NOVELTY - The method involves estimating a total damage factor of a storage unit according to an operation point in course of the storage unit, an operation or environmental parameter, and a target damage factor. A future operation point is determined for the storage unit according to the estimated total damage factor. A selected parameter defining usual use of a vehicle is determined. A desired use mode of the storage unit is determined with respect to a life phase in progress of the vehicle.    USE - Method for managing use of an electrical energy storage unit of an electric engine vehicle i.e. electric car (all claimed). Can also be used for a hybrid vehicle.    ADVANTAGE - The method enables carrying out an automatic total energy optimization in the course of rolling of the vehicle without direct intervention of a driver by preserving the battery, or by offering services and performances to the driver such as in terms of lifetime of the storage unit, energy consumption, repeatability and availability of performances of the vehicle.    DETAILED DESCRIPTION - The parameter defining the usual use of the vehicle is selected in a group including a normal use corresponding to an ageing of the storage unit virtually identical to a preset ageing, less severe use corresponding to an ageing of the storage unit lower than the preset ageing and a severe use corresponding to an ageing of the storage unit greater than the preset ageing. The operation or environmental parameter is selected from a group including an internal temperature of the storage unit, a temperature outside of the vehicle, a temperature at interior of the vehicle, a charge state of the storage unit. An INDEPENDENT CLAIM is also included for a device for managing use of an electrical energy storage unit of an electric engine vehicle.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating a relationship between states of a state machine implemented in a managing device. '(Drawing includes non-English language text)'    Inactive state (F1)    Idle state (F2)    Standby state (F3)    Activation state (F4)    Deactivation state (F8)