Abstract: Provided are flexible interconnect circuits comprising signal circuit elements. For example, a signal circuit element can be formed from the same metal sheet as a signal trace, thereby being monolithic with the signal circuit element. This integration of signal circuit elements into a flexible interconnect circuit reduces the number of additional operations and components (e.g., attaching external circuit elements). In some examples, a flexible interconnect circuit is used in a battery pack for interconnecting batteries while providing external terminals on the same side of the pack. Specifically, a flexible interconnect circuit comprises an interconnecting conductive layer (for connecting to batteries) and a return conductive layer, both extending between the first and second circuit edges. Each of these conductive layers comprises a corresponding external terminal at the first edge, while these layers are interconnected at the second edge.