| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery capable of preventing the whole battery from expanding by expansion of a negative electrode active material layer upon charging without lessening charging capacity. <P>SOLUTION: An insulating layer 12 having a plurality of openings is arranged on a collector 11, and the collector 11 and the negative electrode active material layer 13 are electrically connected with each other in the vicinity of the opening via a conductive plug 16. A recessed section is formed on a surface opposite to a connection section. A separator 3 and a positive electrode 2 are arranged on the negative electrode active material layer 13. In the negative electrode active material layer 13, lithium ions are localized in the vicinity of the opening upon charging, and a localized section of the lithium ions is expanded. Thus, expansion of the whole battery is prevented by making the expansion to be absorbed with the recessed section on the negative electrode active material layer 13. <P>COPYRIGHT: (C)2009,JPO&INPIT |
