Patent ID: 8227107
Filing Date: 2012-07-24
Classification: H01M,Y02E,Y02P,Y02T

Abstract:
1. A cylindrical secondary battery, comprising: an electrode assembly that is composed of a positive electrode plate and a negative electrode plate with a separator therebetween that are overlaid with each other and spirally wound; an outer casing that has a cylindrical shape with a closed bottom, and houses therein the electrode assembly; a sealing cover that seals an opening of the outer casing, and is one of electrode terminals; 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 end surface of the electrode assembly in a side in which the sealing cover is provided, and is joined to the core 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 of the cylindrical part in a direction of the axis, the tab part has a middle portion bent to have a wave shape with an amplitude in a direction that connects the current collector plate with the sealing cover, the middle portion being between a root portion and a tip portion of the tab part, the tab part is electrically connected with the current collector plate at the tip portion by welding and joining the tip portion to the current collector plate, and the tab part contacts with the current collector plate at a wave trough of the middle portion, and is further electrically connected with the current collector plate at the wave trough.