Electrode assembly having separator exhibiting high elongation property and secondary battery including the same

Patent metadata

Field	Value
Publication number	US-2016308250-A1
Application number	US-201515101558-A
Country	US
Kind code	A1
Filing date	Jan 9, 2015
Priority date	Jan 10, 2014
Publication date	Oct 20, 2016
Grant date	—

Abstract

Disclosed herein is a stacked/folded type electrode assembly configured to have a structure in which two or more unit cells, each of which includes a separator disposed between a positive electrode and a negative electrode, each having an electrode mixture including an electrode active material applied to a current collector, are wound using a sheet type separation film, wherein the positive electrode is configured to have a structure in which a positive electrode mixture is coated on an aluminum foil as the current collector and the negative electrode is configured to have a structure in which a negative electrode mixture is coated on a metal foil, other than the aluminum foil, as the current collector, the unit cells include one or more full-cells and/or bi-cells, one of the unit cells located at each outermost side of the electrode assembly is configured such that one outermost electrode of the unit cell is a single-sided electrode, the single-sided electrode being configured such that the electrode mixture is applied only to one major surface of the current collector facing the separator, and the separation film has higher elongation than the separator.

First claim

1 . A stacked/folded type electrode assembly configured to have a structure in which two or more unit cells, each of which comprises a separator disposed between a positive electrode and a negative electrode, each having an electrode mixture comprising an electrode active material applied to a current collector, are wound using a sheet type separation film, wherein
the positive electrode is configured to have a structure in which a positive electrode mixture is coated on an aluminum foil as the current collector, and the negative electrode is configured to have a structure in which a negative electrode mixture is coated on a metal foil, other than the aluminum foil, as the current collector, the unit cells comprise one or more full-cells and/or bi-cells, one of the unit cells located at each outermost side of the electrode assembly is configured such that one outermost electrode of the unit cell is a single-sided electrode, the single-sided electrode being configured such that the electrode mixture is applied only to one major surface of the current collector facing the separator, and the separation film has higher elongation than the separator.

2 . The electrode assembly according to claim 1 , wherein the one of the unit cells located at each outermost side of the electrode assembly is configured such that a separator facing the electrode mixture of the single-sided electrode, i.e. the outermost electrode, is a safety separator, and the safety separator has higher elongation than a separator in each of the other unit cells, i.e. a general separator.

3 . The electrode assembly according to claim 1 , wherein the electrode assembly comprises first bi-cells, disposed at the outermost sides of the electrode assembly, and second bi-cells disposed between the first bi-cells.

4 . The electrode assembly according to claim 3 , wherein
each of the first bi-cells is configured to have a structure in which a first positive electrode as a single-sided positive electrode, a second negative electrode as a double-sided negative electrode, and a second positive electrode as a double-sided positive electrode are sequentially stacked in a state in which separators are disposed respectively therebetween or a structure in which a first negative electrode as a single-sided negative electrode, a second positive electrode as a double-sided positive electrode, and a second negative electrode as a double-sided negative electrode are sequentially stacked in a state in which separators are disposed respectively therebetween, and each of the second bi-cells is configured to have a structure in which a second negative electrode, a second positive electrode, and a second negative electrode are sequentially stacked in a state in which separators are disposed respectively therebetween or a structure in which a second positive electrode, a second negative electrode, and a second positive electrode are sequentially stacked in a state in which separators are disposed respectively therebetween.

5 . The electrode assembly according to claim 1 , wherein the unit cells are full-cells, the full-cells comprising first full-cells, disposed at the outermost sides of the electrode assembly, and second full-cells disposed between the first full-cells.

6 . The electrode assembly according to claim 5 , wherein
each of the first full-cells is configured to have a structure in which a first positive electrode as a single-sided positive electrode, a separator, and a second negative electrode as a double-sided negative electrode are sequentially stacked or a structure in which a first negative electrode as a single-sided negative electrode, a separator, and a second positive electrode as a double-sided positive electrode are sequentially stacked, and each of the second full-cells is configured to have a structure in which a second negative electrode as a double-sided negative electrode, a separator, and a second positive electrode as a double-sided positive electrode are sequentially stacked or a structure in which a second positive electrode as a double-sided positive electrode, a separator, and a second negative electrode as a double-sided negative electrode are sequentially stacked.

7 . The electrode assembly according to claim 2 , wherein the electrode assembly comprises third bi-cells, disposed at the outermost sides of the electrode assembly, and fourth bi-cells disposed between the third bi-cells.

8 . The electrode assembly according to claim 7 , wherein
each of the third bi-cells is configured to have a structure in which a first positive electrode as a single-sided positive electrode, a second negative electrode as a double-sided negative electrode, and a second positive electrode as a double-sided positive electrode are sequentially stacked in a state in which safety separators are disposed respectively therebetween or a structure in which a first negative electrode as a single-sided negative electrode, a second positive electrode as a double-sided positive electrode, and a second negative electrode as a double-sided negative electrode are sequentially stacked in a state in which safety separators are disposed respectively therebetween, and each of the fourth bi-cells is configured to have a structure in which a second negative electrode, a second positive electrode, and a second negative electrode are sequentially stacked in a state in which general separators are disposed respectively therebetween or a structure in which a second positive electrode, a second negative electrode, and a second positive electrode are sequentially stacked in a state in which general separators are disposed respectively therebetween.

9 . The electrode assembly according to claim 2 , wherein the unit cells are full-cells, the full-cells comprising third full-cells, disposed at the outermost sides of the electrode assembly, and fourth full-cells disposed between the third full-cells.

10 . The electrode assembly according to claim 9 , wherein
each of the third full-cells is configured to have a structure in which a first positive electrode as a single-sided positive electrode, a safety separator, and a second negative electrode as a double-sided negative electrode are sequentially stacked or a structure in which a first negative electrode as a single-sided negative electrode, a safety separator, and a second positive electrode as a double-sided positive electrode are sequentially stacked, and each of the fourth full-cells is configured to have a structure in which a second negative electrode as a double-sided negative electrode, a general separator, and a second positive electrode as a double-sided positive electrode are sequentially stacked or a structure in which a second positive electrode as a double-sided positive electrode, a general separator, and a second negative electrode as a double-sided negative electrode are sequentially stacked.

11 . The electrode assembly according to claim 1 , wherein the elongation of the separation film and the safety separator is 105 to 500% of the elongation of the general separator.

12 . The electrode assembly according to claim 11 , wherein the elongation of the separation film and the safety separator is 120 to 300% of the elongation of the general separator.

13 . The electrode assembly according to claim 1 , wherein the separation film and the separator each are an organic/inorganic composite porous safety-reinforcing separator (SRS).

14 . The electrode assembly according to claim 13 , wherein the SRS separator is configured such that an active layer, comprising inorganic particles and a binder polymer, is coated on a polyolefin-based separator subst

Assignees

• Lg Chemical Ltd

Inventors

• Jeong Yu Na
• Jung Moon Young
• Kim Dong-Myung
• Kim Ki Tae
• Lee Sungwon

Classifications

• H01M50/451

  comprising layers of only organic material and layers containing inorganic material · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/105

  Pouches or flexible bags · CPC title

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title

• H01M2/1686

  Electricity · mapped topic