A battery system includes a plurality of electrochemical cells provided within a housing. The battery system also includes a thermal management system configured to provide at least one of heating or cooling to the electrochemical cells. The thermal management system includes a solid state coating having a first metal and a second metal different from the first metal. The solid state coating is configured to pass a current therethrough to create a temperature differential across a first surface of the solid state coating and a second surface of the solid state coating to provide the at least one of heating or cooling to the cells.