During an operation of the energy accumulator, a control unit is designed to detect event data relating to different charging/discharging events of the energy accumulator. The event data for a charging/discharging event indicates an event discharge depth of the energy accumulator within the scope of the charging discharging event. In addition, the control unit is designed to determine a discharge depth distribution based on the discharge data, which indicates a number of charging/discharging events with a corresponding event discharge depth for different discharge depths during the operation of the energy accumulator. The control unit is designed to determine status data relating to a cumulative charging of the energy accumulator based on the discharge depth distribution and based on a discharge depth characteristic curve of the energy accumulator, and/or to adjust an operating strategy for the energy accumulator depending on the discharge depth distribution and the discharge depth characteristic curve.