Multilayered Flexible Interconnect Circuits for Battery Assemblies and Methods of Fabricating and Installing Thereof

Provided are multilayered flexible interconnect circuits comprising multiple conductive layers. Also provided are methods of fabricating such circuits and also methods of fabricating battery assemblies with such circuits. A multilayered flexible interconnect circuit comprises at least two conductive layers and at least one inner insulator, which extends between these conductive layers in some circuit portions and allows for conductive layers to directly interface in other circuit portions (e.g., busbar portions). Outer insulators can be provided to insulate these conductive layers from the environment while allowing some access to these layers as needed. Each conductive layer and insulator can be individually patterned to achieve these functions. One or more insulators support conductive layers relative to each other as well as different portions (e.g., disjoined portions) of the same conductive layer. The same multilayered flexible interconnect circuit can provide battery interconnect, voltage/temperature sense, and/or other functions.