Study of aging mechanisms in lithium-ion batteries for working vehicle applications

The electrification process that is involving Non-Road Mobile Machineries (NRMM) is opening a completely new working scenario for lithium ion based battery packs. Performance in harsh environments, where high power requirements must be satisfied with severe vibrational loads may affect the overall lifespan of each single cell if no specific measures are taken. Lithium-Ion batteries (Lib) ageing mechanisms are mainly related to two types of damage categories: electro-chemical damage where the electrical load and temperature conditions affect the formation rate of the Solid-Electrolyte-Interface (SEI); mechanical damage and material degradation related to vibrations and thermo-mechanical deformations. This ageing mechanisms are highly intensified in NRMMs due to engine vibrations (in hybrid vehicles) as well as to highly unstructured field of operations. In this study, an overview of the ageing mechanisms involving Lib is given. Moreover, an experimental analysis on the effect of vibrations on the overall performance of a prismatic LFP-Lib cell is shown. The cell was tested with an uniaxial shaker with an acceleration profile related to experimental measurements from a real working vehicle studied in previous works.