Failure mechanism of VRLA batteries under high rate cyclic application

VRLA battery?had such shortages: rapid decline on capacity during deep cycles and comparatively short service life.The positive powder of failed battery after high rate cyclic was tested by XRD, SEM and cyclic voltammetry methods.It was found that the major failure mode was the softening and shedding of positive material, which eventually resulted in the deactivation of active material and deterioration of conductivity.