Development of advanced thin/lightweight grids for valve-regulated lead-acid (VRLA) electric vehicle (EV) batteries

Critical goals of the ALABC include improved specific energy (energy-to-weight ratio), specific power (power-to-weight ratio), and life cycles (DST) in VRLA EV batteries. Current factors limiting the realization of these goals include excess grid weight and inadequate active material utilization. In order to resist the active material forces and corrosion effects experienced during EV service, conventional gravity cast book mold grids, as thick as 0.125 inches (3.175 mm) and as heavy as 150 grams, are used. ALABC Project No. AMC-008 investigates the solution to these goals via the development, utilization, and evaluation of new, advanced thin and lightweight grids. Each of two new grid types, Wirtz Conroll and Cominco Expanded Metal, is being evaluated in both "thick" and "thin" plate applications. The thick overpaste plate designs, which significantly increase the active material weight to grid weight ratio, reduce the total grid weight per battery by approximately 50-70%. The thin overpaste plate designs, which enhance active material utilization, increase the number of plates per battery by approximately 100%. The concurrent optimization of both of these plate designs is expected to provide marked insights for the development of future VRLA EV batteries that will meet the ALABC's performance and life goals.