Effect of lead foam grid on performance of lead-acid battery

In order to increase the specific energy and specific power of a lead-acid battery, lead foam grid was prepared by electrodepositing Pb-Sn alloy on a copper foam substrate and used as negative current collector for a lead acid battery whose capacity was limited by the negative plate. Comparing the effect of the cast grid, under the same conditions, the mass of lead foam grid decreases by 35%, and the area of lead foam contacted with active material increases by about 20 times. Under 2 h rate discharge condition, with a high current (3.0 I₂) e and low-temperature (-10°C, I₂) discharge system, the lead foam grid markedly boosts the discharge performance of lead acid battery. It increases not only the negative electrode mass specific capacity by 27%, 37% and 29%, but also the utilization efficiency of the negative active material by 5%. Compared with the negative electrode of cast grid, XRD and SEM results show that after 20 cycles at the state of charge, the sponge lead in the negative lead foam electrode has smaller crystals and less PbSO₄ on its surface. Meanwhile, at the state of full discharge, the PbSO₄ crystals are smaller and occur less on the surface of lead foam electrode. This indicates its active material reacts more uniformly.