| 主权项 |
1. A non-aqueous electrolyte secondary battery, comprising:
a positive electrode composite material layer containing
first positive electrode active material particles containing a lithium nickel composite oxide,second positive electrode active material particles containing lithium iron phosphate, anda conductive material, a ratio of said second positive electrode active material particles in a total mass of said first positive electrode active material particles and said second positive electrode active material particles being not lower than 5 mass % and not higher than 20 mass %, and a standard deviation σ satisfying a condition of 0.28≦σ≦0.52, which is calculated in the following expression (1)σ=1N∑i=1N(zi-1)2(1)when distribution of an iron element is determined by extracting a square measurement region of which one side has a length at least 0.5 time and at most 1.0 time as large as a thickness of said positive electrode composite material layer from a cross-section of said positive electrode composite material layer in parallel to a direction of thickness of said positive electrode composite material layer and conducting area analysis with an electron probe microanalyzer in said measurement region,
where zi represents a value obtained by normalizing ΔIi by dividing said measurement region into N belt-shaped small regions Δyi (i=1, 2, . . . , N) in said direction of thickness and dividing a sum value ΔIi (i=1, 2, . . . , N) of iron element detection intensity at each measurement point included in one said small region Δyi by an average value I of ΔIi. |
