The batteries in some form or the other have been known to be in existence since 1800. But it was only in 1859 that Gaston Plante created a lead-acid prototype that finally evolved into the present-day sealed lead acid batteries. For the first 100 years after Plante’s creation, it served as the only source for rechargeable energy. During the 1920s, the popular electric cars were powered by lead-acid units.
At that time lead-acid batteries were found to be inefficient because the energy/weight ratio was low, being only 0.03 kWh per kg. Although the initial lead-acid units were considered not suitable for the environment because of the presence of lead, further research led to the development of sealed lead acid batteries. These are more environment-friendly than glass bottles, tires, beer cans, and soft drink cans.
Construction Of Sealed Lead Acid Batteries
Sealed lead acid batteries are now being used in many industries like automotive engines, medical equipment, aviation, electronics, telecommunications, solar power, and garden equipment. These batteries are made of a combination of chemical ingredients that react with lead sheets that are placed in the body of the battery. The chemicals include lead, arsenic, calcium, electrolyte sulphuric acid, lead oxide, tin, and lead sulphate.
The other components of a sealed lead acid battery include the battery body which has a re-sealable safety vent, high integrity terminal seal, positive and negative plates, plastic internal container, highly retentive separator, and lead grids enclosed in a metal can enclosure. These batteries also have lead wires that are basically stranded copper wires with insulation and which are coded with red and black colors. The lead wires have their ends dipped in wax, but before using them the wax is removed.
Benefits Of Sealed Lead Acid Batteries
The advantages of using sealed lead acid batteries, especially if they have a lead-tin chemical base, are as follows:
* There is greater volumetric power generated by these batteries per unit weight.
* The cycle-lives of these batteries range between 200 and 300.
* The standby life of a sealed lead acid battery can go up to 15 years.
* These batteries deliver high stable voltage because of their low internal resistance. They also afford greater flexibility of operations because if there is a flat discharge, the discharge and recharge periods are very rapid.
* The temperature range in which these batteries can operate is substantial, ranging from -60 degrees Celsius to +80 degrees Celsius. Similarly, the atmospheric pressure range for operations is Vacuum to eight atmospheres.
* Added to their performance qualities, sealed lead acid batteries are highly tolerant of shock and vibration because of their rugged external construction.
* These batteries are twice as environment-friendly as beer cans; aluminium soft drink cans, glass bottles, newspapers, and tires because nearly the entire battery lead is recycled.
The latest development in the manufacture of sealed lead iron batteries is the introduction of the Li-ion technology in which the energy/weight ratio is nearly 0.16 kWh per kilogram. The electrolyte consists of lithium salts in an organic solvent. Although lithium salts are not very dangerous if handled properly, they are difficult to recycle and their extraction is extremely carbon intensive. As such, this method is not very environment-friendly.