MADAM4Life - Mechanical aging diagnostics with strain gauges, dilation, pressure, acoustics and modal analysis for lifetime prediction

The overall objective of the project MADAM4Life is to monitor different cell states such as State-of-Charge (SoC) and aging processes in lithium ion cells (LIBs), in-operando using different non-invasive mechanical measurement techniques. For pouch cells, experimental modal and ultrasonic diagnostics are investigated for monitoring mechanical material parameters. By combining this with other mechanical sensors, such as for 2D/3D dilation and via modal analysis, as already used today at Fraunhofer ISIT, ISC and TUM, a comprehensive understanding of the mechanical changes in the cell due to different aging processes will now be created, which does not exist today. To create a comprehensive database, ISIT is creating pouch cells of different cell chemistries and acquiring commercial round cells. Adapted aging tests will be performed on both cell geometries.

Detailed models of the considered cell geometries will be developed for an improved understanding of the dependence of ultrasound signal propagation/modification on aging phenomena. These models will further support investigations of the transferability of the measurement methods to the respective other cell geometries.

From the mechanical measurement methods, novel diagnostic methods for battery management systems (BMS) are to be developed, which extend the current condition determination in secondary battery storage systems such as LIBs by means of electrical quantities and temperature, to include mechanical-electrochemical interactions. In particular, a higher accuracy in the determination of the State-of-Health (SoH) shall be achieved and a data-based optimization of the lifetime prognosis shall be enabled.