CYLINDRICAL LITHIUM-ION SECONDARY BATTERY

• Main Author: SANO YOKO
• Format: Patent
• Language: English
• Published: 21.04.2014
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

PROBLEM TO BE SOLVED: To provide a cylindrical lithium-ion secondary battery which has high mass-productivity and large capacity as a compact battery of 8.0 mm or less in outer diameter.SOLUTION: There is provided a cylindrical lithium-ion secondary battery, formed by housing an electrode group having a positive electrode and a negative electrode wound opposite to each other across a separator arranged between the positive electrode and the negative electrode, in a case together with a nonaqueous electrolyte and being sealed with a gasket and a hole sealing plate. The case has an outer diameter of 8.0 mm or less, the electrode group has the negative electrode placed at an outermost periphery, and the negative electrode includes a negative electrode collector, a thin-film negative electrode active material layer formed on a surface of the negative electrode collector and containing an alloy-based negative electrode active material, and a negative electrode lead. The negative electrode lead is plasma-welded to a negative electrode lead end at an outermost peripheral end of the negative electrode collector, placed at an outermost periphery of the electrode group, and also placed within a range in which the electrode group and the case face each other, the negative electrode lead being not welded to a case inner surface and coming into contact with the case to be electrically connected.