Wednesday, July 13, 2011

History and Origin of Laptop Batteries

The battery is an important component of the laptop. It gives the laptop the power of mobility. The efficiency and performance of the laptop greatly depends on the battery when the laptop is not connected to a power outlet. The improved power and increased backup time of laptop batteries is one of the main reasons for the growing popularity of laptops. The modern laptop batteries are far more advanced than their early predecessors.

Laptop batteries have come a long way since their inception. Older laptop batteries were quite heavy and did not provide good backup time.  

History of Laptop Batteries:

Early 80s:
  • AA Batteries:
 You will be surprised to know that older laptops used to run on AA batteries. Many AA batteries were required to run a laptop, and though there were many AA batteries fitted in the laptop, they did not have a long life. The number of AA cells also increased the weight of the laptop. Running a laptop on AA batteries was quite an expensive proposition, and the batteries needed to be changed frequently. The use of AA batteries was also not good for the environment. The discarded AA batteries contained harmful chemicals and only added to environmental waste.

Late 80s:
  •  Lead-Acid Cell:

In the late 80s, laptops ran on heavy lead acid batteries.  These batteries made the laptop very heavy and did not provide any good backup time. The lead-acid cell, however, was the first rechargeable battery to be invented.

Gaston Plante invented the lead -acid cell. It was the first battery that could be recharged by passing a reverse current through it. The lead-acid cell consisted of a lead anode and lead dioxide cathode, and both were immersed in sulphuric acid. Both electrodes of the lead-acid cell reacted with sulphuric acid to produce lead sulfate. 

The reaction caused the lead anode to release electrons, while the reaction at the lead dioxide end consumed the electrons, causing a flow of electric current. The chemical reaction within the cell was reversed by passing a reverse current through it, which was equivalent to recharging the lead-acid cell.

Though these batteries were heavy, they had a considerable capacity to hold electrical charge. The Macintosh portable was powered by a sealed lead-acid cell battery.  However, lead acid batteries were soon discarded when nickel cadmium batteries were invented.