NOVELTY - The energy storage system comprises: a first component (810) configured to provide an energy requirement of an electric vehicle; and a second component (820) configured to provide a power requirement of the electric vehicle. Volume, mass, weight or cost of the combination of the first component and the second component are less than volume, mass, weight or cost needed for the first component or the second component to provide the energy requirement and the power requirement of the electric vehicle. An anode of the second component comprises lithium titanate.    USE - The energy storage system is useful as a battery in an electric vehicle and a hybrid electric-drive vehicle (all claimed) such as stop-start micro-hybrid electric vehicle, mild-hybrid electric vehicle, strong-hybrid electric vehicle and plug-in hybrid electric vehicle.    ADVANTAGE - The energy storage system is cost-effective and reliable and safe to use, and has good performance and cycle life and high specific energy and specific power.    DETAILED DESCRIPTION - The energy storage system comprises: a first component (810) configured to provide an energy requirement of an electric vehicle; and a second component (820) configured to provide a power requirement of the electric vehicle. Volume, mass, weight or cost of the combination of the first component and the second component are less than volume, mass, weight or cost needed for the first component or the second component to provide the energy requirement and the power requirement of the electric vehicle. An anode of the second component comprises lithium titanate. The first component comprises a lithium ion electrochemical cell. The first component includes a lithium sulfur cell and a lithium air cell. The combination of the first component and the second component is cheaper than an energy storage system that includes only the second component and provides the energy requirement and the power requirement of the electric vehicle. The first component includes a lithium ion cell comprising a lithium nickel manganese cobalt cathode and a graphite anode, a lithium ion cell of a lithium sulfur type comprising a sulfur anode and a lithium cathode, or a lithium ion cell of a lithium air type comprising a lithium cathode and a carbon anode. The second component includes a lithium ion cell comprising a lithium titanate anode and a lithium nickel manganese cobalt cathode, a lithium ion cell comprising a lithium titanate anode and a sulfur cathode, or a lithium ion cell comprising a lithium titanate anode and an air cathode.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a hybrid-battery system comprising a high energy density component and a high power density component of different lithium chemistries.    Hybrid battery system (800)    First component (810)    Second component. (820)