Rate-dependent mechanical–electrical–thermal abuse response of fresh and aged tabless 4695 cylindrical cells under radial indentation

Abstract

Electrochemical aging can alter the mechanical abuse response of large-format cylindrical cells, but its effect under dynamic loading remains insufficiently resolved. This study compares fresh and aged tabless 4695 cells at 100 % State of Charge (SoC) under dynamic radial indentation at 5.5 m s −1 with quasi-static indentation at 1 mm s −1 under matched boundary conditions. Two aging histories were examined: room-temperature cycling associated with interfacial growth and low-temperature/high-current cycling associated with plating-prone degradation. Cell-level tests were complemented by Electrochemical Impedance Spectroscopy (EIS), post-mortem Scanning Electron Microscopy (SEM), and single-layer component tests. Under quasi-static indentation, aging reduced the mechanically transmitted work up to major Internal Short Circuit (ISC) by up to 37.3 %. Under dynamic loading, the aging sensitivity differed between the two degradation pathways: for the plating-prone condition it was clearly attenuated (reduction of about 14 % relative to the fresh dynamic reference), whereas for the interfacial-growth-related condition all aged tests fell below the corresponding fresh dynamic ranges in 𝑊 I S C and 𝛿 I S C , albeit with substantial scatter. Dynamic indentation produced steeper force–displacement responses, delayed externally measured thermal responses relative to ISC onset, and less pronounced aging-related changes in the global force–displacement response. In this test series, venting pathways also differed, with dynamic tests more often showing bottom-directed initial venting, whereas quasi-static tests showed more top-terminal bursting or sidewall rupture in aged cells. These results show that aging sensitivity under radial indentation differed between the two investigated aging conditions and that dynamic indentation provides complementary information on transient electrical failure, venting sequence, and post-ISC thermal evolution.