Non-aqueous electrolyte secondary battery and battery pack

A battery pack comprising:

• a nonaqueous electrolyte secondary battery as a cell,
• wherein the nonaqueous electrolyte secondary battery comprises,
• an exterior member,
• a negative electrode containing a titanium-containing oxide housed in the exterior member,
• a positive electrode housed in the exterior member,
• a separator housed in the exterior member, and
• arranged between the positive electrode and the negative electrode, and
• a non-aqueous electrolyte solution housed in the exterior member,
• wherein at least one type or more chain carbonates are contained in a solvent of the non-aqueous electrolyte solution, and
• a non-aqueous electrolyte secondary battery in which a self-diffusion coefficient of the chain carbonate in −20° C. is from 1.4×10−10 to 2.0×10−10 m2/sec, is used as a cell.