| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative electrode structure in which an active material layer coated to a collector can be prevented from being peeled off from the collector, at an inner peripheral part of winding where flection of the collector is tight.SOLUTION: A positive electrode collector and a negative electrode collector 241 are band-shaped members, respectively, and are disposed so that a positive electrode active material layer and a negative electrode active material layer 243 face each other. The positive electrode collector and negative electrode collector 241 are wound, and housed in a battery case while being bent flatly. The negative electrode active material layer 243 contains negative electrode active material particles and a binder. The amount of oil absorption of the negative electrode active material particles at an inner peripheral part 402 of winding of the negative electrode active material layer 243 is smaller than that of the negative electrode active material particles at an outer peripheral part 404 of winding of the negative electrode active material layer 243. |
