| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a lithium ion secondary battery prepared with an electrolyte containing a difluorophosphate in which the duration of a cell-voltage rise after the start of discharge is short in a second self-discharge step. <P>SOLUTION: A cell 100 satisfying at least one of the following requirements (1) to (4), is manufactured in an assembly step. (1) A positive electrode active material 137 is Li<SB POS="POST">X</SB>MO<SB POS="POST">2</SB>, where 1.04≤X≤1.15. (2) The BET specific surface area of the grains of a negative electrode active material 127 is in the range of 2.8 to 5.2 m<SP POS="POST">2</SP>/g. (3) The grains of the negative electrode active material 127 are composed of graphite and amorphous carbon, and the percentage of amorphous carbon in the grains of the negative electrode active material is in the range of 2.5 to 7.1 wt%. (4) The concentration of a difluorophosphate in an electrolyte 160 is in the range of 0.01 to 0.076 mol/L. <P>COPYRIGHT: (C)2012,JPO&INPIT |
