Negative electrode for nonaqueous electrolyte secondary battery, nonaqueous electrolyte secondary battery, and battery pack

A nonaqueous electrolyte secondary battery comprising:

• an exterior material;
• a positive electrode housed in the exterior material;
• a negative electrode spatially separated from the positive electrode and housed in the exterior material through a separator;
• and
• a nonaqueous electrolyte filled in the exterior material, wherein
• the negative electrode includes a current collector, a negative electrode active material arranged on the current collector, and a negative electrode mixture layer including a conductive material and a binder,
• the negative electrode active material is composite particles including a carbonaceous substance, a silicon oxide phase in the carbonaceous substance, and a silicon phase including crystalline silicon in the silicon oxide phase, and
• the negative electrode active material satisfies d1/d0≧0.9 where an average thickness of the mixture layer is d0, and a maximum thickness of a single particle of the composite particles in a vertical direction, the particle occupying the mixture layer, to a surface of the current collector is d1.

A battery pack using a nonaqueous electrolyte secondary battery, the nonaqueous electrolyte secondary battery comprising:

• an exterior material;
• a positive electrode housed in the exterior material;
• a negative electrode including an active material, and spatially separated from the positive electrode and housed in the exterior material through a separator;
• and
• a nonaqueous electrolyte filled in the exterior material, wherein
• the negative electrode includes a current collector, a negative electrode active material arranged on the current collector, and a negative electrode mixture layer including a conductive material and a binder,
• the negative electrode active material is composite particles including a carbonaceous substance, a silicon oxide phase in the carbonaceous substance, and a silicon phase including crystalline silicon in the silicon oxide phase, and
• the negative electrode active material satisfies d1/d0≧0.9 where an average thickness of the mixture layer is d0, and a maximum thickness of a single particle of the composite particles in a vertical direction, the particle occupying the mixture layer, to a surface of the current collector is d1.