passes through a press-roller according to the present invention.

(4) FIG. 3 is a view illustrating a state in which an occurrence of a short circuit is suppressed by a protection layer even though a nail penetrates when the single-sided electrode is laminated on the outermost layer of an electrode assembly according to the present invention.

MODE FOR CARRYING OUT THE INVENTION

(5) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in such a manner that the technical idea of the present invention may easily be carried out by a person with ordinary skill in the art to which the invention pertains. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein.

(6) In order to clearly illustrate the present invention, parts that are not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

(7) In addition, terms or words used in this specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts conforming to the scope of the present invention on the basis of the principle that an inventor can properly define the concept of a term to describe and explain his or her invention in the best ways.

(8) The present invention relates to an electrode assembly and a method for manufacturing the same. The electrode assembly has a structure in which a plurality of electrodes are laminated with a separator 3 disposed therebetween. In the electrode, which is disposed at the outermost layer, i.e., the uppermost layer or the lowermost layer, of the electrodes constituting the electrode assembly, a current collector 1a includes one surface coated with a slurry 1b and the other surface to which a protection layer 10 adheres, and the protection layer 10 is made of a polymer material having a molecular weight equal to or greater than 10,000. According to the present invention, the electrodes may be any of negative electrodes or positive electrodes.

Embodiment 1

(9) As illustrated in FIGS. 2 and 3, an electrode assembly according to the present invention includes a structure in which a separator 3 is disposed between electrodes having polarities different from each other, and the electrodes and the separator 3 are repeatedly laminated (i.e., in FIG. 3, when the lowermost electrode is a negative electrode in which a negative electrode slurry 1b is applied to a negative electrode current collector 1a, the separator 3 is laminated on the negative electrode. Further, a positive electrode, in which a positive electrode slurry 2b is applied to a positive electrode current collector 2a, is laminated on the separator 3). The outermost electrode disposed at the outermost layer is provided with a protection layer 10. For reference, although the electrode in which the protection layer 10 is provided at only the uppermost layer is illustrated in FIG. 3, the protection layer 10 may be provided at the lowermost layer. Further, the electrode provided with the protection layer 10 may be the negative electrode or the positive electrode.

(10) The slurry 1b is laminated to the outermost electrode on a side that contacts the separator 3, and the protection layer 10 is disposed at the uppermost layer (or the lowermost layer) of the electrode assembly.

(11) The protection layer 10 is made of a polymer material having a molecular weight equal to or greater than 10,000. Further, the protection layer 10 is made of a material having electrical insulation to prevent a short circuit from occurring when a pointed object such as a nail 5 penetrates through a pouch (not shown).

(12) Furthermore, when rolling is performed in a state in which the slurry 1b, the current collector 1a, and the protection layer 10 are laminated, as illustrated in FIG. 2, the protection layer 10 may be disposed at an opposite side of the current collector 1a to suppress deformation of the slurry 1b or be deformed to offset the deformation of the slurry 1b and/or the current collector 1a to allow the entire upper and lower layers to remain planar.

(13) In this embodiment, the outermost electrode may be disposed at the uppermost layer or the lowermost layer in the electrode assembly. Accordingly, the protection layer 10 may be disposed at the uppermost or lowermost layer to be closest to the pouch in which the electrode assembly is accommodated (as illustrated in FIG. 3).

Embodiment 2

(14) Furthermore, the present invention provides a method for manufacturing the above-described electrode assembly.

(15) The method for manufacturing the electrode assembly according to the present invention includes a step of applying a slurry 1b to one surface of a current collector 1a and laminating a protection layer 10 on the other surface to manufacture the outermost electrode, a step of allowing the outermost electrode to pass between a pair of press-rollers 40 and thereby to roll the outermost electrode, and a step of laminating the rolled outermost electrode to be disposed at the uppermost or lowermost layer of the electrode assembly.

(16) In particular, the slurry 1b is prepared by mixing a solution containing a binder in a solvent with an active material to have viscosity suitable for coating or applying. Further, in the press-roller 4, an appropriate pressure and heat may be applied to reduce a thickness of the electrode and to increase a density. Alternatively, before the outermost electrode is laminated in the electrode assembly, a process of cutting the electrode to an appropriate size, a process of processing an electrode tab, a process of performing vacuum drying to remove moisture contained in the electrode, and the like may be performed.

(17) When the outermost electrode is disposed at the uppermost layer of the electrode assembly, the protection layer 10 is laminated to be disposed at the uppermost layer. When the outermost electrode is disposed at the lowermost layer of the electrode assembly, the protection layer 10 is laminated to be disposed at the lowermost layer.

(18) According to the present invention having the above-described structure, the protection layer 10 may be laminated on the outermost electrode to suppress or offset the bending or warping force during the rolling. In addition, since the protection layer 10 faces the inner surface of the pouch in the electrode assembly to protect the current collector 1a, the electrode and the electrode assembly may be protected against the external impact.

(19) While the embodiments of the present invention have been described with reference to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.