Lead-Acid Storage Batteries
OPERATON AND CONSTRUCTION
Figure 5. Typical construction of a pasted plate grid.
Positive electrodes are usually of pasted plate or tubular construction. Tubular electrodes are
popular positive plates for heavy cycling applications. This construction uses a frame
structure consisting of a series of vertical spines connected to a common bus. The paste is
held in micro-porous, non-conductive tubes which are placed over the individual spines. A
simplified view of tubular plate construction is shown in Figure 6. Regardless of the plate
type used, the capacity of any battery is increased by adding multiple plates in parallel.
The grid structure in both pasted and tubular plate batteries is made from a lead alloy.
A pure lead grid structure is not strong enough by itself to stand vertically while
supporting the active material. Other metals in small quantities are alloyed with lead
for added strength and improved electrical properties. The most commonly alloyed
metals are antimony, calcium, tin, and selenium.