NEGATIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES, NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, BATTERY PACK, AND METHOD FOR PRODUCING NEGATIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES

摘要

[Problem] To provide a negative electrode active material for nonaqueous electrolyte secondary batteries, which has excellent lithium ion conductivity. [Solution] A negative electrode active material for nonaqueous electrolyte secondary batteries according to one embodiment of the present invention contains a carbonaceous material, a silicon oxide phase in the carbonaceous material, and a silicon phase in the silicon oxide phase. This negative electrode active material has a crack in the carbonaceous material, and the longest side of the crack is not less than 1/5 of the diameter of the negative electrode active material.