The Chemical Secret of the Lead Acid Battery

The lead acid battery has been widely applied as an inexpensive reliable high safety secondary battery for SLI (starting, lighting and ignition) and used in UPS, aircraft and boats with virtually unlimited applications also existing in non-motive situations. Invented in 1859 by French physician Gaston Plante, lead acid batteries has undergone many great improvements, from the general lead acid batteries to maintenance-free sealed lead acid batteries. Besides, they are reliable, mature secondary batteries, globally manufactured and therefore a widely understood technology. The raw material of lead acid batteries is easily gained and needs low cost. And their wide environment range makes them use in many conditions even in the poor environment. Although the acid is harmful for health and new energy technologies are now sweeping the world, the lead acid battery is still tried and trusted, and will last for its more use than before in future.
You may know the varieties of lead acid batteries, such as lead calcium batteries, lead antimony batteries, valve regulated lead acid batteries (VRLA), AGM absorbed glass mat battery, Gel cell, SLI batteries (Starting, Lighting and Ignition), and deep cycle batteries. But do you know how the lead acid battery generates electricity? What’s the chemical secret of the lead acid battery?
Lead acid batteries use a chemical reaction to do work on charge and produce a voltage between their output terminals. They stores electricity through a reverse chemical reaction. The reaction of lead and lead oxide with the sulfuric acid electrolyte produces a voltage. Batteries operate in constant cycles of discharging and charging. During discharge, the lead dioxide (positive plate) and lead (negative plate) react with the electrolyte of sulfuric acid to create lead sulfate, water and energy. During charging, the cycle is reversed: the lead sulfate and water are electro-chemically converted to lead, lead oxide and sulfuric acid by an external electrical charging source.
Take an example for explaining its discharging and charging. When a battery is connected to a load that needs electricity, such as your car, it discharges. It is well known that most cars need its starting battery to get started through the instant large current. This is typical discharging. If you’re driving your car without accessories, the alternator charges the battery by adding current.
Moreover, the lead acid battery can be charged and recharged for many times, which is able to be used for a long time if correctly used. Owing to operating conditions and other factors, a number of other processes may take place in the battery. For example, if there are some scales or other non-reactive material coating the plates, this may make them difficult or impossible to recharge. No one wants its battery in use for a short time. So it is very necessary to check and maintain the lead acid battery if you have one.

Source: www.leoch.com