Abstract: A non-aqueous electrolyte secondary battery according to one aspect of the present invention includes: a positive electrode plate in which a positive electrode mixture layer containing a positive electrode active material is formed on a positive electrode current collector; a negative electrode plate in which a negative electrode mixture layer containing a negative electrode active material is formed on a negative electrode current collector; a separator; a non-aqueous electrolyte; a sealing member; and an outer casing. The negative electrode active material contains graphite and a silicon material. The silicon material contains silicon oxide represented by SiOx (0.5?x<1.6) and a silicon-lithium silicate composite in which a silicon phase is dispersed in a lithium silicate phase represented by Li2zSiO(2+z) (0<z<2). The amount of the silicon-lithium silicate composite is 33% by mass or more and 93% by mass or less relative to the silicon material.

Abstract: A nonaqueous electrolyte secondary cell according to an aspect of the invention includes a positive electrode plate containing a positive electrode active material, a negative electrode plate containing a negative electrode active material, a separator disposed between the positive electrode plate and the negative electrode plate, a nonaqueous electrolyte, an outer can in a cylindrical shape having a bottom, and a sealing member including a current breaker configured to be activated when pressure in the cell reaches a predetermined value. The positive electrode active material is a lithium nickel composite oxide expressed by a general formula of LixNiyM(1-y)O2 (O<x?1.2, 0.85?y?0.99, M is at least one element selected from Al, Co, Fe, Cu, Mg, Ti, Zr, Ce, and W). The positive electrode plate contains lithium carbonate in an amount of 0.01% to 0.2% by mass with respect to the positive electrode active material.