| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery capable of increasing capacity density by arranging a more amount of positive electrode active material directly contributing to battery capacity in the battery by suppressing capacity deterioration caused by a charging/discharging cycle even when a nonaqueous electrolyte amount to be sealed in a battery preparation step is reduced and capable of displaying an excellent charging/discharging cycle characteristic by suppressing buckling of an electrode group caused by the charging/discharging cycle. <P>SOLUTION: In the lithium ion secondary battery configured by storing an electrode group composed of a positive electrode plate and a negative electrode plate through a porous insulator in a battery package together with a nonaqueous electrolyte, the negative electrode plate has a negative electrode active material layer including a carbon material capable of occluding/discharging lithium ions as a negative electrode active material on the surface of a current collector, and a thickness change of the negative electrode active material layer in charging/discharging is 10% or more. An extension rate of the positive electrode plate is 3% or more. <P>COPYRIGHT: (C)2012,JPO&INPIT |
