LITHIUM ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To prevent the occurrence of dendrite caused by the deposition of lithium in the negative electrode side lead wire connecting part of a negative electrode collector by arranging an insulator for preventing lithium ion movement between the negative electrode side lead wire connecting part and the other end part of a positive electrode plate. SOLUTION: A lithium ion movement preventing insulator 4 for preventing the movement of lithium ions is arranged between a negative electrode side lead wire connecting part 2c and the other end part 1d of a positive electrode plate 1. This insulator 4 is composed of, for example a sheet member made of polypropylene and having a thickness of 25 μm, and it includes an opposite part 4a opposite the full surface of the negative electrode side lead wire connecting part 2c and a pair of extended parts 4b and 4b extended from this opposite part 4a to both side of a electrode plate group in a peripheral direction. The extending length of each of the pair of extended parts 4b and 4b in the peripheral direction is set to a dimension enough for preventing the movement of lithium ions.