Assembled battery and battery pack using the same

Abstract

There are provided an assembled battery and a battery pack having excellent cycle characteristics with respect to high rate charging and discharging. An assembled battery according to an embodiment includes at least one first single cell and at least one second single cell that are connected in series. The first single cell includes a positive electrode containing an active material represented by the general formula LiMO2 (M includes at least one element selected from the group consisting of Ni, Co, and Mn) and a negative electrode including a titanium-containing oxide. The second single cell includes a positive electrode containing an active material represented by the general formula LiM′PO4 (M′ includes at least one element selected from the group consisting of Fe, Mn, Co, and Ni) and a negative electrode including a titanium-containing oxide. The ratio of a charging resistance of the second single cell to a charging resistance of the first single cell is 1 or more and 1.5 or less if an open circuit voltage when the at least one first single cell and the at least one second single cell are connected in series is 4.5 V.

Dependencies are inferred from the claim text.