A battery module according to one embodiment includes a first battery unit including a first nonaqueous electrolyte battery, and a second battery unit electrically connected in series to the first battery unit and including a second nonaqueous electrolyte battery. Each of the first and second nonaqueous electrolyte batteries includes a negative electrode including a spinel-type lithium titanate. The first nonaqueous electrolyte battery includes a positive electrode including at least one olivine-type lithium phosphate. The second nonaqueous electrolyte battery includes a positive electrode including at least one lithium-containing composite oxide. The discharge capacity ratio Ca/Cb between the first battery unit and the second battery unit satisfy 1.5