| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and device for charging a secondary battery, capable of completing charge by accurately detecting a change of ionic conductivity when charging the secondary battery using a material having a property of ionic conductivity changing suddenly during discharge as a positive-electrode active material. SOLUTION: The battery voltage of the secondary battery is detected while conducting pulse charge periodically repeating a state of charge for supplying the secondary battery with a charging current and a state of stoppage for stopping the supply of the charging current. When the pulse charge reaches the state of stoppage, a rate of change (inclination) of an open circuit voltage for a fixed period just after the start of the state of the stoppage is computed, and then the rate of change (inclination) of the open circuit voltage and a threshold are compared. When it is determined the rate of change (the inclination) of the open circuit voltage is becomes larger than or equal to the threshold, pulse charge to the secondary battery is completed as a result of ionic conductivity change. COPYRIGHT: (C)2011,JPO&INPIT |
