Patent ID: 9608247
Date: 2017-03-28
CPC Classifications: H01M,Y02E,Y02P

Claim:
1. An energy storage device comprising a spiral electrode group in which a first electrode plate and a second electrode plate having polarity reverse to that of the first electrode plate are spirally wound with a separator interposed therebetween, wherein the second electrode plate is opposed to an inner circumference and an outer circumference of the first electrode plate, portions of the separator comprise reinforced portions, said reinforced portions comprise non-woven fabric, polyolefin, or combinations thereof, the reinforced portions of the separator include a first reinforced portion formed between a winding-start end of the first electrode plate and the second electrode plate located on a radially outer side of the winding-start end, and a second reinforced portion formed between the winding-start end of the first electrode plate and the second electrode plate located on a radially inner side of the winding-start end, the first reinforced portion and the second reinforced portion are arranged apart from each other, the spiral electrode group has a central space, and none of the reinforced portions is located in the central space.