NONAQUEOUS ELECTROLYTE SECONDARY BATTERY AND METHOD OF MANUFACTURING NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

A method of manufacturing a nonaqueous electrolyte secondary having a positive electrode active material layer that includes a positive electrode active material and a conductive additive, the positive electrode active material has a first film formed on a surface of a composite oxide including at least lithium and manganese, the conductive additive has a second film formed on a surface of a carbon material, and the first film and the second film include fluorine, manganese, and phosphorus. The method includes: manufacturing (S101) a positive electrode sheet (140) by forming a positive electrode active material layer (142), which includes a positive electrode active material, a conductive additive, and trilithium phosphate, on a positive electrode current collector foil (141); accommodating (S102) the positive electrode sheet (140), a negative electrode sheet (150), and an electrolytic solution (120) in a battery case; and charging (S103) a battery after the accommodation. During the manufacturing of the positive electrode sheet, a positive electrode active material (170) is a composite oxide including at least lithium and manganese. During the manufacturing of the positive electrode sheet, a conductive additive (180) is obtained by attaching at least one of manganese or manganese oxide to a surface of a carbon material.