Abstract: The cylindrical secondary battery includes a plurality conductive leads, which are formed to be tapered from a root portion to a tip portion, and when a tolerance of a pitch of the conductive leads is ?p and a difference of width dimension between the root portion and the tip portion of the conductive leads is ?w, the pitch of the conductive leads is set to fall within a proper region where a variation range of a numerical value obtained by dividing a standard deviation of the number of layers of the conductive leads when the conductive leads are wound around a current collecting member by an average value of the standard deviations of the number of layers of the conductive leads is a predetermined value or less, and a range of the proper region is larger than the sum of ?p and ?w.

Abstract: An upper base portion of a top portion of a battery cell cap functions as a positive terminal, and paths for flow of electrical current are defined between the top portion and portions for welding. The portions for welding are positioned to face a side wall region between a pair of apertures adjacently provided in the top portion, and the current flowing regions are defined between the portions for welding and the side wall regions of the top portion facing to the portions for welding, each forming a symmetrical current flowing region.

Abstract: In a secondary battery cell including an electrode group that is manufactured by winding a positive electrode having a plurality of positive leads and a negative electrode having a plurality of negative leads, the lengths of the positive electrode and the negative electrode are respectively longer than the length satisfying the rated power generating capacity of the secondary battery cell and are cut not upon a positive lead and not upon negative lead, respectively.

Abstract: An upper base portion of a top portion of a battery cell cap functions as a positive terminal, and paths for flow of electrical current are defined between the top portion and portions for welding. The portions for welding are positioned to face a side wall region between a pair of apertures adjacently provided in the top portion, and the current flowing regions are defined between the portions for welding and the side wall regions of the top portion facing to the portions for welding, each forming a symmetrical current flowing region.