| 摘要 |
PROBLEM TO BE SOLVED: To provide an inspection method capable of quickly judging the life of a used lithium ion secondary battery. SOLUTION: In a used lithium ion secondary battery as an inspection object, discharge is begun up to a time of fixed current drop or after charging for a fixed time, terminal voltage (et) after discharging for a fixed time (t minutes) is measured, difference (ΔEt) of a voltage value (Et) at discharging an unused reference battery for (t) minutes and the terminal voltage (et) of the battery to be inspected after discharging for (t) minutes is obtained, and the life of the lithium ion secondary battery is computed based on this. When it is charged for a fixed time, a fixed offset value is added to the terminal voltage (et) to obtain corrected terminal voltage (et'), and in addition, based on difference of the voltage value (Et) and the corrected terminal voltage (et') the life of the lithium ion secondary battery is computed. By this method, a charging time and a discharging time can be shortened, and hence the inspection time can be shortened.
|
