Nonaqueous electrolyte secondary battery with high temperature and storage characteristics

摘要

In the non-aqueous electrolyte secondary battery of the present invention, the separator includes a heat-resistant resin having chlorine atoms as an end group and the positive electrode active material includes a lithium-containing complex oxide containing aluminum atoms in its composition. Even if the chlorine atoms are liberated into the non-aqueous electrolyte, aluminum contained in the positive electrode active material is selectively leached into the non-aqueous electrolyte, thereby suppressing the leaching of other component elements. Consequently, there can be obtained a non-aqueous electrolyte secondary battery excellent in safety and high temperature storage characteristics.

主权项

1. A non-aqueous electrolyte secondary battery comprising a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, a non-aqueous electrolyte, and a separator, wherein
said separator comprises a first porous film including a heat resistant resin having chlorine atoms only as an end group, wherein the separator is fabricated by applying a solution comprising the heat resistant resin dissolved in a polar solvent onto a second porous film, and then drying, said positive electrode active material comprises a lithium-containing composite oxide containing aluminum atoms in the composition thereof, and said lithium-containing composite oxide is represented by a following formula:
LixM1−yAlyO2  (1)where 1 ≦x ≦1.05, 0.001 ≦y≦0.2, and M is at least one selected from the group consisting of Co, Ni, Mn and Mg,
said heat resistant resin comprises at least one selected from the group consisting of aramid and polyamideimide, and an amount of chlorine included in said separator is 300 to 3000 μg per 1 g of said separator.