Patent Number: 8,715,848

Title: Lithium ion secondary battery with insulating member having a broken hollow portion and method for producing the same

Abstract: An electrode assembly (30) is formed by combining a positive electrode plate (14), a separator (15), and a negative electrode plate (18), and the electrode assembly (30) was wound. An insulating member (21) having a hollow portion (22) is placed on the positive electrode plate (14), the negative electrode plate (18), or the separator (15) before the end of the winding step so that the insulating member (21) is incorporated inside the outermost of the electrode assembly (30) and into a corner portion (31) of the electrode assembly (30) in the winding direction. After a winding end portion (32) of the electrode assembly (30) is fixed, the hollow portion (22) is broken. Thereby, a space (20) resulting from the hollow portion (22) is formed inside the outermost of the electrode assembly (30).

Inventors: Mineya; Kunihiko (Osaka, JP), Kashiwagi; Katsumi (Nara, JP)

Assignee: Panasonic Corporation

International Classification: H01M 2/14 (20060101)

Expiration Date: 5/06/12018