All batteries, lithium ion and otherwise, are a challenge to fully characterize because of the variety of length scales in play and media involved (metals, ceramics, polymers, liquid solvents, etc). Recently electrochemical-acoustic signal interrogation (EASI) methods have been studied as a bridging method for characterization and diagnostics. The performance of a battery is strongly coupled to its geometric regularity (or irregularity). The fundamental requirement for mass conversation within a closed battery coupled with the lack of requirement for elastic conservations indicate that sound speed can be used in multiple ways to probe changes in the electrochemical cell. Akin to the fingerprints of electrochemical impedance spectroscopy (EIS), this method provides direct information on structure and indirect information on dynamics where EIS provides direct information on dynamics and indirect information on structure. In this presentation we present the learnings in electrochemical-acoustic analysis on full cell behavior including lithium deposition (wanted and otherwise), state of charge, state of health, state of power, and gas evolution. Our current understanding of detection limits and potential new applications will also be discussed.