Study Of Premature Capacity Loss On VRLA Batteries

With the aggravation of fossil energy crisis,electric vehicle has got extensive popularization. The VRLA batteries of electric vehicles are tending to development of long life and large capacity at present. However, the phenomenon of premature capacity loss (PCL) often takes place in the using of large capacity VRLA batteries, have influenced batteries'service life seriously. PCL on the large capacity VRLA batteries of electric vehicle which are produced by Lantian company were carried on research.Two kinds of type batteries which are life finished were anatomized. Density of sulfuric acid respectively in the top and lower parts of batteries'polar plate were tested, and positive active material (PAM) was tested by SEM,XRD,CV,IMP.We found reasons of PCL on 6DZM20 VRLA batteries and proposed the following solution to this problem.Effects of three kinds of electrolyteical additives (C₆H₈O₇, (NH₄)₂SO₄, and C₅H₉NO₄) are studied to solve the PCL, the results show that these additives have no influences on solusion to the PCL.SiO₂ powder were additived in the electrolyte to make gel-electrolyte batteries, which have obviously inhibited the sulfuric acid stratification, not only prevented PCL, made the battery obtain very good performance too. The mechanism of gel- electrolyte function is discussed too.