The rapid adoption of electric vehicles (EVs) has increased the demand for efficient methods to assess the state of health (SoH) of lithium-ion batteries (LIBs). Accurate and prompt evaluations are essential for safety, battery life extension, and performance optimization. While traditional techniques such as electrochemical impedance spectroscopy (EIS) are commonly used to monitor battery degradation, acoustic emission (AE) analysis is emerging as a promising complementary method. AE’s sensitivity to mechanical changes within the battery structure offers significant advantages, including speed and non-destructive assessment, enabling evaluations without disassembly. This capability is particularly beneficial for diagnosing second-life batteries and streamlining decision-making regarding the management of used batteries. Moreover, AE enhances diagnostics by facilitating early detection of potential issues, optimizing maintenance, and improving the reliability and longevity of battery systems. Importantly, AE is a non-destructive technique and belongs to the passive method category, as it does not introduce any external energy into the system but instead detects naturally occurring acoustic signals during the battery’s operation. Integrating AE with other analytical techniques can create a comprehensive tool for continuous battery condition monitoring and predictive maintenance, which is crucial in applications where battery reliability is vital, such as in EVs and energy storage systems. This review not only examines the potential of AE techniques in battery health monitoring but also underscores the need for further research and adoption of these techniques, encouraging the academic community and industry professionals to explore and implement these methods.

The analyses have shown that HEPES and TRIS buffers have a significant effect on the formation of hydroxyapatite on the surface of bioactive glass during the in vitro test. The behavior of the HEPES with glass is very similar to that of the TRIS.

A lithium-polymer pouch cell was characterized over one charge and discharge using three different characterization methods. The set comprised electrochemical impedance spectroscopy (EIS), strain gauge measurement, and pulse-echo ultrasound. The results show that the combined approach provides a picture of SOC-dependent changes: the strain gauge reliably tracked external volume changes, pulse-echo ultrasound detected systematic time of flight (ToF) shifts indicative of internal structural, and EIS-reported concurrent changes in charge-transfer resistance (R₁). Moreover, the individual methods—ultrasound (ToF), EIS (changes in R₁), and strain gauges were able to track changes in volume (strain gauge) and internal structure (ultrasound and EIS) of the cell depending on state of charge (SOC). The verification of these conclusions were the specific signatures of each method: the systematic shortening of ToF without new internal reflections, the sensitivity of R₁ to EIS interface modifications, and the direct mechanical shifts of the measured strain gauges. Graphical Abstract