Increasing the specific energy of deep-cycle VRLA batteries by improving material-utilization efficiencies

Increasing the utilization efficiency of the active materials offers the greatest opportunity for improving the specific energy of deep-cycle VRLA batteries. Bipolar Power International (BPI) has been developing lead-sulfate-based high-utilization paste formulations for the past decade, as part of its bipolar-battery R&D program, Previous experiments with these pastes on both flat lead sheets (for bipolar plates) and cast grids have shown substantial improvements in material utilization efficiencies over traditional oxide-based pastes, together with good cycling performance. Recently, BPI has begun investigating the performance of its sulfate-based paste in reticulated Pb-metal foams as a means of further increasing utilization efficiency. The results of these preliminary experiments show improvements in positive-material utilization of at least 30% to 44% at the 1/2 -hour to 10-hour rates, respectively, compared to traditional lead-oxide-based pastes on grids.