Abstract: Provided is a botulinum toxin producing method which is simple achieves a high toxin yield, and obtains a toxin having high specific activity. This botulinum toxin producing method includes: (A) a step in which a botulinum toxin is produced from botulinum toxin-producing bacteria in a medium, and a mixture a is obtained which contains a botulinum toxin, a bacterial component, and a nucleic acid component derived from the botulinum toxin; (B) a step in which the mixture a is subjected to the removal of the bacterial component, and a mixture b is obtained which contains a nucleic acid component and a botulinum toxin; (C) a step in which an endonuclease is added to the mixture b and a mixture c is obtained which contains a nucleic acid degradation product and a botulinum toxin; and (D) a step in which the mixture c is subjected to removal of the nucleic acid degradation product, and an isolated botulinum toxin liquid d is obtained.

Abstract: A cylindrical secondary battery comprises a current collector assembly that electrically connects the sealing cover with a core of one of the positive electrode plate and the negative electrode plate. The current collector assembly is composed of a combination of a current collector plate having a plate shape that is provided on an upper part of the electrode assembly and a current collector lead including a cylindrical part having opposed top and bottom parts and an axis along a main surface of the current collector plate, the top part is joined to a sealing plate that is a bottom surface of the sealing cover, and the bottom part is joined to the current collector plate The current collector lead further includes at least one rectangular tab part extending from an opening edge of the cylindrical part in a direction of the axis, and electrically connected with the current collector plate.

Abstract: The current-collecting lead for being welded to a collector welded to an upper portion of an electrode group and also to a sealing assembly of an cylindrical secondary battery includes: a flat surface part welded to the collector, and a top part formed to be curved and protrude approximately in the shape of a dome from the flat surface part and welded to the sealing assembly. A central opening is formed at a central portion of the top part. Around the central opening, a plurality of welding projections are formed to protrude toward the sealing assembly. The welding projections serve as welding spots to the sealing assembly. The top part is deformed by a pressing force from the sealing assembly to be brought into surface contact with a corner portion of a convex portion formed on a lower surface of the sealing assembly.

Abstract: To aim to provide a cylindrical secondary battery comprising a current collector assembly that is inserted between the electrode assembly and the sealing cover, and electrically connects the sealing cover with a core of one of the positive electrode plate and the negative electrode plate, wherein the current collector assembly is composed of a combination of (i) a current collector plate having a plate shape that is provided on an upper part of the electrode assembly and (ii) a current collector lead that includes a cylindrical part having an axis in a direction along a main surface of the current collector plate, the cylindrical part includes a top part and a bottom part whose peripheral surfaces oppose each other, the top part is welded and joined to a sealing plate that is a bottom surface of the sealing cover, and the bottom part is welded and joined to the current collector plate, the current collector lead further includes at least one tab part having a rectangle shape that extends from an opening edge