INVESTIGATIONS INTO THE ELECTROCHEMISTRY OF RECOMBINANT, SEALED LEAD-ACID-BATTERIES

In modern stationary and cycling operations of lead/acid batteries, ga s-recombination technology is being used more and more frequently to e liminate battery maintenance. Research studies in the Central Laborato ry of Batteries and Cells (CLAiO) are focused on the optimization of t he gas-recombination process in lead/acid batteries, mainly in float d uties. This work includes investigations of the kinetics of gas evolut ion on different types of alloy, and of the effect of paste compositio n and the method employed for electrolyte immobilization (i.e., gel or absorptive glass-mat). Tests have been performed on stationary cells of 4.5 A h capacity (C/10) and using grids of size 66.0 mm X 96.5 mm. The grids were made from low-antimony alloy (1.7 wt.% Sb), lead-tin-ca lcium-aluminium alloy, or pure lead. Investigations of the gas-evoluti on kinetics has confirmed that during the initial phase of float opera tion, the lowest gassing is observed for nonantimonial and pure-lead g rids in cells using absorptive glass-microfibre separators. Higher rat es of gas evolution take place in cells with gelled electrolyte, but t hese decrease as the float operation is continued. Cells have been dis mantled in order to investigate changes in the phase composition of th e positive active material. Changes in phase composition of the active material during float operation have been monitored by X-ray diffract ion phase analysis.