The disclosure relates to an energy storing device for generating a supply voltage for an electric machine, comprising at least one energy supply branch which is connected in parallel and each of which has a plurality of first and second energy storing modules that are connected in series. The first and second energy storing modules each comprise an energy storing cell module, which has at least one energy storing cell, and a coupling device, which is designed to selectively connect the energy storing cell module into the respective energy supply branch or to bridge said energy storing cell module. Each second energy storing module additionally has a cooling element for the at least one energy storing cell, and the cooling element is designed to cool the at least one energy storing cell dependent on a control signal of a cooling controller.