Stack/folding-typed electrode assembly and method for preparation of the same

Patent metadata

Field	Value
Publication number	US-9209491-B2
Application number	US-74767108-A
Country	US
Kind code	B2
Filing date	Dec 12, 2008
Priority date	Dec 14, 2007
Publication date	Dec 8, 2015
Grant date	Dec 8, 2015

Abstract

Disclosed herein is an electrode assembly constructed in a structure in which a plurality of electrochemical cells, formed of full cells having a cathode/separator/anode structure, as basic units, are overlapped, and a continuous separator sheet is disposed between the overlapped electrochemical cells, wherein a unit electrode surrounded by the separator sheet is located at a middle of the overlapped electrochemical cells, which is a winding start point, and the full cells disposed above and below the unit electrode are symmetrical to each other about the unit electrode in the direction of electrodes of the full cells. The electrode assembly is manufactured with high productivity while the electrode assembly exhibits performance and safety equal to those of a conventional stack/folding type electrode assembly.

First claim

What is claimed is:

1. An electrode assembly constructed in a structure in which a plurality of electrochemical cells, formed of full cells having a cathode/separator/anode structure, as basic units, are overlapped, and a continuous separator sheet is disposed between the overlapped cells,
wherein in the structure before the electrochemical cells are overlapped, the full cells are configured to be placed in the same electrode orientation on the continuous separator sheet,
wherein a unit electrode surrounded by the separator sheet is located at a middle of the overlapped electrochemical cells, which is a winding start point, and the full cells disposed above and below the unit electrode are symmetrical to each other about the unit electrode in the direction of electrodes of the full cells,
wherein the unit electrode is an anode or cathode, and
wherein anodes are located at a topmost layer and a bottommost layer of the electrode assembly to form an outer surface of the electrode assembly.

2. An electrode assembly constructed in a structure in which a plurality of electrochemical cells, formed of full cells having a cathode/separator/anode structure, as basic units, are overlapped, and a continuous separator sheet is disposed between the overlapped cells,
wherein in the structure before the electrochemical cells are overlapped, the full cells are configured to be placed in the same electrode orientation on the continuous separator sheet,
wherein a bi-cell (‘A-type bi-cell’), having a cathode/separator/anode/separator/cathode structure, surrounded by the separator sheet, or ii) a bi-cell (‘C-type bi-cell’), having an anode/separator/cathode/separator/anode structure, surrounded by the separator sheet, is located at a middle of the overlapped electrochemical cells, which is a winding start point, and the full cells disposed above and below the bi-cell are symmetrical to each other about the bi-cell in the direction of electrodes of the full cells,
wherein the bi-cell has a different structure than the full cells, and
wherein anodes are located at a topmost layer and a bottommost layer of the electrode assembly to form an outer surface of the electrode assembly.

3. The electrode assembly according to claim 1 , wherein the separator sheet has unit lengths sufficient to surround the respective electrochemical cells, and the separator sheet is bent inward every unit length to successively surround the unit electrode or the central bi-cell and the full cells from the central unit electrode or the central bi-cell to the outermost full cell.

4. The electrode assembly according to claim 1 , wherein the full cells have i) a cathode/separator/anode structure or ii) a cathode/separator/anode/separator/cathode/separator/anode structure.

5. The electrode assembly according to claim 1 , wherein the unit electrode or the bi-cell located at the middle of the overlapped electrochemical cells, which is the winding start point, is an anode or a C-type bi-cell.

6. The electrode assembly according to claim 1 , wherein, when a cathode or an A-type bi-cell is located at the middle of the overlapped electrochemical cells, which is the winding start point, C-type bi-cells are located at the topmost layer and the bottommost layer of the electrode assembly.

7. The electrode assembly according to claim 1 , wherein the outermost end of the separator sheet is fixed by thermal welding or a tape.

8. The electrode assembly according to claim 1 , wherein the separator or the separator sheet is made of one selected a group consisting of micro porous polyethylene film, polypropylene film, multi-layered film manufactured by a combination of the polyethylene film and the polypropylene film, and polymer film for a polymer electrolyte, such as polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, and polyvinylidene fluoride hexafluoropropylene copolymer.

9. The electrode assembly according to claim 1 , wherein the cathode is an electrode manufactured by coating opposite major surfaces of a cathode current collector with a cathode material, and the anode is an electrode manufactured by coating opposite major surfaces of an anode current collector with an anode material.

10. A secondary battery comprising the electrode assembly according to claim 1 .

11. The secondary battery according to claim 10 , wherein the secondary battery is a lithium secondary battery.

12. A middle- or large-sized battery module comprising the secondary battery according to claim 11 as a unit cell.

Assignees

• Kim Kijae
• Kim Min Su
• Lg Chemical Ltd

Inventors

• Kim Kijae
• Kim Min Su

Classifications

• H01M50/491

  Porosity · 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

• H01M50/417

  Polyolefins · CPC title

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• H01M50/46 Primary

  Separators, membranes or diaphragms characterised by their combination with electrodes · CPC title