| abstract |
PROBLEM TO BE SOLVED: To provide a lithium secondary battery excellent in safety when abnormally overheated, reliability against short circuit, and rapid charge / discharge characteristics. A positive electrode having a positive electrode mixture layer containing a positive electrode active material, a negative electrode having a negative electrode mixture layer containing a lithium titanium composite oxide having a spinel crystal structure or a ramsdellite crystal structure as a negative electrode active material, and A lithium secondary battery having a separator, wherein the separator includes a porous layer (I) composed of a microporous film mainly composed of a thermoplastic resin, and a porous layer mainly composed of a filler having a heat resistant temperature of 150 ° C. or more. (II) and the porous layer (I) faces at least the negative electrode, and the positive electrode active material and the negative electrode active material have a primary particle diameter of 1 μm or less, and the positive electrode mixture The problem is solved by a lithium secondary battery in which the thickness of the layer and the negative electrode mixture layer is 50 μm or less. [Selection] Figure 1 |