LITHIUM ION SECONDARY CELL AND ITS MANUFACTURING METHOD

WIPO Patent Application WO/2005/057712

A1

A lithium ion secondary cell has an electrode group comprising (1) a winding core, (2) a positive electrode composed of a positive electrode core member and a positive electrode active material layer supported on the positive electrode core member, (3) a negative electrode composed of a negative electrode core member and a negative electrode active material layer supported on the negative electrode core member, and (4) a porous film formed at least on one of the positive and negative electrodes. The porous film is composed of a filler and a binder, and the positive and negative electrodes are wound on the winding core. At a portion near the winding-start end of the positive and/or negative electrode, a region where an active material layer is supported only on one side of the core member is provided. Further, at a portion nearer the winding-start end than the above region, a region where no active material layer is supported on both sides of the core member is provided. Since the electrode group has such a structure, the damage to the porous film can be reduced, and its safety can be improved.

HAYASHI TETSUYA
OHATA TSUMORU

PCT/JP2004/018264

June 23, 2005

December 08, 2004

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MATSUSHITA ELECTRIC IND CO LTD (JP)
HAYASHI TETSUYA
OHATA TSUMORU

H01M4/13; H01M4/139; H01M10/05; H01M10/04; H01M10/0525; H01M10/0587; H01M50/529; H01M50/409; H01M50/489; (IPC1-7): H01M10/40; H01M4/02

JPH09147916A	1997-06-06
JP2003208918A	2003-07-25
JPH09161847A	1997-06-20
JPH11283676A	1999-10-15
JP3200340B2	2001-08-20
JP3237015B2	2001-12-10
JPH0935738A	1997-02-07

Ishii, Kazuo (3-6 Kitahama 2-chome, Chuo-k, Osaka-shi Osaka 41, JP)

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