MANUFACTURING METHOD OF NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery of 5V class capable of suppressing swelling. SOLUTION: In a manufacturing process of the nonaqueous electrolyte secondary battery of the 5 V class, the initial charge is carried out after assembling a battery, and a battery after the charge is left as it is for 3 to 720 hours in a state that an open circuit electric potential of a positive electrode becomes 3.90 V to 4.88 V (vs. Li/Li+). By doing so, during the initial charge and when left as it is, a uniform protective coating film (SEI) is rapidly formed on the electrode. This protection coating film suppresses decomposition of the electrolytic solution on an electrode surface in a charge and discharge cycle after that. Thereby, the swelling of the battery can be suppressed. COPYRIGHT: (C)2005,JPO&NCIPI