The invention relates to a device for controlling the temperature of an electrical energy store on the motor vehicle side, comprising at least one temperature control system having at least one pettier element, which can be thermally coupled, or is thermally coupled, with the electrical energy store on the motor vehicle side, or to an electrical energy store on the motor vehicle side to be temperature-controlled, wherein in addition, the at least one temperature control system is thermally coupled with at least one temperature-control fluid reservoir containing at least one temperature-control fluid.