| 摘要 |
PROBLEM TO BE SOLVED: To provide means for measuring the concentration lithium ions in an electrolyte appropriately.SOLUTION: A lithium ion secondary battery has an electrode group, a third electrode and a fourth electrode, the electrode group has a positive electrode and a negative electrode, potentials of the positive electrode and negative electrode are detected by the third electrode and fourth electrode, the third electrode is arranged in the electrode group, and the fourth electrode is arranged on the outside of the electrode group. For example, the third electrode and fourth electrode are composed of any one kind or more of phosphoric acid transition metal lithium or lithium titanate, and the fourth electrode is double junction type. |
