| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium-ion secondary battery which has a wider SOC region capable of estimating based on the battery voltage than a conventional one. <P>SOLUTION: A cylindrical lithium-ion secondary battery is manufactured by using manganese-substituted iron lithium phosphate LiFe<SB>0.8</SB>Mn<SB>0.2</SB>PO<SB>4</SB>as a positive electrode active material, soft carbon as a negative electrode active material, and, as a non-aqueous electrolytic liquid, one in which LiPF<SB>6</SB>as an electrolyte is dissolved in a mixed solvent in which ethylene carbonate and diethyl carbonate are mixed in volume ratio of 30/70 so that it may be 1 mol/L. When the SOC dependency of the battery voltage at the time of discharge is measured for this battery under a temperature condition of 20°C by carrying out a constant current constant voltage charge up to a charging upper limit voltage of 4.1V by 1C current and then, carrying out a constant current discharge up to a discharge lower limit voltage of 2.5 V by 0.1 C current, the range of the SOC capable of estimating based on the battery voltage has become a wide range of 0-60%, 75-85%. <P>COPYRIGHT: (C)2009,JPO&INPIT |
