Battery module, battery pack and vehicle

A battery module comprising:

• a first battery unit comprising a n first nonaqueous electrolyte battery, wherein n is an integer of 1 or more, the first nonaqueous electrolyte battery comprising a negative electrode comprising a spinel-type lithium titanate, a positive electrode comprising at least one olivine-type lithium phosphate represented by a formula of LiMAPO4, wherein MA is at least one metal element selected from the group consisting of Mn, Fe, Co, Ni, Mg and Ti, and a first nonaqueous electrolyte;
• and
• a second battery unit comprising a m second nonaqueous electrolyte battery, wherein m is an integer of 1 or more, and electrically connected in series to the first battery unit, the second nonaqueous electrolyte battery comprising a negative electrode comprising the spinel-type lithium titanate, a positive electrode comprising at least one lithium-containing composite oxide represented by a formula of LiMBO2, wherein MB is at least one metal element selected from the group consisting of Mn, Co and Ni, and a second nonaqueous electrolyte,
• wherein:
• a discharge capacity Ca [Ah] of the first battery unit and a discharge capacity Cb [Ah] of the second battery unit satisfy a relational expression of 1.5<Ca/Cb≦50;
• the discharge capacity Ca is a capacity [Ah] obtained by subtracting a capacity Cm [Ah] of the battery module from a discharge capacity C1 [Ah] obtained by discharging the first battery unit of the battery module in a state-of-charge of 100% to a voltage of 1.5×n V at a constant current value of 0.2 C;
• and
• the discharge capacity Cb is a capacity [Ah] obtained by subtracting the capacity Cm [Ah] of the battery module from a discharge capacity C2 [Ah] obtained by discharging the second battery unit of the battery module in the state-of-charge of 100% to a voltage of 1.5×m V at a constant current value of 0.2 C.