Lead-Carbon Electrode with Inhibitor of PbSO_4 Recrystallization in Lead-Acid Batteries Operating in HRPSoC Duty

摘要

The major problem of lead-acid batteries for application in hybrid electric vehicles (HEV) is the progressive sulfation of the negative plates as a result of incomplete charge of the cells in the HEV mode of operation. Under these conditions, recrystallization processes take place whereby big PbSO_4 crystals grow at the expense of dissolution of smaller ones. The present study has established experimentally that addition of poly-aspartic acid to the solution or to the negative paste retards significantly the growth of lead sulfate crystals. Small PbSO_4 crystals are highly soluble and sustain high concentration of Pb~(2+) ions in the solution, thus improving the charge acceptance of the cells. It has also been established that poly-aspartic acid increases the overpotential of hydrogen evolution on the lead electrode. Linear sweep voltammetry experiments and cycling tests of cells under simulated high-rate partial-state-of-charge conditions have confirmed the above effects of poly-aspartic acid.