Rechargeable Lithium Ion Button Cell Battery

摘要

A rechargeable lithium ion button cell battery having a sealed housing comprises an inner casing and an outer casing, both casings have at least one flat area as top or bottom of the battery, and a round or oval sidewall vertically formed to the flat area. An insulation gasket is positioned between said sidewalls, and the outer casing opening is mechanically crimped to complete the seal of the battery. Inside the sealed housing the anode and cathode electrodes are spiral wound with separator to be a round or oval roll. Said roll axis is vertical to the said flat areas of the casings. The two electrodes are tapered in width to fully utilize the inner space. The electrodes comprise current collectors of metal foils coated with lithium-intercalating active materials, leaving small area of uncoated metal foils as conductor tabs for connecting the electrodes to the casings. The tabs could be welded or by tight contacting to the casings, in several options. Insulation washers or tapes are applied to the naked metal surfaces of the electrodes or casings inside of the housing to prevent short circuit and enable the battery to have longer cycle life.

主权项

1. A rechargeable lithium ion button cell comprises:
(a). a sealed housing comprising an inner casing and an outer casing , both casings having at least one flat area as top or bottom of the battery, and a round or oval sidewall vertically formed to the flat area; (b). said sealed housing also comprising a round or oval insulation gasket having a footing rim and positioning between said sidewalls, said footing rim covering the opening end of said inner casing sidewall; said outer casing sidewall is crimped together with the gasket against the inner casing to seal the battery; said housing also contains electrolyte; (c). a first electrode and a second electrode inside the said sealed housing being spiral wound with separator to be a round or oval roll, said roll axis is vertical to the said flat areas of the casings; (d). said electrodes have theirs one small area not coated with active materials, and the exposed metal at said area acts as conductor tab to connect the electrodes with said casings respectively; wherein said electrodes are tapered in width on theirs coated areas, wider at the center of said spiral wound roll and narrower at the rim of said spiral wound roll, and the width of the wider end is 0.1 mm to 3 mm greater than the width of the narrower end.