| 摘要 |
PROBLEM TO BE SOLVED: To provide an inspection method for a lithium secondary battery, which make possible to secure the reliability of the lithium secondary battery and reduce a required time for inspection. SOLUTION: A positive electrode using manganese acid lithium powder and a negative electrode are wound via a separator to manufacture a closed cylindrical lithium ion secondary battery. As a first voltage, a constant voltage of 4.2 V is applied to 100 units of the manufactured batteries for two weeks. Subsequently, as a second voltage, a constant voltage of 3.9 V is also applied to the batteries to charge them for 10 hours and the batteries are left as they are. Then, a battery whose voltage decline rate is more than three times higher than a standard deviation is determined as a voltage declining defective battery. In this inspection method, dissolution of metal powder mixed in the positive electrode is accelerated and sensitivity to the voltage decline due to minute short circuits is improved. |
