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Lead Acid Battery
Lead acid batteries are usually more economical and have
a high tolerance for abuse.At the positive electrode, lead
dioxide (PbO2) is converted to lead sulfate (PbSO4)
and at the negative electrode, sponge metallic lead (Pb)
is also converted to lead sulfate (PbSO4). The
electrolyte is a dilute mixture of sulfuric acid that provides
the sulfate ion for the discharge reactions. Lead acid has
become an accepted high-performance power source for clean
applications. The sealed lead cell consists of positive
and negative electrodes and their accompanying separators
that are wound in a spiral pattern. The electrodes consist
of pure lead grids pasted with mixtures of lead oxides.
These oxides are converted to the proper active materials
when the cell receives its first charge in a process called
formation. The pure lead supporting grids allow the flexibility
needed for winding the plate and also give excellent corrosion
resistance to prolong cell life. The separator consists
of a fibrous glass mat. The cell works as a starved electrolyte
system where the quantity of electrolyte is limited to the
amount that is either absorbed in the plated or wets the
fibers in the separator. The result if open gas paths between
the plates that allow gases evolved during overcharge to
diffuse from one plate to the other where they are recombined.
This recombination provides a closed system reducing venting
of gases under normal overcharge conditions. A resealing
safety vent is provided to handle pressure buildup during
abusive overcharges. Since the electrolyte is recycled,
the water loss that requires routine maintenance or limits
life is minimized. The sealed lead system has proven to
provide high performance and long life in a clean, compact
package.
Work Cited
“Introduction to Batteries: Lead-Acid Batteries”.
Retrieved 19 June 2002 [online]
http://www.hepi.com/basics/pb.htm
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