A hybrid energy storage system, including: - at least two energy storage units, comprising a first energy storage unit and a second energy storage unit, each with a nominal energy flow, - at least one boost converter comprising at least one electronic switch, - at least one buck converter, - at least one control circuit, by means of which the energy storage units (10a, 10b) exchange electrical energy with one another and with at least one external energy sink and, if necessary, with at least one external energy source, by means of electrophysical energy flows in at least one direction, - wherein, by means of the at least one boost converter and by means of the at least one buck converter, the control circuit comprising a microcontroller provides an energy flow from the first energy storage unit to the energy sink in the event that the energy sink requires a higher energy flow than the nominal energy flow from the second energy storage unit, while the second energy storage unit supplies an energy flow of zero or a constant energy flow corresponding at most to the nominal energy flow of the second energy storage unit, - wherein the control circuit comprises at least one decoupling circuit for suppressing positive feedback phenomena in the electronic switch and for blocking reversed energy flows through the electronic switch from the first energy storage unit to the second energy storage unit, wherein the electronic switch comprises at least one MOSFET transistor, - wherein the decoupling circuit is an analogue circuit and comprises at least one limiter, at least one comparator, wherein the limiter is arranged at the input of the comparator and limits the voltage thereof, and at least one AND gate for switching off the electronic switch when the boost converter is switched off, wherein the limiter, the comparator and the AND gate are connected in series, with suppression of the positive feedback phenomena and interlocking of reversed energy flows from the first energy storage unit to the second energy storage unit, - wherein the microcontroller is connected to said decoupling circuit via a data coupler isolating different potentials of the energy storage units (10a, 10b) to disengage the decoupling circuit. - at least two energy storage units, comprising a first energy storage unit and a second energy storage unit, each with a nominal energy flow, - at least one boost converter comprising at least one electronic switch, - at least one buck converter, - at least one control circuit, by means of which the energy storage units (10a, 10b) exchange electrical energy with one another and with at least one external energy sink and, if necessary, with at least one external energy source, by means of electrophysical energy flows in at least one direction, - wherein, by means of the at least one boost converter and by means of the at least one buck converter, the control circuit comprising a microcontroller provides an energy flow from the first energy storage unit to the energy sink in the event that the energy sink requires a higher energy flow than the nominal energy flow from the second energy storage unit, while the second energy storage unit supplies an energy flow of zero or a constant energy flow corresponding at most to the nominal energy flow of the second energy storage unit, - wherein the control circuit comprises at least one decoupling circuit for suppressing positive feedback phenomena in the electronic switch and for blocking reversed energy flows through the electronic switch from the first energy storage unit to the second energy storage unit, wherein the electronic switch comprises at least one MOSFET transistor, - wherein the decoupling circuit is an analogue circuit and comprises at least one limiter, at least one comparator, wherein the limiter is arranged at the input of the comparator and limits the voltage thereof, and at least one AND gate for switching off the electronic switch when the boost converter is switched off, wherein the limiter, the comparator and the AND gate are connected in series, with suppression of the positive feedback phenomena and interlocking of reversed energy flows from the first energy storage unit to the second energy storage unit, - wherein the microcontroller is connected to said decoupling circuit via a data coupler isolating different potentials of the energy storage units (10a, 10b) to disengage the decoupling circuit.