| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery in which durability is enhanced by preventing a separator from being damaged by heat generation due to undue overcharge, and to provide a manufacturing method of a negative electrode sheet for use in the battery and a manufacturing method of a secondary battery.SOLUTION: The secondary battery includes an electrode body 20 produced by winding a positive electrode sheet 30 including an active material layer 34 on a collector 32, and a negative electrode sheet 50 including an active material layer 54 on a collector 52 while interposing a separator 70 therebetween. The negative electrode active material layer 54 is provided, at one end in the width direction orthogonal to the longitudinal direction of the negative electrode collector, with an uncoated part. The separator is formed wide enough to cover the negative electrode active material layer in the width direction. At least negative electrode active material layer formed on the outer peripheral side of winding has a peripheral edge formed at the peripheral edge in the longitudinal direction, and thinner than the negative electrode active material layer on the inside contiguous to the peripheral edge in the width direction, at the end on the side where the uncoated part is not formed. A corner of acute angle of 90° or less does not exist in the peripheral edge. |
