Cylindrical battery

Abstract

A cylindrical battery is provided with: an electrode body in which a long positive electrode having a positive electrode core and a positive electrode mixture layer and a long negative electrode (12) having a negative electrode core (12a) and a negative electrode mixture layer (12b) are wound with a separator therebetween; a bottomed cylindrical outer can for housing the electrode body; and a sealing body for sealing the opening of the outer can. When the number of winding cycles of the negative electrode (12) is counted from the winding start side on the basis of the range of the negative electrode (12) facing the positive electrode with the separator interposed therebetween, the negative electrode (12) is wound for at least 10 cycles. A first mixture layer region (15a) in the negative electrode mixture layer (12b), said first mixture layer region (15a) being located at 25-35% of the total number of cycles of the negative electrode (12), has a low-density region (14b) having a lower density than a second mixture layer region (15b) in the negative electrode mixture layer (12b), said second mixture layer region (15b) being located at a periphery other than the first mixture layer region.

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