Effect of battery fast cyclic charging on the mechanical and fracture behavior of the lithium-ion battery separator

•The electrochemical degradation of battery separator was studied.•Six battery pouch cells were cycled at fast charging conditions.•The anode side showed an increase in the deposit density with increasing numbers of charging cycles.•The fast charging conditions affected the separators’ mechanical integrity.•Damage accumulation in the form of pore closure resulting from creep, fiber fracture and through-thickness crack were observed.