Nonaqueous electrolyte secondary battery

摘要

[Problem] To provide a nonaqueous electrolyte secondary battery exhibiting superior stability characteristics and having charge/discharge characteristics exhibiting a high-rate discharge stroke, even when a lithium-nickel-cobalt manganate and a spinel-type lithium manganate are used as the positive electrode active material. [Solution] A mixture having a specific ratio of a tungsten- and zirconium-modified lithium-nickel-cobalt manganate and a spinel-type lithium manganate is used as the positive electrode active material. Furthermore, a nonaqueous electrolyte having a specific ratio of the content of dimethyl carbonate and the content of a cyclic carbonate is used.

主权项

1. A nonaqueous electrolyte secondary battery comprising:
a positive electrode plate including a positive electrode active material capable of absorbing and desorbing a lithium ion; a negative electrode plate including a negative electrode active material capable of absorbing and desorbing a lithium ion; and a nonaqueous electrolyte including a nonaqueous solvent and a solute, the positive electrode active material containing
lithium nickel-cobalt-manganese oxide represented by Lia(NibCocMnd)(1-x-y)WxZryO2 (where 0.9≦a≦1.2, 0.3≦b≦0.6, 0.1≦c≦0.7, 0≦d≦0.4, b+c+d=1, 0.001≦x≦0.05, and 0.001≦y≦0.05) andspinel lithium manganese oxide represented by LieMn2-fM1fO4 (where M1 is at least one element selected from B, Mg, Ca, Sr, Ba, Ti, Ni, Al, Nb, Mo, W, Y, and Rh, 0.9≦e≦1.2, and 0≦f≦0.1) in a proportion of 60:40 to 90:10 (mass ratio), the nonaqueous electrolyte including cyclic carbonate and chain carbonate as the nonaqueous solvent, a content proportion of the cyclic carbonate being 10% by mass or greater and 40% by mass or less of the nonaqueous electrolyte, and a content proportion of dimethyl carbonate included in the chain carbonate being 25% by mass or greater and 100% by mass or less.