LITHIUM ION SECONDARY BATTERY

摘要

Provided is a lithium ion secondary battery with which it is possible to guarantee safety during a battery malfunction and prevent a reduction in high-performance discharge characteristics. The lithium ion secondary battery (1) has an electrode group (5) in which a positive-pole plate (2), which is a current collector where a positive-pole mix containing a positive-pole active substance has been formed, and a negative-pole plate (3), which is a current collector where a negative-pole mix containing a negative-pole active substance has been formed, are wound with a porous separator (4) therebetween. A flame retardant is added to the positive-pole mix of the positive-pole plate (2), and the mode of the diameter of pores formed in the positive-pole mix as determined by a mercury porosimeter is within the range of 0.5 to 2.0 µm. A path for lithium ion movement and a path for electron movement during discharge are simultaneously guaranteed.