| abstract |
An object of the present invention is to suppress electrode deterioration and battery characteristic deterioration. SOLUTION: A positive electrode having a positive electrode active material layer containing lithium iron phosphate, a negative electrode having a negative electrode active material layer containing graphite, a solvent containing ethylene carbonate and diethyl carbonate and lithium between the positive electrode and the negative electrode And charging the lithium secondary battery having a salt solution, where T is the battery temperature of the lithium secondary battery or the environmental temperature where the lithium secondary battery is placed, and T1 is an arbitrary temperature. , T2 (where T1 <T2), T < In the case of T1, after charging with a constant current until reaching a predetermined voltage, charging is performed with a constant voltage. When T1 ≦ T <T2, charging is performed only with a constant current, and when T2 ≦ T Is Charge of the lithium secondary battery which does not charge, and the charging device of a lithium secondary battery. [Selection] Figure 2 |