Heat-transport-medium circuit for a motor vehicle, in particular a passenger motor vehicle, wherein the heat-transport-medium circuit has: - a first partial circuit with at least one heating device (111, 115) for heating heat-transport medium flowing through the first partial circuit and/or with at least one cooling device for cooling heat-transport medium flowing through the first partial circuit; - a second partial circuit with at least one electrical energy store which is able to be heated and/or cooled by heat-transport medium flowing through the second partial circuit and which serves for providing a supply to at least one electric motor for driving the motor vehicle; and - a mixing device (400; 500, 600) able to be switched selectively into - at least one first operating state for conducting into the second partial circuit a first fraction of heat-transport medium flowing in from the first partial circuit; and - at least one second operating state for conducting into the second partial circuit a second fraction, different from the first fraction, of heat-transport medium flowing in from the first partial circuit and for returning into the first partial circuit heat-transport medium flowing in from the second partial circuit, wherein - the mixing device is able to be switched into at least one third operating state for conducting into the second partial circuit a third fraction, different from the first and second fractions, of heat-transport medium flowing in from the first partial circuit and for returning into the first partial circuit heat-transport medium flowing in from the second partial circuit; and/or - the first partial circuit has at least one passenger-compartment heating device for heating a passenger compartment by way of heat-transport medium flowing through the first partial circuit, and/or at least one passenger-compartment cooling device for cooling a passenger compartment by way of heat-transport medium flowing through the first partial circuit. - a first partial circuit with at least one heating device (111, 115) for heating heat-transport medium flowing through the first partial circuit and/or with at least one cooling device for cooling heat-transport medium flowing through the first partial circuit; - a second partial circuit with at least one electrical energy store which is able to be heated and/or cooled by heat-transport medium flowing through the second partial circuit and which serves for providing a supply to at least one electric motor for driving the motor vehicle; and - a mixing device (400; 500, 600) able to be switched selectively into - at least one first operating state for conducting into the second partial circuit a first fraction of heat-transport medium flowing in from the first partial circuit; and - at least one second operating state for conducting into the second partial circuit a second fraction, different from the first fraction, of heat-transport medium flowing in from the first partial circuit and for returning into the first partial circuit heat-transport medium flowing in from the second partial circuit, wherein - the mixing device is able to be switched into at least one third operating state for conducting into the second partial circuit a third fraction, different from the first and second fractions, of heat-transport medium flowing in from the first partial circuit and for returning into the first partial circuit heat-transport medium flowing in from the second partial circuit; and/or - the first partial circuit has at least one passenger-compartment heating device for heating a passenger compartment by way of heat-transport medium flowing through the first partial circuit, and/or at least